1389 backpacker chrony results - how do they sound?September 7 2010 at 4:22 PM
|Danny (Login danco1987)|
Crosman Forum Member
from IP address 220.127.116.11
I must admit I would have liked a little more power but maybe you guys have got some suggestions.
Right, first of the mods I've done:
18" .177 recrowned barrel
Flat top adjustable brass piston from airgunsmith
Flat top aluminium valve - 0.15 inch added to check valve & a lighter valve
CB breech and extended bolt
Brass Hammer spring adjuster
Trigger sear and spring mods
Silencer and barrel adaptor so total length incl barrel is 24.5" (I'm in UK so its ok)
Brass barrel band and harden steel pin with clips
Vinyl tube transfer port
Crosman Premier heavys 10.5gr
15pumps - Getting average of 661fps = 10.2fpe
Funny thing is, I have been getting 10.8-11fpe before with 13pumps but since I have messed around with the hammer and valve spring, I cant seem to get that sort of power again. Now the best I have managed is 10.2fpe at 15pumps and I don't want to pump anymore than that.
Do you guys know of anymore mods I can do to increase power at 15 pumps or less or what I might have done to decrease the power?
Custom 1389 Backpacker .177
|This message has been edited by danco1987 from IP address 18.104.22.168 on Sep 7, 2010 5:19 PM|