Home Forums Hunting & Shooting AR and Tactical Rifles Why no 243??

Anybody know why AR uppers are not offered in 243? Seems to me an AR-10 (308) could be rebarreled to a 243, 338 Fed, 358 Win or any other cartridge based on the 308 case??

I heard Ruger was going to offer the Mini-30 in 243 but had feeding issues?

Any true insight?

Armalite used to chamber in .243. Are you sure they don't still?

There are lots of them out there.

https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1773

I think they get overshadowed by the popularity of the the 6.5 Creedmoor.

Bingo on the last sentence

I don't understand this. What's wrong with a .308? It will push a 0.525 BC 168gr ABLR bullet about as fast as the CM will push a 130gr bullet with the same-or-lower B.C. Recoil in a semiauto .308 is basically nonexistent for anyone over 100 lbs.

I can remember Springfield armory used to advertise the M1a in 243, the focus was on lady competitive shooting IIRC.

Wilson Combat had barrels in a number of .308 based cartridges - but they’ve closed out a number of them this past year.

Looks like they are down to one .243 offering.

I like mine. Built with a BHW barrel and Aero parts

Lapua brass and 105s blend together perfectly.

If you have to ask why, then you've never had ore experienced one. I know you love your 308, but the 6.5 creed is more of a good thing in an AR10. BTDT. You may also want to compare 140-147gr high bc bullets from the creed to one of your favorite 308 pills.. The ".525 bc" bullet you suggest is lacking compared to a .625 bc 143gr 6.5 bullet launched from the creed. Would a hunter ever notice the difference? Probably not, but long range competitors know and appreciate the edge the 6.5 gives.

I'd take a 308 over a 6.5 Needmor any day. The NeedMor has nothing on the 308 using heavy bullets. It's a fad
Does it shoot flatter than a 308 sure, so will the 243. Big woop.

I think the 6.5 CM is a very versatile round, but I don’t think it’s meaningfully superior to the .308.

If I’m reading correctly, a .308 will launch a 168gr 0.525 B.C. bullet at 2,750 fps (my 20” bbl DPMS does a bit less).

A 6.5 CM will launch a 143gr 0,625 B.C. bullet at 2,700 fps (out of a test bbl).

Cited in at 2” high at 100 yds, at 1,000 yds (at 5,000 ft elevation):

.308:
28.1 MOA low; 1,470 fps; 806 ft-lbs

6.5:
26.7 MOA low; 1,603 fps; 815 ft-lbs

So, the 6.5 is 1.4 MOA higher.

Cool, but a 5% difference in drop and a 9% difference in velocity. The .308 has 17% more mass.

By contrast the 6.5-300 shooting the same 0.625 B.C. 143gr bullet, sighted in 2” high at 100 yds is: 16.1 MOA low; 2,045 fps; 1,328 ft-lbs.

That’s not an AR round, but it’s a meaningful difference.

The 6.5 CM is a fine round, but it doesn’t really offer much that the .308 won’t do.

Where is the wind drift in your evaluation? The comparison between the 2 cartridges has been beaten to death. The one that prevails is always the 6.5 cm. Wind drift is better, retained energy is better further out, its also a more accurate cartridge and does so with less recoil.

The number of people who actually shoot CM beyond a half mile is negligible in number. That’s why I mentioned the 6.5-300. If you’re regularly shooting out to a mile, you likely can submit to moderate recoil, as opposed to the super-low recoil of the 6.5 CM.

The 6.5 CM is popular because it is a SA and fits in an AR10. But there are far better long range rounds if the shooter weighs more than 84 pounds.

6.5 CM:
1,000 yds: 5.6 MOA windage at 10 mph

.308:
1,000 yds: 6.9 MOA windage at 10 mph

1.3 MOA difference.

The OP was asking about the lack of .243 options. Probably not thinking of shooting past 400 yards. Hence my post.

Are many people really shooting the CM regularly past 500 yards? Past 1000 yds?

Most of the CM shooters on here are shooting game successfully at normal, moderate ranges.

If you’re really shooting past a mile, I can say that the 6.5 CM is not the best option. If not, the .308 will do everything it will do and likely more short of 300 yds.

Thee assumption thread this one is....



Insert Yoda picture.

Disregard this thread - I'm an idiot, LOL

Way back in the day when Armalite still had the patent on the AR-10 I had them make me an AR-10T in 243, it was a struggle from the start.
It had feeding issues and accuracy issues. I sent it back to Armalite twice to have it fixed and finally gave up and sold that POS.
I scratched the AR-10 itch and have never had the desire for one since, if it wont fit on an AR-15 platform then I'LL build it as a bolt gun.

I decided to get ONE big AR and it was dirt simple, 7.62x51. A couple more weeks and it should be here.

6X Mil Quad I think.

If you are talking slow fire of a shot or two at ranges less than 1,000 yards, you have a point.
But when we talk about multiple shots as in a competition or ranges over 8 or 900 yards, the 6.5 has it over the 308. The 308 does kick harder and is a marginal long range cartridge that no one would ever choose if they had a choice. Barring these two specific situations, there really isn't much to recommend one cartridge over the other. If we are talking ranges under 600 yards, I'd move to a 155gr Palma bullet to lower the 308's recoil even further. If we are talking 1,000, I'd use a heavier recoiling load for the 308, a 185gr Juggernaut, if I had any desire to be competitive.

Assuming a 10 mph full value wind:

Using my bolt 308 with a 24 inch barrel, 175 SMK at 2635 fps I end up with about 56 inches of wind drift at 800 yards.

Using my 6.5 CM with a 26 inch barrel, 140 Berger Hybrid at 2800 fps I end up with about 38 inches of wind drift at 800 yards.

If you are trying to get first round hits at distance the 6.5 has a significant advantage, but you still need to be able to call the wind. In competitions where you can choose your cartridge, you will have a very hard time finding anyone using a 308. Most are now using a 6mm of some variation in PRS so they can spot their own shots.

True if you aren't trying for long range hits then the ballistic difference is much less important. One thing about a 308 is the barrel will last a very long time all else being equal. But, just like many don't really shoot long range, many don't put that many rounds down the barrel to wear it out either. If you do shoot a lot its a great round to practice with and does just fine for most hunting situations. I have an FN 308 with a chrome lined barrel that has over 7000 rounds down the barrel and still shoots well. The chrome lining helps but so does the cartridge.