Down tuning AR6 pistol

[rkr]

I decided to down tune my AR6 pistol for more shots so a short compilation of what I did.

Installed 10" barrel in place of a 14" I had on the gun, 3.2mm TP, 2.5 mm feed to the pot before firing valve and short 11mm diameter 1.5mm wire hammer spring with little to no preload. Faced the poppet face flat for the part that actually seals and polished the seat flat. Filled to 185 bar, took 12 shots (2 drum magazines) starting from 195 m/s going up to 226 m/s and down to 187 m/s. With JSB Exacts that's 14.5 to 19.5 fpe which means I could actually tune down a bit more and should get another drum's worth of shots from that tune.

Next I decided to cut the hammer spring, tested - gun shoots about 10 m/s lower and I cut some more and then found out it was too short shooting at 85 m/s. Made a new spring, 10mm diameter from 1.5mm wire with fraction of a millimeter preload and with regular JSB Jumbos  I got18 shots from 180 m/s to 212 m/s and the peak is almost at the middle of the string. I think I'll leave it at that, it's good enough for 25M pistol practice.