Crimp

[mag_01]

I crimp heavy loads for consistent bullet pull but how about light target loads --crimp or no crimp ---I would expect a light crimp would do----anyone have any thoughts ?-----Mag

[Dale53]

Some years ago, I ran some tests on crimp with the aid of a very accurate couple of revolvers (.38 Special) and a Ransom Rest. Using the typical HB WC's and cast wad cutters, also, I had better accuracy with a light to medium taper crimp as opposed to a roll crimp. You must be careful, tho', as it is easy to taper crimp too much which will damage your carefully sized bullets.
FWIW

Dale53

[robertbank]

Depends on the calibers and pistols you are reloading for. Autos typically only require a taper crimp to remove the belling ie .45acp, 9MM, 40 cal. In those calibers the bullets are retained by case friction. Revolvers I use a solid roll crimp. Appreciate Dale53 comments but if you are talking practical shooting I don't believe any accuracy improvement warrants the risk of bullet set back and the possibility of a kaboom.

Take Care

Bob

[9.3X62AL]

Boolit/bullet setback--or a slug telescoping out to tie up a revolver cylinder--either event could really be inconvenient, at minimum--not to mention the variance in accuracy such phenomena would introduce. The wadcutter loads mentioned by Dale do not produce significant recoil, and have the advantage of being seated either almost flush or completely so with the case mouth. That's a lot of boolit sidewall to grip the case wall, so a light taper crimp is likely sufficient in that situation.

[georgeld]

When out hunting one time digging in a pocket for ammo.
I cut the Helx out of a finger on a sharp case mouth.

Since then, I very lightly crimp everything I load. Just barely
enough to knock the burr off is enough.

I've just bought and got started loading/shooting a .45 LC.
Those are heavy enough they'll need a decent crimp. So I'll
abide by that on these loads.

Hope the insight helps someone and save's a wicked cut like I had.
Not only made a bloody mess on the gun and things because it was
real hard to stop the bleeding. It got infected too. Hard telling what
kinda nasties was in my pocket.

[Bass Ackward]

From my testing, a roll crimp has tremendous effect on loads up to 20,000 psi. It has a marginal effect from 20k to about 24/5k. Beyond that level and case neck tension provides the most assistance to ignition and bullet crimp is mostly a function of securing the bullet.

But if you are operating below 20,000 psi, then crimp and case neck tension in combination can have dramatic effects on accuracy. The problem is that the need for or the degree of crimp is still tied to powder speed selection AND case neck tension. So what you will find is that the anneal on your brass affects both of these. Complicated huh?

Individual testing is the only practical method for formulating your own opinion.