Positional Point Of Impact Shift
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- čas přidán 28. 07. 2024
- Today we try and answer the question: Does point of impact shift when a shooter changes position, how much and in what way? What can be done to mitigate the shift if/when it does happen?
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I'd love to hear what you have to say.
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For those asking about the rifle.
The rifle is a 6 Dasher built by A-Team Precision. (Brian Allen's company) Curtis Vector action, Muller Works barrel, Manners Stock, Vortex Razor optic, APA little bastard brake. Trigger Tech Diamond. Lapua Brass, Berger 105's, 32.4 grains of Varget. 2908 fps.
Our setups are pretty similar 🙂
I run a similar cartridge (AI 6x47L) In a very heavy rifle. Even with such a soft recoil and a heavy rifle; I've seen at least 1/2 minute vertical shift due to recoil movement. Free recoil would impact higher on target than a firm hold with shoulder contact group size in my case was the same each time. Darrell Holland once stated that there is a tiny bit of rifle movement prior to bullet actually leaving the muzzle......makes sense to me after what I've experienced.
Here is some data to add to your analysis.
Olympic Smallbore 4 position, we get a zero in prone. Most of us shoot smaller groups in sitting. We do not change zero between prone, sitting, kneeling and offhand, each of which has less stability and mass behind the gun. I realze the recoil is negligible, but I also don’t believe it has as much affect as many believe. I think free recoil will provide a baseline. Then if you tie a sandbag on the butt to simulate shooter’s mass and continue free recoil you may be able to truly test the idea. Think you’ll be surprised too.
Thanks for the extra info!
Awesome video, thanks for sharing. I’m doing a little experimenting myself on this, I’m leaning more towards head position and check weld but I need to verify. Keep up the great work my friend!
Thanks!
Great concept for a video! I didn't get to see the footage of you shooting from the kneeling position, but I agree with you that the recoil must have made the rifle drop at the rear. You were more upright in this position and the recoil probably moved your shoulder back further and the stock lower.
Gonagain
What I get from this video is that you sir are an excellent shot! Aside from that I also believe that the “wobble” of your last stance is the reason for your group opening up. Non professional opinion obviously.
Thanks. Appreciate the comment.
I often see higher POI when going from a stable/solid position to a lesser one. IE we usually zero prone with bipods on firm ground and good rear support, then we see high POI shooting from a rucksack or positional stage. I chuck it upp to recoil management and the buttstock recoiling "down" in the shoulder pocket, this is from precision rifle classes aswell as competitions.
PapaSierraOne Agree. Thanks for commenting!
I think I would take it as well, 300 yards and three shot together, spot on brother
What a group! I first thought you mis-spoke by saying from 300 yards. I shot my ruger precision in 6.5 creedmoor the other day from 100 yards with sub 1/4” MOA groups but your grouping puts it to shame. Great job!
Thanks. Pure luck.
Try it again with 120 g Hornady Match (Ballistic tip) 👍🏻
That first group!!! Holy smokes man , good shooting all around.
Chris D Thanks!
I shoot the three again using the bag positioned similarly under the stock-thus omitting the bipod from your prone and modified prone positions. This really deserves a follow up video or three and ultimately larger sample sizes.
Kingston I have to say this often to people, but I am no scientist. I don’t make my videos in that kind of detail. Sorry to disappoint.
Cheekweld gave you different result because you had different pressure from prone\bench to an upright position.
Recoil in my opinion will exploit a weakness through the path of least resistance and introduce that error to the shooter/shooters system, you were at your steadiest and fortified solidly inline behind your rifle in the prone position. A pube off in any direction can mean you miss by a foot at distance I know you know that already as well SD's start to show at around the 300yd mark I know that has nothing to do with your groups for this video but could to someone using factory ammunition not having the precision shooting experience and knowledge you have trying to figure this out. Also, I guess that's why vertical/horizontal stringing can occur even in the prone if you don't load the bipod into your shoulder pocket the same way each and every shot as well proper cheek weld as to not introduce parallax thx keep up the good videos safe shootin'
if you look at your head at 1:30 and 2:56 the tip of your nose is down low, and looks even with your rail. at 3:53 your nose is much higher, so you would be looking down through your reticle, and shift the reticle and the gun up, resulting in a higher group.
RangerCaptain11A thanks for watching and commenting
IMO changing positions changes cheek weld. My basic sniper instructor threatened to duct tape us to the stock if we broke the cheek weld which changed POI.
agree. I think that's a main issue here.
Could be barrel harmonic change slightly to string vertically or could even be the jump of the rifle not being controlled as easily because you’re less likely to keep thebutt of the rifle from jumping down when behind the baricade vs the prone position.
Remember when i said in some positional shooting is is better to favor low on the target, results.
Jim See Yep. I thought that was in relation to larger calibers and free recoil?
I find shooting from the bench or standing with a tripod I have a vertical change of POI with my primary hunting rifle. Some gun writer wrote that he zeros hunting guns from the position he will use in the field because of the same thing.
My POI moves high and left shooting barricades. I think it's where we break the trigger in the wobble and the more I practice of course the more my groups shrink but they remain high left. Dry firing, and looking for the high left shot, i notice i almost always break the trigger on that side of my aiming point.
It's always been taught from the experienced shooters that once you sight in your rifle at the range you should always re- sight in or check your point of impact from a position you'll most likely be shooting from like kneeling or from a pack or tree because it's alway a little different
good advice
It’s a problem of differing cheek positions on the stock. In the Olympic disciplines I shoot it’s one of the most important things to nail down each time.
Regarding the bench position, I'd be curious if your group would have been even smaller if you shot off of a sandbag (using bipod legs folded and resting on top). Harmonic jump from shooting bipod legs off of hard surface like concrete, even with loading.
The sample size is too small to definitively indicate any POI shift from any position.
Did he say 300yds at the first group?!?!
I would be happy if I could shoot such groups consistently at 100!
I think with bigger caliber (like 300 and 338 ) difference would be bigger.And maybe 2 or 3 (or more) shoot few times more.
yeah, I understand some people don't like 3 shot groups. I always do 5 when I'm gathering data, but in this case, I was just looking for POI shift. Didn't really care about the groups.
My question is because of this, if you know you will be shooting from all 3 of these positions in a match, maybe even in the same stage, how do you plan for this poi shift? Is it a consistent shift? How much will it effect hits out to lets say 1000 yds or so at a prs shoot?
Jbrawner1911 it has some effect as you saw. The better your fundamentals and your ability to drive your rifle, the less effect it will have. That being said, when you’re on the clock you are inducing stress and most people tend to perform poorly because they let slide their fundamentals.
I know a lot of shooters that just plan to take 1 to 2 tenths off of their drop data when they switch to higher positional shots.
Hey there, I have a question/test for you. What would happen if you had to zero your rifle using free recoil (benchrest not prs) and see how much we/you as the shooter changes the rifles actual point of impact?
Good idea. Thanks.
Simple physics really, when you are on the barricade your body was more erect and you had less body mass behind a rifle. Believe it or not the rifle does start rearward recoil prior to the bullet leaving the barrel. It isn't much, but it's enough to exploit the difference. Now do the same test but free recoil off the barricade. It's the same argument when you have guys zero in rifles on a Lead Sled and then not understand why their shot goes high when they take a standing or sitting shot in the field on a trophy buck.
good idea on the free recoil. another guy suggested the same test with a rail system. could be interesting.
@@PrecisionRifleNetwork Also maybe try to apply even more rearward pressure with the firing hand than you did for the barricade shot. Similar to what Niles Coyote said, a lot of times when you can't get the same mass behind the butt of the rifle you must "drive" it more and make the recoil come straight back into the shoulder by apply more rearward pressure with the firing hand.
agree. good comments.
Could it possibly be a slight difference of “eye relief distance” ( like between your eyeball and the scope glass) in the different shooting positions. Ie prone is closer to the glass than kneeling etc.
majormitchell01 I wouldn’t think so, but honestly don’t know. 🤷🏻♂️
Slightly off topic, but what do you think about butt pad cant to fit the rifle to your shoulder pocket better, do you prefer to keep it neutral to easily adjust to different positions?
I've heard of some benchrest or civilian marksmanship program guys doing that whenever they change positions. David Tubb recommends it. It's clearly not practical in PRS matches. Too much movement. Not sure really. I leave mine neutral. haven't really had any issues so far.
Thank you, the range I usually go to I have to shoot from the bench so I have my butt pads canted to fit better and more naturally level the rifle, I reckon I should get comfortable with the butt pad neutral because offhand shooting isn't going to happen with that can't.
What caliber, what stock. All make a difference. Sample size is to small. Shoot 3 groups from all 3 position and see what you get.
see pinned post. I agree the sample is too small for the scientific-minded people. lol I am not that guy, so I'm fine with the "relatively speaking" kind of results.
did you see the size of that group !
paul watson lol just got lucky 🍀
What's the rifle set up? Just curious.
The rifle is a 6 Dasher built by A-Team Precision. (Brian Allen's company) Curtis Vector action, Muller Works barrel, Manners Stock, Vortex Razor optic, APA little bastard brake. Trigger Tech Diamond. Lapua Brass, Berger 105's, 32.4 grains of Varget. 2908 fps.
That's damn good shooting.
Thank you Sara.
Joel, I suggest shooting a bigger sample size. 3 shots hardly seems like an accurate representation of your rifle/scope/ammo/self capabilities.
I would agree, but again, I don't claim to be a scientist and usually, my way of doing things doesn't appeal to people who require perfection. Not that you do, I'm just saying I didn't set out to develop and record a science experiment that can be used to help determine the course of life itself. lol Hopefully you found something useful in the video. I learn something every time I do these.
Look, Frank gave you a thumbs down..lol. Good video, brings up some good questions.
I have a secret admirer. You can rest assured that I can put my heart and soul into making the very best videos and there will always be a thumbs down on there within a couple hours of posting. I just wish the person was man or woman enough to message me and tell me why. LOL I don't even care, I'd just like to know.
Interesting. Maybe Try a rail (419 and/or Igw) next time off the wood. Then see how that compares to the others.
actually that's a great idea. I'll remember that. thanks.
I’m all ears.
Hypothesis: hand on scope on barricade. Scope points down, zero goes down, poi goes up.
JT McFarland that would perhaps be a good thought If we were using cheap mounts with a cheap or weak optic. These are built for extreme conditions. You can put a lot of pressure on them. This is not a new technique. Many competitors use it.
Thanks for the reply and all the great videos. I doubt you're incorrect, nor do I believe it's a flimsy optic, but I've just always been skeptical of that technique. If you do a quick bit of trigonometry, you'll find a 2" dispersion at 300 yards only requires 0.001" flex in the scope zero if the bell is only 6" forward of the rings. That's why I always grab the rings and not the scope.
JT McFarland sorry man, you lost me at math. lol
I wonder if your parallax was off.
drjimjam111 negative. Set it correctly before I started shooting, and all shots were the same distance. 👍
I just re-watched this video today and noticed that I accidentally disliked it two years ago. Sorry about that I went ahead and liked it today as I meant to two years ago.
Joseph H LOL 😂 thanks
Jeez...I can't group like that at 100 on my very best day ever lol
It was luck, pure and simple. I usually can't either. I'm usually between 3/8" and 1/2" at 100y. The groups in this video were abnormal. I'm not going to complain though. lol
science tells me if your rifle is perfectly zero perpendicular to a target, any inclination/ deviation of angle to the target will change the point of impact.
Your point of impact shift is because you were touching the top of the scope, putting slight pressure on it. The prone and standing/bench shot, you were only touching the stock and trigger. Hell of a group!
Thanks! It really comes down to body position behind the gun and recoil management more than anything else. I don't agree that the POI was because of putting pressure on the scope. These things are made practically bombproof these days. The slight "balancing pressure" that I'm putting on the optic will have no effect. PRS competition is evidence of this. Most competitors do what you saw me doing.
At 300 yards with a heavy well made scope you won't see a measurable difference. A $300 knock off, yea you might but not a good scope.
Yeah, position and recoil management are a big factor. You did say you are gonna try and keep everything the same as much as possible. Not being able to use a rear bag played a big factor, not resting it on a solid platform like the ground or table. What I meant was more along the lines of harmonics, on where you were anchoring the rifle system down, not if the scope or the chassis is locked down tight. There is another video! Think holding the scope, touching the barrel, or anything other than the stock and trigger cause POI shift? All shot from one position like the prone or bench. I would like to see something like that on video with a similar setup you have. And thanks for responding back, love the channel.
Appreciate that, thanks. One thing about this stuff, there's never a shortage of video ideas. lol
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Weight, try that last group again but add 12lbs to that rifle 😁
lol that’s probably valid
You changed like five or six variables between shots. Not to mention, the gun is at a different elevation each time, changing the trajectory and look angle. Bad test.
lol good luck performing the perfect test of this kind if you have to move your body at all. The whole point is to see what kind of shift takes place when we do have to move our bodies.
@@PrecisionRifleNetwork Perfect might be a stretch, but certainly variables like inclination could be controlled. Since the bench is fixed, shoot from prone on a platform (maybe put a table behind the bench and then lay down on the larger surface) at the same level, and off a barricade at the same height, for example.
Similarly, at least use a pad to rest the bipod on between prone and bench, instead of what looks like soft earth (with a likely loaded bipod) vs hard smooth concrete (minimal if any load). Plenty of folks have done fairly good demonstrations with respect to the influence of surface and bipod loading on POI.
If the desire isn't to isolate these inputs, rather just look at prone vs bench vs barricade in broad terms, then certainly more groups are required. And variables such as barrel temperature and shooter comfort (how long it takes *you* to warm up, get in the zone, stay in the zone, and when you start to fatigue) should be considered. Should be able to do this just as easily with a 10/22 at 25yd as you can with a competition rifle, if we're talking about the position differences. In fact, results from a semi-auto may be more telling, as it is can be less forgiving and precludes the need to break NPOA between shots to work the bolt.