CMMG Sierra accuracy issue

G

Gflysum

Inactive
I just bought a CMMG Sierra A3 upper (.22lr) for my AR-15 after reading reviews claiming the accuracy was better with a dedicated 1 in 16 barrel than the conversion kit with my standard 1 in 9 twist barrel.

I took it to the range yesterday and was very disappointed. At 30 yards, I was getting 6-inch groups (if you can even call that a group). It was all over the road shooting off a bench with sandbags (multiple shooters - so it's not me)

The equipment is as follows:
Upper - CMMG A3 Sierra .22lr
Lower - Bushmaster (standard trigger)
Magazines - CMMG BHOA 26 rd
Optics - EOTech 552 (works like a champ on my .223 upper)
Ammo used: Remington Golden Bullets, Remington Thunderbolt, Federal Champion, CCI mini-mag

I'd take 3 shots at a time -- typical way it went was one would hit 1.5" low and 1.5" right - next shot would be 3" high and 1" left, next shot would be right on (elevation) and 2" right -- several groups were way worse.

a buddy called the armorer at his police department who said the barrel might be loose -- I took it to a gun shop to get it tightened today (they said it was already tight) same result

moved and retorqed the EOTech - same result

any ideas?
 
Just got off the phone with CMMG tech support - sounds like they're going to take good care of me - the upper is going back for a look to see what's wrong.
 
Sorry you are having bad luck on that upper. I bought one a couple years ago and love it. Accuracy is good using a cheap 22LR 4X scope. I killed a raccoon with it about 4 months ago. I use the cheap stuff. CCI Blazer 40grain Lead and Federal 32 grain bulk. No misfires or jams. A good trigger may help with the group sizes.

Lemmon
 
I don't think its the trigger or the shooter - the CMMG rep and I (and a gunsmith in town) think the barrel has a burr in it, causing the poor groups.
 
The Bushmaster trigger is actually very smooth and has very minor creep as compared to other factory triggers I've used - I was pleasantly surprised when I got it. I've got another with a model1sales trigger that was like dragging a cinder block across railroad ties (I quickly replaced it with a 3lb timney that's like butta)
 
I can get 1.5-2" groups at 200yds with the timney - at 100 yards, it'll put 25 shots in a 1" circle all day long - I love it
 
Called CMMG - they wanted me to send it back with a target showing the issues it had. I got the upper back within a week - it had been re-crowned and they put a new .22 chamber adapter in - hope its fixed - going to the range tomorrow to ding out
 
BTW... Remington 22LR currently ( as of the last few years ) has a horrible reputation on various 22LR websites, bad accuracy, bad QC . Stick with Mini Mags, CCI, Fed. 510s.

Just my 2 cents.
 
Took it to the range yesterday - got 2" groups at 50 yards with an EOTech 552 (1 MOA dot) and 1" at 25 yds -- much better - with a scope it would've been tighter - it's not the upper at this point - thanks CMMG!
 
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