338 Lapua AI Different case designs

[Wachsmann]

Just wondering how many different designs is there for the 338 Lapua AI. I know the shoulder angle can very but also does the body taper vary a lot as well. Is there one design that is most commonly used or better than others?

 

[Broz]

Just wondering how many different designs is there for the 338 Lapua AI. I know the shoulder angle can very but also does the body taper vary a lot as well. Is there one design that is most commonly used or better than others?

There are several and yes the case taper can vary. Some of the is by design and some by reamer variation or accident.

I would say the most popular is the 40 degree AI. PT&G has the print but I think JGS does too. I would use the JGS reamer. Redding use to keep dies for this or they can make them. You might want to get their print and send it to JGS if you need a reamer. This is what I would do if I build another 338 LAI

Jeff

 

[ELR Researcher]

Just wondering how many different designs is there for the 338 Lapua AI. I know the shoulder angle can very but also does the body taper vary a lot as well. Is there one design that is most commonly used or better than others?

There is only ONE (1) true 338 LM Ackley Improved. If the shoulder angle has been changed from 40 degrees it is not a true Ackley Improved. PTG has info on the Ackley Improved head spacing - http://pacifictoolandgauge.com/material-downloads/reference-data/ackley-info-sheet.pdf More info on Ackley wildcats at http://www.gundigest.com/wp-content/uploads/GunDigestPOAckley.pdf - while it pre-dates the 338 LM, it gives you the full story of what Ackley Improved is all about - from the source.

As best I know, the PTG ".338 Lapua Ackley Improved" reamer is true Ackley Improved - .338 Lapua Ackley Improved - Pacific Tool and Gauge

All the above aside, people have modified various features of what Ackley Improved cartridges are suppose to be and created reamers with the same and different names - "other" names that get listed as .338 LM AI.

The issue you run into is getting matching dies. Were I building such a rifle I'd go to PTG and buy both a finisher and a resizer - then have your smith cut you a set of dies using the resizer.

BTW, the above problem is NOT limited to cartridges identified "AI". The problem is VERY widespread. The "finisher + resizer" route is the closest way I know of getting a good match short of having custom dies made from 3 cases each 3X fired (full load).

Good luck.