Jump to content
Brian Enos's Forums... Maku mozo!

Mysterious overpressure


BoyGlock

Recommended Posts

4 minutes ago, Hi-Power Jack said:

 

And the saga ends ....    :mellow:

Just for the mean time. When time permits, im gonna tinker that powder measure and see how it really happened. Just too busy now prepping for a big 18stage match this weekend. Solved the problem just in time. But it took a lot out of my training time. 

Link to comment
Share on other sites

  • Replies 57
  • Created
  • Last Reply

Top Posters In This Topic

On 4/29/2017 at 3:59 PM, racer-x said:

Trying to measure the very, very, tip edge of the brass where the brass & crimp end is pretty iffy. I do not trust that method at all.

Better is to just eyeball the cartridge, while adjusting lighting and reflection off the brass, looking for a very slight contour inwards. Hard to see if there is a little "too much" crimp like this, but you can definitely see "not enough".   

 

Best way I found to reliably measure correct crimp is this:

1- measure bullet diameter (.355 in example picture)

2- pull a bullet from cartridge you just loaded

3- look for a very slight indentation ring in the bullet where the tip of the crimp was (tip of knife in picture).

4- measure bullet diameter at the crimp ring (.353 in example picture)

 

My experience is that this is best if .001-.003 less than full diameter measure (I.e. .355 - .353 = .002 ).

This method is 100% repeatable; just need a bullet puller.

 

crimp-1.jpg

crimp-2.jpg

crimp-3.jpg

Those are over crimped.

Link to comment
Share on other sites

2 hours ago, Hi-Power Jack said:

They're overcrimped, IFF accuracy suffers .... 

 

If they're accurate, they're NOT overcrimped.    :) 

Agree but first the head must first be proven accurate prior. 

Had a mysterious (again) experience on this. Not so long ago my longtime everyday-match-practice loads suddenly went tumbling and innaccurate without me changing anything in the reloading bench. Checked and rechecked everything. Tried every loose crimp adjustment for days and weeks. To confound the issue, it happened in 2 of 3 guns. Pretty expensive to change barrel i thought. So finally tried heads from different source for a cheaper solution. The tumbling just went pfffft. It was much later that i learned the manufacturer changed the materials coating the bullet that must have caused my problem. 

Link to comment
Share on other sites

  • 1 month later...
On 5/3/2017 at 4:39 PM, Hi-Power Jack said:

They're overcrimped, IFF accuracy suffers .... 

 

If they're accurate, they're NOT overcrimped.    :) 

I disagree. Those are just definitely overcrimped. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...