Reeder Custom Guns - 450 GNR Case Forming

I've had a 450 GNR barrel for a while now and need to make some more brass for it. I'm using 348 Winchester brass. What is the trim to length for the 450 GNR case?
Also, are there any advantages to using 50 Alaskan brass as my starting point? I already had the 348 Win on hand and assume it will work equally well. Please steer me right if I am wrong.

I have trimmed .348 first then fireformed. But lately I fireform with blanks, then since I can see the chamber line I trim a little behind that. It does not really matter except that they are uniform with each other. That itself probably makes little difference. (Hey Mr. Taffin, a new test)

The AK brass you just neck down, shoot. You can in steps neck up .348 but I like fireforming in one move. I just got a .450 myself. We’ll keep each other informed.

I’ll make me some brass tomorrow.... take pics.

I started with virgin 348 brass. Necked it up using my .358 Lyman M die. Then anealed the cases. Then stepped up to the .40 S&W expander, then to the 45 cal M die. I trimmed them back to about 2.2". I only did 20 cases to start with. I loaded them up with some 400 gr lead bullets and tried fire-forming them this morning using IMR-3031. Maybe I should have used a faster powder. The cases were not formed evenly and I had lots of unburned powder. The only other thing I can think of was that maybe a heavy crimp would have helped form them better. I tried using the seating die (using Hornady dies) to put a heavy crimp on but it just started to crush the case. Whatever it was, the loads didn't develop enough pressure to evenly form the cases. I'll try again later this week.

Without it I have had misfires and partial firings leaving a stinking yellow mass of unburned powder. No problems after I switched to a magnum primer.

Thank you. I was using standard primers. I'll try magnum primers next time I use the 3031.

The brass is thick but heavily tapered in shape and needs to be blown out a bunch. As you figured out. Don't worry too much about an uneven neck, it can be uniformly trimmed. I'm using whatever primers I have on hand, rifle or pistol, whatever. Odd ones on my bench I don't know what they are, found in the primer tray, etc. gonna use them up.

I've used fast flake shotgun powder but I like a dense ball powder. I have a jug of surplus AA #7, hate to "waste" so much but it perfectly forms a case that will be used up to 20x. Honestly you fill the case with powder and make a blank. Some guys add fillers but that is dangerous as cream-of wheat, cornmeal, under certain pressure acts as a solid and can give bad high pressure. I use tissue or Dacron just to hold powder in place and not spill it. I began with half a case full, took it out and it only went "pifffft". Added more and again "piiiffffft". Up to the neck and once more "KA-BOOM!". If you reach full capacity and it still goes "pift" the blank powder is too slow. If a case is not filled out fully, hit it again! The blanks are horrendously loud and flashy, they are to be respected! Unburned granules, flaming granules, will be shot everywhere. Don't let them hit you, the kids, your dog, hay-bales etc. Each "blank" would have propelled (10) .44 Special loads so I don't like to waste it. The powder costs about 25 cents per blank so keep that in mind.

I'll weigh my blank loads and take some pictures today. It will be fun.

This is firing a blank forming either .416 or .476 GNR, same blank forming any of them, either way.
[image]

This is how I made some .50-95 WCF from .348's. Same concept only the Winchester .50 is much shorter and I figured to cut the necks in half to ease trimming chores. These are assembled blank cartridges ready to fire with dacron blanket stuffing, about a 1" square 1/4" thick. Weighs about the same as a mosquito. I fired one, trimmed to make the finished brass far right.
[image]

These are formed .440 GNR brass from the .348 blanks. Note the little bit of brass that went into the chamber throat. That is custom trimmed to suit and allows me a full neck. The advantage of using .348 over .50 AK, if you need one. I just found a deal on bulk .348's so I went with it.
[image]

Nice photos. Thank you.

Especially the fire breathing fire forms

I got a new camera, new phone, and I'm learning a little about editing with the software. I hate some video clips and I'm trying to learn from what I don't like. We'll play and see what comes.

Gary is pretty cool with it as long as I don't implicate him in the mischief.

- No text -

I tried again yesterday afternoon. Used the same 400gr lead bullets and some IMR-4198. Worked like a champ. I now have my perfectly formed cases. Thanks, all for the assistance.

advantage to using the 50 Alaskan case is you don't need to fireform it.

The sizing die and load, super easy don’t have to worry about fireforming. I may have some 50ak brass sized to the 450 GNR at home. I’ll double check and let you know

How many. Primed and some fired

powered by my little forum