357 Mag Crimping

[MADCleveland]

I'm a new reloader and recently loaded 200 rds of new 357 brass with 140gr XTP bullets and Accurate powder. Everything was to spec per the Hornady manual. When the rounds were fired they would not eject from the cylinder easily. Factory loads ejected without issue. So I deconstructed 15 rounds to verify they were loaded to spec. Everything checked out. I emailed Hornady and the only issue they could figure was that that the crimp was too tight. I used a RCBS Rockchucker to load and crimp. The crimps all appear to be within .005-.006 and in the proper cannelure grooves. Not really sure what the issue is.

So, for safety purposes I'm in the process of deconstructing all the hand loads as I don't want to damage the gun or injure myself. I'll reload to spec again. My question is how do I determine the correct crimp? Is a crimp even necessary on 357? Thanks for your advice.

 

[wildcat3d]

Try reduction of load by a few tenths, are you shooting over a chrony or something to check speed to verify that it's not just a hot load in your gun? need to start below spec's and work to max. just taking a poke in the dark here. my 38's are way to hot with some powders and bullets loaded to spec's I use just enough crimp to make sure nothing moves, just set by die instructions.

 

[RegionRat]

My question is how do I determine the correct crimp? Is a crimp even necessary on 357? Thanks for your advice.

If we talk in generalities, the 357 magnum does better with a crimp when in the context of full pressure loads.
All of them should go boom, but the goal is a better performance comes from more consistent ignition, and in the context of these pistol magnums it usually requires the additional starting pressure from that roll crimp.

With plinking loads, a light taper crimp is more than enough.

At any point, you should name the specifics of your charge and powder here. It would help.
Did the phone tech advise you to drop the charge down a few tenths, and shoot over a chrono?

Going forward, I would not start a rookie loader with what we would call a high pressure defensive load. You should get a mentor and start with lower pressure target loads and give yourself time to learn the ropes, and then creep up to high pressure JHP loads.

The use of a chronograph is a better way to go if you don't have an experienced mentor along for the ride. That way, you would at least have a reference frame for normal versus abnormal velocity, hence the pressure.

 

[jds holler]

For my curiosity, what kind of revolver are you shooting. jd

 

[DocBII]

MADC,

Are you seating and crimping at the same time? If so, try seating and crimping in separate steps.

HTH,
DocBII

 

[joshb]

“Everything was to spec per the Hornady manual.”
That’s a little vague. What is your load?
Powders can vary, lot to lot.
Every gun is a little different.
Lots of variables besides crimp.

 

[vonb]

Are the unfired loads easy to remove from your cylinder or are they difficult to remove? If they are easy to remove, you are most likely over pressure. If they are difficult to remove, you have too much crimp and are bulging your cases. Ease up on your crimp.

 

[243winxb]

Crimp it.

 

[joshb]

Here’s a point I just had to relearn: I’m getting back into 44 Magnum reloading. I went out and bought Magnum Pistol Primers. Seems simple and logical…right? Well…when I started CAREFULLY reading my manual, the loads presented were based on the use of Winchester Large Pistol primers. That in itself can make a difference between a “max load” and an over pressure load.
This is why experienced reloaders work up loads for each gun. We NEVER just grab a load from the book.

 

[243winxb]

Do jump crimp test.

OP- Last seen Wednesday at 4:59 PM

 

[jds holler]

I had a similar problem with my "brand spanking new 686" twenty odd years ago. The cause was simply lack of detail work on the extractor star, and chamber mouths. It was as if they missed the final polish and inspection on my revolver, and the edges on the cylinder mouths needed to be "broke" and smoothed a touch. And the difference between a reloaded case and a factory shell was indeed enough to cause a problem.

Over the years, S&W has had a few rough patches when quality control wasn't stellar. jd

 

[K22]

Need reload data you used.

Yes, a crimp is necessary for a 357 Magnum revolver for two reasons: to prevent bullet movement in adjacent chambers of the cylinder from recoil, and to provide for proper ignition of the powder. As someone else posted, a roll crimp should be used for magnum loads and either a roll or taper crimp can be used for light target loads.

An improper roll crimp can cause a bulge at the neck making the cartridge difficult to chamber. After firing this would blow out and not cause ejection issues. Since factory ammo extracted without issue, my best guess is that you are over pressure with your reloads. That is usually the cause of difficult extraction when there is not a defect (tool marks) in the chamber walls. If the latter was present, you would notice extraction issues with the factory ammo. You should also be able to see such chamber defects with the naked eye.

If you PM me, I can instruct you on how to apply a proper roll crimp, but I do not believe this is the source of your extraction issues - it's over pressure.