Proper crimp

[urnsrus]

Can you suggest the proper crimp for a .38 super (124 MG JHP w/ 7.8gr VVN350)

Thanks

[Hi-Power Jack]

David, crimp doesn't vary from bullet to bullet or from powder to powder.

If you set your crimp die to the proper setting, it's good forever.

Before you load up a lot of ammo, it's good to run the Plunk Test ...

Make sure cartridge completely enters the chamber, and will

rotate and drop freely.

If you have too much crimp, it will affect accuracy and leave a mark

on the bullet (if you pull a bullet that has been reloaded).

It's not really a "crimp" for semi-autos - more of removing the belling

you made to the case so you could easily seat the bullet.

[urnsrus]

Thanks Jack. I didn't think it made a difference with bullet or powder, just mentioned it in case someone would ask.

Currently at the collar, it is about .375

I will go pull that bullet and see if it creased the bullet.

[Sarge]

Jack,

Good advice. I might add that some brass will have thicker/thinner case walls so crimp is not always good forever. Unless 38 brass is uniform from brand to brand like 9mm isn't.

[Hi-Power Jack]

I set the "crimp" on my two SDB's four and twenty years ago,

and haven't touched them, since.

I load 9mm minor and major, with 115's, 124's and 147's;

using range brass (except military, S&B & A-Merc's)

and haven't had any problems in my four 9mm guns

(2 Browning Hi-Powers and 2 TruBor's).

[amada8]

It's not really a "crimp" for semi-autos - more of removing the belling

you made to the case so you could easily seat the bullet.

As a beginning reloader, I have found that I do not agree with the concept of "just remove the belling" so YMMV.

After my first 2000 cartridges in 9mm, 10mm and .40 S&W, I was getting good but not great accuracy or consistant velocities. I use my chrono for every new trial of ten and bench rest 30ft shots. The key finding was a sooty outer case. Because I reload light powder charges I assumed that that was the cause....that the case wasn't getting enough pressure to seal the case against the chamber. About a month ago, I was befriended at the range by an old time reloader who looked at a before and after and suggested that it didn't look like I had any crimp. As I have 35 years experience using a caliper on a daily basis for my job I was fairly confident that I had the crimp die set to remove the belling. Another clue is to look at factory ammo.....every round I look at has a positive taper at the tip of the case head. So I concluded that "just removing the bell" was not a proper taper crimp.

I now crimp to slight indention in the plating. According to what I have read, the plating is mostly .005" ±.001 thick and I would estimate that my crimp is less than half that....but does leave a slight crease on the bullet that is visible when pulling apart a completed cartridge. (It is written around the web that you "don't want to break through the plating).

The past 3000 cartridges out of my 650XL have yielded:

*more consistant velocities, often with single digit SD results.

*groupings are tighter....now closer to 1.5" because....well I am not a great shooter yet.

*spent cases are much less sooty....much less.

*using .1- .2 grains less powder load for same velocity range

Again YMMV but my personal feeling is the statement "crimp only enough to take the bell out" is not accurate.

Edited December 15, 2014 by amada8

[Youngeyes]

It's not really a "crimp" for semi-autos - more of removing the belling

you made to the case so you could easily seat the bullet.

As a beginning reloader, I have found that I do not agree with the concept of "just remove the belling" so YMMV.

After my first 2000 cartridges in 9mm, 10mm and .40 S&W, I was getting good but not great accuracy or consistant velocities. I use my chrono for every new trial of ten and bench rest 30ft shots. The key finding was a sooty outer case. Because I reload light powder charges I assumed that that was the cause....that the case wasn't getting enough pressure to seal the case against the chamber. About a month ago, I was befriended at the range by an old time reloader who looked at a before and after and suggested that it didn't look like I had any crimp. As I have 35 years experience using a caliper on a daily basis for my job I was fairly confident that I had the crimp die set to remove the belling. Another clue is to look at factory ammo.....every round I look at has a positive taper at the tip of the case head. So I concluded that "just removing the bell" was not a proper taper crimp.

I now crimp to slight indention in the plating. According to what I have read, the plating is mostly .005" ±.001 thick and I would estimate that my crimp is less than half that....but does leave a slight crease on the bullet that is visible when pulling apart a completed cartridge. (It is written around the web that you "don't want to break through the plating).

The past 3000 cartridges out of my 650XL have yielded:

*more consistant velocities, often with single digit SD results.

*groupings are tighter....now closer to 1.5" because....well I am not a great shooter yet.

*spent cases are much less sooty....much less.

*using .1- .2 grains less powder load for same velocity range

Again YMMV but my personal feeling is the statement "crimp only enough to take the bell out" is not accurate.

Without seeing your reloads I can't speak to your crimping. I can say that sooty cases and poor accuracy can come from too light a load. Putting in a tight crimp may be increasing the pressure and give you a more complete burn. Your sizing die gives you the tension needed to hold your bullet in the case. I've never needed to add any extra crimp for any semi auto bullets. Revolvers need a crimp to hold against set back. In my limited experience, if you see a crimp ring indented in your bullet, it's overcrimped. As you say, YMMV