338-348 Ackley Improve

[Chief Paduke]

I recently obtained a 338-348 AI, dies, cases, and bullets. However, while there are some loaded cartridges, there is no loading data. Does anyone have any loads using IMR 4350 and 200, 225, and 250 grain bullets? Does anyone know which of the old Ackley books/manuals contain this particular cartridge? Thanks for any guidance you may offer.

[gamekeeper]

Bump.

[Leverluver]

First off, I don't think you are going to find any data by Ackley as I don't think that the cartridge was an Ackley invention. More than likely it was an invention or alteration based on the 348AI. AS to why; like most wildcats, the reason is lost to history. Even if you did find Ackley info, that stuff is beyond borderline dangerous as it was done long before common use of pressure data. When one acquires something as esoteric as a wildcat of a wildcat, there is little to no data available.

You say that you acquired the dies; I am presuming that you do not have a rifle yet. If so, I wouldn't bother with a lever as there is very little bullet choice for a lever except for the Hornady gummy bear or maybe Hawk. If single shot, use whatever fits the throat. As for data, you get to be a true wildcatter

[Chief Paduke]

I do have the rifle. It is built on a Siamese Mauser action, which is pretty stout. I also received some loaded cartridges. While I can pull a bullet(s) and identify them, and I can weigh the powder, I have no way to Identify it. The rifle has a Shilen barrel and Timney trigger and shoots well. Recoil is pretty strong, and I have only shot what appears to be 200 and 225 grain bullets. I have yet to try what are probably 250 grainers.

[earlmck]

I would probably use 348 Win data for the given bullet weights to get a starting point. The slightly smaller bullet diameter would just about be compensated by the slightly extra case capacity from the Improved chamber. Close enough for the kid here, who has on occasion popped a primer.

I looked in QuickLoad to see if I could get you any advice but they don't have the 338/348 in their data bank. They did show about a 5 -grain capacity increase going from regular to AI in the .348 case.

[DocRock]

I endorse earlmck's advice. The smaller bore/vs increased case capacity should mean that 348 Win data is a safe starting place. Slowly working up from a published 348 load with similar bullet weight while carefully observing primers and measuring case head expansion should be safe enough.

I certainly wouldn't be shooting unknown handloads made by someone else!

[3leggedturtle]

Cool, i had mentor that built 3 or 4 wildcats on the Siamese action. I have both Ackley books but aint close to them. CRS aside, 1st edition had alot of info on wldcats based on the 348. Hope you can post some pics of your rifle.

Welcome to Best Gun Enabler Forumn!!! Todd/3leg