all good points.. glad everyone thinking a bit about this.. as of today,, 250 rnds.. no issues. first strike 100%. yes, trigger is 'slightly heavier' than when 13lbs minus spacer. but the break is the same with a CGW race hammer, crisp, no creep.
per my tool an die days... yes.. adds PRE-load tension.. and MAY shorten spring life (reasonable), but still is can be very effective in the right application.
I really feel allowing a mere .032-.035" (thousands of an inch, to those not familiar.. human hair about .003-.004" thick) is the key here. I haven't had time to check if I can go to .045" deep on backbore and then remove spacer. seems interesting doesn't it w/ a stock CGW slightly pre loaded 13lbs spring?. the transfer of energy is crucial to my mind. allowance for transfer of kept energy via a slightly longer contact period b/t hammer and firing pin seem to be the key.. I can't get away from that aspect. adding pre-load to hammer spring is a basic in tool/die performance day to day stuff... why over purchase a springs.. if a bit, small amount of pre-load works.. again.. maybe a 14lb or or a back bored retainer to .045 with a 13lb spring is the 'magic' .... don't know..
I just know what I have works.. easily and fine.. replacement on main springs is relatively cheap. for what I get. reliable fire first strike on all .22lr ammo tried thus far.. and crisp break..
and kudos to JoeL... still uncleaned. post 800rnds. and counting.
peace to all,
K in MI
please, everyone keep checking stuff out.. I think we on a reasonable break thru.