Cratering on primers

[jds holler]

I kind of look at cratered primers as just one piece of evidence that I might have high pressure. The other evidence would be extreme flattening, ejector swipe, tight bolt lift, chronograph says high fps --

Without any other evidence, cratered primers don't mean much. jd

 

[Bora72]

Have your bolt firing pin hole bushed. Problem solved. See Carlsbad, he's the man.

Hello,
I live on Italy, here have some gunsmith and the costs are too crazy.
But I don't think that are a common work here...

 

[Bora72]

GTG = Good To Go

Good to go like 15 o more firing?

 

[Bora72]

He's in Italy, stuck with Europe gunsmiths.

Unfortunately for the gunsmithing side...

 

[Bora72]

I kind of look at cratered primers as just one piece of evidence that I might have high pressure. The other evidence would be extreme flattening, ejector swipe, tight bolt lift, chronograph says high fps --

Without any other evidence, cratered primers don't mean much. jd

The gap from the pin and hisnhole and the free bore are the cause by my think

But the photo of the primers.
Left 35gn and 139 Scenar
Right 36,5gn and 120 ppu

 

[SeabeeKen]

The gap from the pin and hisnhole and the free bore are the cause by my think

But the photo of the primers.
Left 35gn and 139 Scenar
Right 36,5gn and 120 ppu

I dont believe its a pressure problem. Enjoy

 

[Bora72]

I dont believe its a pressure problem. Enjoy

I think the problem are the inertia pressure.
The next trip to the range I make the same load but with more freebore

 

[SecondsCount]

The question is being asked as to why one of the loads has signs of higher pressure, not how to fix the cratering, etc.

I did some testing in GRT. The 139 Scenar load has a greater seating depth and increases pressure around 1000 psi.The loads are in the low 40K range, well under what the cartridge is capable of.

Gun companies need to understand the important of using a small firing pin when chamber for a cartridge that uses a small primer.

 

[Bora72]

The question is being asked as to why one of the loads has signs of higher pressure, not how to fix the cratering, etc.

I did some testing in GRT. The 139 Scenar load has a greater seating depth and increases pressure around 1000 psi.The loads are in the low 40K range, well under what the cartridge is capable of.

Gun companies need to understand the important of using a small firing pin when chamber for a cartridge that uses a small primer.

Hello, unfortunately every company make some choices, sometime this choice result the choice of the century, some time Renault the bad choice of the century....

If I find one gunsmith on my country that cam make the mod for a rasonable cost I ask if can change also the large firing ping with a small version

 

[NorCalMikie]

Primer cratering is a product of the firing pin hole in the bolt face generally being to large and having a loose fit to the pin diameter and possibly having a chamfer. Bushing the bolt face and reducing the firing pin to 0.062 fixes this????

How bout a simple headspace issue?? NOT barrel/chamber firing pin bushing issue problem BUT, brass too short for the chamber? Round goes BANG, brass moves back in the chamber and the primer gets "cratered". And you never have to think about bushing the firing pin AND, you can spend those extra $$$ not spent on reloading components. Do the easy stuff first.

 

[William Vogel]

How bout a simple headspace issue?? NOT barrel/chamber firing pin bushing issue problem BUT, brass too short for the chamber? Round goes BANG, brass moves back in the chamber and the primer gets "cratered". And you never have to think about bushing the firing pin AND, you can spend those extra $$$ not spent on reloading components. Do the easy stuff first.

He claims that the brass fits the chamber and that the bullets being really close to jam is causing a pressure spike. So if the brass fits then it’s back to the firing pin fit to the firing pin hole. I’ve been in this situation. Reducing pressure will alleviate the craters but it doesn’t appear that there are any additional pressure signs.