Initial chrony testing done . Filled to 230 bar , shot two mags over the chrony , start at 790fps and ending at 845 FPS on the twelfth shot with 190 bar left . Looks like my porting is spot on and I just need to add some spring to get it where I want . This was done with the factory spring and adjuster flush with the receiver . I have a good assortment of springs and I think I found a combo for a short twin set up with no preload . I did however forget to order some 30mm rings . Sure wish they had cut the picatinny slots in the receiver . Amazon should have some medium / high rings that will have to be rushed in .
I guess I forgot to add the bullet weight, 70 grain from a 257420 arsenal mould. The stock spring is pretty weak , if the new spring doesn’t work I’ll be making a peek valve and open up the valve inlet. I haven’t touched the porting at all yet . This is as it comes from factory , all straight cut .
I found a heavier spring ,cut it so that when the adjuster was flush it had 1/8 of gap . Ran another two mags over the chrony . Starting at 230 bar again with the same 70 grain bullets . First shot at 890 FPS so I knew it helped . The following 11 shots had an ES of less than 20 FPS and ended at the same 190 bar .it was almost like shooting a regulated gun only at 125 FPE . Im sure I could get another mag as the peak was on my last shot at 910 FPS . Ill do some accuracy testing and that should tell me if I should increase the hammer tension or leave it as is . So far color me impressed , this was one of the easiest conversions Ive done to date . Putting the numbers in Lloyds efficiency calculator the rifle is at 1.87 FPE/ci, those are the best numbers Ive ever done even with my low powered .22 disco build . That 31 barrel must be the reason .
Wait a minute.... You went from a 1/8" spring gap and 890 fps to full coil bind at 895 fps at 230 bar.... and yet the gun shoots 910 fps at 190 bar?....Does not compute.... Bob