To Crimp Or Not To Crimp

[b2e]

I have heard that the case tension should hold the bullet. In "The Glock in Competition" Guide, it says to crimp to hold the bullet. I'm using a Glock 35 40cal. with 180gr. Laser Casts. Which is the best and safest way to go?

[HSMITH]

With an autoloader you don't need to hold the bullet in, you need to keep it from going in deeper. Case tension or a horrificly overcrimped round are the only things that are going to do this for you.

Set your crimp to JUST iron the bell out of the case and lay it back against the bullet. If this approach bothers you get an EGW Undersize die and use it, bullets DON'T slip in decent brass using it.

[MichiganShootist]

Case tension should do the "job" ... so many times the crimp has to do with allowing the round to feed well.

Many others are more experienced reloaders than I... but In my experience.. It is very hard to "over crimp" unless you are using plated bullets and they tend to be more difficult to deal with.

[RC1]

Here is a quote from BENOS,(Mar 28 2005, 04:23 PM) , that might be helpful

"Back in the ol' days, when we didn't have the luxury of crimping as a separate operation, we'd adjust our combination seating/crimping die to remove the flare, hopefully without cramming the case mouth into the bullet too much. Then Mike Dillon came along and built machines that seated and crimped in separate stations! Wow - crazy stuff. And then he even started making dies that crimped auto-pistol cartridges correctly, that is to say didn't actually "crimp" at all, but simply removed the flare from the case, laying the (flared) case mouth perfectly flat against the bullet.

Unfortunately, somewhere during the taper crimp die's evolution (from the roll crimp die), no one bothered to rename it so as to not mislead folks, for generations.

Roll crimping should do just what the name implies - the case mouth is slightly (or sometimes drastically, in the case of a heavy recoiling revolver) rolled into the bullet's cannelure. Which helps prevent the bullet (in the unfired rounds) from moving forward in the case in a revolver. Since revolvers typically headspace on the rim, as long as the roll crimp doesn't deform the bullet's bearing surface, no harm is done with even a heavy roll crimp.

Since autoloaders headspace on the case mouth, however, the case mouth should never be crimped so that the case mouth penetrates into the bearing surface of the bullet. So in the case of an autoloading pistol, the "taper crimp die" should never actually crimp the case mouth into the bullet in any way whatsoever. The roll of the taper crimp die is to remove the flare previously applied to the case (in order to seat the bullet without shaving copper/lead) - returning the case mouth so that is snug down on the bullet, but not crimping the case mouth into the bullet at all.

After some experience one can learn to "see" (without tools) if this has been done correctly. (Either too much or too little.) But until then a good set of calipers will guide you as you adjust the "Flare Removing" die. Using the thin part of the calipers (near the tip), measure the loaded, flare-removed round's case mouth at the very end of the case. The result should be the sum of the bullet's diameter plus 2 times the case mouth's thickness. (Usually .010" for most cases. So in the 40 S&W, the Flare Removing measurement should be approx. .420". Or at the tightest, .419". And be sure to "roll the case mouth around," so you don't just measure it in one spot.

Actually (taper) crimping the case mouth into the bullet almost always results in a loss of accuracy. Not removing the flare enough results in malfunctions. Some gunsmith's will recommend "taper crimping" more than what was previously recommended, and that is easy to understand as to why.

If you remove the flare precisely as outlined as above and your pistol (still) has any sort of feedig malfunctions, I can say for sure that crimping the case mouth more is not the solution. Once I learned how to properly set this dimension, I never experienced any malfunctions due to not enough "taper crimp" in over 20+ years of shooting 20-40,000 rounds/year."

be

[Bill Rosenthal]

Get a Lee factory crimp die and never think about it again!

[Joe D]

I just remove the flare. I do it in two steps - seat then taper crimp. I have stopped using a Lee FCD all together. There is really no reason to use a Lee U/EGW die either. The standard Lee carbide sizing die works just fine.

[Suburban Commando]

The Lee sizing die really shrinks the brass down, if you can manage to get a bullet in, you really don't need to crimp.

To set the seating/crimping die, I set the flaring die to give an exaggerated flare, and then I can check to see if the die is crimping enough by measuring. When the seating/crimping has gotten rid of all the flare, I know it's set properly.

My Hornady Lock-N-Load ejector spring won't clear an FCD at station 5, so I just stopped using the FCD. I don't seem to be missing out on anything, all my rounds have dropped into the gage so far, and the ammo is more accurate than UMC or WWB.

ETA: If you are using bullets with die grooves, a separate crimping die would make getting the OAL correct a lot easier.

Edited February 15, 2007 by Suburban Commando

[LPatterson]

What happened to the old fashioned tried & true method of pressing the bullet against the bench with your thumbs. Every case and bullet will give a different crimp number based on wall thickness & bullet diameter not to mention type of bullet. A lead bullet may be faster going down the barrel than a plated bullet but a plated bullet is easier to move in the case. However a plated bullet is sticker when it hits the feed ramp and is easier to set back, which is no fun when the pieces start flying.

[WildWest N AZ]

Ive been loading 40 for over a year and half. Not that this makes me a pro any way but Ive found that when using Lee factory crimp Ive set it to spit my rounds at .420, considering the factory spec is .421 dont have my manual handy but I think thats correct for the case. And as stated above if using mixxed brass U will get different readings? If U ever have any ? on if its not crimped enough push it into the work bench, the old tried and truth way to say the least! U dont wont setback with a 40 because its a high press round as it is, can exceed them really quick and mess your gun up..

[ParaJoe]

What happened to the old fashioned tried & true method of pressing the bullet against the bench with your thumbs.

+1

Joe

[shred]

Crimp's job is not to prevent set-back unless you are crimping into a cannelure or crimp groove intentionally (which is very unlikely for any Glock round, this being the Glock forum)

The thumb test is a good one, but adding crimp if it doesn't pass is the wrong way to go about fixing it-- look at the sizing and expanding steps instead.

[David Sinko]

My Glock 35 lives on range scrap brass and plated bullets. When I first started loading for the .40 S&W I bought a set of RCBS dies and no matter how I adjusted them many of the bullets in the loaded rounds would easily push deeper into the case when pushed against the loading bench with even mild pressure. I then bought a Lee carbide factory crimp die which helped a little but the problem still persisted. Just applying more crimp is NOT the answer. This causes lots of problems in an of itself. I loaded a few rounds without even bothering to bell the case mouth just to see what would happen and some of those would compress too. So the problem is obviously with the resizing. I then heard about the Lee U die and since I live 15 minutes from EGW I drove over and bought one. Then good things started to happen. The problem was solved! I still use the factory crimp die and I do slightly crimp the case mouth into the bullet. It's probably not necessary but I like to be sure that there is no flare whatsoever. I find that the polygonal rifling is very forgiving with plated bullets and the plating has never separated, though that has happened to me with S&W revolvers, but that's a different story.

Dave Sinko

[Lee Bell]

Set your crimp to JUST iron the bell out of the case and lay it back against the bullet. If this approach bothers you get an EGW Undersize die and use it, bullets DON'T slip in decent brass using it.

I used to do this. Now, I tapir crimp a couple thosanths to smooth the transition between bullet and case to make feeding as reliable as possible.

Lee