Home Forums Reloading Big Game Rifles Fireforming 8mm AI cases

I've just finished reaming out the chamber of my first wildcat - an 8mm-06 AI - in a Czech 98/22 Mauser that had a touch too much headspace at the start. I can't hardly seat a bullet out long enough to touch the lands in this rifle, even after the rechambering was completed. I might be able to seat my Hornady 220 gr bullets out that far, but I don't want to waste those bullets, since Hornady has discontinued them. I've resized a number of 30/06 cases and prepped them for fireforming. I'm looking for the best way to fireform.

I'll soon be replacing the trigger and the stock, so the rifle will be ready for action soon. I like the COW (Cream of Wheat) method, but I don't have any Unique, Bullseye, or Red Dot (I use Green Dot in my 20 ga loads).

Any tips?

TXLoader

The Lyman cast bullet handbook shows 12 gr. Green Dot as a starting load for 120 gr bullet in the 8mm mauser, should work in your Ackley. I'd start with 10 gr and work up till I see slight pressure signs. By the time you start to see pressure your cases should be forming nicely.

TX,

I think you and I are the only two people in the world with a 8mm-06 AI. I have just started load development. My first fireforming loads were with standard 8mm-06 max loads reduced by one gr. (IMR-4064, I think) They didn't form as well as I would have liked. I tried corn meal with 10 grs. of HP-38; that didn't work real well either.

I used 220 gr. Remington bullets that I bought in bullk from Midway. They do have a more rounded profile that the Spire Points from Hornady. Am getting ready to shoot it again on the next trip to the range.

You may have to go as high as 16 grs. of Green Dot to get your case to form with cereal.

In Ackley's book he states that max loads for the AI version are 5% over the standard 8mm-06. That is the only reference to loading data that I can find. Speer #9 lists reduced loads with IMR-4198 starting with 26.0 grs. and maxing out at 30.0 for a 225 RN. I would think that should work with the Rem bullet for forming loads.

Hope this helps...Keep in touch...the9.3Guy

If your chambering has a good crush fit at the point where the neck meets the shoulder, I would use maximum 8mm-06 loads to fireform the cases. I have had two of these barrels, and this is what I did. The Ackley cases will fireform better under full power loads. Remember, when you rechambered to the improved version the max pressure of the standard loads will be quite a bit less in the new chamber. Enjoy your 8mm-06 Imp.--it is one heck of a cartridge and it will do anything a .300 Win mag will with a lot less recoil.

Craig

Sambubba,

when I reamed out the chamber, I reamed only as much as I needed to such that the action would...

...close smoothly on a go gauge;

...not close on a no-go gauge;

...and close with some slight resistance on a 30-06 case necked up to 8mm with no other changes.

Does that qualify as a good crush fit between neck and shoulder?

Bear with me - I know that is a novice/foolish question to ask, but this is my first rechambering project, so I have to ask it.

I know that when I have fireformed brass, my AI's start loads will be just under the regular 8mm-06 max loads. I'm figuring to work slowly up to a simple 5% over the regular 8mm-06 max load and use that as my maximum safe ceiling.

My first wildcat adventure continues...

'Loader

When you have a crush fit you have a light ring at the junction of the shoulder and neck. When you close the bolt, you will fill some resistance at the last 1/3 of bolt travel. If you have this, there is no need to seat the bullets into the lands. If you don't, Stonecreek's suggestion that you create a false shoulder would be the way to go if you cannot seat a bullet into the lands. I had a crush fit on my .280 Ackley and I still seated the bullets into the lands. This gave me perfectly formed cases with no danger of excess headspace. For an improved case, you need to have less than zero headspace--some say about .004.

Thanks. I'll coat up a couple of cases and see where the fit marks at.

'Loader