Home Forums Hunting & Shooting Custom Rifles & Wildcats .243 Win. vs. .243 AI

I have a custom 243 with a match chamber. On my 5th loading my reloads won’t chamber. Apparently the brass flows forward and a guy needs to inside neck ream at a certain point, depending on your chamber dimensions. I believe blowing it out to an ackley or just doing a 6 creedmore would solve the problem. If I had to build a new rifle tomorrow given the choice of a 6mm Creedmoor, 243, or 243 ackley I would choose the Creedmoor because of case design.

Partly it is, but the shoulder angle is quite different with the AI, directing the gas into the neck instead of the throat.

6 SLR solves the shoulder angle and no fire forming...

I own 6, 243's all of them are AI's. So some of the issues are already resolved with the price of dies, which cost about the same as a box or 2 of bullets over and above the cost of SAAMI dies.

One of the points often brought up is barrel life, a good argument. What is often forgotten is that a large percentage of shooters need to forget about that issue as they would be hard pressed to put a thousand rounds down range in the next 10 years. Secondly I've yet to see any proof that SAAMI chambered cartridges are easier on barrels than AI's, some reports to the contrary.

Another issue is you have to fire form. Of the 30 - 40 AI chambered rifles I have, I have yet to find one that didn't shoot well enough fire forming brass that I wouldn't take on the most important hunt of my life. I took at very nice 180 class mule deer the day after taking delivery of a custom 280 AI after sighting in with 6 shots fire forming 145 Speer flat base bullets.

Factory ammo, kind of a moot point as AI chambers done properly will shoot just fine. Although I couldn't prove that point as I haven't shot 40 rounds of factory ammo in the last 50 years out of a center fire rifle.

Velocity issues. Hell there has been many arguments over 300 Savage, 308, 30-06 to fill all the pages of the campfire. You want a 22" 243 and want to maintain the same velocity as a 24"- 25" 243, the AI is your answer.

Lots of to do about nothing.

Now lets talk about that dreaded belt on belted magnums, and to really pizz off the anti AI folks. I don't have to trim brass.

Is the 243 SLR and 243 Imp 30 degree the same cartridge?

I just built one. Just starting to develop loads with the new Hornady eld 103 grain, RL26 and lapua brass. Part of the Ackley thing is the tinkering one does to develop brass etc. Lord knows folks turn necks, sort brass , use Vern junkie machines to check bullets etc etc, all seeking that tiny edge in performance. I can see both working just fine."....some guy came up with the term rifle looney.......man was that spot on. Goodshot

6mm Wasp, pretty much has this subject covered. Rio7

+1

Could not have said it better.

I would add that a 6 Remington is a long action cartridge.

I think a much better cartridge would be a 358 Winchester AI necked down to 243. GD

I think a .280 AI necked down to .264 would be even better.

Ed

Actually the the .270 Win. necked up to 308 would be the prefect do all cartridge.

Dang, why didn't I think of that!

Ed

I'm going to build a light weight 6mm Rem with a 7.5" twist barrel. I can't find any real measurable differences in it and the 6mm Creedmoor. I don't think an AI modification would gain me any significant velocity.

What action length are you building the 6mm Rem on?

I've owned a dozen or so rifles in 6MM over the past 50 years from Rem/Rug/Win, all short actions, have shot bullets in the 75 to 100 range and have never seen how a longer action would have made a noticeable difference.in performance.

I still have my first 6MM, a 660, and my last, a 20" 700 with the X'd out 6MM REM MAG barrel stamp.

I recently did a 7t 243ai and have been very happy! with out pressure signs I’m getting 3175 with the 105 hpbt using rl26.

Hondo, It's a custom barrel for my R8 Blaser. I'll use a 7x57 megazine insert that will give me plenty of room for stretching out the big, long ones.

No, the SLR has the shoulder/neck junction squeezed backward to make a longer neck emerge.

The Imp 30 has the shoulder blown out but maintains the short neck.

Thanks Dakota! I was wondering.....

I can trim cases after dark in my basement. I cannot fireform that way. AI chambers are a Kool-aid drinkers champagne. They create more real world problems than they solve.