Additional brass fatigue may be a factor, but factory crimped rounds are more consistant shooters and we worry less about bullet setback.



Every month we go through 1000 reloads (give or take) and 100 rounds of our carry ammo. Those factory rounds keep us familiar with the feel of our SD ammo, confirm proper operation with that ammo, and they serve to replenish our brass. When we use our Lee Factory Crimp die the cases may split their rims earlier, but at a 10 to 1 replenishment we never run low.

 

Great info as alwasy KR.

I use Lee Factory Crimp Dies on every caliber I reload.

 

Some kind of crimp is absolutely necessary on pistol calibers, most rounds will either experience set back or in the case of heavy revolver loads the bullets can actually drift forward out of the case, sometimes jamming the cylinder. Most rifle calibers don't require a crimp.



Here's what happens with multiple chamberings in auto pistols, bullet setback can cause pressures to skyrocket, enough to destroy the pistol. These rounds were found at an ammo inspection at a police dept, a real possibility of a KB (kaboom) existed.

 

John has it right - setback can send pressures soaring. Check the table at the link below - pressures can climb to 3-4 times the SAAMI maximum of 35K psi for a .40.

CALIBERS -- Why the 180gr Bullet is a Bad Choice for .40 S&W

Some kind of crimp is absolutely necessary on pistol calibers, most rounds will either experience set back or in the case of heavy revolver loads the bullets can actually drift forward out of the case, sometimes jamming the cylinder. Most rifle calibers don't require a crimp.



Here's what happens with multiple chamberings in auto pistols, bullet setback can cause pressures to skyrocket, enough to destroy the pistol. These rounds were found at an ammo inspection at a police dept, a real possibility of a KB (kaboom) existed.

 

I believe in the Lee FC die for pistol rounds also.

 

Thanks everyone. As I said in 'intros' I'm hear to learn.

I'm convinced. From what I've heard and seen here, I will FC all of my 9mm rounds!

 

Stand way clear of those shooting pistol ammo without a crimp. Less likely to get fragged when their gun explodes. Not actually comparing apples to apples here, but I had this inadvertantly happen to me before. I was loading 300 gn hard cast for a Ruger .44 mag that I liked to hunt with, or use as a back up for black bears. I was at the range, testing some loads that worked fine before, but I had changed lot #'s for both powder and primers. I fired about 8 or 9 rounds, and then I fired a round, all off of sand bags, when I knew something terribly went wrong. The recoil was awsome, and actually sent pain through my arm and elbow. Then I noticed that the crane was bent, and I had a heck of a time getting it apart to remove the remaining ammo. I (pre-intrenet days) called Ruger to see if anything could be done as far as repairing it, or was it totally FUBAR. I admitted to them what happend, and found that when I set my dies up, I didn't inspect the crimps well enough, One bullet had set back, and thus the Kaboom! They actually sent me a new gun, which amazed me, but the real crux of the story is this. If that gun had come apart, I could have just as well been holding a grenade. Big chunks of metal could have killed me instantly. A very stupid oversight on my part, but I've never gone without checkin the crimp again.



The bottom line here is, that the above posted pictures are exactly what could happen to you, if you don't crimp ammo, especially in a magazine fed hand gun.



You're "friends" who want to extend brass life, at the risk of their own and others lives, aren't being frugal, and in my opinion, are being especially selfish, as to the safety and well being of their shooting friends, standing next to them at the range.



J.

 

Words to live by jbylake.

 

interesting thread. I only crimp enough to remove the belling on the case so the round chambers reliably. I wouldn't even call it a crimp, more like a de-belling. The lee carbide sizing dies all seem to be very slightly undersized, so there is no way there is going to be any setback without a crimp.

 

95% of USPSA/IDPA shooters reload. Many shoot 9mm (Production/SSP). The basic procedure for low-power target loads, in 9mm, often shooting LONG 147gr bullets, is to simply remove the bell, with no crimp.



YMMV.



JeffWard

 

There is a 9mm spec as to case mouth diameter. I taper crimp to meet the spec to allow it to chamber and no more. Mainly it just removes the bell.

 

I run Dillon dies in my Hornady LNL press, and I always crimp on all my semi-auto rounds. I generally turn the crimping die 1/4 of a turn instead of the recommended 1/8 turn after contact to ensure that I get a good crimp. I then use a micrometer and chamber check them to make sure they are okay, then test feed all ten rounds ten times and check with a micrometer again to ensure that the bullets don't set back during feeding.

I called Hornady about two weeks ago and talked with a guy that said he shoots 1000 yard benchrest in .308 bolt action and that he never crimps his rounds because they are more accurate that way. Bolt action with single shot chamber loading (without a magazine) is one thing, but a semi-auto or revolver is something completely different. :smiling:

 

I've seen nothing to indicate any early fatigue of 40SW or 45ACP cases from even a substantial crimp. Given how often both calibers can be reloaded (close to infinitely nears as I can tell), I see no reason not to crimp.

I've had a number of cartridges where the bullet could be pushed into the case with my thumb, and by simply being dropped on the garage floor. I'm not talking 0.015" or so, I'm talking closer to 0.040" or more. I don't think that's good, at least not for 40SW where my loads, at least, tend to be up closer to the pressure max.

My experience using both Lee factory and Hornady taper dies has been many, many dozens of reloadings. I'd actually guess somewhere around 50 is average for my brass so far. I've expanded every one, and crimped every one--and so far I have not had ONE case crack at the mouth.

I expand as little as I can get away with and still have my bullets not get jacked up on their way into the seating die. I crimp so it "looks nice" and I'm unable to push the bullet in with all my considerable, manly might.

 

If you are shooting lead boolits and sizing them .357/.358 then don't use a Lee FCD. All you end up doing is resizing the lead boolit and having a nice straight case. I reload about 30K of 9MM a year using lead/plated and FMJ bulltets and never use a roll crimp. All the 9MM requires is a taper crimp as do .40cal and .45acp. Never use a roll crimp on a pistol cartridge that requires head spacing off the case mouth ie 9MM, .40cal and .45acp. All these cartridges just require a gentle taper crimp sufficient to remove the bellling. Applying a roll crimp on these cartridges can actually loosen the bullet not tighten it.

ScubaBoy you mention reloading for rifle bench rest shooting, auto pistol reloading and revolver. All three involve different crimping issues. What you do for one application does not necessary follow through for another. Too, the amount and type of crimp for any of the three mentioned can determine by the type of bullet used. And oversized lead bullet may require noting more than removing the belling while a undersized plated or FMJ bullet may require a roll crimp for a revolver or tight taper crimp for a revolver eg I use my Lee FCD for rifle all the time while I think the FCD for pistol is an answer to a non-existant problem. Note the two dies do not work the same way ie FCD for pistol vs FCD for rifle.


Take Care

Bob