New rainier arms upper causing major accuracy loss

[ziconceo]

I just got my Rainier arms upper in the mail today, installed it on my 300 blk ar and took it to the range.

Oh, and the barrel was torqued to 45ftlbs

Before I put the upper on, I got 1moa groups with my reloads. After I put it on They went to 3 moa. bleh

Both groups were from a sandbagged bench at 100 yards.

What gives? any advice?

here is the upper I got:

https://www.rainierarms.com/rainier-arms-forged-mil-spec-upper-minus-fa-w-logo

[scotty99]

What upper was giving you 1" groups? Same optic on both uppers?


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[ziconceo]

What upper was giving you 1" groups? Same optic on both uppers?


Sent from my iPad using Tapatalk HD

Good question, my standard spikes upper

[xOperator]

how does an upper effect accuracy?

[ziconceo]

how does an upper effect accuracy?

Well, for one it holds the barrel in place, I imagine that's got to do something with it

[shafferds]

How tight is the extension pin in the slot on the new upper? If you have any play your alignment maybe off a hair.

[ziconceo]

How tight is the extension pin in the slot on the new upper? If you have any play your alignment maybe off a hair.

Tighter than the old upper, but still went right in

[steelheadmike]

Maybe try lapping the upper. The face may be less than square.

[ziconceo]

Maybe try lapping the upper. The face may be less than square.

What part of the upper? By face do you mean the front of the barrel thread area?