Has anybody played with the 450-348 Ackley Imp. ?
I found a really nice Ruger # 1 in that chambering with loading dies and it just had to come home with me.
So, now begins the quest for load info and I'm thinking that maybe 450 Alaskan data might be a good starting point.
Any suggestions / tips will be gratefully accepted and appreciated .

And a Happy Thanksgiving to all !

I have an original Winchester 71 in 450 Alaskan. I think you would be safe using 450 Alaskan data to start with. I know the Ackley version has more capacity than the Alaskan but not sure how much.

Lucky you got dies with it. I searched a long time for dies for mine and finally had to buy a set of new dies which must have been made of gold bssed on the cost.

PS I find Bullseye and corn meal will form a perfect 450 Alaskan case without needing any form dies or tapered expanders. As long as new cases are used I have no failures.

338 Guy....do you anneal your brass or not ?
My Win 71 is still a 348 so I have lots of brass for same.
I've avoided the temptation to re-barrel it to 450 Alaskan, but its been tough.
Saw a really nice Win. 71 in 450 Ak. a few years ago in a Bellingham pawn shop for $750 but when the clerk found out I was Canadian he wouldn't sell to me...store policy.

I haven't found it necessary to anneal the brass if I use new cases. I tried using fired cases once and had problems with splits around the shoulder when fire forming. The Bullseye method forms perfect cases without any case loss.

My Model 71 was a 450 Alaskan when I bought it at a gunshow in Puyallup. It is a pre-war with the bolt peep sight. I really like the gun and the balance/handling is wonderful.

I have an old article in a 60s era Guns & Ammo that was about the various Ackley improved versions of the 348 in Model 71s. If you want I will try and locate it and I can send you a scanned copy of it.

That old article sounds like it might be a very interesting read...