Alternative calibers for the AR platform

BillBro68

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What are the calibers you have other than 5.56 and why did you choose it? Being the most sold rifle in the US for a while now there are numerous calibers available, some great, some good and some absolutely useless.
The only one I chose is the 6.8SPC and chose it because of its pedigree, its parts commonality, its ability to use the standard size frame, the lethality of the cartridge inside 400yards ( though I'll go to 500 occasionally) and its usefulness as a hunting cartridge and available hunting bullets. For me it just made the most sense for an all-round, useful caliber. It offers performance far in excess of the 5.56 but it's not a 7.62, it's right in the middle. Developed by mil folks who know guns and ammunition, the AMU and a SF legend who's seen combat and then some and they should know what compromises will work. No, the 6.8 is not the latest and greatest. No it's not a long range precision round either but it's very fun to shoot, has great capacity, it hits steel plates hard but the recoil is barely more than a 5.56. I've developed several very accurate rounds for mine too. I just really enjoy shooting it.
What other calibers do other members have? What do you like/dislike? Thinking about another caliber? What is it?
 

PanHandlerFL

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5.56s and 9mm ARs, 9mm pistol build was just to see what all the fuss was about. It was a ball and plenty fun until the ammo ran out for just "fun" times. I was chewing up 9mm like it was .22lr. and liking the expansion I was getting with SD rounds within 7 yards (home-clearing distance). I'm an AK fan and like Babbonbobo am going to dip my toe into 7.62..AR47?!
 

Babboonbobo

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5.56s and 9mm ARs, 9mm pistol build was just to see what all the fuss was about. It was a ball and plenty fun until the ammo ran out for just "fun" times. I was chewing up 9mm like it was .22lr. and liking the expansion I was getting with SD rounds within 7 yards (home-clearing distance). I'm an AK fan and like Babbonbobo am going to dip my toe into 7.62..AR47?!
Gots me one of those AK thingys in that 7.62 caliber, it has a heavy milled receiver and all Magpul furniture, it's quite fun.

For 9mm fun I have the MP5
 

Mike A1

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I have shot AR pistol chambered in 5.56x45mm yet I feel a 45 acp in an AR pistol with brace would
be just fine for fast close up work. 9mm would work also, however with all the stability of that Braced pistol.
Why not use the 45acp instead? It's light & fast, should be a fine performer.
 

Dub

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I have shot AR pistol chambered in 5.56x45mm yet I feel a 45 acp in an AR pistol with brace would
be just fine for fast close up work. 9mm would work also, however with all the stability of that Braced pistol.
Why not use the 45acp instead? It's light & fast, should be a fine performer.


I like your thinking.


A .45 is always a great solution to any weapon in my amateur opinion.

I'm a biased fan, though. .45's just work.
 

mm1911

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Have thought about 300 blackout but I would probably wind up sticking a mag with 556 in it, buddy of mine has one and absolutely loves it, a pcc in 45acp sounds like fun, those fat little boolets make me smile
 

BobT

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I'm something of an oddity in the AR15 community in that I don't own one in 5.56/.223. I have 2 in the .277 Wolverine caliber and a third barrel waiting to be made into another one. I have a 6mm Mongoose, sort of a maximized 6x45. I also have a couple of .300 Blackout pistols that I enjoy shooting with my Banish30 suppressor. I think my next one will be a .450 Bushmaster. A PCC in .45ACP sounds like fun too!

Wow, just realized this is my first post, I've been a member for a while, thanks for having me!
 

CECannonJr

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I'm something of an oddity in the AR15 community in that I don't own one in 5.56/.223. I have 2 in the .277 Wolverine caliber and a third barrel waiting to be made into another one. I have a 6mm Mongoose, sort of a maximized 6x45. I also have a couple of .300 Blackout pistols that I enjoy shooting with my Banish30 suppressor. I think my next one will be a .450 Bushmaster. A PCC in .45ACP sounds like fun too!

Wow, just realized this is my first post, I've been a member for a while, thanks for having me!
Welcome from eastern NC. Glad to have you!
 

BillBro68

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It seems that I'm somewhat of an oddity too, just in the other direction, being that I only owned ARs in 5.56 until very recently.

First off welcome!! The more the better. I'm behind the lines in mary- land. Of course we all seem to be behind the lines these days.

Second, what's up with the 277 Wolverine? Is it an ARP tube? Like it?

Serious question to all who have an AR in an PC, were they hard tuning and getting all the components to play nice? What is your confidence level in them? Would you feel 100% grabbing it in the middle of the night if it was all you could get your hands on? Wait, if it was all you could get your hands on I guess you would have to use it. Ah crap, you know what I'm asking, how do they run?? I'm sure alot of companies out there have come up with some fine parts for an AR in say, 45acp, 9mm, etc and theyve been around for a while now so I HOPE folks have got the bugs out by now but last I looked into them ( and that was a long time ago, and probably out of sheer boredom) it just seemed to me that they weren't worth a darned. I've seen them on the line before and all they seemed to generate was alot of pulling of the charging handles, cursing, weird looks and blaming of ammo.

I've got the 6.8 figured out and even that took some tuning finesse and patience. Mind you all, I have no serious interest in owning an AR in a pistol caliber or really any non typical rifle rounds but I do enjoy learning and hearing what other shooters have, like, enjoy and use and why.
 

Justirv

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First off, I'm behind enemy lines in CA, that is the basis (driving froce) for much of my activity and choices. For me it all started with a .223 as only available pre-ban a long time ago. Then 5.56. When standard capacity mags, which had been grandfathered up to that point, became an issue, i discovered I could build a .458 SOCOM Upper, and converted existing mags with a simple mag follower (I love that thumper BTW!). From there the affliction continued, as CA continued to restrict ARs. So it meant I needed to build more, before the opportunity to own became non-existent. Next was 300BLK, which I also love, but great precautions must be taken, that rifle has distinctive markings along with gray ceracote. All 300BLK mags have bright orange tape, following Ghost Buster protocol, "Don't Cross the Streams" (or 223/5.56/300BLK mags). Then 6.8 SPC II, which is a great all-around caliber, plus future mil-spec (some variant at least). I also got on the 6.5 Grendel train, wanting to go out a little farther with some energy, for target/varmint a 224 Valk will suffice. It really depends on what your intended use is. There are several additional calibers now available, long range target, any North American hunting, bug or small, and big bore. The AR platform can fill any need. If by chance it can't, you move up to the AR-10 platform. .308 in a 22"+ barrel and PRS stock with bipod and nice glass can reach out, followed the the 6.5 Creedmoor, which will really get out there. 308 in a 16" carbine is my favorite battle rifle (ok carbine for you purists). The choices are amazing.
Enjoy the research and get what works for you. And if you want to explore other options, a dedicated upper and bcg in a new caliber keeps the cost down.
 

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