6 prc vs 243AI

[Ice-kub]

I'm almost done FF'ing 100 pcs of brass for my 243 AI, I look at like additional practice/trigger time. I'm not running hot loads at all and getting a pretty good pop on the shoulders. FF'ing has been fun and is allowing me to gather data that I will use when it comes time to finalize the load.

Barrel life with longer heavier bullets should get you somewhere close to 1000 rounds of barrel life I'd think? 100 FF cases isn't going to hurt me in the long run.

 

[Article 4]

Barrel life with longer heavier bullets should get you somewhere close to 1000 rounds of barrel life I'd think? 100 FF cases isn't going to hurt me in the long run.

My last 6 CM had 1650 rounds before opened up and I run it hard sometimes. Careful use might get more

 

[ddowning]

I have run 243AI barrels to 2500 rounds and still had 5 shot groups under 3/4 moa. I used h1000 and n165 with heavy bullets and scrubbed the throat to bare metal every 200 rounds to get that kind of life. Normally get top accuracy for around 800-1000 rounds then drop 40 fps. Seat bullet closer to lands and add powder. Good to around 1700-1800 rounds. Will still shoot 3/4" for 10 shots at 100. Move bullet out and add powder. Good until it dies. Around 2500 rounds is Normally when they open up to more than 3/4 moa for 5 shots. I tried to take one to 1 moa for 5 shots at 100 yards but it started shotgunning at 2700ish rounds.

I'm in the middle of my 7th and 8th barrels doing it like this and it is pretty consistent. Getting max performance out of shorter barrels might require some less throat friendly powders that I don't have experience with running for multiple barrels.

 

[Ice-kub]

I have run 243AI barrels to 2500 rounds and still had 5 shot groups under 3/4 moa. I used h1000 and n165 with heavy bullets and scrubbed the throat to bare metal every 200 rounds to get that kind of life. Normally get top accuracy for around 800-1000 rounds then drop 40 fps. Seat bullet closer to lands and add powder. Good to around 1700-1800 rounds. Will still shoot 3/4" for 10 shots at 100. Move bullet out and add powder. Good until it dies. Around 2500 rounds is Normally when they open up to more than 3/4 moa for 5 shots. I tried to take one to 1 moa for 5 shots at 100 yards but it started shotgunning at 2700ish rounds.

I'm in the middle of my 7th and 8th barrels doing it like this and it is pretty consistent. Getting max performance out of shorter barrels might require some less throat friendly powders that I don't have experience with running for multiple barrels.

That's more rounds than I'll probably ever shoot out of a single rifle. I'd say the ackley is most likely my choice if I can round up some good brass.

 

[Ice-kub]

Okay so I did some math based on the sammi specs of the parent cases, maybe in out to lunch but, using the numbers of the 243 win and 6.5 prc, the prc is actually a slightly shorter case. If the neck size is the only measurement that changes, Ie, 6.5-6mm, than you can load a 115 berger with the boat tail junction at the neck/shoulder junction and it's "2.910, mag length in the rifle currently is 2.960", feed ramp is notched. 6 prc may be a very viable cartridge in a short action 700. I don't think it's worth messing with fire forming 243 for the extra juice.

 

[dirtytough]

My 243 easily hit 3000 fps with a 108. There is no way I’m fire forming and messing with an AI to get more velocity.

6 creed, 243, or 6 PRC would be my choices.

 

[AZ_Hunter]

My 243 easily hit 3000 fps with a 108. There is no way I’m fire forming and messing with an AI to get more velocity.

6 creed, 243, or 6 PRC would be my choices.

Barrel length?

 

[justin davis]

My 6 creedmoor is going 3130 avg with 108’s. 24” barrel.

 

[ddowning]

The difference between 6cm, 243, and 243AI is miniscule. You will have to stand on the gas on a 6 Creed to get the velocity you will get with a 243AI at lower pressure. I run 105s at 3150-3200 fps in a 243AI with a 26" barrel. It runs at pressures low enough that I can get mud puddle in the action and magazine and have zero issues with sticky bolt or blown primers.

243 to 243AI are going to run very close to each other. Math says there should be about a 2% difference in velocity between the 2. The advantage to the ackley is the shoulder angle and less case taper. It will hide pressure and stretch less. Less trimming and more brass life. The disadvantages are fireforming and there are no saami standards so getting chamber and die to match can be a bit expensive or a pita. When I started shooting 243AI in 2016 I bought 500 pcs of Winchester brass. I am still using most of them with 25+ firings in a spare rifle that I hand my friends. I bought 500 pcs of Peterson a few years ago and plan on getting several barrels worth of life out of it.

With Winchester brass in a straight 243 I was not getting that good of brass life and I had to trim basically every firing.

The ballistics aren't really that different. 6 prc is a monster. I do not have one, but you should get a jump in performance and a significant loss of barrel life.

 

[Ice-kub]

Well I've settled on the 6prc, got some adg brass, a selection of slow powders, the dies, the reamer and barrel. Just waiting on a 6mm sizing ball for the redding size die.

 

[AZ_Hunter]

I feel like a 6mm-284 is the happy medium between a 243 and a 6PRC. I was considering the 243AI, but the velocity gains seem basically minuscule and the PRC is a monster as a previous poster stated. Split the difference.

Simple neck down with a bushing die is no big deal and no fireforming as with the AI is a big plus. Good brass available. Just seems like a logical choice to me.

 

[BDWMT]

Wyatt’s Barney box conversion makes the 243, 6 PRC and 6-284 all god options in a short action.

 

[dirtytough]

Barrel length?

It’s a factory Tikka so I believe it’s like 22 7/16”.