08-02-2014, 04:30 AM
(This post was last modified: 08-02-2014, 06:47 AM by gastonglock21s.)
Smokepole50 Wrote:I measured the two carrier key opening/bore with my calipers. The new R-Guns F/A carreir key measures .178 and the carrier key that came with my AA upper measures .179 soooo....
I guess I must have just seen an optical illusion caused by the difference in the new carrier key having a clean sharp bevel at its mouth and the older AA carrier key having the bevel some what rounded/smoothed off by the gas tube and dirty from firing the rifle. Looking closely I can actually see the bevel at the mouth of the AA provided carrier key which I did not see before. I guess I should use my eye glasses a bit more often or perhaps clean my bolt carrier more often.
Thanks for the measurement data. It makes me feel good to know the opening is the same.
Variable.......You might be remembering correctly depending on when you bought your uppers from AA. I have had this upper for quite awhile and it is possible that Bill was not building uppers at that time with F/A carreirs because the ATF had not ruled them OK to use back then.
Glad to help.
I bet if you were to measure the bores on the keys with a bore gage or verify with pin gages they would likely be within the .1805-.1813 dimension. Accurately measuring a small id bore like that is not ideal with a caliper but you got to use what you got.