Is Overcrimping My Problem?

[Shane Tuttle]

On a loosely related thread I started below, I talked about overcamming. Another problem I came up with may be due to overcrimping. During post inspection, I found that some of the bullets would fall into the case. I used a bullet puller and inspected the bullet. Found that the lower portion showed visible signs where it was crimped. I took a measurement which was .351" - .352". Is this normal?

I'm using a Hornady Lock 'N' Load press using Hornady dies including its taper crimp die.


http://www.thefiringline.com/forums/showthread.php?t=319432

 

[carprivershooter]

Over crimping

Sir, In my humble opinion, I don't think you are crimping enough. If the bullet is able to be pushed into the case I think your not cramping enough. the cramp is to hold the bullet in place and to maintain good head space. I would try loading some dummy rounds trying different crimping presures and see what happens. I use a Lee Turret press and had a simular prolbem. On the lee press when you set the bullet it also cramps it. I had to work not only the depth of the bullet but the amount of crimping. just my thoughts. I am still a newbe only load about 3000 rounds loaded. good luck.

 

[kraigwy]

What are you loading? Sounds like you are not sizing the cases enough or belling the case too much if its a straight wall case.

You talk about a taper crimp I'm figuring your loadind straight wall cases. The of course need a taper crimp but you dont want to crimp them so much they are squeezing the bullet to the point of deforming them.

 

[LHB1]

Tuttle,
What caliber are you loading? 9mm? What do the bullets measure before loading into case? They should NOT be significantly reduced in diameter after seating/crimping. FWIW, bullets in straight, rimless cases to be fired in semi-autos are held in place by the case resizing performed in step 1 of reloading process. After seating new primer, the case is belled LIGHTLY in step 2 (just enough to allow bullet to be started into case). Powder is thrown in step 3. Bullet is inserted into top of case and seated/crimped in step 4. Some reloaders do seating and crimping in separate steps/dies/stations. Taper crimping such cartridges is done ONLY to remove the small belling/flare performed in step 2 which allowed easy insertion of bullet. If you overcrimp in final step, you can crush the bullet which will retain the smaller diameter while the brass case will spring back slightly from bullet and thus leave the bullet loose in case. BAD procedure, that.

 

[D. Manley]

Assuming you are loading 9mm (?), I'd say you are indeed overcrimping. As many times as its been posted over and over again, a lot of people still believe the crimp is to "hold" the bullet. On straight-walled, auto-loading pistol cases, the re-sized case provides tension for the bullet and the "crimp" should only remove the flare (bell) from the case mouth. Over-crimping will have precisely the results you described...loose, under-sized, bullets and, the potential for disaster. Measure your bullets before seating and again after...if they're reduced by crimping, there's your answer. Calipers are your friend...crimp to: case wall thickness x2 + bullet diameter.

 

[Shane Tuttle]

Sorry, fellas. One of my pet peeves on this forum is when an OP doesn't give enough information to help troubleshoot the problem. I happen to be the guilty party here. I must have gotten in a hurry during my entry that I forgot to put it in.

Yes, it is 9mm.

I would try loading some dummy rounds trying different crimping presures and see what happens.

This is what I started the other day. It appeared that after bullet seating it was fine...at first. Then after I taper crimped the bullet, I could with a bit of pressure shove the bullet down into the case.

I had to work not only the depth of the bullet but the amount of crimping.

There may be a number of problems and I think the taper crimp die is exposing them, not being the culprit...

What are you loading? Sounds like you are not sizing the cases enough or belling the case too much if its a straight wall case.

I have the sizing die set right. The before/after measurements are on par what I used to get with my previous die set.

Per the belling issue: The Hornady expander just feels different than the Lee I used to use. Still, I think it's set up correctly also. I have it set so that the belling is just enough that it doesn't shave the jacketing but not so much that the bullet easily sets on the case by itself.

You talk about a taper crimp I'm figuring your loadind straight wall cases. The of course need a taper crimp but you dont want to crimp them so much they are squeezing the bullet to the point of deforming them.

Yes, straight wall.
That's what my concern is. The crimp seems too much. When I pulled the bullet, the lower portion that was seated into the case was obviously smaller. It was still concentric, but I don't ever recalling any bullets being like this.

What do the bullets measure before loading into case? They should NOT be significantly reduced in diameter after seating/crimping.

Before= .355 After= .349-.351

If you overcrimp in final step, you can crush the bullet which will retain the smaller diameter while the brass case will spring back slightly from bullet and thus leave the bullet loose in case.

And this is what I've been thinking is happening but I wanted to ask around before wasting any more supplies.

 

[LHB1]

Tuttle,
From the additional info, it sounds like you are on the right track in reducing the amount of taper crimp so it doesn't deform the bullet. As suggested before, the final crimped diameter should be very close to twice the case neck thickness plus the original diameter of bullet. Let us know how your next batch of reloads work out. Good luck.

 

[Nnobby45]

Good grief, gentlemen. If you check out the manual and look at the spec. for case mouth diameter, and set your crimp die accordingly, then you've properly crimped the thing.

For example, the proper case mouth diameter for .45 ACP is .472. I crimp mine to .471 or .472. Lead bullets I crimp to .469 because, long ago, Bill Wilson recommended it when .45's were used for IPSC with lead SWC bullets. Works fine. Crimp too much and you loosen things up.

Folks just need to quit trying to swage the bullet during the taper crimp process, and only crimp enough to straighten out the case walls. The case secures the bullet, not the crimp. As mentioned, on lead bullets, I crimp slightly more. LOL.

If you can push the bullet into the case right after seating, then you have another issue to deal with. For example, I have some plated bullets in .44 Special for which, only about an 1/8th of an inch at the rear of the bullet is the proper diameter, the bullet diameter gets less as the bullet tapers forward---but that's another issue.

If the bullet is secure before the crimp, but not after, then refer to the above.

 

[F. Guffey]

Tuttle8, I do not want you to run out and purchase anything, just consider the options, there is a roll crimp, taper crimp and the sizer die. I have no reservation crimping 9MM Luger or 45 ACP with a sizer die, I seat the bullet in one operation and crimp the bullet in another, I have a Ruger P 90 that likes new commercial ammo, or hand loads that are crimped with a sizer, I do not 'full length crimp', I take the wrinkle out of case to make the P90 think the cases are store bought.

With a bullet seated in a case without a primer or powder, crimp the bullet with a sizer, then pull the bullet with the inertia hammer, I do not want to talk it to death but it is said the case pops out and the lead shrinks and does not recover etc. etc..

F. Guffey

 

[Shane Tuttle]

Just to give you guys an update:

I backed off my seating die about a turn and then reset my OAL to 1.147". Also, the taper crimp die in the 5th station got turned out several turns and then started over on the crimping process. I gradually turned it back down until it was just kissing the mouth of the case.

It seems to to the job so far. I think these combined items were the problem. I only worked up about 60 rounds so far to test fire. Hopefully, I'll be able to head to the range this weekend to verify proper operation.

My dimensions look good and I tried to hand squeeze the bullet to see if they would compress. No defects noted at this time.

I'll keep you guys/gals updated. I really appreciate the responses. It's nice to have a board like this with helpful people.