Home Forums Hunting & Shooting Custom Rifles & Wildcats The 22 'ACM' (AntiCreedMoor)

What makes a 30 degree shoulder easier than a 40 degree 22-250 AI shoulder or the 28 degree 22-250 shoulder if you're going to fire form cases?

Isn't the whole point of the 22 CM to have a standardized quicker twist to allow for the use of longer/heavier bullets than typical 1-14" ROT 22-250s?

A2700 and Win760 along with H414 are the same powder. But you knew this right?

In general, a 30 degree shoulder feeds better from a magazine than a 40. That's important for a production gun. The "easier" was in reference to the great 22-250 AI...a bit of tongue in cheek.


The 22 Creedmoor is nothing new. It's been around for decades as the 22-250AI...the only difference being the shoulder angle. What the Creedmoore designers got right was the neck and throat dimensions when it became a SAMMI cartridge. But accuracy minded 22-250 AI builders were already doing that for this and many, many other cases for over a half a century before the 'miraculous' Creedmoors appeared as a production item.

The twist rate has zero to do with the chamber dimensions. You change the freebore (throat) length to fit the bullets you are going to shoot for the best accuracy. Again...standard accuracy design 101.

The custom reamer used on this build was a no-turn 22 Creedmoor with a .030 freebore length for bullet weights appropriate for the jacket lengths/weights being used. With a throating reamer, this reamer has cut chambers for the 7-8 twist for the longer bullets that have been killer good for accuracy. And with a separate neck and throat reamers, it's made up great 6 Creedmoors with multiple bullet lengths with the appropriate twists.

Not everyone is into lobbing long heavy projectiles with rainbow trajectories and using a LRF to range targets. Many of us enjoy the challenge of eyeballing a 'dog for distance, doping the wind and connecting. The accuracy of conventional BR quality conventional bullets is an added plus.

Hope this helps. -Al

What is a 223x38 ?

It was a 223 with a 38 degree shoulder that was experimented with in the '70's for BR use. -Al

Long time back, I had Fred Hasecuster chamber an old PPC barrel into a 6x47x45 for PD's. (6x222 Rem Mag Improved w/ a 45* shoulder)

I got another 9K rounds out of that tube, hated to see it die......

It was a 223 with a 38 degree shoulder that was experimented with in the '70's for BR use. -Al

I did my 22 ACM last year, but on the 47 case.

18" tube with a 12" twist, running 52 Bergers at 3800. Had to step down the H-4895 to make it snort.

Just what the doctor ordered for dark opps.......

Aalf is that a blast can and do you find it helps a lot? I dont use suppressors but have wanted to experiment with a blast can.

Aalf is that a blast can and do you find it helps a lot? I dont use suppressors but have wanted to experiment with a blast can.