Shot Grouping

[Longbeardnc1]

What do you all think about this target? Just wondering if anyone could give me some clues to what might be the problem here. As you can see each of the three shot groups have a low hit. These low hits were the first to be fired in the three shot series, I might also add that all three groups were shot from a bipod at 50 yards - using different reload combos for each group. The groups were shot in series with hardly any cool down time (just the time it took to load 3 shells in the mag between groups)

The gun is a custom AR-15, 223 cal. that I built from multiple parts; it does have a heavy 20-inch Olympic competition bull barrel (not free floating). I don’t have a lot free time to shoot or a good location so any and all input would be greatly appreciated.

Thanks

 

[Whitman31]

Loose nut behind the buttplate...

 

[Jim Watson]

Lessee, now.
The barrel is cold for the first shot, even just for the reload time.
You are not in a solid position for the first shot.
You are shooting at an indistinct scribble instead of a clear aiming point.

I pick door number 2, it is a lack of technique.

 

[rcmodel]

* Cold Barrel?

* Cleaning the bore between each group?
( First shot, or more, out of a clean barrel will often be out of the group.)

* Are you letting the rifle load the first round from a locked open bolt, or easing it shut slowly?
(That can possibly create different parts settling & lock-up on the first shot.)

* Powder position in the case caused from above?

* What ever it is, I don't think it's your shooting!
(Two shots touching in all three groups says to me you are doing most of it right!)


rcmodel

 

[cuervo]

If all three rounds are being loaded into a magazine and then shot, and it's the first shot each time, it could be the way the bottom rounds are putting pressure on the top round when it's loaded into the chamber. Or it could be that you're taking the top round from a locked-open bolt, but the other two are loaded by recoil.

What happens if you single load each round, or have three magazines, each with a single round?

 

[DMK]

What happens if you single load each round, or have three magazines, each with a single round?

That was my thought too.

 

[YardVarmint]

IF, the first shot is the low one I would say it's the target quality. You are probably picking up on the slightly darker impression the hole would make and aiming a bit higher.

 

[Longbeardnc1]

Loose nut behind the buttplate...

HA!! That'd be me.....

Or it could be that you're taking the top round from a locked-open bolt, but the other two are loaded by recoil.

This is a good point. I was press for time when I shot these groups and to be honest I didn't even think about how the first round was being loaded.

Cleaning the bore between each group

No I didn't clean the barrel between groups but since all three groups "mirror" each other I'm not sure if that would be a factor here. I'll be sure to do it next though.

Thanks all, that'll give a few things to check next time.

 

[W.E.G.]

Load the rounds single-feed, and see if it changes the groups.

 

[rcmodel]

No, don't clean the bore between groups!

You will be sure to have wild shots in each group if you do.


rcmodel

 

[theCZ]

There are a whole lot of things you can do to clean that up. Are you using optics? Do you have a rear rest when using the bipod? Are you prone or at a bench? I also think you would benefit from a better "target" reference! Those scribbles just don't cut it for trying to shoot tight groups.

 

[Longbeardnc1]

Are you using optics? Do you have a rear rest when using the bipod?

Yes I'm using optics and no I didn't have a rear rest, I'll also use a better target next time and try to find a location where I can shoot from a benchrest. If you look at the target the low shots in each group was the first shot fired for that group. Looking at all three groups I don't think the problem is with the optics or rest since all three appear to be identical...could be though. Also keep in mine each group was shot with a different load configeration.

No, don't clean the bore between groups!

You will be sure to have wild shots in each group if you do.

Gotcha

Load the rounds single-feed, and see if it changes the groups.

If the pattern doesn't change this would rule out what - Bolt, magazine and possible barrel heat related problems? Just curious.

 

[DoubleTapDrew]

Try reading this. Pretty intersting: http://www.6mmbr.com/verticaltips.html

 

[Longbeardnc1]

Good site

 

[Stinger]

I don't guess that I see a problem.

Oh, I see, it is at 50 yards not 100.

What do your groups measure? What do they look like at 100 yards?

I'd say your main problem is an unstable rest. Loose the bipod, get a front and rear rest, then report back.

 

[Longbeardnc1]

What do your groups measure? What do they look like at 100 yards?

1/2 to 1 inch at 50, sorry I havent had chance to shoot it at 100 yards.

I'd say your main problem is an unstable rest. Loose the bipod, get a front and rear rest, then report back.

I hope so, I just thought it was odd that the 2nd, 3rd and following shots (not shown in this target) all touched each other and the first shot of each group fell 1/2 to 1 inch below all the other shots.

 

[Stinger]

Yeah, it is really important that you remove or limit all potential variables. I've noticed that with my guns, the loose nut is almost always me. When I can limit the potential impacts that I can have on my shooting, then my performance is much better. Did that make sense? It did in my head.

When you are talking about fractions of an inch, obviously every little thing you can limit will help.

 

[GarandOwner]

Possible combination of unstable rest, and anticipating the recoil from the first shot, I see a lot of people shoot like this because on the first shot of a new string, they anticipate the recoil and "lean into it". It's subconscious, you may not notice it, and it would account for your first shot always being low.

 

[Longbeardnc1]

Possible combination of unstable rest, and anticipating the recoil from the first shot,

Ok yea….. I see what you mean. For the past several years I’ve been shooting a scoped 870 loaded with magnum turkey loads, it kinda kicks a little harder than the AR.

Did that make sense?

Yes thanks