Are these results standard for the BCM SS410 barrels?

[sidewaysil80]

I posted this on Snipers Hide to get a little more insight, but I figured I'd get more useful experience from the AR crowd over here.

I recently picked up a 18" BCM SS410 complete upper to compete in the DMR matches held within my region. I had VERY good luck with the Rainier Arms 18" Match Barrel in the past, so I figured the BCM SS410 Match Barrels would yield similar results. I tested the following types of ammo:

Freedom Munitions .223 69gr HPBT
Freedom Munitions 5.56 77gr HPBT
Federal Gold Medal Match .223 69gr (Sierra Match King bullets)
Fiocchi .223 69gr (Sierra Match King bullets)
Fiocchi .223 77gr (Sierra Match King bullets)
IMI 5.56 69gr (Sierra Match King bullets)
IMI 5.56 77gr (Sierra Match King bullets)

I shot two 5 round groups back to back (minus time to prep/reload magazine) on the Larue .5" Grid Targets you see below @ 100yds. The one with three different variants was shot back to back but with the different types of ammo. It was an indoor range, well lit, and using a Vortex Viper PST 2.5-10x32.















I guess I expected more out of this setup and am curious if this is normal? If it is, then so be it. However I was wondering if these groups look sporadic or perhaps indicative of an underlying issue? If so I'll reach out to BCM to take a look at it and give me their verdict.

Below is what I was able to get out of the Rainier Arms Match Barrel with 69gr and 77gr Federal Gold Medal Match as well as PPU 75gr and what my expectations were based on.

[sidewaysil80]

I forgot to mention that the barrel was broken in following the Krieger recommended break in procedures per BCM instructions. Everytime it has been cleaned a Dewey coated rod and JP bore guide have been used.

[Endur]

Not encouraging considering I have recently purchased a BCM SS410 for an SPR build.

[Ryno12]

I would say no, it's not normal. I've shot 10 round groups under an inch with my 20" SS BCM and I'm by no means a precision shooter.

[Eurodriver]

Was it just the barrel you bought? What kind of muzzle device is on it, who installed it?

[sidewaysil80]

Was it just the barrel you bought? What kind of muzzle device is on it, who installed it?

Sorry, should have posted that earlier.



Upper is a complete factory BCM upper receiver group. It features their 18" SS410 barrel, Bootleg Inc. pic-mod handguard, BCM Gunfighter Comp, BCM gunfighter charging handle, BCM complete bolt carrier group.

Lower receiver is a complete factory BCM lower receiver group with intermediate (a5) buffer system. Scope is mounted via American Defense Manufacturing recon scout mount.

[Eurodriver]

Sorry, should have posted that earlier.



Upper is a complete factory BCM upper receiver group. It features their 18" SS410 barrel, Bootleg Inc. pic-mod handguard, BCM Gunfighter Comp, BCM gunfighter charging handle, BCM complete bolt carrier group.

Lower receiver is a complete factory BCM lower receiver group with intermediate (a5) buffer system. Scope is mounted via American Defense Manufacturing recon scout mount.

Is the scope the same one you used on your RA match?

There's definitely an issue.

[HKGuns]

Are you sure the scope is mounted securely?

[sidewaysil80]

Is the scope the same one you used on your RA match?

No, I had the same make and model on the Rainier rifle but I sold the entire rifle and setup. I wanted to get back into DM Matches so I bought the BCM rifle and scope. This particular scope was purchased used but it appeared to be in virtually brand new condition. The gentleman who I purchased it from claimed it was never mounted.
The only other difference is the Rainier had Seekins Precision rings as opposed to the one piece ADM Mount on the BCM.

Are you thinking the opening up from tight group to large group you see in some of the pictures could potentially be due to the optic? I was thinking that but figured it wouldn't group at all if the scope was bad.

Are you sure the scope is mounted securely?

After setting it to optimum eye relief I used a small level on the receiver and small level on the top of elevation cap. After ensuring they were even I tightened the mount gradually at the bottom rings, then top rings, torqued the bottom rings to 25-30 in/lbs, then torqued the top rings to 25-30 in/lbs using a wheeler fat wrench. I followed the instructions supplied with the ADM mount.

(I genuinely appreciate everyone's input by the way)

[Vegas]

I have the 16" version on a factory upper. It took a good few hundred rounds for the accuracy to improve for me. I am by no means a sharpshooter and probably average about .85 MOA with my handloads using Hornady 75gr and a little less with Nosler 55gr Varmint projectiles. I posted a thread when I first got my upper asking about accuracy expectations. I recall someone with the 18" upper posting about some impressive results.