hey guys..
ive been trolling for some yrs now, from home in PA, and now in Europe.. and wanted to say a big thanks for all the info that has lead me in the right direction all these yrs...
but now i need to reach out for specific help with my setup..
ive tried several different weights and springs to accomplish a reliable SBR F/A platform using my personal NFA lower that is now using a law tactical folder and the upper off my issued S/A rifle 11.5".. i say now using cause it has proved more reliable with it then without it.. the added bolt weight must have helped..
both rifles are 100% reliable on its own upper, mine with the 14.5" and the S/A 11.5.. but when switched, the SBR on my lower is tempermental.
the upper is agency issue and swapped every few rotations, so i cant really change the gas block without raising flags why i want to change it and have a duty weapon signed out to me..
BUT... the problem ive been having are all too common, Ive searched, short stroking with occassional FTF and stove pipes, OVER stroking and the bolt slamming the receiver extension, and more so contradicting effects from each setup when using the agency issue birdcage quick mount CQB50..
but 99% my problems arise under full auto fire with an occassional on semi auto, cold or hot barrel doesnt matter, 109, 855, 193, nato issue LC, hornady hunting, 55-62-70-77 grain ammo doesnt matter, with or without suppressor doesnt matter..
ive been battling this issue for 3 yrs now and i am now looking into the captured spring systems but they arent cheap to be testing diff mfgs to no avail..
so im asking if anyone has any insight on this..
lower specs: Colt with hiperfire EDC F/A, very reliable..
upper specs: Unknown mfg, M4 extension, CHF, Nato 1/7, nitrate 11.3" bolt face to crown..
NEW gen 3 pmags
ammo as listed above..
and a box of springs, buffers, custom lead weights, 2 new BCGs with no luck thus far..