rbertalotto
05-07-2012, 06:43 AM
I know this has been discussed a thousand times here on the forum. But the 38-40 is new to me so I'll simply add to the conversation.
The issue is this cartridge was designed for a full case of Black Powder which will limit the bullet from migrating into the case when hammered by other cartridges in a magazine tube on a lever action rifle.
When smokeless powder is used there is a large airspace under the bullet and the bullet needs a strong crimp to keep it in place. But the 38-40 uses extremely thin brass and does not share the neck tension of other types of brass.
The bullets I'm currently casting do not have crimping grooves Lyman) or the crimping groove is in the wrong place and the cartridge OAL is too great to feed properly (LEE)
I ordered the RCBS mold that should have the crimp groove in the proper location.
Here is where I stand:
First some info: www.rvbprecision.com (1873 Winchester article)
I slugged my bore .395 bore / .398 groove
I'm using a LEE seating die with a roll crimp. I loaded thirty cartriges with smokeless powder for my first range session. With five in the magazine, the last two failed to feed because the bullets had been pushed completely into the case.
Here is the issue. My bullets are dropping at .403 and the hole in the die that the bullet must go through before the die can contact the shell and crimp the bullet is only .4015.
So the die knocks the bullet into the mouth of the case before the die can do its crimping. Not good. (Although this would be fine with Black Powder as the powder itself will limit bullet travel within the case.
I need to size my bullets to .401 or use a LEE Factory Crimp Die.
I ordered a .401 sizing die for my STAR lubrisizer from Lathesmith. And I have the LEE Factory Crimp Die and a set of RCBS Cowboy Dies in 38-40 on the way.
Lots of experimenting required............
The issue is this cartridge was designed for a full case of Black Powder which will limit the bullet from migrating into the case when hammered by other cartridges in a magazine tube on a lever action rifle.
When smokeless powder is used there is a large airspace under the bullet and the bullet needs a strong crimp to keep it in place. But the 38-40 uses extremely thin brass and does not share the neck tension of other types of brass.
The bullets I'm currently casting do not have crimping grooves Lyman) or the crimping groove is in the wrong place and the cartridge OAL is too great to feed properly (LEE)
I ordered the RCBS mold that should have the crimp groove in the proper location.
Here is where I stand:
First some info: www.rvbprecision.com (1873 Winchester article)
I slugged my bore .395 bore / .398 groove
I'm using a LEE seating die with a roll crimp. I loaded thirty cartriges with smokeless powder for my first range session. With five in the magazine, the last two failed to feed because the bullets had been pushed completely into the case.
Here is the issue. My bullets are dropping at .403 and the hole in the die that the bullet must go through before the die can contact the shell and crimp the bullet is only .4015.
So the die knocks the bullet into the mouth of the case before the die can do its crimping. Not good. (Although this would be fine with Black Powder as the powder itself will limit bullet travel within the case.
I need to size my bullets to .401 or use a LEE Factory Crimp Die.
I ordered a .401 sizing die for my STAR lubrisizer from Lathesmith. And I have the LEE Factory Crimp Die and a set of RCBS Cowboy Dies in 38-40 on the way.
Lots of experimenting required............