doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Light primer strike

Recently, I posted about a light primer strike issue I am having with my Boswell hammerless 12g gun. It has been occurring on a fairly regular basis using different brands of factory 28 g trap loads and reloads using NSI primers in straight wall hulls. Today, I fired 50 of the original Winchester AA compression formed reloads using Win. 209 primers without a misfire. Previously all misfires have happened when using the wider NSI (nobel sport) primers which suit Winchester straight wall hulls as the Win 209 primers are not wide enough to insert correctly in these hulls. The Win 209's are a snug fit in the older, compression formed hulls only.

It appears that my early 1950's vintage gun, which has just had new springs fitted and has adequate firing pin extension from the breech face and is not off face, will only function using the older type AA hulls with the Win 209 primers. The indentation made by the firing pin on the Win 209 primers is certainly more pronounced than the Nobel Sport and most other straight wall hulls on the market.

I would check the depth of how far the shell head fits into the ejector/extractor. I had a hammer gun that would not shoot Winchester 209 primers in the left barrel, tried swapping mainsprings, made firing pin nose longer to no avail. Other primers worked fine. Noble Sport primers are about .001 larger in diameter compared to Winchester primers. There is a tool available that will resize your primer pocket but I don't know if that is worth the effort.
Good luck.

I dislike NSI primers. Poor quality control. 2-3 per 300 FTFs in my k80.
I think the metal is harder. Too hard, based on light primer strikes
The red cap that protects the primer is gone in 5-8 per 100.

I have to fire them in another gun to use them up and will not buy them again

I would suspect rim thickness / rim cut depth.

8,000 current production NSI 688 primers have functioned perfectly for me over the last year and a half in a variety of guns including a K-20, Browning target guns, Berettas, a Rizzini, and several automatics. Zero misfires.

I did identify 3 missing flash hole seals (green) in the primer tray and did not load those primers. I've had this with Win 209 also.

I just bought 20,000 more NSI 688 and highly recommend the primer.

Winchester primers being a loose fit in current production Winchester hulls? Color me skeptical...

The way you describe things it sounds like your chamber rims are cut slightly too deep. That’s where I would check next.