243AI or 6mmAI m

[LRSickle]

Okay, this makes some sense, but how much life are we talking and is it even worth worrying about? Out of the 2 I'd still pick the 6AI. Thanks for the input on neck lengths.

I might be able to offer a little on this. I have a 6mm AI and "the little woman" just sold her 243 AI. Both shot H4350 with 90gr Berger Target jammed .010 into the lands and both had nearly the same amount down the tube. The only thing different was grains of powder. Since both guns shot well with the Bergers jammed .010. I was always checking the throat and chasing the lands so I kept track of throat erosion in each. With the exception of my 6.5x284, I don't seat at the lands so I don't often check my other guns. The 6mm's throat erosion at about 500+ rounds was .0065, the .243 was .004. So there is a difference but not enough that I would pick the .243AI over the 6mmAI. But then again, there's not a lot of performance difference between the two.
Besides, really, if you shoot a lot isn't a barrel a consumable product anyway.

 

[Tikkamike]

good point, i wish i had a bunch just sitting there like a bolt bin, lots of different sizes and shapes haha

 

[B23]

I'm struggling to see how a 6ai would have double the throat life of anything with smaller case capacity.

When it comes to throat life it's always been explained to me "more fuel, bigger fire" and that's what eats throats in a barrel.

 

[LRSickle]

I'm struggling to see how a 6ai would have double the throat life of anything with smaller case capacity.

When it comes to throat life it's always been explained to me "more fuel, bigger fire" and that's what eats throats in a barrel.

Sorry Bud, I didn't explain myself well enough. Taken from a baseline max OAL measurement during load developement and the time we both reached 500+ rounds, my 6mmAI throat had eroded .0065 and Lisa's .243AI had eroded less at .004. I don't know exactly how many Lisa shot but between the two of us we consumed a carton (plus) of CCI primers and we both shot about the same amount. I included the test targets, recorded velocities, dummy round, dies, modified OAL case and any other records I had upon the sale of of the gun so I couldn't measure the .243AI.
How I got the numbers is by measuring my 6mmAI, which is in my safe, and going to my reloading room and looking at the label on the case of the last reloads we loaded for the .243AI.
Sorry about any confusion, Chuck.

 

[B23]

Chuck, it wasn't your post I was talking about it was one a few posts before yours that claimed a Rem6AI would have double the throat life of a 243AI which I find very difficult to believe considering the 6ai has a bigger case capacity, ie. more fuel means bigger fire and that is what I've always been told eats throats.

I like the Rem 6mm and 6ai as well as anyone but I struggle to buy into to how the Rem 6 with it's long neck will give it more throat/barrel life let alone double the life. Stranger things have happened but this is one of those I'd have to see it to believe kind of things.

 

[LRSickle]

Chuck, it wasn't your post I was talking about it was one a few posts before yours that claimed a Rem6AI would have double the throat life of a 243AI which I find very difficult to believe considering the 6ai has a bigger case capacity, ie. more fuel means bigger fire and that is what I've always been told eats throats.

I like the Rem 6mm and 6ai as well as anyone but I struggle to buy into to how the Rem 6 with it's long neck will give it more throat/barrel life let alone double the life. Stranger things have happened but this is one of those I'd have to see it to believe kind of things.

Good, we see the same thing. In fact my findings echo exactly what your saying. Cool.

 

[Trickymissfit]

I'm struggling to see how a 6ai would have double the throat life of anything with smaller case capacity.

When it comes to throat life it's always been explained to me "more fuel, bigger fire" and that's what eats throats in a barrel.

the turbulence point does more to damage a throat that anything else. The ideal T.P. is in the first third of the neck from the shoulder. This isn't something I dreamed up, but thoughts from folks a lot smarter than the average joe pulling a trigger.

The "the more fuel; the bigger the fire" theory is also correct. But not as much as the T.P. Those big over bore cartridges simply blow powder down the tube. The actually tend to etch the rifeling, so many are now claiming. Can't prove it by me.
Ackley said more than once the max case capacity for a 6mm round was the 57mm Mauser case. There have been a gazillion 6mm case designs come out of the barn over the years, but none of them really gain all that much over the generic 6mm remington case. The 6mm Ackley is a case in point. You get about 175 fps if your lucky. Then you look at the 6mm-06 and the 6/.284. Even greater powder capacity; yet all three are fairly close to each other in velocity. I think it's called wasted gun powder in the end. The 6BR loaded very hot; will push a 105 grain bullet at 2850 fps using AA2520 powder(one guy was getting a confirmed 3005fps). A .243 will push the same bullet 3000fps with 35% more powder, and still not be as accurate. The 6mm Remington will go about 100fps faster at best. Then the 6/284 is about 100fps faster yet (54gr, H1000). Certainly an overbore cartridge is hard on barrels, but so is a poorly designed neck and shoulder on a case
gary

 

[B23]

This is an interesting theory but we will have to agree to disagree on this one.