Caliber for a CB on AR-15

[wv109323]

I have a stripped lower for the AR-15. If you were going to build a rifle on the AR-15 platform and use cast boolits only: What Caliber and why?
Also what rate of twist for your caliber choice? and barrel length?
Due to my eyesight it would be a flat top upper with a scope. Rifle would need to function in semi-auto mode.
I look forward to your comments

[odfairfaxsub]

alot of people choose reduced h-4895 and they use gas checked 225 style molds from rcbs alot.

[Hamish]

You could make the argument for *any* of the cartridges made on the platform. Wha'choo wanna do wid it be de question.

It has been stated quite eloquently elsewhere on this forum that the .223 is just about THE most versatile cartridge on the planet. I would agree. Load it down to 22 rimfire to essentionally 22-250, and anything in between.
That said, working with those teeny little pills is kind of a pita.

(I'm saving up for a 7x45 upper myself, cause I like the 7TCU, nice size to work with, it kills deer quite well, standard bolt face, and it was my first t/c barrel shooting ihmsa.)

[wellfedirishman]

WV,

I'd recommend a 300 whisper aka 300 AAC Blackout. It will shoot any standard 30 caliber bullet, so there is a huge variety of molds available.

Model1Sales sells a 16" 300 Whisper flat top upper for about $365 shipped (without bolt). I bought one a while back and have been very happy with it. It is a 1/8 twist so will shoot big heavy subsonic bullets.

With a 180 gr Lee mold lead boolit with gas check and 12.5gr w296 I was getting 2-3 inch groups at 100 yards. With some experimentation I am sure that would improve. It functioned fine in semi-auto mode.

You can make 300 Whisper brass from 223 casings, and a set of Lee dies is $33. It is a fun caliber to shoot.

[garym1a2]

9mm if you want effective short range and cheap reloads
7.62x40WT is easy to find 1:12barrel from Wilson, I am thinking of this on.

[Calamity Jake]

What ever caliber you choose, us a 1:12 twist

[BD]

.450 Bushmaster uppers come stock in .451 with a 24" twist, shallow rifling just like the .45 acp. Think 45/70 in the AR 15 platform.
BD

[madsenshooter]

I like the 6x45, but if I had to do it again, it wouldn't be a Obermeyer 5R 1/8 twist barrel. Though it can be made to work. http://castboolits.gunloads.com/showthread.php?t=121224

[johnly]

Just bought a Remington R-15 in 30AR. Hopefully it shoots cast as well as my 7.62x39mm upper.

I'd really like to have a 458 SOCOM for shooting cast in an AR-15. Big, heavy, and lead, who could ask for more?

John

[castblaster]

I sure like my 300 blackout with lead.







Matt Hooper