Roll crimping .357 further seats the bullet

[6pak]

Sometimes when I get my bullet depth all situated and I go to add a roll crimp, the act of crimping seats the bullet even further. Very frustrating. This happens when seating 357 rounds using a Hornady seating/crimp die. After I set my bullet depth I back the seating stem out to adjust the crimp, just like the manual says, but once I start the production run, the bullets get seated an additional .008 or so. Any thoughts on this?

 

[1911Tuner]

It's hard to imagine that +/- .008 inch will make a whit of difference. Factory loaded ammunition will vary that much or more within the same 50-round box.

 

[Walkalong]

After I set my bullet depth I back the seating stem out to adjust the crimp, just like the manual says,

OK.

but once I start the production run, the bullets get seated an additional .008 or so. Any thoughts on this?

It just means you didn't get the seater stem exactly right when readjusting. No big deal. Probably need to turn it down a schosh more. When we readjust the seater stem after adjusting the crimp (With the round in the die) we often don't screw it back down tight enough on the bullet.

 

[Uniquedot]

Since it's seating the bullet deeper you are screwing the stem down too tight on the bullet after setting crimp depth. Adjust it to just touch the bullet and then apply only a slight amount of pressure being sure to hold it there securely whilst you tighten the stem lock ring.

 

[Walkalong]

Yep, I guessed which way, so if I'm wrong, Uniquedot is correct.

 

[buck460XVR]

Is this when seating and crimping in one step or two? While others have addressed what may be happening in a one step scenario, in a two step scenario it might just be the action of rolling the brass downward into the cannelure that is changing the OAL. The brass is grabbing the cannelure and is moving the bullet downward as the crimp is being pushed downward. This is how a roll crimp is made. Not a big deal with revolver ammo as long as you are still crimping in the cannelure.

 

[Sunray]

You only need a crimp for very hot loads and any used in a lever action. In your case, use less crimp. It doesn't need to be much to hold the bullet in place. And 8 thou will make no difference.

 

[6pak]

Yeah, this is for seating and crimping all in the same pull. Thanks for the input everyone. I am anxious to get home and take another crack at it.

 

[ArchAngelCD]

Do you really understand how very small a difference .008" is?

If that's the biggest problem you run into you are doing just fine.

 

[gamestalker]

Often times the variance one experiences will be the combined result of olgive inconsistencies of the bullet, and also variances in brass trim lengths. Those two factors alone can easily create .008" variances. And although inconsistent brass trim lengths don't actually effect oal, it does give the perceived appearance, and can also effect the location and quality of the roll crimp.

But as other's have said, .008" is meaningless with rimmed handgun cartridges. If the crimp is in the canelure and sufficient for the load being used, and the bullet seated so as to not interfere with cylinder rotation, all is well and good, other wise make die adjustments, and, or trim brass as necessary to rectify the problem.

GS

 

[Steve C]

Your nit pickin' about stuff that makes no difference, esp. in a revolver cartridge. The only OAL I pay any attention to is to make sure the bullet chambers and doesn't stick out beyond the face of the cylinder in the shortest chambered revolvers I have (Colts). No other OAL measurement is important. The crimps function is to hold the bullet in place and prevent bullet movement, either pull under recoil, or setback when feeding or from pressure from other cartridges in a rifle tube magazine.

 

[joneb]

Back out the seating stem so the case mouth crimps in the middle of the cannelure. For hollow points with a delicate nose I seat and crimp in two steps.

 

[somerled]

Other issues could be brass that is not trimmed to a uniform length, brass from different manufacturers or case lots, or an oversize expander plug. It does help sometimes to seat and crimp in two different operations.

 

[murf]

that happens to me all the time when i apply a heavy crimp and my cases are different lengths (it doesn't matter if you seat and crimp in one step or two). the crimp grove on a lead bullet is ramped, and the crimping part of the die will suck the bullet back into the case until the case rim gets to the bottom of the crimp.

i wouldn't worry about it.

murf

 

[Catpop]

I found when trying to crimp kieth style bullets on the rear of the front driving band to get 1.590 I actually pushed the bullet forwad increasing the oal to 1.605.