Fotis;
Top of the morning to you sir, I hope the day's breaking bright and clear for you folks and all is as it should be for you and yours.
Since you've already received a lot of fine advice I'll try not to repeat it too much and still relate my experiences in fire forming.
For the record, I've fire formed for .22-250AI, .250AI and .338 Win Mag cases into .308 Norma. The .338 into .308 Norma does result in a shorter neck than spec calls for, but it's been working fine for nearly 30 years as far as I can tell.
In the smaller cases I used WW231 and Bullseye for powders and was happy with both.
As well, I tried the COW along with shortening and wax as a plug. While it wasn't so bad in the .250AI, somehow it really baked a lot of crud in the barrel of the .22-250AI, why that was I can't say, but it took markedly longer to clean. It's a Douglas Premium Match Grade barrel in that rifle by the way - so fairly smooth inside as far as I can tell with my naked eye.
In the .308 Norma, I've gone to using cast bullets, seated out to contact the lands slightly. I want to say it was 12grains of Bullseye and a 170gr cast bullet in the .308 Norma.
My neighbor was reloading for a .30 Gibbs and after some research and help from our resident writer John Barsness, I suggested they do something similar with it, that is to say a medium load of H4895 and a lighter bullet seated to just contact the lands. The cases they showed me formed perfectly so again showing there's a few ways to arrive at a desired destination.
Overall, I seem to recall that the bullet touching the lands method was a faster cleanup than any COW fire forming I've tried and that's definitely how I shall be fire forming my next batch of .308 Norma cases.
Hopefully that was useful information for you or someone out there in the ether space. All the best and good luck on your hunts this fall.
Dwayne
