It will make a difference on follow up shots you are mounted to barrel nut which is a transition piece, chamber is in the barrel not the receiver so heat, and extraction can cause a shift. . Also check barrel nut after 100 rounds this is not a 223 have had correctly torqued nuts loosen on an Alexander Arms upper ,what made me check point of impact was changing with each shot
Building 12.5 Pistol!
Hi,
Decided to build a 12.5 Pistol as something a little easier to carry in a truck or an around the house defense weapon.
Most that I saw at my LGS were expensive and did not have what I really wanted in the build.
I had a Tactical Machine Lower left from 3 I purchased at one time.
Faced the upper EXPO receiver, to get everything as straight as possible, removed about .005 to get square and flat face.
I show a pic of the upper on a flat mill vise with a square, this proves nothing for accuracy of course, but was just curious and in for the education.
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Decided to build a 12.5 Pistol as something a little easier to carry in a truck or an around the house defense weapon.
Most that I saw at my LGS were expensive and did not have what I really wanted in the build.
I had a Tactical Machine Lower left from 3 I purchased at one time.
Faced the upper EXPO receiver, to get everything as straight as possible, removed about .005 to get square and flat face.
I show a pic of the upper on a flat mill vise with a square, this proves nothing for accuracy of course, but was just curious and in for the education.
