30-30 COL headache

[coondogger]

I just loaded a small batch of 30-30 cartridges. The receipe called for IMR 3031 with a 30 cal jacketed 150 gr RN bullet. It stated a maximum COL of 2.550. But more importantly, a minimum COL of 2.540. I trimmed the once fired brass to 2.030. When seated toward the bottom of the cannelure, they all measured around 2.540. But after crimping, they measured between 2.532 and 2.537.

Two questions:

1. Why so much movement with the crimp?

2. Are they ok, pressure-wise to use in a lever action rifle?

 

[forty_caliber]

Looking at the Lyman 50th Anniversary table. The OAL for that bullet is 2.540 max. It looks like the length is fine to me. .003 and change isn't much to be concerned about.

Did you use a roll crimp or taper crimp die. Too much crimp might explain the difference in COAL.

.40

 

[tightgroup tiger]

Seat up higher in the cannular, the crimp is pulling the bullet down in the case as it folds in. You will still loose a few thousands but not 8 thousands.
I think the swing you are seeing is because of different length brass in a fixed height die.

 

[coondogger]

Looking at the Lyman 50th Anniversary table. The OAL for that bullet is 2.540 max. It looks like the length is fine to me. .003 and change isn't much to be concerned about.

Did you use a roll crimp or taper crimp die. Too much crimp might explain the difference in COAL.

.40

I used a roll crimp die and went an extra 1/2 turn past minimum.

 

[joneb]

the crimp is pulling the bullet down in the case as it folds in

That makes sense.
Could try a Lee collet crimp die, I use it mostly for plated bullets.

 

[Muddydogs]

My experience is if the bullet is moving during crimping your crimping to much, back the crimp off a 1/4 turn and see if that helps. The Lee rifle FCD works a little better for crimping 30-30 rounds then using the seater die crimp function.

 

[coondogger]

 

[coondogger]

That makes sense.
Could try a Lee collet crimp die, I use it mostly for plated bullets.

That's what I'm using; the Lee Factory Crimp die.

 

[ArchAngelCD]

The min for the cartridge is for the chamber more than the cartridge. I few thousands of an inch won't effect anything, your proper crimp is into the groove like you did. You are at check-in because you trimmed the case to the min. How did you measure the case length after trumming? Is it possible the case is .003" short causing the OAL to be slightly short?

As said above, that small a difference is nothing to be concerned about.

 

[coondogger]

My experience is if the bullet is moving during crimping your crimping to much, back the crimp off a 1/4 turn and see if that helps. The Lee rifle FCD works a little better for crimping 30-30 rounds then using the seater die crimp function.

I'm going to try that. I suspect you're right.

 

[ArchAngelCD]

You posted the pic as I was writing. In the picture that crimp seems to be a little tight. It might be the photo but maybe not. You might want to lessen the crimp slightly, not because of length, just for a proper crimp.

Edit: autocorrect got me again!

 

[stringnut]

If you crimp and seat in one operation the bullet is being pushed further by the seating plug as it is crimping. You have to seat one to depth , back off the seater, adjust the crimp, them run the seater in until it touches. If seating and crimping separately make sure you back off the seating plug ( or stem) before seating.

Also when roll crimping the case mouth metal is being displaced inward and toward the rear of the case simultaneously . This will shorten things a bit. If your cases vary in length the amount of difference can be quit a bit.. However is not anything to get excited about.

. If overcrimped the case necks can show can show a bulge. If it chambers with normal force bulges cartridges can be shot. Being a rimmed case, headspacing on the rim, the bulge will be smoothed out the same as fire forming rim less cases.

The col being slightly under length is completely immaterial. There is not enough difference to matter. Case volume variation will be a far greater difference than being that tiny bit short..

 

[coondogger]

If the mild weather holds, I'll test these out this weekend.

 

[joneb]

That's what I'm using; the Lee Factory Crimp die.

Using the Lee collet crimp die with a cannelured bullet, try seating the bullet deeper so the crimp is centered with the cannelure.

 

[BSA1]

Your crimp looks a bit to tight to me also.

Easy test is to put the nose of the bullet on a hard surface and push hard on the cartridge. Measuring the oal before and after will tell you how tight the crimp is.

Unless you are near max load I would not worry about excessive pressure. Overcrimping will wear out the case mouth quicker and maybe make chambering the round more difficult.

 

[joe-bue]

Have you checked the position of the cannelure on the bullet, I had a box about 2 years ago that the cannelure was off by about its width. I contacted the manufacture they had me send them 5 bullets. About 3 weeks later i got a box in the mail with a letter. They said that they had a problem with the manufacturing, and sent me a new box thanking me for notifying them.

 

[Bfh_auto]

In 30-30, I seat to the middle of the cannelure.
I crimp and seat in the same step so I set the crimp to barely contact the inside of the groove
I have not had issues with bullet set back.