Over Crimped Brass?

[Flakker]

My friend and I were making some .308 hand loads the other night when we came across a problem. 15 out of the 60 brass cases we seated and crimped the bullets into seemed to be "over crimped". We immediately checked over all of the rest of the recently hand loaded bullets to make sure there were not any more messed up ones in the lot. My question is how did this happen? Is this a problem with the die or just some wonky brass? The brass we were using was Winchester and some Remington but both types of brass had this "over-crimping" issue so it doesn't seem to be a manufacturer defect. (btw I used a Lee die if anyone asks)

 

[338RUM runner]

Were they all trimmed to the same length, if not that could be the problem.

 

[Flakker]

They all measured up the same so I am assuming that's not the issue, these things are pretty bent, I don't think they will even chamber, not that I am going to fire these things.

 

[2ndamendfan]

If it is a LEE FCD trim length should not be an issue since the die is moved by the shell holder or the shell plate, but neck thickness does make a difference with the FCD. If is a Lee bullet seater/crimp die then trim length does matter. Either way you need more brass prep.

 

[918v]

You have the seater die adjusted wrong. Back the die out and turn the seater stem in.

 

[Flakker]

It is a seater/crimp die. Sounds like more prep may be the deciding factor here. When slowly using the press the shells were perfect, not at all bent or over crimped. Human error is probably at fault.

 

[mtrmn]

I found it best to NEVER seat and crimp in the same operation.
I also found that the std roll crimp in the seater die is far too sensitive to even the slightest variation in case length and NECK THICKNESS.
Use a Lee factory crimp die in a separate pass on a single stage press or a separate station on a progressive.
Back in days of old, before the Lee FCD was available, I learned to crimp by "feel" on my single stage press and managed to MOSTLY eliminate the overcrimped cases. Again, this was a separate additional step using the seater die with the seater stem backed off.
The overcrimped rounds will still pass the plunk test in most cartridge headspace gages. These gages are usually simply drilled to a certain depth to check headspace and case length. JP RIFLES make a case gage that is made using actual chamber reamers, so the interior walls of the gage are tapered just like your chamber. They're made in 223 and 308 and every round I load gets dropped in these gages before it goes into the ammo can. These gages will catch ANY anomaly that may prevent proper chambering. Link: JP - Gunsmithing and Maintenance

 

[Flakker]

Thanks for the info mtrmn, I think I will be ordering one of those gauges asap, takes the guesswork out of it. I definitely agree when you said that that roll crimp and seater die is far too sensitive! I messed up a few cases the other night with it! I will be using a separate die for now on as well, it really sucks when the ammo you are working hard to make doesn't turn out so a new die is very much so in order.

Thanks again for the help!

 

[rjacobs]

I will echo that I dont like dies that seat and crimp in the same die. You never seem to be able to get them set just right. Get the seating set and go to adjust the crimp and now the seating is off and you start over. Sounds like the die started to crimp the case before the bullet was fully seated and as you were continuing to seat the brass rolled over.

A picture of said bad rounds would help out.

 

[mtrmn]

I will clarify abit here. When I said I learned to crimp by "feel" with a regular roll crimp seating die, I was not using the seating feature-it was backed way off. And I DID NOT GO FULL STROKE WITH THE HANDLE. I only went until I felt slight resistance and just a touch more. The least amount too much and the case would bulge just below the shoulder, renderingthe round unable to properly chamber.