300 BLK has no cycling issues if you for example buy an AAC brand upper or rifle, or one that works as well.
All 300 BLK uppers use a normal Colt M4 spring.
The buffer needed depends on what the barrel was designed to use. I read and re-read your post. I could not find what brand rifle you...
I would't describe it that way. It is all about gas port size. The correct gas port size for a pistol length gas system does not allow H110 or Lil'Gun to cycle with subsonic.
The correct subsonic powders, with any length gas system, remain the same - A1680 (not called AA1680), A5744, RE-7...
No - 300 BLK is much closer to 308 than you think. Let me give you three examples:
110 grain TAP 308 is 2800 fps from a 16 inch barrel. It drops to the muzzle velocity of 300 BLK at 130 yards. So 308 only has a 130 yard advantage for this bullet. If we consider 400 fpe to be the max range, then...
308 is much more effective, but it is a lot more recoil and the guns are much heavier. I have struggled with the 308 vs 5.56mm debate in the past for my own home defense, and I really wanted to make 308 work. I bought SR25s, FALs, and M1As. In the end, they are just too big and heavy for me...
Actually in every case I have seen, if a gun won't run subsonic, it is simply because the manufacturer made the gas port too small or speced too heavy a buffer.
300 Whisper is a proprietary version of the 300-221 Wildcat. 300-221 came before 300 Whisper(R), not after. Also, cartridge names (at least in SAAMI) never begin with a . So it is 300 BLK, not .300 BLK.
I wanted to see what it could do at long range, so I went to a 600 yard range and was able to hit the 3 inch X-ring (1/2 MOA). No, not every time - just a few times out of 20 shots, but I was around the 10 ring a lot. You could definitely scare a bad guy at that range if you had to. It is going...
Sierra 240 bullet is 1.590 long.
Temp = 0F
Velocity = 850 fps
Stability 0.976 - not enough.
The 220 gets 1.292 - indicates enough but not by much.
But the reality is, the bullets have some dynamic instability which is not known to these twist formulas and so the normal guidelines of...
No, it is not a 0.5 MOA system, but it was used to shoot a 2.75 inch group at 500 yards.
When you shoot a good group, it does not make your rifle that all the time.
0.85 MOA is the best we have averaged in 300 BLK test barrels over 50 rounds (10 groups of 5 rounds each).
Remington ammo has crimped and water proof primers. That costs more. They use the Sierra bullet. That costs more. They double-strike the brass to make it like NATO hardness. That costs way more, and NO ONE else does this. No corners were cut - the opposite in fact, unless you mean not...
While subsonic ammo is hard to make varmint-rifle accurate, I did not expect the Savage to be as accurate as possible because they went with a 1:10 twist and a 20 inch barrel.
1:10 twist will not stabilize 220 subsonic ammo.
A 20 inch barrel will sometimes make the subsonic ammo transonic...