Quoted:
I'm always told by an older reloading friend to have an open and inquisitive mind.  

On initial thought as a cast boolit shooter I'm not warm to the idea of over crimping my bullet and effectivley sizing it even smaller than what the barrel wants.

Quoted:
I am not even sure what a negative -.004 crimp means or how Sweeney makes the measurement.   But, I like a heavy roll crimp on my 44 mags to 1. prevent bullet creep in revolvers and 2. to assure good feed in my '92 Puma lever gun.    I have seen photos of Dryflash3's large cal. pistol roll crimps.  I dare say they are more than negative .004.

PS:  I think Sweeney has or had an account on ArfCom.

Adjectives are very poor substitutes for numbers. This has become my pet pieve, why ? Because this creates unnecessary confusion and endless posts that start with.

"Is this enough crimp." Ending with. "My cartridges won't feed."

Then the poor fucker winds up in some 1911 forum somewhere being told he needs everything from new recoil springs to send it off to a competent smith. In between these suggestions are new magazines, extractors and shooting lessons.


It's simple math but what do we tell folks ? Set the die to where it just removes the flare. Last time I checked no one makes a "remove the flare die." Not Dillon, Redding, RCBS, Lee, Hornady, NOBODY.

EVERYONE mentioned makes a crimp die and setting a crimp die is done like everything else reloading, by computing simple elementary grade math. Looks something like this. ( bullet diameter + brass casewall thickness x 2 = maximum setting for crimp die. So if we have a .355 bullet using Winchester brass and we want TO SET THE CRIMP DIE, elementary level math looks like this.

(.355 + .010 x 2 = .375) So with these numbers I take a belled or "flared" piece of brass, place in shell holder, extend ram and run my CRIMP die down tight on belled case that I belled .004 over sized case mouth. Then crank my CRIMP DIE down anywhere from a half to three quarters a turn further and lock.

No crimp at all, still requires the use of a crimp die, meaning a CRIMP has been applied.

Now, take the same numbers from above. (.355 + .010 x 2 = .375) Although we, with experience know what removing the flare is. What we take for granted is how this is perceived. Think back when all this was new and your overwhelmed. Someone, somewhere taught you the math for a ZERO SUM CRIMP. If not, then maybe you were touched and figured it all out because, well, your smart. Whatever..... Most folks need voltage before the light comes on.

Ok, let's look at zero sum crimp, light crimp, medium crimp and heavy crimp. You won't find this written down anywhere folks. This is what teaching others has netted.

Bullet diameter + case wall x 2 = zero sum crimp. This is, 0.000 (zero). Light crimp is - 0.001 (negative one thousanths). Medium crimp is -0.002 (negative two thousanths). Heavy crimp is -0.003 (negative 3 thousanths).

Someone said Patrick Sweeney had a book out on reloading. In his book he suggested 0.004 crimp ? I'll have to get that book, but that's excessive. Some history on Patrick takes him back in time before IPSC, through IPSC and into USPSA. Knowing his history I have no problem believing this because these sports reward speed far more than accuracy. Modern ammunition manufacturing crimps to negative three thousanths, heavy crimp. So Patrick's a bit off the chart. Said this just because I knew it would come up again. Didn't respond when posted but it can't be let go without discussion. Patrick has been around long enough to know negative four thousanths would not win him a bullseye match. For most of the new guys, just finding something that works is challenge enough and we've all been there.

Someone, one time made the mistake of saying. " Well that's all good and fine but some of us are math impaired ! " Ok, I said. If you think about it we measure oal with a caliper, powder by grain on a scale that measures by grain, we use dial gages to measure things like primer depth and cartridge neck runout. What you're really saying is you're "reloading impaired.".

Quoted:
I read it. I'm not changing what I do.

Quoted:
I posted this in another thread.

Beings you're new to this and these cartridges are new for your gun and don't have a firm grasp on tailor making cartridges to a specific feed channel. Yes, I'd recommend a medium crimp.

Now someone's gonna come along and say BS and my unsaid reaction will be, .

Take your caliper with you sometime to a gun shop. Tell them what your doing and you'd like to see every make and type of cartridge they sell. Mine said sure and starting hauling boxes from behind the counter. Bass Pro didn't give me a second look. Measure loaded case mouths on pistol cartridges. Lee didn't name their factory crimp die what they did for nothing. Almost all ammunition makers crimp by at least .001. Hornady has been the one exception and guess what ? Hornady now crimps their Critical Defense ammunition. The reason most use for not crimping is because straight wall pistol head spaces off the case mouth. While true, your weapons feed channel depends on bullet ogive to navigate its way to chamber. Setback can really screw with feed geometry. At a minimum use a light crimp until you get to know the craft a little better.

By the way. I can't hand groups of heavy, medium, light or zero sum crimped cartridges to a novice shooter a discern a difference in crimp by their groupings.  People go overboard to make this an issue when it's not.

Patrick says everything that needs to be said in his article.

Quoted:
I read it. I'm not changing what I do.

Quoted:
I posted this in another thread.