8mm-06AI forming and loading.

[VenisonRX]

Wasn’t sure the best category to place this in so I put it here. Please move it if it needs to be.
Saw an interesting rifle at a gun show that was priced extremely well and couldn’t pass up since I’m a lover of Mauser sporters. This is a sporterized Persia Mauser that had a German machine gun barrel turned down to a threaded straight bull barrel and was rechambered in 8mm-06AI. It also came with a set of 8mm-06 does and an 8mm-06AI neck sizing die. Is it a beautiful example of a Mauser sporter, not particularly, especially with a threaded stubby bull barrel and a decently grained but otherwise milk toast montecarlo stock. But it’s something someone like me can love.

Being essentially a double wildcat it’s difficult to find much information on loading. I understand what 8mm-06 is and I understand what Akley Improved is. I’ve worked with converting 308 to 7mm-08 (not out of necessity obviously, only so I could learn about conversions) and 30-06 to 35 whelen so I have some basic knowledge on cartridge conversion but I’m not an expert. At the moment I have two questions. Looking in the Handloaders Guide to Cartridge Conversion, it says to use a tapered expander to expand the neck up to .323 then run through an 8mm-06AI full length resizing die. My die isn’t full length so what about fire forming a normal 30-06 directly either via the cornmeal method or whatever it’s called or just firing 30-06 that I don’t have a use for? The second question is where to start for load data. I’ve got several manuals Speer, Hornady, Barnes, Lyman, and Sierra. Between those I’ve got a decent amount of data for 30-06 and 8mm-06 and the Sierra also lists 30-06AI. Where would a good starting point be and where should I consider my limits? I already know I want to go with the 170gr SST and I’m leaning towards IMR4064. Thanks for the inputs.

[slam45]

RX

i have not messed with a 8mm-06 or the AI bit but do shoot a 338-06 and have some observations... going up to 338 from standard 06 brass just requires running brass through the larger die, a tapered expander and a little lube in the case neck and they work great in a rifle that has the headspace correct... i know in my rifle '06 loads can provide a starting point to work up from and most AI mods chamber and fire the non AI rounds fine and then they are fire formed and can be neck sized going forward... should be an easy and fine shooting conversion with few problems... annealing the brass will help with case life...

[littlejack]

RX
I have m48B bo chambered in 8mm-06AI. When I bought it, it had never been issued. Still had plenty of cosmolene. I kept the stepped barrel. Had it chambered in 8mm-06AI.I had it bead blasted, blued and put a Bishop stock on it. Mine sports a 3x9 Leupold scope. It has the original 24" with the 9.5" twist. I tried the SST 170 grain, but it did not shoot well. Very well may have not liked the twist rate. My go to bullet is the Nosler 200 grain partition. With 55 grains of IMR 4064, that 200 grain bullet runs a solid 2800 fps.
As for the 30-06 cases; you can expand the necks just by running the lubricated case neck over the expander. The inside diameter runs about .320. That'll give you a good friction fit. You don't have to size the case on the first firing, "IF" the fired 30-06 case will chamber in your rifle. I use once fired range brass. I chamber the empty case to see if the bolt will close, even with or preferably with needed pressure. If it takes pressure to close the bolt, there will be no headspace when fireforming your case, and no case stretching. Hope this helps.

[VenisonRX]

Little jack and slam. Thanks for the replies. Sorry for the late answer. Took the time to do some research (bought the P.O. Akley book) and reread/take in what you guys said. Looks like the basic idea is to approach this as a double wildcat. The first step would be to convert my brass to 8mm-06 and then fire form into the AI. I’ve annealed and run a couple test cases through the 8mm-06 dies. Then I’ll fire form and see how they go. The cases I used were some range brass in 30-06 and 270. It was the nice nickel plated federal brass so I had to give the 270 a try. I’ll trim the 30-06 brass until the neck is square and whatever length that yields is what I’ll trim the 270 to. Any flaws in my logic that you can see in this process?

[littlejack]

It's not necessary to full length size your 30-06 brass in the 8mm-06 die. All you have to do, is open the neck up to accept the 8mm bullet. If you can close the bolt on the loaded cartridge with the 8mm bullet, it will fireform to the AI case. Both the cases headspace at the same place on the shoulder. PO Ackley designed his AI chambers to fire factory parent ammunition to fireform to his AI chambers.

[26Charlie]

It would seem to me, you could load up some pleasant shooting loads in the 8mm06 brass with a cast bullet, maybe 20 gr 4198, and develop a useful CB load at the same time as fireforming the A I brass. I sort of did that, back in the day with 284 Win brass, when 7x55mm Swiss brass was not available (& you could buy a m1911 Schmidt-Rubin for twenty-five dollars). Just saying.

[littlejack]

26Charlie:
You are correct, you could do that. But, it has been my expierience that trying to work up a good accurate load while at the same time fireforming your brass, was counter productive for me. Especially as finicky as cast boolits are. But, there is that option to try.