Alternate calibers for 556 AR reciever.

[Bored1]

Not sure how exactly but I have ended up with an extra aluminum lower receiver in 223/556 and am thinking about building another "dreaded black ninjee rifle". Looking for suggestions for calibers other than 223/556 that I can use this lower for and as many 223/556 standard parts as possible to help keep costs down and spare parts consolidated.

300 blackout appears to me as two close to the ballistics of 7.62x39 (which I already have a semi auto in) for me to do that. The rifle won't get a suppressor so that doesn't fit into my needs.

Of course would like something that is cast boolit friendly.

Been looking at a few of the 45+ caliber options. What do you guys suggest?

[bruce drake]

25/223 or 6mm/223 are a couple of wildcats you might want to play with. same bolts, uppers and magazines. just need a new barrel...Welcome to the fun zone of shooting something other than a 223...

[clownbear69]

Ill suggest 6.8. While it wont use the bolt, barrel or magazine, its very accurate and an awesome hunting round.

If your considering something in the .45 cal range the only two I know is 450 bushmaster and 458 SOCOM. of the two I would go with the 458 SOCOM its more or less a 45-70 semi auto.

[Bored1]

Honestly right now I am open to pretty much anything. Just looking for some different ideas.

reading about the 458 I do like it however, appears brass and components get pretty pricey. Also been looking at the 450 bushmaster.

Just got done reading some on the 6.8, and looks like that may be an option too. Guess the thermold mags I've got a bunch of will work without any work so that would be a plus.

Really just tossing ideas around and seeing what sticks, so keep up the suggestions guys!

[crawfobj]

I have a 9mm upper that's so much fun that I built a pistol to to with it.

[Moonie]

You don't have to have a suppressor on a 300 for it to be a great rifle. We have 2 of them in the family and they are great shooters, light recoil and accurate. You can shoot them to their full capability with Lead. I also have a 6.8, haven't shot it since I built the 300.

[Combat Diver]

I've been looking at the 6x45 (6mm/.223), all is required is a new barrel. Black Hills makes factory ammo or just run your .223 brass in a 6x45 die set. There is also the 6.5 Grendel, 6.8 SPC and SPC II, decicated .22LR gun, or .30 Rem AR.

CD

[madsenshooter]

I liked the 6x45. Even with a fast twist Obermeyer barrel, I had some fun with it.

[Whiterabbit]

I made my own. like 300 whisper, but in 7mm, since im set up for 7mm. Uses 7tcu dies cut down, you just short chamber your AR barrel with the 7 tcu reamer. uses 223 everything minus the barrel. Unfortunately, that barel price might be high cause its a full custom. Noone I know makes 7mm AR barrel blanks.

[Bored1]

Looks like I am going to have to look at the 6x45 some more. Hadn't dug to much into that one.

[freebullet]

450 bushmaster is looking better and better the more I look at it. Looks like it would be cast friendly with heavy boolits.

[woodsxdragon]

i've got a 300blk pistol and i'm building a 6.8 upper for my ar15. different rounds for different distances.

[xacex]

There are so many choices without changing anything but the barrel. 300 blackout/fireball,7.62x40WT,25-223,6.5PCC,6.8 Wolverine to name a few. Then you have the others that require a bolt change, and barrel like the 6.5 Grendel, 50 Beowulf, 6.8spc, yada,yada ,yada. Too many choices. Determine what your goal and use will be, then decide on three calibers that will get you there. You will find parts for one. 50 beowulf is fun, but it eats lead and powder quick. The grendel is nice and more capable than I am at long distance. The ones that I have that get used the most are the 300 Blackouts. 223 hardly gets out that much, and if it does it is the pistol, and I bring a brick of .22lr and a m261 with blackdog mags.

[NavyVet1959]

I like straight walled cartridges since they seem to last so long when you reload them. As such, I would like to see a .223 blown out to be a straight wall. That would be around an 8mm (.3256) bullet. Not as many choices on molds though as you have with .308 caliber bullets. I've considered creating a 300 AAC with the spare lower and upper that I have. Just need to get a barrel (and quit procrastinating). I'm thinking a 300 AAC pistol might be a bit more practical than the 5.56 pistol that I had thought about building. I've already got a 230 gr mold for it.

[clownbear69]

The one thing I forgot to mention in my first post is if you go 300 BLK the nice thing is you can use your broken 223 cases. In essence extending the life of single piece of brass almost doubled before you need to throw it in scrap bin.

Also not mentioned as well is 50 Beowulf as well. Expensive like .458 SOCOM. Yet ive always considered these for a potential semi-auto elk gun

[freebullet]

The beowulf does have some impressive energy #'s behind it. Should be cast freindly with the heavies too.

[Bored1]

Gonna look more into the 450 bushmaster and 50 beowulf.

[xacex]

Gonna look more into the 450 bushmaster and 50 beowulf.

I wanted to do a 458 socom originally, but could not find a barrel. Same with 450 bushmaster after a year of looking. I jumped on a midway 50 beowulf barrel made by Saturn when it came available, and I am glad I did. Very fun gun, and accurate in the right hands. I can't shoot it as good as some friends I have handed it too, but it is capable of MOA with cast. You have to jump on the brass, and barrels when they come up because they go fast. The brass lasts a long time as long as you keep the chamber free of oil, and load at max. If not the brass will telescope,collapse and be to short to use. It has to grip the walls of the chamber because of the rebated rim.
I took that upper, and the 6.5 Grendel elk hunting this year.

[xacex]

I like straight walled cartridges since they seem to last so long when you reload them. As such, I would like to see a .223 blown out to be a straight wall. That would be around an 8mm (.3256) bullet. Not as many choices on molds though as you have with .308 caliber bullets. I've considered creating a 300 AAC with the spare lower and upper that I have. Just need to get a barrel (and quit procrastinating). I'm thinking a 300 AAC pistol might be a bit more practical than the 5.56 pistol that I had thought about building. I've already got a 230 gr mold for it.

Its been done! Look up the 338-223 straight, 338 thumper/whisper. Impressive numbers with that one as well. I would not mind doing one myself.

[DCM]

Too many choices!
http://www.calguns.net/calgunforum/showthread.php?t=337969

[xacex]

Too many choices!
http://www.calguns.net/calgunforum/showthread.php?t=337969

Oh man, that list is WAY behind now. So many new ones need to be added.

[Bored1]

Oh man, that list is WAY behind now. So many new ones need to be added.


Which is exactly why I asked those that know more than me!!! LOL. Barely treading through the information by myself, helpful to hear from others what works, doesn't work, or is just plain a waste. Not trying to reinvent the hammer, others that know WAY more than me are doing that, just trying to find a hammer that fits my needs the best!

[dk17hmr]

I have had a couple 6x45's in ARs they are probably the best for standard 223 parts. The 25-223 I have in a bolt action is a great round and I wouldn't turn down a barrel for one at a good price. 300 Blackout/whisper is fun, I had a carbine and now have a pistol in that round. 6.8spc is probably my favorite general use cartridge p-dogs to elk.

I have a handful of AR's an no 223.....probably should get one.

[gustusj]

Check out the 6.5 PCC (Patriot Combat Cartridge. ) Similar to the 6x45. I've got one and really like it. I've taken a couple of deer with the 100gr. Hornady and the 85 (?)gr. Is a quick and accurate little bullet. Some are pushing it near Grendel speeds. I've not ventured that fast, but have had good results. There's a long thread on AR15.COM about it and they have a website up about it too. DR69R is one of the folks behind it. I've had great luck and it's been a pleasure working with them. Check it out.

[Blammer]

I would suggest a 25/223, only think you'll need is a barrel and some dies.

http://i54.photobucket.com/albums/g81/blammer8mm/Targets/001-1.jpg (http://s54.photobucket.com/user/blammer8mm/media/Targets/001-1.jpg.html)

[Blammer]

now if I could only learn to shoot that 5th shot better.

[Whiterabbit]

for cast, don't forget 358 gremlin. The Grendel necked up to 358 cal. Should go well if you already cast for 357 mag.

Also consider the 338 if you already cast for 338 federal.

Not sure if cast in the bushmaster or he Beowulf is worth it due to case length issues. but maybe. The case lengthmeans you wont be able to push bullets hard, but maybe that's a good thing in an aluminum gun.