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The firing pin in my CMMG broke today. The rifle started shooting very weird with stove piping, FTF and lots of misfires which I put down to not cleaning or using for a while.
Anyway, I set about cleaning it tonight and stripped the bolt to find the pin is in two bits aaarggh
Whats the life expectancy of these pins? I've put around 6000 rounds through it from new but on reading comments on forums people are getting up to 18000 rounds from a pin.
How many rounds are you getting before a pin change?
Looks like another trip to the land of Lantac next Week.

Mine don't even last 12 months which is probably less than 5000rds, just buy loads and treat them as consumable.
They last longer if you have a working BHO to prevent dry firing, mine snapped last week on an empty chamber when I thought there was a round up the spout.

I’m on my fourth and about 34,000 rounds in.

This last one was a posh one from Suffolk Rifle, it’s lasted a fair while. I’m considering having some titanium ones made or something more hardy at least.

I run a Guiselle SSA-E trigger in mine which packs quite a punch I think.

I have started to consider them a consumable, there’s always one in my magpul grip wrapped in a paper towel along with some springs and an extractor.

I wonder if Mr Paa could knock up some long life ones? hint hint

Gazza wrote:I wonder if Mr Paa could knock up some long life ones? hint hint

He has my spare as a sample so its on the cards i think

I have some Titanium here awaiting my attention to build a handful.

put me on the list please

What sort of money are they going to be rolled out at Dave? and when do you envisage availability?

It's a long time since I studied any mechanical engineering, but looking at the surface of the remainder of the firing pin after the narrow pin section that contacts the primer has fallen off, it appears to me to be a fatigue failure where the last remaining bit of metal fails just where the pin steps down to the narrow section. Every time a round is fired, that narrow section bends a little, and as the firing pin can not rotate, the bending is always in the same direction, upwards I think. Titanium might be a more durable material in this application than stainless steel, although I wonder if the tip will be hard enough.

Worth trying though, it's a real pain when the pin goes.

My pin had been broken for a fair few rounds by the looks of it as the two broken halves had been peened (is that the correct term?) by hitting each other over and over again as each round was fired. The misfires must have been when the tip of the pin had moved round in the bolt causing a no strike situation.
It would be better if the pin was tapered but I can see this being a ball ache to do as the bolt would have to be tapered too.
Could the point where the pin steps down have a radius rather than a 90 degree step? would this aid reliability?