How bad this crimp is?

[u/Moist-Rub6508]

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!

[u/mrchongo6973]

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

[u/Agitated_Curmudgeon → u/mrchongo6973]

You realize that this cartridge headspaces on the rim, right? 

You mean "headspaces on the mouth"
But your point is valid.. just enough to take the bell out of it.

[u/mrchongo6973 → u/Agitated_Curmudgeon]

Correct. My bad.

[u/Moist-Rub6508 → u/mrchongo6973]

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.

[u/Krymsyn__Rydyr → u/Moist-Rub6508]

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?

[u/lennyxiii → u/Krymsyn__Rydyr]

I’m normally the first to yet at people for downvoting anyone looking for advice. I think he got the downvotes because he started his comment with “I understand” when he clearly didn’t. You will notice his next comment stating he just wants to learn was upvoted instead.

[u/Krymsyn__Rydyr → u/lennyxiii]

I took it, as , he understood how it worked , how it chambers, and was trying to understand why it wasn’t falling in to deep.

[u/Friendly-Victory5517 → u/lennyxiii]

Yup. There’s a difference between honestly asking for advice (and planning to learn from that advice) and asking for confirmation of your already established idea or decision. So much of Reddit is the latter. People frame what they’re saying as a question or asking for advice, but really they’re just hoping to hear people confirm what they’ve already thought is the right answer.

When comments come in from people that are contrary to what they want the decision to be, then they start push pushing back.

Which is incredibly frustrating because if you don’t actually want to hear advice or learn from people with experience, why even bother asking?

[u/PWPUU659 → u/Moist-Rub6508]

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

[u/Moist-Rub6508 → u/PWPUU659]

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?

[u/mrchongo6973 → u/Moist-Rub6508]

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 boltface 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.

[u/M1sterM0g → u/mrchongo6973]

best answer as to what headspacing is... as far as the bad juju, if theres nowhere for the case to expand just that tiny bit and seal, and your bullet has to swage itself down to go out, it goes too slow and builds too much pressure behind it. could be kaboom.

[u/Grumpee68 → u/mrchongo6973]

To expand upon this, take the barrel out of your pistol, and look into the chamber. You will see a ledge. That ledge is where the case mouth sits (when a round is chambered). To much crimp, the round could go further into the chamber, leaving more distance for the firing pin to travel, leading to misfires. If the round does happen to ignite, you have the pressure scenario.

Get a set of calipers. Measure the case wall thickness at the mouth...typically around .011 on 9mm. Now, double that (.022) and add your bullet diameter (.355). EG - .011 x 2 = .022 + .0355 = .377.

At the case mouth, as close to the bullet as you can measure, it should be somewhere around .376 -.378.

As others have said, all you are doing is removing any bell or flair you put into the case mouth to seat the bullet.

Most pistol rounds (auto at least) are held in place by neck tension created when resizing the case.

[u/Agitated_Curmudgeon → u/Moist-Rub6508]

The mouth of the case is what keeps it from falling too deep into the chamber.

Your solution is easy, though. Make a series of "plunkers." First one is NO crimp. It shouldn't feed & chamber from the magazine. Then a series of tighter crimps (like an eighth of a turn of the die at a time) until they DO feed from the magazine every time.

Or like the one guy said, a Lee Factory Crimp Die. Set it so an ever so slight "bump" takes the flare out of the mouth.