Loading oversize bullets in 44 mag cases

[glockky]

My marlin 1894's barrel slugs at .4325". My mold drops a bullet which is .4335" which I run through my lyman 4500 with a .434" sizer die just to lube.

Today I tried to load some of these oversize bullets and ran into all kinds of problems. I had to expand the case so much that it put a huge bell on the end of the case just to get the gas check started in the case.

The real problem came when I went to seat my bullet. The case was expanded so much that it would not hardly fit into my seating die and took quite a bit of force. I noticed after seating a few that the brass was slightly bulged on once side of the case.

I checked a few rounds that I had loaded and they chambered fine in my rifle. My question is how do I avoid these problems?
Do I need to modify my dies?
I am using the 3 piece RCBS dies set.

[dilly]

I think one thing you can do is use the same type of brass so the wall thickness is consistent between rounds. It may help when some chamber and some don't, which drives you crazy.

You might be able to hone out your sizing die to save work hardening on your brass, but I'm not really sure. I feel like that would solve a lot of issues.

[1Shirt]

Good and practical advice dilly!
1Shirt!

[dkf]

Should expand the brass with an m-die or a custom made plug for in a Lee universal expanding die. This way you add some flare to case mouth and open up the inside of case enough to provide bullet tension without swaging down the bullet. Most die sets size for use of a .431" at the largest diameter bullet.

[Cowboy_Dan]

I have simelar issues when I load .45 Colt. That pistol's groove diameter is .4585, so I use tiny .45 rifle boolits and expnd the mouths huge. The boolits cause the brass to have a reverse bottleneck, but t has always seemed centered so far.

I have considered having a custom mold made with a heeled boolit and powder coating it, but haven't done it yet. Not sure how I would crimp it, though.

[Nueces]

Bet you could crimp a heel boolit with a modified Lee collet crimp die...

[runfiverun]

Try a backed out steel die set for sizing.
You can also seat in a 45 colt die then barely run it into the 44 die to crimp.
I have to get a little creative with my 44-40's and the 45 die is what I use there.
You'll have to look around a bit for a flair tool to make things work better.

[bobthenailer]

for my 44,s that use cast boolets sized @.433 dia , I only size about 1/2 of the case and use a turned down .452 expander plug that now measures .430 dia with excellent results.

[Blammer]

get one of NOE's expander inserts for the Lee Universal expander, at the size you need, that will take care of the brass problem and the bulges. As for seating, put the seating plug as far down as possible so you are using the "bottom" of the die, it tends to be a little more generous there.

[rintinglen]

get one of NOE's expander inserts for the Lee Universal expander, at the size you need, that will take care of the brass problem and the bulges. As for seating, put the seating plug as far down as possible so you are using the "bottom" of the die, it tends to be a little more generous there.
+1
Either an over-size M-die or an NOE will likely be your friend. The issue is that your expander plug is undersize by .002", and your sizing die is working a bit over much. You will have to address this to cure the problem. If you or a friend have access to a lathe, you could make your own expander plug that would help or track down a spare sizer die and polish it out a thousandth or two to minimize down sizing in the first place.