260 Ackley vs 260 standard rem

[kneedoc]

In process of having 260 built on Surgeon action. 24" tube to be fitted. Question relates to the potential velocity advantage of 260 AI against the 260 Rem, in the 24' tube, for 130 gr projectiles. I am concerned as to the increased hassle of generating fireformed cases etc for the AI, but if there is likely to be a demonstrable advantage, then I will just suck it up and deal with the those hassles.

 

Thoughts gratefully received.

 

James

[baldie]

Welcome to the board James .

 

I,ve had just the same dilemma myself recently. I,m going to build a .260 rifle on our new action for a showpiece etc. I have a very nice mod which is fairly heavy. This means i,m going to plump for a 24" tube myself. Most tactical rifles have this length anyway. I have both reamers, but i,m going with the std chamber for several reasons. Firstly, i haven,t found any dies that match our reamer [which is std ackley ] this means custom dies. Secondly, i dont think there will be any advantage , velocity wise, from a 24 inch tube with the ackley....its too short, and thirdly, forming the brass is a right pain, and it also needs a magazine modification to make it feed. Using the new reloader 17 powder, will effectivley make up the shortfall in velocity, without all the grief.

Hope this helps.

[Gun Pimp]

I agree with Dave - stick to the standard 260 Rem. You will use up too much barrel-life fire-forming for little, if any, advantage.

If it was for a 1000 yard benchgun - maybe go AI, otherwise stick to the 260 Rem - but neck-up 243 lapua brass!

Cheers

Vince

[kneedoc]

Gents,

 

Thanks for the information, which is very helpful indeed. I will stick to the standard 260, it looks like.

 

Looking forward to the rifle coming through and doing a bit of load development.

 

All the best.

 

James

[Andrew]

There was a great study done here in which it was found that in most cases, the velocity increase was equal to 1/4 the increase in case capacity, and visa-versa. I have used it as "rule" and it has worked out well. So, if you could squeeze a 10% increase in case capacity, you would yield, at best, a 2.5% increase in velocity... all other factors being equal.~Andrew

[kneedoc]

Andrew,

Does the 10% producing 2.5% trend apply across the board, in your experience, or is it more applicable with smaller capacity cases? Presumably as one approaches an over-bore configuration, all advantages are more or less negated?

James