Crimp without Reducing OAL

[Flux Capacitor]

I decided to crimp my plinking rounds. I am following a DVD reloading tutorial. In the tutorial, he seats the bullet and measures it up with a caliper and then crimps it. He then takes that first round and uses it to setup the seater die to seat and crimp at the same time.

My problem: I made the first round at a perfect 2.20 OAL. After I crimped it, it was a tad smaller. If I use this to setup the seater die, all the rounds will be smaller than 2.20 OAL. Below is what I am doing per the video.


1. I am making a first round without crimping. I am up to the point of making fine adjustments adjusting the bullet seater screw and seating the bullet to get the OAL to 2.20".

2. Then I setup for crimping (initial setup after making the first round). I back out the "bullet seater screw" and the seater die. Then I insert the round I just made. I screw in the seater die until it stops. Then I take the bullet out. Then turn the die 1/4 more turn. Insert the round, raise the press and its crimped! But then the OAL is a little bit smaller than 2.20!

I just need to make one perfect round to setup the die and start churing them out. AM I doing something wrong?

[J-cat]

You can never achieve perfection by seating and crimping at the same time. If you overcrimp, the case mouth will dig into the bullet shank and pull the bullet into the case. You should back off the crimp. Or trim each case to the same exact length. That way all the bullets will be pulled inside the case the same amount.

[bruceflinch]

What round are you loading? The combo seater/crimper die is a bit tricky & frustrating. What was your final OAL after crimping? A couple thousands may not matter.

[Beelzy]

You're doing it the hard way.

Set the die to seat the bullet a couple of thousanths high, then when you
finish the stroke the seating die will seat the bullet further into the case by those few thousanths upon crimping. It takes some practice, so be patient.

Of course cases that measure all the same length will deliver better results.

[morphius]

Kinda vague Flux

Without noting what cartridge, you're going to get a variety of advice and opinions. Here's one from me

I'm assuming 2.20" is a .223 Remington load, maybe using a 55gr FMJ bullet with cannalure for an autoloader rifle (AR-15 / Mini-14)?

If so, consider the option of using a separate crimp die, such as the Lee Factory Crimp die. This has a collet that squeezes the case neck and thus not affecting your OAL. The Lee FCD's are rather inexpensive and works expecially well for loads intended for autoloader rifles. You can have consistent OAL to fit loads consistently into magazines and not worrying about buldging shoulders due to seating and crimping cases that are longer than trim length and causing feeding failures.

[cassius]

OP fails to mention if he is using a roll crimp or taper crimp. A taper really shouldn't be affecting OAL.

And the later poster stating to just start out long is correct.
If your intent is to use a combo die on a progressive press, then do the things you need to do to accomodate that method. Instead of getting bogged down into using the equipment improperly trying to compensate for an issue in the inappropriate way.
There's a proper method to adjusting a combo seat / crimp die, to get the OAL and crimp how you want them. The OP isn't using it.

[EOD3]

IMHO, you should never seat and crimp in the same operation. After you seat ALL your bullets, back out or remove the seater plug before you crimp. If you're already doing this and still having problems, buy one of the Lee Factory Crimp dies (read the instructions CAREFULLY) and never look back. I use them on .223 to 45/70 and they're hard to beat.

[gdoldave]

lee collet crimper

A Lee collet crimper will solve all crimping problems . Mine also tightened up groups considerably.

[shonc99]

If you are using a seating die to seat and crimp, you first have to adjust the crimp and then the seating depth.

With the die backed out just far enough so as to not crimp, adjust the seating depth until desired OAL is reached. Then back the seating depth knob out far enough that it won't seat the bullet deeper as you screw in the die body to increase the crimp. Once you have reached the desired crimp, with the seated cartridge (at desired OAL) raised fully in the die, screw the seating depth knob until it touches the bullet. You may have to adjust the seating depth knob ever so slightly one way or another due to slop in the press, die, etc.; but otherwise this is the best way to set up the die. Also, case length is critical as minor variations in case length will result in differing amounts of roll crimp.

You will have to have a cannelure on the bullet in order to roll crimp, which in effect pushes (rolls) the neck against the bullet. Without the cannelure, the neck will get squashed down like an accordian. Even with a cannelure'd bullet, too much crimp will result in a squashed neck. This is because the force required to roll crimp the brass is also close to the same force required to crush the neck.

[shonc99]

IMHO, you should never seat and crimp in the same operation. After you seat ALL your bullets, back out or remove the seater plug before you crimp. If you're already doing this and still having problems, buy one of the Lee Factory Crimp dies (read the instructions CAREFULLY) and never look back. I use them on .223 to 45/70 and they're hard to beat.

IMHO the Lee Factory crimp die is hands down the easiest and simplest way to provide a firm crimp. When the shellholder is coming up on the ram, it pushes against the bottom of the die, which is a collet that crimps around the neck. You can't over crimp because the collet in effect bottoms out. Simple, easy and inexpensive.