"Do all" 10.5" barrel?

[AlcoholicusMaximus]

Yes..... the holy grail of .300 whisper barrels... I want to have a 10.5" .300/221 barrel that will cycle 220gr. subsonic smk's and 180 gr. supersonic game kings in an AR15, without an adjustable gas block.
I am willing to do load development until California falls into the Ocean. Is this even feasible, Or should I wait until John perfects his Switchblock? As of right now, I am going to put a .080 gas port at the pistol position after the barrel comes back , chopped to 10.5". Just need to know If anyone is cycling the action with both sub & supersonic ammo and this barrel config. .......

[Ron458]

LMK what you find out. I just finished an 11" from a PacNor poly & figured I would need to make an adjustable gas block. It would be nice to have a DO ALL brl. Ron

[TheAlmightyBob]

I've got a 10.5" noveske that has cycles everything from 130 soft points, to 220gr mk. One good thing I think about this lenth I have found is that the 220gr pills only dropped an inch under the 130gr pills at 100 yards. I think that maybe because the barrel is so short, that its not burning all the powder in supersonic loads with while is enough to get them going supersonic, its just barely enough burn time to get them there.

[pug]

For your stated weights it will certainly cycle with a fixed gas block. In fact for 220 grain subs and 180gr supers I might would put a .070" pistol port first and see what happens. You can always go larger if needed but not vice versa.

[Ron458]

TheAlmightyBob, what gas port do you have? Inquireing minds want to know. Thanks, Ron

[TheAlmightyBob]

well, I'm not sure if this is going to help at all. I don't have any precision measuring equipment for such a small hole. The best I could think to do is use drill bits and see what would fit in the hole. Here is my findings.

3/32 bit wouldn't fit, but it was damn close. (3/32 = .09375)
5/64 would fit with room to spare. (5/64 = .07812)

So I tried to do some math to see what the middle point is and I came up with .08593. So I guess the best guess I could make is that its near .086" but seems closer to .090"

[Ron458]

Thanks I owe you one. Compiling gas port sizes for difernt brl lengths/manufacturers. Sounds like.090 I will start smaller to be sure but this realy helps. Ron