AR trouble. Equipment failure?

[DamnDave]

I have now taken this to the range a couple times now. I cannot find a load that my rifle likes. I'm just trying to now see if something is wrong with the rifle. Before I call RRA, some opinions will be helpful.

Rifle in question

RRA Predator Pursuit 20" 1:8
Primary Arms 4-16x44 scope on a Burris PEPR
Geissele SSA trigger

The best group I shot was a .8 MOA at 100 yrds but the avg is hovering around 1.5"-2". This was during load development with 69gr SMK over various powder charges of TAC, Varget & AR-Comp. All rounds were loaded to 2.25"OAL and brass trimmed to 1.75". Rem 7.5 primers and all brass was sorted by headstamp.

I have tried to do a process of elimination to see what might be wrong. 1st I let another shooter fire some rounds. He's a good shooter and can easily group sub .5moa all day. His groups were approx 1.5". Next I thought it might be my cheap scope. I put on a Schmidt & Bender on there and tried it that way. No dice. With the S&B on there I shot 2 groups with FGMM 77gr. Both groups were approx 1.5".

Only other thing I can think of is that my upper doesn't like higher grain bullets? I'm heading over to ASR tomorrow morning to try some Hornady 60gr V-Max rounds I loaded up today.

Does anyone have any other suggestions on what it may be?

 

[KAZ]

Re: AR trouble. Equipment failure?

I may have the same rifle new this month and have only tried AA2520 because I happened to have an 8 lb jug used in my 308 loads. These groups are rapid fire 10 shot strings of SMK 52 & 69gn. It also loves IMR 4895 with both bullet weights. I am shocked at how sweet the RRA two stage trigger has turned out to be. Regards

 

[jakew912]

Re: AR trouble. Equipment failure?

I know that the higher the rate of twist, the heavier ammo the barrel can handle. I have a 1 in 7 on an LMT 10" upper. I never use less than 62 gr. If yours is 1 in 8, that is a pretty aggressive rate of twist, so I would think you should be able to handle the heavier weights.
I have no experience with RRA, personally, so I can't really give you any input on their rifles.

 

[Alaskaman11]

Re: AR trouble. Equipment failure?

Have you tried to set the bullet closer to the lands? Just thinking that maybe you have a long throat and you might be giving to much jump.

 

[LoneWolfUSMC]

Re: AR trouble. Equipment failure?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AlliedArmory</div><div class="ubbcode-body">
Does anyone have any other suggestions on what it may be? </div></div>

If it doesn't shoot with a known shooter, known optic and known ammo, then it's time to call the manufacturer.

The call is cheap. Components and time are not. If you have made a good faith effort to figure out the problem, then there is no shame in calling the manufacturer for guidance or a resolution.

 

[ROCKRIVER308]

Re: AR trouble. Equipment failure?

I have the Rock River A4 Varmint 20", and it shoots 1/2-3/4 moa with my handloads. It is a 1/8 twist barrel.

69 Grain nosler, H335, CCI small rifle standard primers, win cases, 2.265 oal.

My friend has the same rifle exactly, and uses 69 noslers and Varget. Shoots just as good as mine.

 

[Scottmilk9]

Re: AR trouble. Equipment failure?

I have a couple of observations:

1st: Put that scope on another gun and shoot groups to verify its not the scope.

2nd: Are you used to shooting gas guns rather than bolt guns, follow through is of the utmost importance.

3rd: Do you have a gunsmith? AR Armorer working for you at your shop? It could be something simple like barrelnut not torqued down, bur in the barrel from gas port, etc...

Good luck and let us know what the outcome is.

 

[DamnDave]

Re: AR trouble. Equipment failure?

Well now.....

Hit the range today and shot some 60gr V-Max bullets over TAC. Here is what it did.

I did 2x 5 shot groups for each load. The measurements are the avg of the 2 groups. Rested on a bipod and rear bag. All shots were taken at 100 yrds. About 85 degrees and less than a 5mph wind. Perfect day for shooting.

24.6gr TAC .761"
24.8gr TAC .679"
25.0gr TAC .778"

I'm still looking to improve this, but am I asking too much from this rifle?

 

[ROCKRIVER308]

Re: AR trouble. Equipment failure?

Great shooting. Your groups are hovering around their accuracy guarantee. (3/4 moa). The rifle should be capable of just a bit better than that, maybe tweak your load a bit or focus on trigger squeeze more. My best group with mine is .47 moa 5 shot group at 165 yards.

My "hole in one" at the short range is 5 consecutive shots inside/cutting a 1" bull at 165 yards. I dont achieve that goal very often, but it is not the rifle's fault.

Rock River makes very accurate rifles, make sure you squeeze the most out of them.

 

[DamnDave]

Re: AR trouble. Equipment failure?

I'll work around that 24.6gr TAC load to see if I can fine tune it a bit more.

Got some 52gr SMK on the way and will try those next.

 

[sobrbiker883]

Re: AR trouble. Equipment failure?

69SMK is NOT too long for a 1:8. You should be able to run inside an inch with them around 2750fps in any quality 20" AR that has a 1:8 tube.

Look elsewhere like Scott mentioned if the shooter and optic have been taken out of the equation.

I'd get some FGMM or Hornady factory ammo to baseline, then find the problem. Load development with a bad barrel or loose barrel or other problem is a waste of time and money.

 

[USACS]

Re: AR trouble. Equipment failure?

You might also want to try using RE15 for the heavier 77gr loads. I used Varget and got about .8moa, but pulled .460moa with RE15 with the same charge and configuration.

If you can pull 3/4moa with a rifle, that's still very good. Pulling 1/2moa or better is not difficult for a .225/5.56, but certain rifles just may not be up to the task.

Also keep in mind that a rifle barrel may not be pin-point accurate right away. You may need to get some rounds down range and foul that barrel up a little to get a good wear pattern going. Many snipers I talk to only clean their barrels when the accuracy drops off, and they hate cleaning their barrels because they have to "re-season" their clean bore barrels with a couple dozen rounds downrange before the accuracy comes back.

 

[Texasshooter30]

Re: AR trouble. Equipment failure?

My two cents. One of the best reads in my opinion.

http://optimalchargeweight.embarqspace.com/

 

[DamnDave]

Re: AR trouble. Equipment failure?

Getting much better groupings now with the 52gr SMK and 60gr V-Max. Looks like it just likes the lower grain bullets better and needed some breaking in.