Primers backing out on 180 semi

[45C]

Hello everyone
I just tried a couple of primed cases in my KD 180 to test the trigger and the primers backed out a small bit.

Is this gonna be an issue?

The cases have been sitting for a few years, already primed. If that matters.

Thanks

BrianView attachment 559227

 

[ryan]

Perfectly normal. Hitting the primer on an empty case causes the primer to back out. Nothing wrong at all.

 

[B]

Low pressure loads (or no pressure...) That is completely normal.

 

[45C]

Whew.. lol
Thanks

 

[Leatherstocking]

Does indicate excessive headspace. Reduce shoulder bump advised.

 

[B]

Does indicate excessive headspace. Reduce shoulder bump advised.

You should try reading his post again.

 

[Leatherstocking]

Let’s see…
The firing pin strikes the primer and drives the case forward until the shoulder stops it, and the primer detonates. The primer backs out.
If the headspace was spot on, the primer would be supported by the bolt face, and wouldn’t back out.

 

['Boo]

Let’s see…
The firing pin strikes the primer and drives the case forward until the shoulder stops it, and the primer detonates. The primer backs out.
If the headspace was spot on, the primer would be supported by the bolt face, and wouldn’t back out.

So what do you suggest proper headspace should be?

If the case didn't move forward it would mean there is no headspace which is not really desirable in any hunting rifle much less a self-loader.

 

[barsik]

hypothetical question.. would measuring the height of the primer above the case head be a reasonably accurate measurement of headspace? btw, there's nothing wrong with your gun as others have already stated.

 

[Ganderite]

Let’s see…
The firing pin strikes the primer and drives the case forward until the shoulder stops it, and the primer detonates. The primer backs out.
If the headspace was spot on, the primer would be supported by the bolt face, and wouldn’t back out.

Good theory, but it does not work that way. The explosive force of the primer backs it out, compressing the brass length. It happens on full power loads too, but then the pressure pushes the case back onto the bolt face.

 

[Ganderite]

hypothetical question.. would measuring the height of the primer above the case head be a reasonably accurate measurement of headspace? btw, there's nothing wrong with your gun as others have already stated.

No.

But if you partially seat a primer, then gently close the bolt all the way, the amount the primers sticks out of the case would then be a headspace measurement, on a rimmed case. On a rimless case, there is a lot of variation in the case length.

 

[Leatherstocking]

Some good information in this thread.
Yes, some headspace is necessary.
If Ganderite says it doesn’t work that way I’m sure it doesn’t.