223 Ackley and short bbls

[jpretle]

In my view the reason for an Ackley chambering is to gain velocity, so I am wondering why there are so many chambers done on short bbls, in the 20"-22"-24" range. I think some of the velocity can be picked up w/ strategic use of powders, but certainly not all. Seems to me, the greatest advantage would be 26" and maybe longer. Length depending of course, on intended use.
Somebody please enlighten me.

 

[jpretle]

Somebody has got to have some thoughts on this.

 

[MQ1]

+1 on not having to trim cases. The velocity increases are nice, but the work saved in trimming is in my opinion the biggest plus of an Ackley Improved chamber...

MQ1

 

[jpretle]

I have 4 AI chamberings and am aware of the no trim benefits. However, I am not convinced a 20" bbl will maintain velocities of a standard chambering in say a 26" bbl.
Does any one have some hard numbers????

 

[savagedasher]

Here is some rough numbers 20'' bbl at 51283 psi 3098 FPS 26'' bbl same pressure 3280 Fps
That is with 53 gr v max. Most Ackley work far better with longer barrels The sharper Ackley shoulder slows case stretch. Larry

 

[jpretle]

Would the heavier bullets, (75g-80g) give similar results---velocity-vs-velocity???

 

[savagedasher]

Adjust the powder and not making any other changes Other then going to 80 gr v max 20'' bbl 2560fps 26'' bbl 2689 fps. These are just rough numbers Larry