What Caliber to Build an AR15?

[melensdad]

I've got some new lowers coming in and need to build up some new guns with these. I'm looking at 4 to 5 more builds, so multiple calibers are possible. The ONLY configurations I will consider are the politically INCORRECT versions. So they will have flash hiders, probably but not necessary bayonet lugs too.


Anyone think the AR57 upper is a good idea? The AR57 uses the little 5.7 round, the 50 round FN magazines, and ejects down through the mag-well.

How about the 358 Gremlin wildcat? That is a deer legal hunting round here in Indiana, but I'd prefer to stick with factory ammo. Still the Gremlin has a lot of promise and would be a great deer legal gun. One thing that keeps me away from an AR based Wildcat is the fact that Remington is slowly rolling out new ammo announcements with rounds specifically designed as AR15 based HUNTING rounds. I figure that eventually they will legitimize a 358 caliber bullet for us Hoosiers???

I'm thinking another 6.5 Grendel would be good and probably a 6.8 Rem SPC would be good too. I don't have either of those in "M4" type configurations.


So what are your thoughts? If you had some extra AR lowers available for some new builds, what caliber and politically incorrect configuration would you build?

 

[nighthawk80]

You can get one in 5.45x39. Or go with a pistol round like a 9mm for some fun plinking. Not to mention a .22!!!
Or even the 300 whisper.

 

[shooter521]

IMO, stick with proven, available calibers. That leaves out the 358 Gremlin (or any other wildcat), as well as new "trick" calibers like the 30 Rem AR.

In anything but its armor-piercing (unavailable to commoners) variety, the 5.7 round is little more than a novelty, and is ballistically on par with a .17HMR or .22Mag. Plus, it's expensive and can be hard to find. Nevermind that the AR-57 upper uses a number of proprietary parts and requires a unique manual of arms compared to ALL your other ARs.

6.5 Grendel and 6.8 SPC are both worthy of consideration, as is .300 Whisper. Go 458 SOCOM if you want an Indiana deer-legal setup. How 'bout a dedicated .22LR?

 

[cce1302]

IMO, stick with proven, available calibers. That leaves out the 358 Gremlin (or any other wildcat), as well as new "trick" calibers like the 30 Rem AR.

In anything but its armor-piercing (unavailable to commoners) variety, the 5.7 round is little more than a novelty, and is ballistically on par with a .17HMR or .22Mag. Plus, it's expensive and can be hard to find. Nevermind that the AR-57 upper uses a number of proprietary parts and requires a unique manual of arms compared to ALL your other ARs.

6.5 Grendel and 6.8 SPC are both worthy of consideration, as is .300 Whisper. Go 458 SOCOM if you want an Indiana deer-legal setup. How 'bout a dedicated .22LR?

What he said. and maybe add .204 because I think it's going to stick around as a varmint round, though I haven't seen it in the politically incorrect variety. (Seems like it's usually with a 24" free float barrel).

 

[paddling_man]

+1 for the .458! I would love to have one!

 

[melensdad]

Already got 2 in 6.5 Grendel, 1 in 458 Socom for hunting, a dedicated 22lr, a 9mm and a bunch in 5.56 in various configurations.

I know nothing of the 300 Whisper ballistics and availability. Can someone enlighten me? I thought that was a wildcat too???

Seems like the 6.8 Rem is probably something to add, maybe 2 of them in various configurations. An M4 type and then maybe something in the 18 to 20" barrel range?

I'd like to add another 6.5 Grendel, something in a lightweight version because both of my current 6.5 Grendels are heavy. One is long range, the other is set up with tactical rails, heavy barrel, etc. So a M4 type 6.5 Grendel is probably a good choice, especially since WOLF announced that it is coming out with an inexpensive steel cased round that will be priced in the same range as the 7.62x39 pricing.

While the 5.7 is a proprietary animal, it does appear to be a round that is actually gaining some traction in the market.

 

[shooter521]

Already got 2 in 6.5 Grendel, 1 in 458 Socom for hunting, a dedicated 22lr, a 9mm and a bunch in 5.56 in various configurations.

And you're wanting to build 4-5 more without duplicating? Wow. Gotta give ya props for having ambition; managing all those different configurations and calibers would be more of a headache than I'd be up for.

I know nothing of the 300 Whisper ballistics and availability. Can someone enlighten me? I thought that was a wildcat too???

SSK's Whispers®
"Designed by J.D. Jones in the early 1990's, this cartridge was the first of the Whisper cartridges and is intended for use in sound-suppressed AR-15's. The .300 Whisper is probably the most versatile of the Whisper series cartridges. It is based on the .221 Fireball case. Bullet diameter is .308 inches.

Supersonic loadings defeat the design purpose of this round but are available and do provide increased velocity, energy and penetration at the expense of greater noise. This cartridge has found limited use in some SWAT and Special Forces units."

.300 Whisper started life as a wildcat, but Cor-Bon has since started offering ammo for it.

Seems like the 6.8 Rem is probably something to add, maybe 2 of them in various configurations. An M4 type and then maybe something in the 18 to 20" barrel range?

I would do an M4 type and a registered SBR in the 8-11.5" range, but that's just me. I don't think 6.8 would gain much out of a longer barrel.

While the 5.7 is a proprietary animal, it does appear to be a round that is actually gaining some traction in the market.

Not in the markets I'm familiar with... And the fact remains that the commercial 5.7 loadings are anemic at best. Heck, even the AP stuff isn't all that great; there have been *many* documented failures to stop with it.

FWIW.

 

[melensdad]

And you're wanting to build 4-5 more without duplicating? Wow. Gotta give ya props for having ambition; managing all those different configurations and calibers would be more of a headache than I'd be up for.

At this point its not too bad. 6.5 Grendel is my favorite, keep that on hand in case lots. 5.56 is pretty much the same. 9mm duplicates some of my handguns so I keep that around too. And then the common 22lr for plinking. The oddball is the 458 Socom. I don't handload that one yet, its a hunting gun and not lots of rounds to through that one, not lots of ammo on hand for that one either.

Adding another Grendel doesn't complicate my life in any way. So that is actually likely. Probably add at least one more 5.56 variant, maybe a national match configuration as I don't have one of those. Again that won't complicate my life.

But then I am sort of loss as to what to do with the others.

Adding the 6.8 brings me some new grief, I have nothing else chambered for that round. And as it doesn't offer any advantage over the 6.5 Grendel, and at long range is worse, so the 6.8 Rem is not high on my list.

Another Indiana deer legal chambering would be nice, which is the reason I sort of like the 358 Gremlin.

 

[fireball168]

IMO, stick with proven, available calibers. That leaves out the 358 Gremlin (or any other wildcat.

The folks on this board are closer to anyone in the world for Gremlin parts, info and supplies. The first that are offered for sale will be on this board.

If I was just looking for something to play with, I'd be contacting Ron Williams and getting one of his 7.62x25 Tok, 45 ACP or 10mm gas operated uppers.

 

[Helrazr1]

You can get one in 5.45x39. Or go with a pistol round like a 9mm for some fun plinking. Not to mention a .22!!!
Or even the 300 whisper.

I personally would stay away from the 5.45x39. To date, I don't believe that there are any domestic manufacturers of this round, and in the event of a ban on the importation of ammo, which is the latest gossip, you're stuck with a rifle that you can't get ammo for. At least not until someone decides to start producing it here.

 

[RJW]

Two Grendels one hunter and one long range set up. 2 458 socom. 16 inch hunter and carbon fiber barrel 20 inch, a little more reach out and touch. Also 45 ACP upper.