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Is it possible to crimp too much?

Posted: 03 Dec 2019 21:21
by Lufbery
The title says it all -- is it possible to crimp too much?

My bullets look pretty good, but I've heard that too much crimp can cause pressures to get too high. Naturally, I'm trying to be fairly gentle and consistent with the crimp, but it's hard to tell if I'm doing too much.

I haven't gotten out to shoot the first rounds I've loaded yet.

I'm using Trail Boss in .38 Special, if that makes any difference.

Thanks!

Re: Is it possible to crimp too much?

Posted: 03 Dec 2019 22:08
by larryw
Don't worry about crimp -vs- pressure in 38spec, non issue.
When im crimping cast or jacketed into a canular or crimp groove,
with standard 38spec loads, I want to visibly see some crimp rolled in.
38spec +P loads, I wanna see even more of a crimp.
Hot, heavy .357mag, 44mag, hunting, barn burner, hand hurters
I want to see one heck of a heavy crimp.
You don't want any bullet pulling out of the case under recoil.
If it comes out far enough, it will lock up the cylinder.
Plated bullets are a different story, the plating is thin enough that a
bit to much crimp will cut the plating. I use a taper crimp for these.
It's pretty tough to get into trouble with 38spec, that doesn't mean
Do as you please. Stick to published loads, "Start low & work up" is
A clasic handloaders mantra & one we take very, very seriously.
Well, I bet this made things clear as mud for you ?
Very good question by the way.

Re: Is it possible to crimp too much?

Posted: 04 Dec 2019 05:27
by GasGuzzler
The only thing less dangerous in reloading than .38 Special is Trail Boss. It's barely flammable. You'll be fine with crimps. Maybe we need to find/make some pictorial examples to post...

Re: Is it possible to crimp too much?

Posted: 04 Dec 2019 12:48
by Ohio3Wheels
Roll or taper crimp I check by pushing the bullet nose against the bench. If it moves not enough and I screw the die down about an eight of a turn and try again with ANOTHER case. It wont take you long to find the setting. With roll crimping you're best off if all the cases are the same length or as close to it as your trimmer will get them.

Make smoke,

Re: Is it possible to crimp too much?

Posted: 05 Dec 2019 08:10
by Macd
What Larryw said. I will add that jacketed should be only roll crimped into a crimp groove or alternatively taper crimped. Bullet creep in revolvers is outward and can lead to a jammed cylinder. Been there and it is not fun. In autos it is inward and this can cause pressure spikes. As Ohio3wheels notes, having cases all the same length is a good practise.

Re: Is it possible to crimp too much?

Posted: 05 Dec 2019 11:59
by mikld
Yes, you can crimp too much. Too heavy a crimp often results in bulged cases and distorted/ruined bullets. I have used some "monster" crimps on some near max 357 and 44 Magnum rounds without any apparent increase in pressures (and I did get a bit more consistent velocities, but not as good accuracy). I would suggest getting a factory round and compare your crimp to the factory crimp as a starter; make your crimp look like a factory crimp. I have only used Trailboss in some 44 Magnum loads and used a "standard" roll crimp on 240 gr RNFP bullets. No problems I could see.

I like to roll crimp my revolver rounds just enough so the case mouth is rolled to the depth/bottom of the cannalure or crimp groove, but that takes a bit of practice and good inspection. For later in your reloading; there are other crimps that work quite well. For my revolver rounds I use a Redding Profile Crimp and for some of my 44 Magnum rounds I use a Lee Collet Crimp, both are excellent tools...

Re: Is it possible to crimp too much?

Posted: 06 Dec 2019 18:01
by Lufbery
Thanks for the replies. When I talk about crimping, it's with the Lee Loader. I don't have anything else right now. I _think_ I'm okay. The crimps look okay to me, and they're in the crimping groove of the bullets I'm using. We'll see when I go shooting this weekend.

Thanks!

Re: Is it possible to crimp too much?

Posted: 07 Dec 2019 10:29
by horseman
Lufbery wrote:Thanks for the replies. When I talk about crimping, it's with the Lee Loader. I don't have anything else right now. I _think_ I'm okay. The crimps look okay to me, and they're in the crimping groove of the bullets I'm using. We'll see when I go shooting this weekend.

Thanks!


The way I set my crimp die is to run my fingernail down the bullet towards the brass neck, if I feel the neck I add more crimp until it's a smooth transition. You will also be able to see the brass "curl" into the crimp groove. To some this may seem a bit much but it's worked for me for quite some time now. Of course this does not apply to rounds that "head space" off the case mouth where a taper crimp is needed. I haven't had a bullet jump crimp for many years now so I'll just keep doing it this way. Looks good too. :D

Re: Is it possible to crimp too much?

Posted: 07 Dec 2019 12:44
by mikld
Yep, crimping with a Lee loader can be a bit frustrating, consistency wise. I used a Lee Loader for two years exclusively, and it just takes practice to figger how hard to hit the die. For revolver ammo crimping is not as critical as some believe, just crimp enough to keep the bullets in place and try to be consistent...

Re: Is it possible to crimp too much?

Posted: 08 Dec 2019 23:56
by Fyodor
There even is a thread here in the forum, where one user (ahem...) overcrimped and didn't realize. I think I ... "the user" named that thread "bent cartridges".

;)