357: Crimp before or at cannelure?

[Psychbiker]

These 357 will be semi hot rounds with 13.5gr if 2400 and with a coated 158gr rnfp bullet.

Manuals differ in OAL. Some have 1.590 and others have 1.550 or 1.570.

Bullet I’m using will need a OAL just of 1.570 in order to crimp at the crimp groove.

Photo below is 1.575 and crimped just shy of the groove. I’m also using the Lee COLLET crimp die. Not a taper crimp or roll crimp. Was suggested to use in rounds that are used for not revolver and rifle.

Does that round look good?

Should I let it out to say 1.580 and don’t worry bout the crimp groove?

I can also run it a little shorter but then pressure spikes will likely happens using 2400 powder.

[zouaveherb]

I would put a heavy roll crimp into the cannelure. I would also back off the charge a bit and work it back up while monitoring for pressure signs like flattened/cratered primers, extraction difficulty, etc. You want a heavy crimp for hot rounds because it gives the cartridge more consistent ignition and you also lower the risk of the bullets in the unfired rounds moving under recoil.

[bruce381]

put at the cannelure then you will reduce smashing the bullet in a place it is not made for

[Sandspider500]

That looks like an acme 158gr rnfp, which is a copy of a laser cast 158gr rnfp.
From laser cast load manual
Standard pistol loads
158gr rnfp 2400* start 14.2 1336 max 15.3 1460 1.570

Rifle loads
158gr rnfp 2400 start 10.0 1378 max 13.0 1593 1.575

Any crimp for a revolver will work in the rifle. The revolvers crimp is preventing the bullet from coming out of the case from recoil. The rifles crimp is preventing the bullet from being seated farther into the case from recoil and cycling the action. I like the collet crimp die and I usually use it for heavy loads or for a bullet that if crimped in the groove would be to long to cycle from the magazine.

As said above by Zoua, with slow powder in magnum pistol a tight crimp will give a better powder burn and a more consistent velocity.

[Sandspider500]

Modified collet crimp, works perfectly for a bullet such as the Lee 457 340 (on the right) which if crimped in the groove would be too long to cycle in my rifle, so I seat it a little deeper and create a crimp groove with the collet crimp.

[Psychbiker]

Modified collet crimp, works perfectly for a bullet such as the Lee 457 340 (on the right) which if crimped in the groove would be too long to cycle in my rifle, so I seat it a little deeper and create a crimp groove with the collet crimp.

On the modified collet, you took the collet out and sanded the top right? I saw that on a casting forum.

What does that benefit? I couldn't determine if that's something I needed to do.

As for the OAL, going 1.570 will likely but the crimp right in the groove.

These are SNS Casting hi-tek coated.

I'll be going with 2400 powder and max is 14.5 charge I believe. I was going to start with 13.5 and honestly pump out about 500 of them.

Friends and I are going camping in 10 days, I don't think I'll be able to try different charges.

13.5 of 2400 with a 158gr seems about 85% of max and a popular load with 357 mag shooters.

[Elgatodeacero]

There is nothing unsafe about your crimp technique/location.

The question is will it yield accurate ammunition, and you have to fire some at a target to determine that.

Traditionally, one would roll crimp in the crimp groove and work up load that way.

The Lee factory crimp die uses a collet to squeeze the crimp, but it also post-sizes the loaded cartridge, which some people feel ends up resizing lead bullets too small causing leading and accuracy problems.

My guess is your coated lead bullet load will work just fine.

[Sandspider500]

There is nothing unsafe about your crimp technique/location.

The question is will it yield accurate ammunition, and you have to fire some at a target to determine that.

Traditionally, one would roll crimp in the crimp groove and work up load that way.

The Lee factory crimp die uses a collet to squeeze the crimp, but it also post-sizes the loaded cartridge, which some people feel ends up resizing lead bullets too small causing leading and accuracy problems.

My guess is your coated lead bullet load will work just fine.

Lee tries to confuse everyone with the names for their crimp dies. The Lee factory crimp die for pistol cartridges has a ring inside that resizes cartridges, and it might squeeze your bullet depending on the size of it and thickness of brass. The Lee collet crimp die for pistol cartridges has a collet inside that crimps but has no ring inside that resizes brass. The Lee factory crimp die for rifle cartridges is the same as the Lee collet crimp die for pistols, I have no idea why they did this with the names.

[Sandspider500]

On the modified collet, you took the collet out and sanded the top right? I saw that on a casting forum.

What does that benefit? I couldn't determine if that's something I needed to do.

As for the OAL, going 1.570 will likely but the crimp right in the groove.

These are SNS Casting hi-tek coated.

I'll be going with 2400 powder and max is 14.5 charge I believe. I was going to start with 13.5 and honestly pump out about 500 of them.

Friends and I are going camping in 10 days, I don't think I'll be able to try different charges.

13.5 of 2400 with a 158gr seems about 85% of max and a popular load with 357 mag shooters.

SNS, acme, laser cast, all dropped from a mold cut with the same cherry.

I modified the collet because it was also crimping above the brass, so it was squeezing just above the brass as well. Top of collet was milled, bottom of collet was milled and the bottom of the die body was milled down. This moved the crimp farther down on the brass.

[pennstater]

I load Missouri 158gr rnfp bullets, like the one pictured above to 1.570". Looks exactly like the one above. My load is 12.5gr 2400 for my Henry(20" barrel). Avg MV is right at 1500 fps over the screens. Accuracy is very good. I use the Lee carbide factory crimp die. Light to medium crimp.

MLC