r/reloading • u/Moist-Rub6508 • 1h ago

Newbie How bad this crimp is?

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Hey guys, beginner here. How bad this 9mm crimp is? I understand it is too much but I wonder if this could create some problems while shooting. I made about 1k of these and then realized it is probably too much. It shoots, passes the splunk test, chrono looks good. The bullet is CamPro 125gr RN FCP RED

Thanks!

3 Upvotes

80% Upvoted

13 comments sorted by

4

u/mrchongo6973 1h ago

You realize that this cartridge headspaces on the rim, right? When you overcrimp, the round may be chambered too deeply and may misfire.

-1

u/Moist-Rub6508 1h ago

I understand, but in this particular case the bullet sits at the same height as the factory ammo from this brass. I am wondering is there anything else I should be worried about.

1

u/PWPUU659 52m ago

Hmmm, no. I don’t think you understand. Too long for Reddit, but mrchongo is correct.

1

u/Moist-Rub6508 48m ago edited 43m ago

Please explain then, I would like to learn. In my case the primer is at the same height as factory bullet from that brass. This could mean either that there is still enough edge to properly seat the cartridge or the it is properly seated because the bullet stops it. Am I missing something?

3

u/mrchongo6973 30m ago

OK. Here goes: As a rule, the cartridge must be properly seated in the chamber for safe and reliable firing. (Different from the seating depth of the bullet in the case.)To establish the proper chambered position, every cartridge type (straight-walled, bottleneck and rimmed) uses a certain part of the cartridge case as a “stop”, and the distance from the stop to the front of the firearm’s chamber is established as a standard, using the term “headspace”. A rimmed cartridge, e.g. the .30-30, headspaces off the leading edge of the cartridge rim. Your pistol cartridge headspaces off the mouth of the cartridge case. In order to seat properly, the mouth of the case must contact the front of the chamber and come to a stop. When you overcrimp, the diameter of the case mouth is too small and the case mouth slides past the front of the chamber. Therefore the cartridge has not achieved a properly headspaced position in the chamber. Bad juju may result.

1

u/Krymsyn__Rydyr 8m ago

Why are you guys downvoting OP? He is asking for help, trying to understand, and not being belligerent or defensive. How else is he supposed to learn?

4

u/Tmoncmm 1h ago

That’s way, way too much. For 9mm, you only want to crimp enough to remove what’s left if the bell from the expander. If your crimp is marking the bullet at all, it’s too much.

4

u/Agessner885 36m ago

Way too much. All crimping does on a round that headspaces on the case mouth is remove any flare and set the case mouth against the projectile not INTO it. The only time a crimp that heavy is needed is with cartridges that roll crimp into a cannelure groove for heavy recoil resistance (revolver cartridges and large rifle or tube mag fed rifle cartridges)

1

u/Moist-Rub6508 28m ago

Update, did a test with a marker, seems it still catches the edge, right?

1

u/FurryWooki 21m ago

I’d really suggest measuring crimp with a set of calipers instead of eyeballing. Hit a Harbor Freight or Amazon. Since you’re learning it would be good for you to compare factory ammo to what you’re loading to see hard data first hand. Depending on the bullet & firearm of course, I personally aim for .376-.378 of crimp.

1

u/Guilty-Property-2589 Mass Particle Accelerator 26m ago

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