CMMG firing pin life expectancy?

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bradaz11
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Re: CMMG firing pin life expectancy?

#11 Post by bradaz11 »

does it look like this?

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if yes, where did it break?
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Re: CMMG firing pin life expectancy?

#12 Post by safetyfirst »

Mine broke at the 90 degree step every single time.
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Re: CMMG firing pin life expectancy?

#13 Post by bradaz11 »

safetyfirst wrote:Mine broke at the 90 degree step every single time.
would machining that step flat, then drill a hole down, and insert a hardened pin into that (ala home made punches etc) not make for a better design? what sort of dia are we looking at?
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Re: CMMG firing pin life expectancy?

#14 Post by safetyfirst »

Nice idea. Want me to get the callipers out on Monday?
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Re: CMMG firing pin life expectancy?

#15 Post by Gazza »

It broke here....
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Re: CMMG firing pin life expectancy?

#16 Post by DL. »

That's appalling. Did they not do any research and development before they launched those rifles onto the market?
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Re: CMMG firing pin life expectancy?

#17 Post by dromia »

Lot of discussion about it here:

https://www.full-bore.co.uk/viewtopic.p ... firing+pin

Seems like an ongoing issue that the manufacturers see fit to ignore.
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Re: CMMG firing pin life expectancy?

#18 Post by bradaz11 »

safetyfirst wrote:Nice idea. Want me to get the callipers out on Monday?
well as long as you have around 1mm of side wall I would think it would be good enough. the tailstock on my lathe isn't great atm (lathe project is taking a backseat til I actually can think of stuff to make and get some decent size material - like some 3" plastics, anyway), but for the accuracy needed i reckon a face cleanup and then chuck it in a decent drill press would get a good enough result.

If sizes are about right, I wonder if it would be worth tapping it and using a cut down stainless screw? either that or might find some sort of hardened pin available online.
This sounds a bit amateur, but i'd try first to just glue it in with something like PVA, that would probably move with it, but not hold it in too hard. It only needs to overcome the inertia of the bolt afterall??
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Re: CMMG firing pin life expectancy?

#19 Post by Gazza »

I think Mr Paa should make a few quid from a redesign/material change of this pin.
So Dave, on it this week coming? lol
Put me down for at least one maybe two :good:

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Re: CMMG firing pin life expectancy?

#20 Post by bradaz11 »

Gazza wrote:I think Mr Paa should make a few quid from a redesign/material change of this pin.
So Dave, on it this week coming? lol
Put me down for at least one maybe two :good:
totally agree, but if a bit of home machining can get it back in action for now, while you wait for the Shed to free up some space for a more permanent fix, where's the harm?

it's already snapped off, what will drilling a hole in it do to make it worse?
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