What the crimp

[AJC1]

bulletion the left is an rmr that was pulled from a test case I used to verify seating depth on a plunk test and represents what my crimp does to the bullet when loaded for fire. The right bullet is a factory Winchester. Either I'm way to crimp sensitive or they are waaaaay over doing it... survey says?????

 

[Hartkopf]

View attachment 1001294 bullet in the right is an rmr that was pulled from a test case I used to verify seating depth on a plunk test and represents what my crimp does to the bullet when loaded for fire. The right bullet is a factory Winchester. Either I'm way to crimp sensitive or they are waaaaay over doing it... survey says?????

Which bullet is which again? You have two “rights.”

 

[AJC1]

Which bullet is which again? You have two “rights.”

Sorry. Fixed

 

[Jesse Heywood]

What cartridge? I would assume the Win bullet had the crimp ring rolled in during manufacturing.

 

[ballman6711]

They don't want the bullet to move, either for chambering/setback reasons or to promote a more complete burn of the powder they are using.

chris

 

[jebova2301]

Winchester QC is about as good as using a sieve to hold water. Check the length of the brass. I have had some of their 9mm NATO brass be as long as 20.1mm and it was crimped into the bullet all the way and making the same coke bottle effect you have there.

 

[Hartkopf]

I’ve seen some 40 S&W factory rounds that were crimped like this..........

I did not shoot them. They plunked a mile deep so I contacted the manufacturer and they bought them back.

 

[bluejay75]

To further what Chris said above. Consistent burn and pressure on a light charge of fast powder. I’m sure there was air space in that load with that much crimp. Any amount of compression with fast powder and a heavy crimp is bad stuff.

 

[Walkalong]

To further what Chris said above. Consistent burn and pressure on a light charge of fast powder. I’m sure there was air space in that load with that much crimp. Any amount of compression with fast powder and a heavy crimp is bad stuff.

Explain that please

 

[PO2Hammer]

9mm?
If so left looks good, right seems excessive.

 

[AJC1]

Yes 9mm. In a magnum i might buy it with a heavy roll crimp.

 

[Herman B]

Post a photo and show us what the W crimp looks like. Perhaps the W bullet rolled-off the bullet line with that groove. Doesn't mean the groove must be must be used, in the case of a taper crimp.

 

[bluejay75]

Explain that please

Factory 9mm is going to be a fast burning powder. Fast powder cannot be compressed. I’m sure to make sure the charge never compressed or to load as little powder as possible for cost savings that much crimp brings the pressure up into a good operating range.

 

[Mark_Mark]

I’ve seen some 40 S&W factory rounds that were crimped like this.......... View attachment 1001300

I did not shoot them. They plunked a mile deep so I contacted the manufacturer and they bought them back.

THAT’s factory??? looks like a sausage

 

[lordpaxman]

I don’t purchase a lot of factory 9mm but the few WWB I have don’t have that much crimp on them, and what is there more resembles a taper crimp.
From the picture from @AJC1 it’s difficult to see if was supposed to be a roll crimp (unlikely) or the crimp step is way out of spec. I’d contact Winchester if I saw these.
I’d also see how these plunk, it appears they won’t headspace on the mouth. Good luck.

 

[FROGO207]

Usually the factory ammo is made to work reasonably well in any firearm of that caliber so they use a fast propellant (cheaper) and good crimp to stop bullet movment. Still this seems really excessive for a round that headspaces on the case mouth. That looks more like what you would expect on a roll crimped 38 SPL to me. What did the case neck look like before you pulled it? Any more for a pix?

 

[Hartkopf]

THAT’s factory??? looks like a sausage

Yes. Worse than just bad IMO. It would seem the OPs rounds must have looked something like the pic I posted.

 

[whughett]

How does one “roll crimp” a cartridge that head spaces on the mouth of the case.
Decades in the game and here’s me thinking only rimmed cases are roll crimped.

 

[Walkalong]

Especially when the dies come with a taper crimp.

 

[Bang!]

They are “waaaayy over doing it.” Yours is almost too much, also. Ideally, the bell would be removed leaving no mark on the bullet and the completed round would plunk into the chamber.

For 9x19 you’re just removing the bell you made earlier in the reloading process to seat the bullet. You’re not “crimping” anything, really. For straight walled cases the word should really be changed from “crimping” to “bell removing” since these headspace off the case mouth.

So many people are confused when it comes to crimping. Crimp is so often confused with the job of neck tension. They’re not the same thing. Over crimping (taper) rounds such as 9x19 and 45acp can lessen neck tension and leave the bullet so loose it can be spun in case by hand. With this in mind you’re not trying to effect any powder burn rates or pressures.

 

[whughett]

For 9x19 you’re just removing the bell you made earlier

Technically I do believe one is “crimping” it’s just a taper crimp. One can actually set the die for a straight wall case down far enough to leave a noticeable taper at the mouth and around the bullet. ive tried that with 45C on lighter weight groove-less bullets designed for 45ACP. Trying for a multi use bullet as it were. Didn’t work out so bought a 200 grain mold with a crimping cannula.

 

[jebova2301]

Not the best pictures, but here are some of my win 9mm NATO rounds. Purchased 2017 or 2018. The mark/light grove right above the Mariana trench in the bullet is from my collet-style bullet puller.

 

[mdi]

For me, my ammo and my guns, most of the pics depict much too much crimp. None of my 4 semi-auto rounds are crimped enough to mark/dent a bullet. I could probably reseat a pulled bullet because none of my semi-auto handloads are "crimped". I just remove any flare with a plain taper crimp die and plunk test...

 

[Hartkopf]

I did some experimenting with a Glock 19 and it would run the hell out of rounds that were left flared .002 or so. Also, I have some factory 9mm GoldDots that have a small edge roll, like from a dull cutter. Hundreds of these have been run through two different Glocks with no issues.

 

[Mark_Mark]

I did some experimenting with a Glock 19 and it would run the hell out of rounds that were left flared .002 or so. Also, I have some factory 9mm GoldDots that have a small edge roll, like from a dull cutter. Hundreds of these have been run through two different Glocks with no issues.

Well, Glock runs everything because of the unsupported chamber