243AI, is it dead in the water?

[fabricator21]

I also switched to rl23 in my 243ai and my 6.5 prc not quit as much velocity but much better e.s and s.d numbers

 

[milo-2]

It will depend on the reamer used I had mine set up for the 115 berger and a standard short action would not work my loaded round is 2.905

Sorry, but Accurate mag non binder plate mags allow for up to .2.990" OAL's, Defiance Deviant, Impact, Mausingfield, and others more than capable of feeding this length case.
Some actions need the bottom of the feed ramp machined out, it is a 15 minute job.

 

[kenacp]

I shoot the 243AI with a Rock Rem. varmint 24"barrel. A bit heavy but shoots 1/2moa

 

[GLTaylor]

A 243 was the first rifle I bought as a kid. Had a love affair ever since. Got tired of having to trim cases every 3 firings or so, so I had it rebarreled to the 40° AI shoulder. Case growth stopped. Rifle is now on it's 5th or 6th barrel and second stock.
I shot sporter class BR with it, prairie dogs and a bit over 100 deer with it so far. Keep your bbl at least 26" to get full value of the increased powder charge with all the new powders. N560 is great with 105s. That's heaviest I've shot. Good for PDogs to >1000 yds.
Also got a 6BR and 6x47. Neither can keep up with the 243AI. Mine feeds fine from factory Rem mag.
Yes, you can fire form from factory cartridges.
However, it's better to get brass and seat bullets to the lands to fire form. This holds the shell firmly while forming - and the forming loads are usually Very accurate. My last batch of 100 was formed on a p dog town!
I'm now a big fan of Hammer bullets. Just worked up a load and got to shoot one deer before our season closed. Looks VERY promising for next year

 

[Kanoeking]

Re26 is a distant memory, lol. I have been using RE23 just because it is available.

Have you messed with H1000 and the 115's?

 

[Bob Wright]

Have you messed with H1000 and the 115's?

Cannot find it either. If It ever shows up, I will buy 8 pounders of each, RE26 and H1000. Getting frustrated for sure.

 

[nicholasjohn]

I'm definitely not opposed to hearing others' opinions. In fact, that's exactly why I asked the question. While I'm very much so leaning 243AI I'm open to suggestions. I plan on using a 7 twist and originally hoping to hang around a 22" RemAge tube but the deeper I dive into this build the mote convinced I am that 24"is the point of diminishing returns in the 6mm world. That's fine. My current rifles are running 26" pipes and all is well with it.

You might want to consider going with the 26" barrel, since you're used to that length anyway. Performance will definitely be better, and the balance of the rifle will feel more familiar to you. I have a 30-06 Ackley that was initially built with a 26" barrel, and it felt clumsy to me. I had it cut back to 24", where it feels just fine. The same loads chronographed 100 fps slower after the barrel was shortened. ( I had been expecting about half that much velocity loss.) That was with 180-grain A-Frames and H-4350. You will be using powders that are slower-burning than that, and it may be even more critical to have a longer tube.

 

[Tony243]

Have you tried RL 26?

I haven't tried RL26, only because I am converting to Viht N500 powders for all my loading. Yes, it's a bit pricey, but the speed, accuracy, cleanliness and consistency combination these powders offer can't be beat IMO.

 

[ButterBean]

A 243 was the first rifle I bought as a kid. Had a love affair ever since. Got tired of having to trim cases every 3 firings or so, so I had it rebarreled to the 40° AI shoulder. Case growth stopped. Rifle is now on it's 5th or 6th barrel and second stock.
I shot sporter class BR with it, prairie dogs and a bit over 100 deer with it so far. Keep your bbl at least 26" to get full value of the increased powder charge with all the new powders. N560 is great with 105s. That's heaviest I've shot. Good for PDogs to >1000 yds.
Also got a 6BR and 6x47. Neither can keep up with the 243AI. Mine feeds fine from factory Rem mag.
Yes, you can fire form from factory cartridges.
However, it's better to get brass and seat bullets to the lands to fire form. This holds the shell firmly while forming - and the forming loads are usually Very accurate. My last batch of 100 was formed on a p dog town!
I'm now a big fan of Hammer bullets. Just worked up a load and got to shoot one deer before our season closed. Looks VERY promising for next year

Plus 1 on the Hammers

 

[JASmith]

I'm in the process of building a new long range plinker/Varminter/antelope/deer rifle. The conundrum I'm in is I'm hung up on calibre selection. I know I'm going to build this rifle in 6mm. I'm utilizing a Remington 700 SA. I plan on shooting 115's or 105's. I'm very interested in the 243 Ackley but I'm also open to the 6mm Creedmoor and the 6x47 Lapua. Looking for opinions.

The .243 has a tremendous following and excellent reputation among hunters.

If one looks at performance numbers, however, one could forecast the .243 following, especially for new rifle purchases, to diminish compared to the Creedmoor as time goes by.

The 6mm Creedmoor uses a shorter case -- think of it as a shortened version of the AI but with an easily formed shoulder angle that reduces manufacturing costs. The shorter case makes using sleek, heavy bullets more feasible with standard mag-lengths than either the 243 or the AI.

I was able to grab information from Ammoguide.com and used the Velocity Estimator there to get velocities for the same bullet and barrel length for the 6mm Creed, 243 Win, and 243 AI. I chose 24" and 105 gr bullets.

• 6mm Creed: 2973 fps
• 243 Win: 3016 fps
• 243 Win AI: 3135 fps

The wind drift penalty from the approximately 45 fps between the Creed and the 243 won't be noticeable for almost every precision shooter.

The ~160 fps between the Creed and the AI might be noticeable. The penalties, however, are magazine and OAL challenges plus significant barrel life penalties.

The "long range plinker/Varminter/antelope/deer rifle" suggests the OP plans to shoot the rifle a fair bit, which means that the first 1,000 shots will come sooner rather tha later.

ADVANTAGE: 6mm Creedmoor.

 

[Kanoeking]

I also switched to rl23 in my 243ai and my 6.5 prc not quit as much velocity but much better e.s and s.d numbers

What kind of numbers are you seeing? What length bbl and twist rate? Bullet weight?

 

[ButterBean]

The .243 has a tremendous following and excellent reputation among hunters.

If one looks at performance numbers, however, one could forecast the .243 following, especially for new rifle purchases, to diminish compared to the Creedmoor as time goes by.

The 6mm Creedmoor uses a shorter case -- think of it as a shortened version of the AI but with an easily formed shoulder angle that reduces manufacturing costs. The shorter case makes using sleek, heavy bullets more feasible with standard mag-lengths than either the 243 or the AI.

I was able to grab information from Ammoguide.com and used the Velocity Estimator there to get velocities for the same bullet and barrel length for the 6mm Creed, 243 Win, and 243 AI. I chose 24" and 105 gr bullets.

• 6mm Creed: 2973 fps
• 243 Win: 3016 fps
• 243 Win AI: 3135 fps

The wind drift penalty from the approximately 45 fps between the Creed and the 243 won't be noticeable for almost every precision shooter.

The ~160 fps between the Creed and the AI might be noticeable. The penalties, however, are magazine and OAL challenges plus significant barrel life penalties.

The "long range plinker/Varminter/antelope/deer rifle" suggests the OP plans to shoot the rifle a fair bit, which means that the first 1,000 shots will come sooner rather tha later.

ADVANTAGE: 6mm Creedmoor.

I disagree, I see no advantage

 

[Kanoeking]

The .243 has a tremendous following and excellent reputation among hunters.

If one looks at performance numbers, however, one could forecast the .243 following, especially for new rifle purchases, to diminish compared to the Creedmoor as time goes by.

The 6mm Creedmoor uses a shorter case -- think of it as a shortened version of the AI but with an easily formed shoulder angle that reduces manufacturing costs. The shorter case makes using sleek, heavy bullets more feasible with standard mag-lengths than either the 243 or the AI.

I was able to grab information from Ammoguide.com and used the Velocity Estimator there to get velocities for the same bullet and barrel length for the 6mm Creed, 243 Win, and 243 AI. I chose 24" and 105 gr bullets.

• 6mm Creed: 2973 fps
• 243 Win: 3016 fps
• 243 Win AI: 3135 fps

The wind drift penalty from the approximately 45 fps between the Creed and the 243 won't be noticeable for almost every precision shooter.

The ~160 fps between the Creed and the AI might be noticeable. The penalties, however, are magazine and OAL challenges plus significant barrel life penalties.

The "long range plinker/Varminter/antelope/deer rifle" suggests the OP plans to shoot the rifle a fair bit, which means that the first 1,000 shots will come sooner rather tha later.

ADVANTAGE: 6mm Creedmoor.

There's a hidden benefit to the AI's ability to utilize slower powders due to the case size, from what I've gathered. That being said, is barrel life diminished as greatly as it would be if using 4350 speed powders?

 

[Kanoeking]

I disagree, I see no advantage

I tend to agree. It's similar to the "no trim" philosophy on the AI