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The chamber was cut to give steeper shoulders and a slightly wider forward case body. I take 300 SAUM brass and neck it down to 7mm so the case unfired is not going to be a perfect fit in the chamber until the first firing when the brass will flow to the chamber and all is good. I have fire formed many cases but had a few where the primers failed to go. It has to be either the case moving forward very slightly under impact or the firing pin not moving forward enough, or the primers being dodgy.

Firing pin protrusion is .050" and I would have expected it to be closer to .070"

So, after you've fire-formed your cases and then made some "proper" loads, so you still have mis-fires then?

ovenpaa wrote: It has to be either the case moving forward very slightly under impact or the firing pin not moving forward enough, or the primers being dodgy.

Or the wrong size wildcat (eg case length, distance to shoulder etc?) for your wildcat chamber.

Robin128 wrote:Or the wrong size wildcat (eg case length, distance to shoulder etc?) for your wildcat chamber.

The chambering is a tad complicated but yes it was chambered for SAUM brass and it is only a smallish percentage of new brass that failed, once shot they are great.

I have just stripped and cleaned the bolt assembly and pin protrusion is now at .0530" which is ample. I do wonder if it is a combination of hard BR primers and new brass that has not yet been correctly formed. The cases are now built with normal CCI primers however I am tempted to pull the lot and load with Magtech primers as they are very soft.

Out of all the primers I have used it is only these CCI BR primers I have had issues with and I am sure if it was a known issues the American forums would be full of it.

Mark - Just went to check the lot number on the outer box but realised I have thrown it away as I am down to my last 300 BR primers so all I have is the inner boxes they are packed in.

I just measured the firing pin protrusion on my Barnard and it is .... 50 thou. Never had a misfire, but I did fit a new spring recently, which improved long range elevations considerably (bolt lift was noticeably stiffer).

Faulty primers are extremely rare but if a primer is seated too deeply or with excessive force, it may break up the primer pellet and cause a misfire.

HTH

Stan

ovenpaa wrote:

Robin128 wrote:Or the wrong size wildcat (eg case length, distance to shoulder etc?) for your wildcat chamber.

The chambering is a tad complicated but yes it was chambered for SAUM brass and it is only a smallish percentage of new brass that failed, once shot they are great.

I have just stripped and cleaned the bolt assembly and pin protrusion is now at .0530" which is ample. I do wonder if it is a combination of hard BR primers and new brass that has not yet been correctly formed. The cases are now built with normal CCI primers however I am tempted to pull the lot and load with Magtech primers as they are very soft.

Out of all the primers I have used it is only these CCI BR primers I have had issues with and I am sure if it was a known issues the American forums would be full of it.

Mark - Just went to check the lot number on the outer box but realised I have thrown it away as I am down to my last 300 BR primers so all I have is the inner boxes they are packed in.

if you are going to thetford next make sure you speak to Danny about this hell confirm what i have already said.

spud wrote:if you are going to thetford next make sure you speak to Danny about this hell confirm what i have already said.

I am trying to thing who Danny is... I am at Bisley next weekend so will miss the Thetford meeting, tell him to take extra ammunition as they are shooting at three distances.

DannyT (Trowsdale) the ginger one

So I take it no problems with light strikes once the brass is formed?

Sim G wrote:So I take it no problems with light strikes once the brass is formed?

Actually they look about the same for both new and once fired brass... The strike looks good, annoyingly I have now popped the last two primers that failed.

The thing is if it fires once it is always OK afterwards so I am starting to think it has to be something in the forming process.