Every barrel will be different even from the same manufacturer . I have 2, 16" carbine barrels from the same manufacturer , same twist , same FSB, same everything
One rocks a 4.2oz buffer and cycles even the cheapest low powered ammo , the other chokes all over its self with anything over a 3.8 oz buffer shooting the same cheap ammo . So for a person to just throw stuff together without tuning small steps at a time is looking for problems , Really there is no need for a heavier / stiffer spring unless your so over gassed that you truly need it with a heavier buffer . There are many ways to tune and buffer weight is #1 , it will make or break a rifle on reliability . I pour my own weights for my buffers so its easy for me to throw one together to try out , Most any setup I know I can start around 3.4 oz and still be reliable as the factory carbine buffers are 3.0 oz . I always tell the new guys I shoot with , if it runs on the factory carbine buffer and isnt getting excessive impulse and or recoil leave it alone . Your just messing with disaster for a failure , especially cycling issues .
Who wants a weapon that wont run 100% ? especially when you may need it most
I wont keep a gun that wont run every ammo reliably , alot of friends are against steel cased ammo , you know they know everything and it wears out the $12 parts faster . Lemme tell ya for just going out and practicing drills and going thru 300-500 rds and I spend $219 per 1000 compared to their $370 @ 1000 rds of brass , I can buy a hell of alot of ejectors , extractors and springs with that $150 so dont let that take away from your fun . I will not keep a upper that steel cases hang up in ,and will not run everything reliably , Why ? because it better be able to run everything reliably that may be all thats available is what it may or may not run on