How Much Crimp???

[gene10pntr]

How much taper crimp is too much? I crimp just enough to let it drop easily in a case gauge. Does too much cause fliers? Should the crimp vary on different types of boolits?

[Hick]

I'm probably in the minority here-- but I only crimp my 38 Special and .357 Magnum loads. The 223 Rem, M1 Garand, 32WS and 30-30 loads have no crimp. But then again, I don't shoot much in the way of hot loads. So for most of my shooting any crimp is too much.

[MyFlatline]

At times I will play with the crimp for accuracy.. On my 45 colt, a heavy crimp did better with 10 grns, of Unique than a weak crimp. Your milage may vary...

[Hickory]

For me, the rule of thumb is this:
Fast burning powders in revolvers - no crimp.
Slower burning powders in both rifle and handguns will get enough crimp that will keep the bullet from pulling out of the case. There is no reason to over do the crimp, it will only weaken the brass and distort the shape of the boolit.

[Wayne Smith]

I'm probably in the minority here-- but I only crimp my 38 Special and .357 Magnum loads. The 223 Rem, M1 Garand, 32WS and 30-30 loads have no crimp. But then again, I don't shoot much in the way of hot loads. So for most of my shooting any crimp is too much.

Unless your 30-30 is a bolt or single shot the tubular magazine requires a crimp in most cases to prevent the boolit sliding back in the case under spring tension and recoil. I do not rely on neck tension alone to accomplish this.

[sandman228]

I usually just go by the instructions on the lee factory crimp die for all loads. the only round I crimp heavier than the die instructions call for is 45 colt . I load 45 colt with imr 4756 if I don't crimp heavy I have allot of unburned powder . this may change when I'm out of 4756 and have to move onto another powder choice since 4756 is not longer in production .

[Hick]

Unless your 30-30 is a bolt or single shot the tubular magazine requires a crimp in most cases to prevent the boolit sliding back in the case under spring tension and recoil. I do not rely on neck tension alone to accomplish this.

The key here is my comment that I generally do not shoot hot loads. But yes, these are tubular magazine Winchesters, and I have had no problem yet-- 13,000 rounds fired and counting. There is an excellent study done (which I cannot find at the moment) of the "problem" of needing crimped cases in tubular magazines, which pointed out that due to newtons first law the cases in the magazine do not experience the actual recoil of the shot fired. The rifle recoils backward but the magazine spring flexes so that the loaded rounds do not recoil significantly. I'm not the expert on this, but I can only say that I've never had a problem with bullets pushed down in the cases.

[Bill*B]

You will get as many opinions as there are shooters! Not saying that it's right, this is just how I do it - all my repeating rifles get a solid, tight crimp - be it roll, taper, or Lee - but tight! I don't want bullets moving under recoil. Single shots get a rather light crimp, just enough to barely roll the brass in so there is a smooth edge to it. Bill

[facetious]

I tryed a ladder test with 4227 in my .308 first with just enough taper crimp to take out the flare and give a light crimp, then with the Lee factory crimp die crimping it just enough to see it. With the taper crimp 17grs gave the best group but the Lee crimp gave the best group with 18grs. So maybe the extra pull helped.

[Grmps]

To much crimp on a 9MM can downsize the boolit and cause leading and other problems. 9mm is the worse for this since it has a tapered case.
Some people crimp more on lite loads to give the powder more of a chance to build up the pressure.

[M-Tecs]

How much taper crimp is too much? I crimp just enough to let it drop easily in a case gauge. Does too much cause fliers? Should the crimp vary on different types of boolits?

Rifles or semi-auto handguns?

[gene10pntr]

I should have said for 9mm semi-auto...my bad

[M-Tecs]

Back when I was shooting Bullseye with a 45ACP I did test different crimps on my cast loads for accuracy. .468" on the 45 worked best for me. If I remember correctly that is about .004 total crimp. I have never tested any of my 9mm.

[TXCOONDOG]

I crimp all my semi-auto’s pistols enough to remove the bell/flare for reliable feeding.