9mm crimp question.

[wblacksh]

Is this too much, too little or is the crimp just right?

Left is an uncrimped, right is crimped and pulled with a bullet puller.

This a 124gr xtreme bullet in 9mm.

Thanks.

[GrumpyOne]

IMO, a tad too much.

[trouble]

I can't tell you that your crimp is to much or to little. But when I crimp my 124 Extreme bullets that much my pistol shoots 5" inch groups. When I crimp them to just show a slight distortion in the plating I get 2" groups.

[KustomHolsters]

That is to much in my opinion. There should be just a faint line around the bullet.

[fishsticks]

Typical measurement is .378 for crimp on 9mm. Have you measured it? As others have said, with a plated bullet that's likely too much.

[wblacksh]

Thanks. I have reduced it a bunch so that the crimp is slightly noticeable.

[Steve RA]

You really don't want to crimp, all you want to do is remove the flare. If the sizing die is correct the finished round will look "wasp waisted" which will grip the bullet tightly and also prevent set back.

[Hi-Power Jack]

when I crimp that much my pistol shoots 5" inch groups. When I crimp them to just show a slight distortion in the plating I get 2" groups.

When I set my "crimp" on my SDB many years ago, I crimped

just enough so the round would chamber (removed enough

of the belling). [9mm]

When accuracy suffered, I realized I had too much "crimp",

so I backed it off a bit, until the round chambered, but was

accurate.

Set it, and it hasn't changed in ten years.

BTW, when I bought a 2nd SDB in 9mm, it came from the

factory "just right" - I've left it for the past four years, and

it is perfect.

[Postal Bob]

You really don't want to crimp, all you want to do is remove the flare. If the sizing die is correct the finished round will look "wasp waisted" which will grip the bullet tightly and also prevent set back.

+1 This is exactly what you want with taper crimp cartridges. Just remove the flare, without any bullet deformation.

Roll crimp cartridges are a different story.

[chuckols]

Steve RA & Hi-Power Jack say it! best. I use the KERPLUNK test I learned from these guys previously to define the LEAST amount of crimp necessary to get a round that chambers w/o resistance. We all have guns of whatever caliber you are reloading. Use the bare barrel next to the reload station to drop in a finished round and get that satisfying KERPLUNK sound. You know it will chamber. If you then want to fiddle w/th added crimp(beleive it will improve accuracy) then go ahead and try a few and shoot 'em. Your choice for that gun.

Peace,

Chuck

[papaairbear]

For plated bullets I use twice the case wall thickness + the bullet diameter. If a bullet measures .355 and one side of the case mouth measures .011, the proper crimp woul;d be .377 for a 9mm round.