inconsistent seating

[Bluetick]

I have some Montana cast bullets, a product which I have found to be excellent in the past. The ones I'm using in this instance are 405 gr, flat nose in 458. The cases are once fired and have gone through the sizer/de-capper die. The first two bullets seated ok but with a little shaving, leaving small burrs on the mouth of the case. The next two, however, were too loose. In fact, when I checked them for OAL, the calipers pushed the bullets all the way into the case. What gives? Some are too tight and some are too loose? Or is it the brass?

[smithnframe]

I’m assuming it’s 45/70 brass? Did you full length resize the brass? Did you champher inside the case neck?

[richhodg66]

With cat bullets, especially plain based ones (no gas check) you need to flare the case mouth a little to start the bullet. Most straight walled pistol cases die sets do this, but your .458 dies probably do not and you should get one of the Lee Universal Expander dies which cost about 15 bucks but are very useful things if you reload much.

Not sure why your dies are not sizing your cases. My .458 dies are old Herters dies and they do this just fine. Make sure you are running the cases all the way into the sizer die, the shell holder should touch the bottom of the sizer die when the ram is fully up. The only other suggestion would be to mic a few of the bullets and make sure they are really what they are supposed to be, it's possible they are under sized.

Welcome to the forum, by the way. Lots of experience here to help you out.

[JRLesan]

First off, mike the od of the bullets to determine whether bullets or brass is at fault...

[contender1]

Mixed brass by chance?

[sparky45]

STRONGLY suspect your brass is the problem. Brass prep is one of the golden rules.

[Joe504]

Measure everything.
Boolits OD
Brass OD at the neck, pre and post sizing
Brass ID at the neck

Then you will know what the problem is

Sent from my SM-G955U using Tapatalk

[Three44s]

What dies are you using?

For cast or jacketed bullets you will need a flaring die.

Bevel the inside mouths of your cases.

Hope that helps!

Three44s

[FISH4BUGS]

Another possibility that you are "short stroking" your press.
That means that you are not TOTALLY going to the bottom of your stroke on the press. It doesn't take much.

[mdi]

Any time there is a fit problem, first item in a trouble shoot is measure. Measure the bullets, measure the case mouth, and measure a sized case. This will get you started for a remedy. If you know where the problem is originating, you can concentrate on the why and fix it...

[warren5421]

What machine you reloading with? Check your expander die, take it apart and clean it. You using a bullet seating/crimping die, take apart and clean. Check and see the dies are not moving.

[1hole]

What gives? Some are too tight and some are too loose? Or is it the brass?

Well, I don't know for sure but it could be your new bullets aren't all the same diameter. I do know that even if your press and dies are Lee they aren't changing diameter in use.

[oley55]

nary another word from the OP, I hope he didn't get scared off.