75 grain 223 ammo. What of that?

[ali]

I'm picking up some 75 grain 223 ammo. My concern is the barrel rifling appropriate (or at least usable for plinking) for this heavy a 223.

Please advise.

 

[rasputin8]

I would go 1:8 or 1:7. It may stabilize in a 1:9 but don't be surprised if it doesn't.

 

[FredAlert]

+1 I've seen it work fine at distance with some 1:9 barrels so don't just take people's word that it won't work but you're better off with faster barrels.

I would go 1:8 or 1:7. It may stabilize in a 1:9 but don't be surprised if it doesn't.

 

[ali]

I am liking what I'm hearing as it will be shot out of a 1/8 and a 1/9. Hurra!

 

[83rdrecon]

It loves 1 in 8

 

[georgeib]

1 in 8 is probably the perfect barrel twist in an AR, it'll stabilize 85 grains. Don't know why they even make 1 in 7.

 

[jwhited]

1:7 fo' sho'.

 

[Chuckdog]

It's the length, not the weight that dictates the required rate of twist. Most figure longer and heavier as the same, but they aren't.

Any Barnes bullets will be very long for it's lightweight. Some very lightweight Barnes may not stabilize in a 1/12 barrel, maybe not even a 1/9? But I know of a 70 grain Speer round nose .224 that will stabilize in most 1/12 barrels.

Many 75 grain bullets are just too long to fit in a magazine and still manage to have any room left in the case for powder. The 70 grain Speer is a very good deer bullet, and will leave enough room for a sufficient dose of powder to push it.

The 68 grain Hornady is about as long and heavy as I shoot. All of my 1/9's have stabilized the 75 gr Hornady, but I wouldn't count on any Barnes or other mono-metal near that weight stabilizing due to their excessive length.

 

[Smiley]

The heaviest round I have seen that will fit in AR mags is 77gr. The MK262 is really accurate out of a 16" 1/7" barrel in my experience...