.223 or 40 S&W

[connecticut-yankee]

I have 3 9mm semi-autos, a S&W Model 28, and a Marlin .357 magnum lever action rifle.

I'm looking for one more caliber to use the would be accurate out to 200 yds. I've been looking at AR-15 in .223 and have also been looking at 40 S&W beacause I can get pistol and rifle.

I'm interested in what your opinion is. I've been told that the AR-15 in .223 doesn't particuarly like cast boolits.

Or is their a better caliber than the ones I'm looking at??

Thanks for the read.

[paul h]

If you want to extend your range, then definately get an AR-15. I haven't shot cast out of a 223, so can't comment on it being cast friendly. But in terms of shooting small groups, very mild recoil and inexpensive handloads, it's tough to beat an AR chambered in .223/5.56. In practiced hands the AR is capable out to 600 yds.

[OuchHot!]

I haven't tried cast in .223 but there are a few posts here abouts by those who do and shoot them from an AR15. If I were to try cast in one of my AR's I would like to build an upper for the 6.5 Grendel...that looks to me to be a good cast caliber. It has a very good reputation on deer.

[paul h]

One thing to note on how friendly (or not) the AR-15 is to cast is what the barrel twist is. If you get an AR with a 1-7 twist, odds are it'll be more challenging to get it to be cast friendly than with a slower twist. The fastest twist I'd want in an AR for cast is 1-9, and slower still would be better for cast.

[Oreo]

What about bullet stabilization? You aren't getting nearly the RPMs with boolits for any given barrel twist rate because you can't drive a boolit as fast as a bullet. Both bullets and boolits of the same weight will require the same RPM for stabilization.

[MasS&W]

Wait, you want the .40 for shooting out to 200 yards?

[paul h]

What about bullet stabilization? You aren't getting nearly the RPMs with boolits for any given barrel twist rate because you can't drive a boolit as fast as a bullet. Both bullets and boolits of the same weight will require the same RPM for stabilization.

The issue isn't just a bullets weight, but it's length. A shorter bullet needs less spin to stabalize than a longer bullet, and due to both the density and shape of cast bullets, they are generally shorter than jacketed bullets.

A 1-9 twist will stabalize most 22 jacketed bullets, it's the super long ones such as hornadys 75 gr a-max that really needs a 1-8 twist to stabalize, or even the 1-7 twist for the shorter barrels. But then the 75 a-max is really too long to seat in a 223 case and fit in an AR-15 magazine. My SWAG is that a 1-9 will both stabalize a 70 gr cast bullet, and allow higher velocities as they twist rate isn't trying to tear the bullet apart the same way a 1-7 would.

I've stabalized 55gr jacketed bullets in a 1-14 twist 218 mashburn bee, and given it was a 10" handgun barrel, velocities off the top of my head were in the 2400 fps range. If I were to build an AR-15 for shooting cast I'd honestly choose a 1-12 twist if possible. It will be much more friendly to cast, and I find 50-55gr jacketed bullets more often than not do everything I want in a 223. But most AR's built these days are 1-9, 1-8 and 1-7 twist. I think 1-9 is the best compromise though it's a compromise towards jacketed bullet performance, not cast performance.