9MM Taper Crimp?

[stodd]

Hello,

I'm trying to do the taper crimp on my 9MM loads and i currently have the taper crimp at .003 different at the case mouth and the rest of the case. Is this good or is it too much taper crimp?

Thanks.
Stodd

 

[loadedround]

I have never attempted to measure the crimp on my 9mm or 45 ACP rounds. Both need a very slight taper crimp and the easiest way to do that this as follows. Seat your bullet to the proper depth, back off your seater stem, screw your seater body down until it just touches the case mouth raise handle and turn die body a little less than a quarter turn, lower handle to crimp and lock die body and seating stem in place. The 9mm just needs a kiss of crimp assuming all cases are of the same length.

 

[Walkalong]

More than needed, but OK.

What is important is that all the cases, long or short, get enough to remove the bell. If you adjust the crimp for that, none will get too much either.

 

[stodd]

Thanks guys.. I've backed off the taper crimp alittle bit and now have a difference of .001 for the taper.

Had a question about the OAL with this berry 124 grain RN DS bullet i'm loading. I'm load them with bullseye powder and looked at the lyman's manual i have for data and found a 125 grain jacketed bullet starting charge of bullseye was listed at 3.9 grains with a OAL of 1.075. I've loaded 10 rounds ea at 3.9 and 4.0 grains.

I was told by a few ppl to try seating this berry's bullet to OAL 1.125. I'm trying to learn and figure out how the OAL plays in when loading for the 9MM.

What is the difference if i loaded the same charge of 4.0 grains of bullseye with a OAL of 1.100, 1.110, 1.120 or 1.125?

I've noticed some of the store bought ammo for the 9MM OAL's are all different.

Thanks..
Stodd

 

[Deus Machina]

1.125 is sort of a rough 'standard' for 9mm.

The OAL will affect the pressure and velocity; the shorter the OAL, the further into the case the bullet is, and thus the less space the powder has.

Don't load any shorter or with any heavier charges than you are without checking for pressure signs.

My CZ, for example, doesn't like anything at 1.125. I've got blunt lead RN I actually have to load closer to 1.05, and stick to the starting weight. I've since swapped that mold out for one a grain lighter and a good deal pointier, and that seems to be more forgiving.

 

[rcmodel]

I'm trying to learn and figure out how the OAL plays in when loading for the 9MM.

Proper OAL is determined by the shape of the bullet, not so much by the weight.

If you notice, the 125 grain load showing 1.075" OAL in the Lyman manual is for a Sierra JHP with a wide flat HP nose, and a full diameter shank extending far up the side of the bullet.

JHP and Truncated Cone bullets always have to have a shorter OAL because of the flat tip and long bearing surface that will hit the rifling leade sooner then a RN bullet.

You are using round nose Berry bullets with a much smaller rounded nose section and less full dia shank exposed.

1.125" - 1.150" would be a much more realistic OAL for that RN Berry bullet, or any RN bullet for that matter.

I've noticed some of the store bought ammo for the 9MM OAL's are all different.

Again, that is because they all use slightly different bullet nose designs.


rc

 

[stodd]

RC,
Thanks for info..

 

[rfwobbly]

Back to the taper crimp.....

I like to measure mine, so here's how I do it. I look at the SAAMI case diameter at the case mouth as given in your manual. For 9x19 that number is .380". I then set my taper crimp die so that I'm getting a diameter of .002" less than the SAAMI number (.378"). That's just the last 1/32" of the case mouth. The crimp die just acts on the tip of the mouth and nothing else.

I follow that with 2 tests...
• Crimp a plated bullet into a test cartridge, knock it out with a kinetic hammer, and make sure the crimp did not leave a mark (a waist band) on the bullet.

• Drop a test cartridge into your naked barrel's chamber. It should fall all the way into the chamber using ONLY its own weight. In fact, the cartridge will usually make the barrel ring when this happens.

 

[1SOW]

rfwobbly +1 with a priviso:

With the Federal 'family' of cases (FC, Speer, *-*, CCI) you will get a different crimp than you will with Winchester thickness cases (Win, WC, PPU, R&P). The difference is small, but noticeable on a single stage or turret press when pulling the handle. I measured .001 or slightly more difference at the case mouth, but I know that a dig caliper has up to +/- .001 error.

With my turret press , without changing the sizing or taper crimp die, an FC case will seat a bullet .002-.003 deeper than a Win case will seat it. I have checked this many different times and it is 'consistent'.

In reality, it will make no significant difference for the crimp; but for me it's worth knowing there is a difference in the cases..