Just bought a set of Ackley 223 die's cheap and cant decide which rifle to rechamber, have a New England Firearms single shot and a Ruger Mk II, Which one do you think? and has anyone loaded for this before? what should I start with for fire forming and what kinda powder / bullets: do they like etc.

Id have to check my reloading manuals or the website of po makers. You should, also.

The NEF will probably be the less expensive way to go, but if you're looking to get the absolute best possible accuracy, the Ruger might be a better choice. If you just want something to play around with, either will work just fine.

As far as fire-forming loads, I've always used a mild powder charge under a heavy-for-caliber bullet, seated at, or slightly into, the lands. There are other ways to go about it but as long as the case is formed properly, I'm not sure it matters all that much.

What ever bullets your using now in the 223 will work when it rechamber to the 223AI and I might use the same powder also. If you have a good load I would drop that load 1gr and worjk up and watch for pressure.

I've always used new barrel for my Ackley's and to cut a new chamber for the AI you want to set the barrel back and thats something your gunsmith might tell you which rifle be best to use. I know nothing about the NEF if it could or couln't be set back.

If you look at the loading data for the 223 most manual start to max loads are 2gr spread and you see appr 200/400fps difference in velocity. 1/2 gr can be a big deal in pressure for the 223AI. Here something on the 223/223AI http://www.6mmbr.com/223Rem.html 223AI info is after the 223.

I had my first 223AI build 1993 and I used a 1/14 twist barrel and being an avid PD shooters I found a good load using new cases. I just loaded up about 250rd and shot PD and that gave me 300rd of brass. I did the same thing with the 2nd 223AI and I'd use 26" long barrels so I got a good gain in velocity. Well good luck

I'm interested in the 250rds yielding 300 pieces of brass.

thank you.

Me too guess I should of said load up 300rds!