crimping soft lead bullets

[whatwehavehere]

Will crimping soft, swaged bullets swage or shave what's inside the case to the crimp diameter when the round is fired? That'd be using a Lee factory crimp and hornady swaged 240gr .430 bullets which some youtube gun "experts" report to be soft. Or would the brass straighten out before the bullet is entirely out of the case?

 

[Leadeye]

Lee FC dies will straighten and swage a soft bullet to diameter, however that same soft bullet will bump up some diameter when fired. Don't know what revolver you're using but checking the cylinder throats is a good idea as they will swage a bullet down in size just like the die. I like Lee FC for straight wall cases, I use Redding profile crimp for others.

 

[ol' poke]

the brass will straighten out.

 

[sloughfoot]

The brass opens up to the chamber dimension before the bullet overcomes inertia and starts moving forward.

Basic physics. The amount of crimp is not consequential.

 

[Alpo]

All good answers. If you are using very soft lead, be prepared for a lot of solder in the throat. Hardcast bullets are preferred.

 

[whatwehavehere]

Thanks for the input folks.

 

[noylj]

Bullets have what is called inertia due to their weight--the case mouth has much less inertia. It takes some time to start the bullet moving. During that time, the pressure has already worked on the case and opened it up.
Please remember, metallic cartridges have been around for about 150 years and lead bullets have been used during all that time. If there was an issue, it would have been addressed by now.
Things to note:
1) Roll crimps are applied to the crimp groove in the cast bullet or, if the bullet is too long to fit in the cylinder, over the bullet shoulder or along the bullet ogive or, if the bullet is too short, even into the lube groove. Seating should be done such that the case mouth is slightly below the top of the bullet's crimp groove. The crimp groove or cannelure on jacketed bullets is much longer than the range of case lengths and I have never found an increase in accuracy by trimming cases to a consistent length.
2) Use enough case mouth flare to ensure the bullet does not get shaved during seating. More flare is better than not enough.
3) Crimp should be separated from seating. Otherwise the crimp is occurring while the bullet is still being seated.
4) The case ID should be expander to 0.001-0.002" under actual bullet diameter--otherwise the bullet can be swaged down during seating. All handguns up to and including .44 Rem Mag work just fine with 10 BHN alloy.
5) If the alloy is under 15 BHN, it should be at least 0.001" larger than actual groove diameter. If the alloy is 15 BHN or more, it usually does better if it is at least 0.002" larger than actual groove diameter. The bullet also needs to be at least a snug slip fit in the revolver's cylinder's throats. If the throats are smaller than the actual groove diameter, you'll never get lead bullet to work well.