How much crimp is enough - .40S&W

[nm3]

I'm currently setting up my dies for my first batch of reloading. My instructions for the RCBS 3pc Carbide die set say the crimp dimension is to be equal to or .0005"-.001" smaller in size than the dimension of the case at the base. Currently I have my die set up so that the taper crimp dimentsion is equal to the base dimension. Is this OK or should I go smaller? If so, how much?

FYI - The factory crimp on the Federal .40S&W 180gr FMJ is .002" smaller.

 

[tlen]

I crimp to .421" with a Lee FCD and haven't had any problems.

 

[Walkalong]

Remove the bell, and a hair more. (With a hair being = to .000 to .002)(To account for differences in case length.

 

[Motownfire]

Walkalong nailed it. My crimp die is set to just take the very minor flair that I have my powder charge/flair die set to make so I can seat the bullet. I have found that with .40S&W you don't need much of a crimp at all. I load my 180 grain bullets http://www.missouribullet.com/results.php?category=5&secondary=11 with 4.7 grains of Unique. After 1500 or so rounds of plinking with this set up, I have found that this works well. I don't have access to a chronograph but they sure do feel like the factory Federal 180 HST's that I carry when fired from my G23 and G27.

 

[nm3]

Well, I think I have to try a little more crimp. I tried my test "dummy" round in the barrel and while it went in the chamber fine the slide was not completely "in-battery". I think I will tinker somemore. Unless, not haveing a primer in the case would cause the slide from staying out-of-battery.

I appreciate the help as I said before, this is all new to me.

 

[nm3]

Well, I reworked my die and got the crimp a little tighter, but it still didn't make a difference. I did get it to work though, my being new to this and all. I put the round in the chamber before and the slide didn't go into battery. If I put the round in the magazine it was fine.

 

[FROGO207]

Your problem might be that the bullet is engaging the rifling too soon as the oal is possibly different for that bullet from one that works. you might want to check that.

Don't forget that you want that end of the brass casing to hit the lip in the chamber and stop to keep the round spaced properly in the chamber. If it is crimped too much it will slide in too far and cause big problems.

 

[nm3]

The length and crimp diameter was fine/within spec. My problem was due to the way that I put the bullet in the chamber and slowly released the slide that the extractor never cammed over and engaged the groove on the back of the case. Once I put the bullet in the magazine and released the slide it was perfectly fine.

I appreciate the help.

 

[rfwobbly]

Well, I reworked my die and got the crimp a little tighter, but it still didn't make a difference. I did get it to work though, my being new to this and all. I put the round in the chamber before and the slide didn't go into battery. If I put the round in the magazine it was fine.

WARNING !!
You need to remove the barrel from the gun and work with the naked barrel.

The properly crimped auto cartridge will fall all the way into the chamber using only it's own weight. You should hear a faint ringing sound as the mouth of the cartridge strikes the end of the chamber. Only the rim and extractor groove should be showing. You should be able to freely rotate the cartridge in the chamber, without the bullet's nose snagging on the rifling. If there are any questions about this last item, then color the bullet's nose with a marking pen and look for scrapes.

On most pistols you will NOT be able to simply put a cartridge in the chamber, and then lower the slide and have the gun go into battery. The extractor is designed to have the cartridge ONLY be fed upward from the magazine. If you do load the gun this way, then slide HAS to slam closed in order to get the extractor to step over the cartridge rim.

But the best way for reloaders to test ammo is to work exclusively with the naked barrel.

Hope this helps!

 

[LiveLife]

The properly crimped auto cartridge will fall all the way into the chamber using only it's own weight. You should hear a faint ringing sound as the mouth of the cartridge strikes the end of the chamber.

+1. Even in my tight Lone Wolf barrels, my loaded rounds drop in freely with "clink" sound as the case neck hits the chamber.

The extractor is designed to have the cartridge ONLY be fed upward from the magazine. If you do load the gun this way, then slide HAS to slam closed in order to get the extractor to step over the cartridge rim.

Guilty here. I have done this all of my life. I usually save up any questionable loaded rounds during my quality checks and put them in a separate box. I shoot these rounds one at a time. I load them into the chamber by hand with the slide locked back and I release the slide. I have not had problems with my extractors (Glock, M&P, Sigs, 1911s, Makarov, etc.).

One time, while trying to load a light load for a new female shooter, the powder charge was too light to cycle the slide. I had loaded 300 rounds. Instead of pulling bullets, I single round chambered and released the slide three hundred times.

 

[nm3]

It does help and I appreciate it. I also understand about pulling out the barrel and using it as a gage. The test round I was using in the firearm had no primer or powder in it.