Which is more accurate?
Vložit
- čas přidán 16. 06. 2024
- Unfiltered MAC on Twitter: / mac_arms
Join Patreon and support MAC! / militaryarms
Political Commentary: / @secondlegacy
Follow and support us on Utreon!: utreon.com/c/militaryarmschannel
Follow us on Rumble: rumble.com/user/MilitaryArms
MAC T-Shirt Store: ballisticink.com/collections/...
Modern Gun School: www.mgs.edu
Many have asked me what the accuracy difference between 1:7 twist rates and something like 1:12. In this video we find out. We also test to see if there is a measurable velocity difference. - Zábava
I want to see that 55gr 1/12 twist when it hits ballistics jell vs the 1/7.
He did one awhile back on watermelons. Interesting results.
@@David-xs9nv my favorite vid….been shootin my 1:12 fn spr vs my dd5v3 1:11 and fn likes 168s and below and dd 175smk it’ll put 5rds on a Pepsi lid@100yrds…fn put 5 168gmm in a dime….
I’d rather see 1:14 vs 1:7
I’ve seen it and 1/12 is has better wound channels !!!
Tim did a watermelon test with the 2 rifles and same ammo... 1:12 EXPLODED the melon
I was surprised a little by the 62gr in the 1:12''. I didn't see that in my testing of the Brownells 1:12'' barrel until I got over 69gr.
More proof that barrels don't adhere to physics but to some ancient form of magic, maybe Indian astrology.
Yeah, I’m a little skeptical of the relevancy of these results because they are based on only one group of each configuration, and only one type of ammo in each bullet weight. I’m also curious about what they do in ballistic gel. The “lore” I have heard says that when fired from the 1 in 12 barrels the bullets are far more likely to immediately begin tumbling on impact with the intended target and do more damage.
From my experience shooting M855 in Model 604 M16s, some rifles stabilized the heavy projectiles no problem. Other rifles had groups open up to perhaps 6 MOA. Never saw any tumble.
We were allowed to use M855 in the 1/12 rifles. They just told us accuracy would suffer, but still good enough to fight with. 🤠
@@Skenderbeuismyhero It's so much into it, even two rifles of the same brand and barrel length can get you different velocities. Tightness of the chamber/bore, smotheness and so on, nobody is able to produce with zero tolerances, and if it was possible nobody would pay that price.
@@marinioaweischo6614 yeah, especially when these aren't exactly high end custom rifles, and they're shooting cheap .223 ball out of 5.56 chambers(I assume.)
Thank You, H&R for bringing back into production these M16's. We enjoy them. Thanks MAC for the video. Blessings.
Can you ask federal to lower their prices a bit or offer more bulk packaged products? I love their ammo too but it is often the most expensive on the shelf even for plinking ammo
@@fate930TargetSports USA for ammo.
I saw a video with two rifles like yours, one with a 1/12 & other 1/7 twist.
When shot into ballistic gel, the 1/12 would take a violent, almost 90° turn and yaw out of the gel while the same ammo out of the 1/7 kept a almost straight shot path into the gel.
I just wanted to share what I had seen with the two different twist rates.
Great video Mac, love those "old" AR platforms.
You are correct. The weapon system was designed to have incredible terminal ballistics in the human body. The design was to cause as much damage as possible and to stay within the rules of the Geneva convention.
This is the reason for the debate in 223 killing ability with ball ammo. The guys with the 1:12 twist say it is devastating and guys shooting 1:7 don' t see the same effectiveness. That's because the 1:7 bullets tumble creating huge would channels and the 1:7 doesn't. Of course with newer ammo especially solid copper 1:7 twist works beautifully.
Geneva dealt with POW treatment. The Hague convention of 1899 dealt ammunition restrictions and assorted topics relating to war.
The U.S did not sign this treaty.
Having said all that, the notion that the .223 Remington was designed to destabilize on impact is an oft repeated falsehood.
"If you must kill, please do it in this way. It reduces the amount of blood left on the ground afterward."... haha. @@ecleveland1
Now I have to crack a history book again. Thanks...
@@ErikHenrichsen
Great video! I was getting ready to swap my 1:12, 20" Barrel to a 1:7, 20" so it could fire more varieties of ammo and you uploaded this at a perfect time!
Back in the '80s, I read an article in SOF magazine, where this test was performed, with the same results. So, there are no surprises here, but it is nice to see you validate it.
EXCELLENT job as always. Interesting, and relevant content. Thanks MAC !!
Awesome video! Very useful information. Thanks guys.
I agree with needing a larger sample size for velocity. 36 fps difference? As Paul Harrell would say: that's within the variation of one round to the next; not enough difference to make a difference.
Is the tighter twist converting more energy into angular velocity? Most likely, and I'm sure there's math that will support that. Does that make a difference? Probably not in a vast majority of use cases. There might be one extreme example where it might, like shooting at a very long distance, but I doubt it within the standard use case of the round (within 300 yds).
Exactly the video I wanted to see , thank you !
Your videos are always very informative
Excellent video this is something I wanted to know
Very informative. Thanks
thanks for making this video! answered some of my questions,curiosity
Another fun vid, Thanks Tim.
Really enjoyed, good info, thanks
Thanks for watching!
@@Militaryarmschannel your content is always first class.👍
Awesome stuff! 😊
Great Show
I know this pertains to the clones that said, it's been my experience with standard rifles today the 1/7 is best for 62 grain and heavier but the 1/9 is optimal for 52, 53 and 55 grain bullets...using a 16" barrel.
Great video , always wanted to see a wring out of the two twist rates. Would love to see more about other twist rates and higher bullet weights
Certainly interesting results... wonder if it would be similar with other manufacturers, and different barrel lengths. I imagine the 1:7 would be better for a shorter barrel, as they both kind of compensate for each other in this regard. There are just so many things that can affect accuracy though, it is impossible to test them all. Thanks for sharing, and maybe next time use a magnified optic, might help you compensate for the older eyes. I'm nearing my 40's and am noticing my sight is getting worse, so a big scope really helps!
Interesting results. Thank you
I bought two A1 clones opting for 12-twist. Love them!
Rather interesting sidenote, while doing research to make my own rifle, I came across an aged formula for determining optimum twist rate for a given barrel length and projectile weight/diameter ratio. It is crazy accurate from the tests I've run on various projectiles and explains a wealth of information on why twist rates are what they are for particular projectiles.
Do you mean the barrel's overall diameter? As if the formula's taking resonance into account? Should that be the case, it'd be super interesting, didn't know it could affect accuracy at relatively short ranges. And if it isn't the case, sir, you still just sprouted something that sounds extremely interesting to look into. Any tips on where to look for? Google became kind of a... say, "sponsor catalogue", not yielding results unless someone payed first, or happens to be hippiepedia. Have a good one!
Huh🤔!!! Interesting results. Awesome review brother. SF!
Thanks for watching my friend.
That's awesome content right there.
would like to see comparison alongside 1/8 .223 wylde barrels
I have that barrel, 20". I run 75 grain Hornady and have MOA or better at 100 yards, I roll my own. I would group 55 and 62 grain like this video.
Now THIS is actually something I have wondered.
Thanks for finally comparing the velocity between the two twist rates with the chronograph! I've been curious about the twist rate effect on bullet speed for a long time now. Really wish 1/9" twist barrels were still common like they used to be. Seems like the best compromise for a 16" pipe.
Note that a higher twist rate will impart more angular velocity to the bullet which adds to the bullet's energy. It makes up for the lower velocity in terms of terminal effects.
Even 1:9 was used by bushmaster on 20" Got it. Love it.
Old Mini 14's ran a 1:10 twist. Bullet always leaves the deer sideways out to 120 yds (55gr).
Good video.
The 1 in 12 twist is perfect for the 55 gr bullets. When I was in the Army, (69-72) we used the Colt scope for testing some M16A1 rifles. All would shoot into an inch at 100 meters with the military M193 ammo. I worked in a depot weapons shop.
Concerning your vision, try an adjustable aperture.
Thank you for reminding me that we could measure rifling twist by revolutions per minute on the projectile. I had trouble enough with my command while on active duty during the change-over from M16A1 rifle with M193 ball to M16A2 rifle and M855 ball. "Is that green tip going to start fires?"
You also demonstrated a slight difference in velocities with a small sample size, reminding me that I have to take greater care defining what my own test results tell me. Off the cuff it makes sense that a 1:7" twist would produce more barrel friction than a 1:12" twist and produce lower velocities. You pointed out the need for more shots fired to validate results--and you used H&R barrels in testing--good call. I don't know if other brands of barrels would change the results. My test results will vary due to test equipment, test conditions, barrel brand, ammunition maker, and bullet design--but the figures should be close.
The M193 and M855 projectiles are boat tail bullets with spire points. Some .223 Remington bullets have flat bases, different nose profiles (ogives--can shift center of air resistance), may have hollow points (shifts the bullet's center of gravity) and may be shorter or longer projectiles. The 1:7" twist was to stabilize the M856 tracer in sub-zero temperatures. The M196 needed 1:12" rifling for stability under Arctic conditions--the original 1:14" twist rate failed to stabilize tracer rounds. What this means for the shooter is that using bullets heavier than 55 grain in 1:12" can possibly work okay and that bullets heavier than 62 or 64 grains can be stabilized in 1:7" barrels. The way to find out is shooting benchrest groups at 200 yards under anticipated shooting conditions--yes, I know, firing at 100 yards may be the limit due to available shooting range facilities. Bullet length makes a difference. This difference is more important to handloaders using custom bullets and demanding maximum performance. Firing those heavy and long 64-grain M855 factory loads through an old Colt SP-1 (1:12" rifling) to a maximum range of 50 yards from off-hand positions on eight-inch bullseye targets or M9 silhouettes probably won't yield significant differences in precision. Using the same rig on jackrabbits at 300 yards will--if the shooter can see the target and aim from a steady position. About three inches at 100 yards won't cut the mustard when the target is 300 yards away and smaller than three inches.
Great information
Thnx
Great video
Interesting vid, just for general thought I bought a colt A1 AR sporter in 1978. Like new con 1in14.shot great made in 1973, in mid 80s retired to the back of the safe.
Thanks for all your work.
I work in EOL care.
Getting old is a blessing, sir.
Rock those eyes with pride and happiness.
Yup, getting old beats the alternative. LOL
Perhaps in the future you could test the 16" barrel vs the 20" barrel using the 55 gr and the 62 gr rounds. Most AR15's I see sold are the 16" variety. Thanks for your outstanding videos!!
Very good video. If you spin something faster, it takes energy.... basic thermodynamics state that nothing is free. The marginal velocity reduction of a faster twist rate was something that I have often wondered about. Clearly, by moving to faster twist rates, the trade off of stabilizing a wider range of bullet weights was a good call. I learned something today and thank you.
I bought a model 1 sales 12" twist bull barrel for next to nothing once and built a rig for my friend to use on vermin and with 40grain vmax it was a laser beam. 1/4 moa with hardly any reciol, he LOVES that rifle. It's all about the right system.
1/4” group at 100 yards? How many shots did you fire in that group? 1?
Very interesting. Kind of what I expected.
FWIW. Desert Shield/Storm. My USAF TACP with the 2nd BDE/101, was issued M-16A1s. The Army had A2s with their 62 grain bullets. With the Army issued ammo, our USAF A1s were key-holing the rounds at 25 yards. The 101st was awesome, and issued us all new A2s.
I prefer 1:8 twist as a good over all with the vast majority of 556 ammo I can find on the market. Works best with any thing 62 to 77 gr bullets. But still works just fine with M193 and anything 50 to 60gr and also 80 to 87gr bullets.
1:7 twist is perfect if you like to use heavy hard hitting or long raing bullets 69gr and all the way up to 90gr or I think 112gr is the heaviest bullet offering in .223.
But will still do ok with 55gr to 68gr that most of your ball ammo is going to fail into.
1 : 12 twist. Your sweet spot for accuracy is probably going to be with in. 40 to 64gr. Probably best with 45gr al the way up the 62gr that's not M855/ss109. Assuming you are not planning to shoot past 300 meters. Or gofers at 100m
Very interesting results indeed.
Thank you
Dang, love that chronograph!
Gun Kenobi with an interesting vid. Cheers Mac.
I feel you pain with the eye sight, had to go to a crossbow with a scope because if I focused on the pins I couldn't see the deer clearly if I focused on the deer I couldn't see the pins. That all happened at the age of about 62, love the content keep it coming!
Thanks my friend. Yeah, I hate that I'm not able to focus as sharply as I once could. I love shooting iron sights and the day I lose that ability will be a very sad day.
@@MilitaryarmschannelPat Mac has some really good content on this exact topic.
Might help in some of your applications.
, my fiend is 8 years older than me, he's 68 and doesn't need glasses after laser eye surgery
I'm in the same boat. My eyesight has been slowly degrading. Nowadays, I'm happy to hit a pie plate at 100 yd with iron sights. But thankfully, there are plenty of optics available!
Just paint or replace the front sight with something high-vis. It’s still hard to focus on a black front sight even with good eyes.
Imagine what the 1/8, 223 wylde, 20 barrel would do... supposed to be some of the most optimal for everything from 55-77 grain.
Back in the 1980s just prior to when NATO adopted the SS109/M855 62-grain "green-tip" enhanced penetration round for the 5.56x45mm cartridge as its standard, army testing of twist rates found that 1:9 was optimum for stabilizing both the old 55-grain M193 round and the new M855. However, trouble hit when the 62-grain tracer was tested; it was not stable out of a 1:9 barrel, due to its greater length than the standard M855. The army switched to a 1:7 which solved the problem, albeit at some cost in accuracy with M193.
If you plan to use exclusively 55-grain (or lighter) ammunition, then the 1:12 with a 20-inch barrel is optimum; it is close to the original configuration designed by Eugene Stoner et al.(which was 1:14). However, if heavier and/or longer fare are to be employed, a faster twist is needed. Every barrel is unique, but most 1:9 tubes will stabilize adequately up to 69-70 grains or so, some a bit heavier. If 70+ grains are to be used frequently, then a 1:8 or 1:7 are best.
Service rifle competitors who single-load shots of 80+ grains for the 600 yard stage sometimes use a slightly faster twist than 1:7 to achieve optimum results.
@GeorgiaBoy: You know your stuff. Most of my friends never knew about anything slower than a 1 in 12 twist.
1:8 seems to be a good all around twist rate for 55 gr varmint loads and even heavy 77 gr loads
@@terrysaunders2026 - Thanks for the kind words. I have always been fascinated with military history, and in this case, small arms development. The place you really hear about very light bullets and relatively slow twist rates is in the varmint shooting community. I'm not a part of that, but picked up a few things here and there. Bolt-action rifles in 1:12 or 1:14 are quite common with people shooting prairie dogs at 400-500 yards away using 40-grain pills at 3,500 fps MV in some cases.
Getting back to Stoner's design, the initial AR15 in 1:14 tested well in typical temperate climate conditions, but failed to stabilize 55-grain slugs under cold/Arctic tests, which is why Army Ordnance asked for it to be changed to a 1:12 twist for the M16A1. That's the story I've seen in the histories of that time.
Great info. Thanks.
There’s absolutely no sense in getting a barrel twist slower than 1/9 if accuracy and bullet weight variety are at the top of your priority list. My experience is based on the use of ammunition I handloaded for my .personal 223/5.56 rifles.
I have 7, 8 and 9 twist rifles that ALL shoot 0.5 MOA or better at 100yds with bullets ranging from 50 to 75 grains. My 1/9 twist.223 bolt gun shoots 45 caliber sized, one hole, 5 round groups at 100 yards, .904 inch, five shot groups at 300 yards using a 69 grain Sierra TMK and the last time out fired a three shot group at 925 yards that went into under 5 inches with a Hornady 75 grain ELD MATCH bullet.
I’ve tried every grain weight bullet between 70 and 80 grains and the ONLY bullet that has worked is the 75 ELDM. Every bullet between 45 and 69 grains shoots bug holes. I’ve never seen or heard of a 1/12 twist barrel shoot what I would consider acceptable accuracy with anything over 55 grains.
The ability to accurately hit my intended target consistently for maximum terminal effect is far more important than the hoped for, maybe, possibility of a bullet tumbling and maybe traversing the target in a direction that possibly increases its terminal effect. I’ll take alittle extra bullet weight and “put it right there” accuracy any day over 3 to 6 inches at 100yds….
@military arms channel:
No key holing with 1/12” barrel and 62 grain bullets?
When we took our GAU-5s to the range with 62 grain ammo we got frequent key holing at 100 yards and beyond.
around '84, we started hearing rumors about a new round being developed for the M-16. it was supposedly designed to penetrate a WWII style metal helmet at 800 m. it was going to be a "flechette" round where the copper jacket peeled away halfway to the target increasing the range. gotta love rumors but this was most likely the testing of the heavier grain rounds for the rifle at the time. (too many people complaining about the lack of stopping power of the smaller caliber). i never fired the 'new' round as i got out of the service in mid '86 but watching this video, i can bet there were a BUNCH of US Air Force Security Specialist pissed off to beat hell trying to get their re-certs done on the same rifle they've used for years, which suddenly started pushing out 7 MOA groups. lol. not sorry i missed that sh*t sh*w.
i loved that rifle. after 30+ years, i decided to build my retro M-15/AR-16, complete with the slick side carry handle upper and 20" 1:12 twist pencil barrel. only thing different is the Brownell's retro 1x4 scope because... uh...er... you know.... the eyes t'aint what they used to be.
another rumor i've heard about the 55g FMJ is it's "sweet spot" is at the 3,200 fps range. something i've noticed from all manu's is 3,000 fps is the most you'll get, as replicated here in this video. it would be interesting to see if there's an accuracy improvement using Lake City brass while pushing that 'optimal' speed range. regardless, 55 grain FMJ at 300 yards is devastating to a 5 gallon jug of water there's a video on CZcams about it ; )
Thanks, MAC.
1 - I'd buy one of those for the 20" barrel, and 'cause they're being made by one of the M1 Garand manufacturers 🙂And would go with the "variety of ammo" twist rate 😛
2 - That's a beautiful dagger. Sometimes seemed to have a second bevel, but depended on the angle. Is it Lockwood? Loved the fittings and leather color choice 🙂
Thanks for the vid Tim! Was super helpful indeed! 😀
I own a 1:7 Wyndham weaponry retro M16 and love it.
I have 2 Windham's, A 16" and a 20" retro . Love them both.
Yes, that is definitely the class way to go. 👍
I had a rifle with a 1/9 twist that couldn't stabilize a box of M856 Tracer (64 or 65 grain I believe) rounds that I had. Couldn't accurately hit a steel gong at even fifty yards with it.
Switched to a 1/7 twist on my upper, works fine now.
Another wonderful video. If you ever redo this, add in your notes to add 40 grain. I bet 1/12 will be very accurate and in same area as 55 but 1/7 will have a noticeable impact shift. Again, great video, love you channel, and I'm suprised I'm note subscribed. I'll fix that.
Got a military standard (civ) AR A1 2nd hand in the late 70's. Measured the twist myself and came up with a 1 in 14. Yes you heard correct 1 in 14 twist. 55 gr @ 100 was about 4-6". @ 200 it opened to about 6-8". The 62 gr out of the 20" barrel got a little squirrelly @ 100. One 5 rd group would be 6-9". The next grouping would be 9-12". I was using a 3' sq backing for my target @200. This is where the grouping got really squirrely. At 200 yards, out of a 10 rd string, I generally could find 3 or 4 bullet holes in the 3' backer.
Interesting results. I like to think if optics was possible if the results would have been the same. I just recently did a comparison between two builts. Same bolt assembly, upper and lower, but different barrel twist and length. One rifle has a Green Mountain 1:6 19-inch barrel: 77 grain @ 100 yrds .34, .41, and .63. Other rifles have a Citerion barrel 1:12 20-inch barrel 55 grain @ 100 yrds just as good. .40, .46, and .57. When time permits, revisit this, but this time, switch the bullets weighs and see what happens. Thank you for sharing.
This is awesome
As others have stated it would be interesting to see a comparison using ballistic gel...but I would use a scope to get more refined shots...
Great video! How does the 1 in 8 compare ?
I love and hate that you brought up the 8k bcm rifle! I've been so waiting for you to be able to finish getting it to 10k!
As far as your “old” eyes go, both my parents had the eye surgery to improve vision/remove cataracts. They were in their sixties and loved the results. I am now approaching the same age, however I could never deal with the massive amounts of eye drops you have to do for a couple of weeks after the procedure.
Thats weird, my test results were different. My 1-12 twist was key holing at 50 yards with anything over 55gr. Pretty crazy to see key holes already at 50yds!
yeah i've experienced very similar results, my 1:12 twist would keyhole 69gr @ 25yds! really only stabilizes 55gr.
This video made me feel nostalgic so i look at how long i have been watching this channel and realized i started watching when i was 28 and now im 41😂
The earlier TM's from the military specifically discussed the differences in M193 and M855 in the A1 and A2 rifles, detailing terminal performance on target as well as POI shift and how much a soldier can expect accuracy to degrade in putting M855 in the A1 rifles.
I'd like to see Tim do a video on the different chambers(.223, .223 Wylde, and 5.56), and see how it effects the velocity, and the accuracy of 5.56 and .223 rounds, preferably the same loading from the same manufacturer.
I remember when I used to be more interested in ammo, and getting the right HD round, and I would look up a loading in .223(for example Winchester Ranger/LE line), and compare it to the same load, but in 5.56, and the 5.56 loads were always(well, usually) 1-200fps faster than the .223 loadings. I always wondered if they were using the same rifle/barrel to test the velocities, and if it was chambered in .223 or 5.56.
Also, as someone who grew up in a red dot/optic world, and who still isn't great with iron sights on a rifle, especially when shooting "dynamically", moving, rapid fire, etc., I can't even imagine how hard(and scary) it must have been for those kids in Vietnam(and other conflicts with other rifles) who may have never even shot a rifle before, all of a sudden getting thrown into firefights in the jungle against men who've been fighting wars for the past decade or two.
I take it Mac is proud of Standing on the square.
You live in Indiana if I remember correctly. I'm in Southern Indiana so can confirm, yes humidity can be horrible here, can be 100% at any point.
I use a 20inch Wilson Combat barrel heavy bull,1:8 twist. It gives me quarter size groups at 200 yds with 68 Hornady Frontier bthp match ammo😊
With the slower twist rates adding velocity in mind I would recommend the 1 in 8 twist not the 1 in 7 twist. The 1 in 8 twist stabalizes 77 grain perfectly fine with the added bonus of a bit more velocity.
Great Video!!
You try to explain this to new AR15 shooters at the range and look at you sideways.
Mean while they blow through a couple hundred rounds of ammo and never hit the bullseye.....
Wasn’t expecting my guy to pull out a dagger 🗡️
Would have liked to seen these test done with M193 and SS109.
Still good information.
I run a 1:7 16" barrel... Hornady Black 62gr consistently runs a 1 1/2-2" group at 100 yards...5 and 10 shot groups with the occasional flyer
I have a Rem. 700 with an 18-inch 1in 12 twist 223 barrel. 50 grain is .5 moa but 77 grain in any brand key holes and is all over the place
Good test, Tim! Still, I think I would like to see the same test with a couple of scoped rifles (not something attached to the carry handle, however! I have had zero luck with such scopes in the past and do just as well with iron sights!). I'm old enough that I have either red dots or scopes on everything! I've never once hunted any big game without a scope due to relatively poor vision. I'd also like to see some mil spec ammo included, M193, M855 & maybe even SS109, which are all relatively (for the moment) available. I believe a decent scope evens out the difference between a shooters ability and the ability of a rifle to group.
Of course, the bottom line is going to depend on individual rifles as well. Not all rifles are created equal, even if they have consecutive serial numbers from the same manufacturer. It's just a fact of life and it's pretty unlikely that any two rifles will shoot exactly the same groups with any given ammo, even with everything else being as equal as possible. It could happen... but I wouldn't bet a nickel on it!
Basically, rifle accuracy is a crap shoot, involving not only the rifle and accessories (scope, mount, rests, etc), weather, how the shooter feels that day and what phase the moon is in! Plus a bunch of other stuff I won't even try to mention. If you were to shoot 50 groups, on different days, with each type of ammo, you might get some meaningful statistics... but only with those lots of ammo! There's always a little bit of voodoo mixed in with testing of any kind, it just can't be helped, short of spending all your time and money, not to mention barrel life, on testing! Even if you did, it would only apply to those two rifles! The only solution is to do the testing on your own rifle. And to do enough to prove to yourself, that X brand (or, in my case, X load) is the best for your needs. It's like zeroing your rifle... yeah, you can follow the general rule (whichever one you like, 25 yards, 50 yards, 36 yards, etc., etc!) but without a chronograph and accuracy testing, it's nothing more than a SSWAG - a Semi Scientific Wild Assed Guess! Which means you're going to get SSWAG accuracy out of your rifle. But hey, if that's good enough for you, great! Personally, I want to know where my rifles shoot... preferably exactly where they shoot!
Cheers,
jc
I remember the old video where Tim shot 1/7 16 and 20 inch ARs and a 1/12 AR at watermelons. The 1/12 AR was devastating, but the 20 inch 1/7 did ok too. I bought a 1/9 20 inch Colt MT6700 a d it was pretty accurate.
Would love to see what a 1/9 twist would do. As for not seeing the front sight as clear, as my doctor told me when I was complaining about all my aches and pains "it's much better than the alternative. Also gel tests would be interesting.
According to Chris of Small Arms Solutions… the penetrator core in the 62 grain is not properly centered and causing fliers and lower accuracy. And because of the 62 grain being more intended for the machine guns like the FN Minimi.
I'd like to see this same test on a Lead Sled with scopes swapped and sighted in on each rifle. That's damn good shooting for open sights but once you stretch out to 100 yards the scope would eliminate some errors. Great video though!
Thanks for the video! Would like to see what 77 grain will do.
Highschool would have been so much better if Mr. Teacher whipped out a dagger for his pointer ~ nice touch on the data breakdown.
Interesting 👍🏻
Light bullets, slow twist. Heavy bullets fast twist. Back in my gun repairing days I had a Sako heavy barrel in .222 sent my way because is was lacking accuracy. I happened to remember that model had a 16 twist so I loaded up some 45 grain bullets. It turned into a tack driver with that load.
I watch the Military Arms Channel quite often. Excellent information and testing. I realized just now I hadn't subscribed yet...Now I feel guilty !!
Exactly! I think the 1:7 twist was really designed to stabilize tracer rounds. The problem is that this kind of twist rate decreases the effectiveness of M855. I have had very good results with my 1:9 twist for M855 (accuracy wise). Not sure how good the terminal ballistics are. Another great video!
The variety of ARs gives you the paradox of choice. I've done so much research trying to find the "best specs".
I’d like to see a 1:14 barrel thrown in for once… Including a 1:9 would be useful as well…. Using bullets from 40gr up to 77gr…
Maybe a summer project for me…
With 1 in 14 and 1 in 12, make sure you hit "watermelons", not regular melons or cantalopes etc, for the full effect, because of the pocket of air in regular melons inside, you won't get the hyperstatic effect. :)
@@thesanfordmethod1905 As fun as that would be, I want to concentrate on accuracy measurements. I may look into a block or two of ballistics gel though as I would love to see the various wound channels with the various weights through the various twists and how they will differ… especially a 1/14 with some 40gr blitz or TNT varmit bullets at 3600fps…
If you do, go by length of the bullet. The longer they are, the more revs are needed. You can find the same mass with different lengths and different mass and same lengths.
From there the more mass is on the outside or mass removed from the center the easier it is to stay on route rotating along the same axis.
I have a IWI Zion with 1:8 twist that won’t shoot 69gr under 4 moa. I also have a Barrett with a 1:7 twist that shoots the same load sub moa.
REC7? Mine also shoots 77gr SMKs at 1 MOA or less.
@@Alshen Yessir, gen2
It seems to make sense that many, including bushmaster centered around 1:9 twists. Makes some sense that it might retain better velocities, and accuracy would still be really acceptable for 55 gr use. I had never seen a 1:12 barrel before.
Keşke benim olsa. Eline diline sağlık. Adana'dan selamlar.
I first 223 rifle is a Stevens 200 with 12 twist. With 55 gr bullets it would group them into about 1/2 groups and all the holes in the target were round. With 62 gr bullets it was about 1.5 groups and very few had rounds holes in the target. Most were about twice as long as they were wide. Evidence the bullets were not stable. Much further away and they would probably start to tumble.
I recently bought an AR-15 rifle with an 8 inch twist. Haven't had a chance to repeat the testing on it but I feel I can assume the 55 gr bullets will leave round holes as well as the 62 gr bullets. I have only shot a few rounds for function testing, none for accuracy. Being a not to expensive AR I doubt it will shoot as well a the bolt gun.
With a 24" 1:9 barreled Bushmaster Varminter I can keep it at 0.5" or lower with Speer Gold Dot 75gr if I do my part.
Would love to see how a 1in8 twist would do. Many guns were coming out in that twist rate a few years ago
The most accurate AR I ever had was assembled with a surplus 1:14 original non chrome lined barrel that I got from SARCO in 1985. Only mods were a free float tube and a special hand grip screw that took the slack out of the trigger. Factory FMJ 55gr 1 to 1 1/2 inch. Hand loads 55gr SP 1/2 to 1 inch. And my all time best 53gr flat based match that would do under 1/2 all day. Those were 5 shot groups. Never shot or owned any other AR that could do that even with expensive match barrels.
Real early M16’s had a 1-14 twist rate.
Technique is there ,eye sight is not on a rest at that distance. Worth bro.
Here's a solution to that out of focus front sight post: a scope. I would really like to see this test redone at 300 meters, with at least a 6x optic, and proven high quality ammo like Black Hills. I am not surprised at the results for the 1 in 12" barrel.
I was first issued and trained with the M16A1 in the army with a 1:12 twist. At a Canadian Bull zero target I could put two rounds in the same hole at 25 meters with government ball ammunition. I could do the same with the M16A2 with the 1:7 twist. . We used a different zero target for it. I prefer the Canadian Bull. The difference ammo made a difference. The manual said that the A2 could use the NATO 5.56 as well as the M193 ball round of the A1. Although not as accurate. However, the M16A1 couldn’t shoot the 5.56 NATO round well it went off target. I carried the A2 during Desert Storm. The A2 was better in some ways. But because it was Zeroed slightly differently from longer range you had different hold offs for it. I preferred the A1 because it was zeroed out to 250 meters but you could still hit the 300 meter target with iron sights without a significant hold off.
I really struggle with iron sights too given my aging eyes. One thing that might help you in this scenario is to pull that rifle back a few inches to get that front sight out of the sunlight.
In very simple terms, the heavier the projectile (it is actually a function of bullet length and sectional density, but we are simplifying things here), the faster (lower number) twist rate you are likely to want to utilise. It is bullet length that determines twist rate not weight.
Shhh not so loud. It seems most of the viewers of this video think something of scientific value was presented.
You have to shoot hundreds of rounds of increasingly harder to stabilize bullets all sorted for imperfections from each rifle. Than take the ratio of decreasing accuracy and compare. Especially since you are using different barrels
Fun fact with your fun fact you actually dont use s.d but the ratio between the width and length the density has more to do with the bullets acquired momentum and how far it will travel before losing its stabilization