Quote Originally Posted by tiny68 View Post
After supper I went to the shop and took some measurements. I took one of the brass that did not fire and pulled the bullet and primer. I started adding scotch tape. On the 3rd piece I couldn't close the bolt. If a took a piece of the brass that did fire I couldn't close it with one piece of tape. I measure the brass to the shoulder with a 0.330" gauge: The go headspace gauge measures 1.455. The fired brass measured 1.452-1.453". The misfires all measured that 1.448-1.449", which would have been what I set dies for. This brass had previously been shot in this barrel, but installed on a different action. I measured some of the LC brass that I purchased in bulk 5-6 years ago as once-fired, which all was 1.455-1.462" at 0.330". I couldn't even close the bolt on any of it. I assume this was fired in some type of an auto with a lose chamber.

I guess I will pick out a new set of brass and process them with a longer shoulder. I still don't see why this doesn't ignite when I extended the firing pin to 0.060" protrusion. This is way more than the extra couple of thousands I have in headspace play.

Tim
Looking at your brass dimensions, even if the primers are seated another .002" below the casehead thrown in for good measure, a .035" protrusion is more than enough to ignite a primer. As a matter of fact the shorter protrusion allows the firing spring more time to accelerate the firing pin increasing its primer impact energy. Increasing the protrusion beyond .035" does the exact opposite. More isn't always better.

Looking at your primers I'm seeing inconsistencies in the pin fall, less impact depth which is a result of something padding the pin fall. At this point I'd pull it out of the stock, primer a few pieces of brass then try firing them. If they ignite then its something with the stock. Typically its the sear making contact.

If they don't ignite then you have an action issue.

The very first thing I would look at is the sear. Remove the trigger leaving the sear installed and check it's movement making sure it moves freely it's entire length the travel. Next reinstall the trigger and check it's full length of travel again.

Next, you'll have to look at the bolt assembly. There's a laundry list of possible problems that can cause padding of the pin fall, the cocking piece sleeve out of round( egg shaped), the firing pin bent or ground off center, the bolthead retaining pin hanging up, crud in the bolthead shaft at the step past the vent..... the list goes on. Its only a matter of finding which one or a combination of them.

Bill