At my lgs a winchester model 94 ae tempted me for two months and in a weak moment I bought it. I do have a couple of boxes on the way and I can reload those after I have shot them. My research shows that you can use a redding form and trim die to form 444 marlin to 307 and I will probably have to do that. However the 308 marlin express is nearly the same size except they set the shoulder back a small amount to probably keep people from using 308 ammo. Can I use 308 Marlin brass and fireform to 307 using the COW method?
(the 94 is so pretty and I am weak - lol)

Too bad I'm out of the county. I sold my 94 in .307 and I have several bags on new brass in my reloading room. I have no clue on .308 ME brass, but I kept that one.

I believe I read somewhere that 308 Win brass may work..?

Buckeye if you ever get back I would be interested in buying your brass. 308 brass will work if you resize the brass so that it is tight against the bolt, but it doesn't always extract very well. It does feed from the magazine ok.

I'll send you a pm when I make a return trip.

You can use just about ANY cartridge with the standard 308/30-06 dia. base...I've used 7/8mm/30-06/308 and some other metric/American cases, just be careful not to create an headspace issue or overload staying well below the published pressure limits for the various "standards" and you need to set up a motorized way to trim the longer case or you'll wear yourself out cranking a handle.

Size down slowly until you can just barely close the lever on the case. You can use those cases to fireform AND work up loads/chrono at the same time.

My switch barrel Marlin 336 will shoot mixed rimless/rimmed cases without a hitch in the 356 Win/444M and the shortened 458 WM and 450 M case.

7/8mm case work great for making 444 M cases because the case OAL is almost the same and after resizing to the larger dia. bullet the cases will shorten anyway...hardly any trimming.

I spent almost one year working out the bugs on 307/308/356W/358W, 444M, 458WM and 450M and several wildcats based on various cartridges for use in the Marlin levergun platform, testing all kinds of cases to see which work the best/easiest, when 444M cases were hard to find and also testing the BS found on the forums from the know-nothing naysayers who never did anything themselves, only repeated what they read online from other know-nothing naysayers.

Do a forum search as I did post some of that data before getting fed up with the mindlessness on this and other forums...I also posted on GBO and Leverguns forums.

REMEMBER!!!!...if you are working with "wildcats" and using other than OEM cases, it doesn't take much, especially in a levergun, to get into the danger zone and ruin a nice rifle or worse.

You DON'T NEED FORM DIES... I used standard sizing dies to form...sometimes you need to use several different sizers or use a seater die to form down...it depends on what cases you start with and what you want to end up with...you have to figure this out yourself...CAREFULLY.

Enjoy your toy.

As to trimming, use a file trim die from RCBS or whoever, hacksaw the case then file to specs. Save a lot of work and much more accurate.

In fact, in many cases, you can use the file trim die as a form die followed by a full length resizing die...This might work for you??? and save some bucks..I have no experience with the 307 Win. For a long time I ran 30-30 dies thru my 25-35 file trim die, then my 25-35 full length die to load my 25-35.

Fortunatly 25-35 brass has become available again, and I got real lucky and found a very old gent who had 25 fresh clean boxes of 25-35, he had been hording for years..I bought them all.