Primers

[gbal]

I agree primers can make or break a load. I will no longer use Fed primers in small rifle, they are soft. I always do a primer test among the various primers I have, as a fine tune. I find I tend to gravitate to CCI450's or CCI BR4. Some will improve load ES and group size by as much as 50% with a simple primer change. Some primers are interchangeable. I had a Fed let go at the shoulder radius on my 223 at well below max pressure. Neil M bushed the firing pin and reworked the bolt face so that fixed that problem.

 

I knew about the Feds being soft from the many articles I've seen over the years. Some good info in the following link. http://www.jamescalhoon.com/primers_and_pressure.php The case head expansion theory is one I tried. However it has since been debunked by others with vastly more knowledge than me. Personally I found it to be a waste of time. There are too many variable at play and you will get the expansion he talks about on safe loads in factory ammo in some chambers.

 

 

 

If you use a K&M primer tool you will also realise that some primer manufacturer dimension tolerances are better than others. The worst for me is Remington. They are complete tat AFAIC. From my experience the best seems to be CCI.

 

As for reading primers as a tell tale? Factory Remington rifles have a sloppy firing pin hole and will crater at well below max loaThe QL help file has a very good section on excessive pressure signs including photographs. The one thing that becomes very clear is that reading the primer after firing is unreliable at best. It has some photo's of normal looking primers on 308 loads that were producing a measured 78,000psi!! If you know your rifle and how thing look, it's better than nothing. It's a very rough guide at best and should not be used as a sole indicator of pressure.

 

Confused...I am.

 

ATB

 

Hmmm....can we reasonably say at least,that any abnormality in a fired primer is a sign that something is not as it should be,but there are several things to look at for the cause.

On the other hand,if a fired primer looks normal,this is no guarantee that everything is as it should be.

 

You give interesting examples of both of these.There are of course more.

 

Gbal

 

 

[achosenman]

Hmmm....can we reasonably say at least,that any abnormality in a fired primer is a sign that something is not as it should be,but there are several things to look at for the cause. On the other hand,if a fired primer looks normal,this is no guarantee that everything is as it should be. You give interesting examples of both of these.There are of course more. Gbal

Absolutely Gbal. That is exactly my take on this.

 

I got into looking at primers in depth a few years back, including looking at brisiance . It's quite an interesting subject and far from simple. Some would be amazed by how much something as simple as the primer seating depth and primer type can affect the load.

 

I went through lots of priming tools before I settled on one that scratched my particular itch. At least when you nail a problem to your satisfaction, you can move on to the next.

 

ATB