.40 S&W crimp or not crimp


May 5, 2014, 10:37 AM
I just start reloading .40 S&W. Right now I start up with a Berry's 165 gr bullets. Hard to find data and able to understand how a plated bullet will work once is been fire on a weapon. Now that I have make some Rounds with a 700x powder. my question is. "Do I need to crimp or not....?"

The bullet is a 165 gr 401 plated. You can see the case wall tension that will hold the bullet firmly in place been a .401
The bullet fits perfect on the gauge die size, with out crimp! The C.O.L is 1.125 been a really high pressure round I really don't want to crimp it to create a higher pressure and get a KABOOM.....!

This .40 S&W is going to use on a Glock 23. What is your expectations.

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May 5, 2014, 10:55 AM
I use a light taper crimp to straighten out the slight bell. I have found that loading plated bullets is helped by applying a bell before seating to keep the bullet from scraping improving accuracy. If the neck tension is sufficient (you are not belling) and they feed, you are good to shoot if you are not trying to wring out the best accuracy.

May 5, 2014, 10:57 AM
Taper crimp on auto pistol calibers does not hold the bullet in place.
It is used to straighten the case mouth bell and make the case mouth straight again, with perhaps a very slight taper to improve feeding.

With .400" bullets the case mouth should measure .421" after taper crimp.

Using .401" bullets, set the seating die taper crimp for .422".


May 5, 2014, 11:20 AM
It's all about bullet tension with auto rounds.
Make sure you use a minimum amount of expansion and flare at the case mouth. Taper crimp just enough to remove the flare.

May 5, 2014, 12:18 PM
The flare that I do on the case is very small, I do a single reload one at the time I have to check the size of the case mouth when I get home tonight with out crimping it. And see what will be the size of the case mouth.

The wall tension that is create when the bullet is seated, it almost make the flare despair.

May 5, 2014, 01:44 PM
To test your methods, I would recommend making up some dummy loads (no powder, no primer) with the components you're using and cycle them through your gun. Load them in a mag and pull the slide back and let it fly forward, simulating the feed cycle. If your tension is good, they should only set back .005" or less after 3 times through the gun.

May 5, 2014, 02:15 PM
This is great thank so much for the tip. I will definitely will do this tonight! The limit movement from the bullet seated should be .005" thanks everyone...!

May 5, 2014, 03:31 PM
Actually, bullet movement when fed/chambered from the magazine should be zero.

Since most of my reloads are fed/chambered once before being shot (I use factory ammunition for SD/HD), I check for sufficient neck tension of my reloads with one feeding/chambering from the magazine.

While no bullet setback is preferred, If I measured bullet setback of few thousandths, I would not worry but would investigate and try to attain zero bullet setback by adjusting my OAL/dies/reloading practice.

40S&W Glock chambers will accommodate longer than SAAMI max of 1.135" OAL for typical TCFP bullet shape and I have used up to 1.145" OAL with reliable feeding/chambering from the magazine.

Try 1.130", 1.135", 1.140" and 1.145" OALs and see which OAL produces the least amount of bullet set back. Never know, you may not experience any bullet setback at 1.130"+.

May 5, 2014, 05:59 PM
Another simple test, make up a dummy load (no primer no power). Set the bullet side down on a hard surface and push down with hard pressure by hand. If it moves it's not enough crimp as you could never do that with a factory load.

May 5, 2014, 06:18 PM
I use a light crimp with a Lee factory crimp die for all of my .40 cal loads.

May 7, 2014, 12:00 AM
I have make 7 dummy rounds and I did the test on puting the rounds through the weapon. I have the same C.O.L. 1.125" doing the same things 8 times.... No setback at all......:) also I check the diameter of the bullet and is a .422" the same on all of them... I will try them over the weekend and I will let everyone know about the grouping that I will get. Thanks everyone for all your help.

May 7, 2014, 02:27 AM
I am with Lennyjoe but then I use a FCD or a roll crimp on everything as I only load +P rounds on everything.

May 7, 2014, 04:36 AM
I run everything thru a Lee FCD, usually a very light crimp. Just enough so the pistol round drops in my case gauges

May 7, 2014, 06:33 AM
I have no problem on dropping the the bullet on the gauge die whatsoever.

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