Im in process of planning out a 6.5 Grendel AR that will have a fixed stock, either the Magpul PRS or Fab RAPS. I would like to use a rifle length system as I already have the spare parts, and would like to try a low weight carrier and buffer setup. My intention is to try to make a A5 buffer system with a rifle length tube. Based on what I have found online:
Carbine extension: 7 - 7.25"
A5/SR25 extension: 7.75 - 8"
Rifle extension: 9.5 - 10"
Sources:
https://www.ar15.com/forums/ar-15/Rifle ... /4-770078/
https://www.reddit.com/r/AR10/comments/ ... ffer_tube/
So is it a fair assumption that putting a ~2" delrin spacer within a rifle tube would give it effectively the same internal depth as an A5 extension?
Brownells has some premade options that could work, however they may add an extra 1/2" or more to convert into a carbine length rather than A5.
https://www.brownells.com/gun-parts/rif ... er-spacer/
https://www.brownells.com/gun-parts/rif ... ck-spacer/
