So... I want to get another AR. But since I have a bolt gun, a Mini 14 and an AR in .223 I want to try an AR in another caliber. I have been researching 6.5, 300 BO and 308. But I also see that DPMS and Rock River offer .243 ARs. Based on ballistic performance, recoil, ammo weight and ammo cost the .243 seems like a valid option.
So... Anyone have a .243 AR? What is your experience with it? How does it compare in performance with non .223 ARs?
Thanks in advance.

I looked into building one of these a while back, but ended up going with the 6.5 Grendel (which I'm happy with...except for the almost complete lack of local support for the cartridge). IIRC, the .243 is too long for the AR platform...you'd have to build it off of an AR-10. Someone can correct me if I'm wrong or if there are exceptions to this, but that's why I shied away from it.

The .243 WSSM will fit, but I found it very hard to find parts for an AR in that caliber. Not to mention, the WSSM is even harder to come by locally than the Grendel. If you do end up getting one, I'd be interested in hearing about it...I've still kinda got the bug .

depending on tonights lottery numbers,
this has been on my .243 wish list for a couple of years
https://lmtdefense.com/firearms/lm308mwsf

3600 bucks? Yike! The DPMS is MSR of 1200. And I think they are AR10 type rifles. .243 is a necked down .308, IIRC.

I own a 6.5 Creedmoor AR-10. I've shot a number of 308 AR-10s, a few 6.5 Creed AR-10s, and briefly one 243 AR-10.

The first things you'll notice going from an AR-15 to an AR-10:
- more recoil
- heavier parts moving back and forth during the recoil cycle
- the above two issues make an AR-10 harder to as accurately as an AR-15

All things equal -- rifle type and weight -- the 308 caliber has more recoil than the 6.5, which has more recoil than the 243. A 243 probably has at least double the recoil of a comparable AR-15 in 223.

IMO an AR-10 should weigh more than a AR-15. The additional weight is not a bad thing when it comes to controlling recoil.

If you plan to shoot a lot, understand that the smaller bore of the 243 results in lower barrel life than a 6.5 or 308. If you measure your annual round counts in the dozens or a hundred per year, this isn't a factor. If you shoot a thousand or more rounds per year, be prepared for periodic barrel replacements with the 243.

What's your primary use for the AR-10? Hunting, plinking, varmint control, ringing steel, competition? Consider all the costs of the system -- rifle, magazines, sights/optics/mount. Plus the potential options of bipod, light, muzzle devices, etc.

A 243 puts more energy on target than 223, regardless of distance, for comparable bullet types. It will almost certainly shoot flatter and with less wind drift than 223. A 243 can shoot very accurately, however this depends a lot on the ammo and the shooter.

Thanks, Fritz!
It will be an all around rifle for me and I don't plan to put a whole lot of rounds through it. I am looking for better performance than .223 without a great deal of added expense. The DPMS is a fixed stock HBAR type. My ballistic software with the .243 90gr Nosler was pretty impressive for velocity, trajectory (flat shooting) and energy. 100gr bullets are usable as well.

6.5 Creedmoor has become popular enough that ammo is widely available.

It would be another option although given the criteria you have listed 243 would probably work just fine.

6.5 Grendel doesn't have as much power as any of the AR-10 offerings but you can stay with a small framed gun if you go that route. Worth considering. It has enough oomph for deer and the difference in energy is noticeable on steel targets.

243 is an old round and also passes the Walmart test, which is a good thing!

When I was looking for something milder than 308 I looked at the 243, 260 and 6.5 Creedmoor the Creedmoor is what I eventually chose and have been very satisfied with 3,5" at 500 is hard to argue with, but to be fair I've only got 210 rounds down the tube.

An LMT MWS with a .243 barrel has always been on my "that would be so cool to have" list. I really like the cartridge and think it would be great in an AR platform.

For a while, Remington was producing their AR in .243 with a crappy camo finish. I will look around for a cheap used one. That would (maybe) make for a good project.

The Remington R25 G2 is just a rebadged DPMS G2. The DPMS G2 is good to go, so the R25 G2 would be one of the few Remington products I'd consider owning.

However, the R-25 G2 isn't listed in .243 anymore, so they may have discontinued that caliber. Likewise, the DPMS G2 Hunter models were offered in .243 as well, but I don't see them listed on their website in that caliber any more either.