Charge (and method) needed to fire form 308 and 300WM

[theshootist]

I would like to fire form some 308 Win and 300WM cases using pistol powder and cream of wheat. I'm open to using a substitute to cream of wheat, I just figured that cream of wheat would be the cheapest and easiest to find. Just wanted to have the cases pre fire formed before beginning load development.

Searches on CGN and elsewhere didn't yield much for results.

Could you recommend a method?

Specifically, could you recommend a charge weight in grains for these two calibers? I have available for powders: HS6, Tidewade, Titegroup, Clays, H110, 700X and 800X.

Do I have to pack the cream of wheat tightly? Not sure how much to add.

Thanks for your help folks.

 

[LUTNIT]

When I was doing it I'd use a charge of 12-15gr of most any fast pistol/shotgun powder (titewad, titegroup, clays, 700X, or 800X should all work) with the cream of wheat filled over that. Candle wax used to seal the cream of wheat into the neck.

I don't fireform my brass like this anymore as it doesn't produce enough pressure for case conversions and I found it made little difference in my load developments (I'm not a long-range match shooter though; just trying to stay under 1 MoA up to 300yds).

 

[diopter]

Fireforming from which cases?
No point in fire forming a .308 to a .308, you do that on it's first loading anyway.
I would see if new brass needs annealing, then FL size it to minimum specs, check the case length and go at it.

 

[207SE]

For 308 Winchester.

For palma brass
8.0 gn titegroup
30.1 gn cream of wheat instant
small rifle primer

For standard lapua brass
8.5gn titegroup
29.6gn cream of wheat instant
large rifle primer

Plug the top with criso you only need enough to keep the COW from coming out and don't get it on the case. Works best applying the crisco with a syringe.

Make sure to clean your chamber every 20 rounds or before. If you start seeing stippling on the brass that is the COW in the chamber. If the crisco builds up in the chamber it will dent your brass.

I did 400 before the worlds and had no issues other than some cases had dents or stippling from not having my chamber clean enough. Just used those as foulers and sighters.


Not sure what charge to use for a 300 win. mag.

 

[theshootist]

Fireforming from which cases?
No point in fire forming a .308 to a .308, you do that on it's first loading anyway.
I would see if new brass needs annealing, then FL size it to minimum specs, check the case length and go at it.

I want to fire form the cases so that they just need to be neck sized with a lee neck sizing die. After that I would lightly / partially outside turn the necks. I wish to do this in order to get the most accurate results from ladder/OCW load development. It would save me a trip to the range, but my main concern is to get the most accurate data for load development.

I have never found the need to anneal. Maybe I do but I just don't know it? Never get any split mouths. After about a half dozen firings I find what usually ends the cases' life is that the primer pockets become too easy to press in primers using a hand priming tool.

I wish to fire form 308 cases in my 308 bolt action, and fire form 300WM cases in my 300WM bolt action.

 

[Dogleg]

I use 14 grains of unique to blow .300 Wins into .458-300, and .375 H&Hs into .458 Lotts. I fill the case with cream of wheat and plug with the cheapest soap from the grocery store. One or two out of 50 will split; annealing would likely save those few, and those that had early neck failures after.

I don't really think you're going to get the results you're looking for.

 

[Kelly Timoffee]

Load em and shoot them.

If you were going from one chambering to another (.308 to 7/08 or 7RM to 257WBYnafter you sized them) or something I would and have done what you are planning, but to fireform with the same chambering seems a bit redundant.

Going to have to FL size anyways after a few firings.

When I did .308 sized cases I used 5-7 gr of pistol powder , cream of wheat , tissue.