I recall reading on this board that someone suggested grinding down the tip of the M261 firing pin for better reliability (less area=greater impact strike in the smaller area). Has anyone tried this? I've been getting a few misfires with mine lately (almost always the first round in the mag, for some mysterious reason). Did it work? Any effect on accuracy? (I have another .22 rifle that SHOULD be accurate but isn't, and it seems to give very light firing pin strikes as well.)

The likely cause for a first round misfire is the closing of the charging handle not being brisk enough and the bolt not being fully forward.  

That is probably the issue.  unfortunately you can't charge and release without the handle-- maybe a good solution would be a weaker spring on the latch, or no latch or modding to a side charger.

Or a rubber band a modified latch with rubber band to pull the latch forward-- if you have a scope or carry handle knob you could throw a stiff rubber band from the knob to the handle. it would probably solve the problem.  


It could also be stripping that first round is tough due to stronger spring pressure.  

The problem is usually going to a non standard fire control.....aftermarket trigger set.  To get a better trigger pull a light hammer spring or lighter hammer has less impact on the firing pin.  The firing pin is just a big round surface that may not detonate the rim of the cartridge under these circumstances.

The solution is to 'chisel point' the tip of your firing pin.  Leave about a . 050" flat on the end vertically.  Grind a 30 to 45 degree on each side of the end of pin.  DO NOT take material off the end itself.  

This is a simple 'must have' mod done to your M261 to help reliability.  It is the best 22 conversion available.  With a custom dedicated barrel it will equal or outshoot a match 10/22 rifle.

Well, I did it. Didn't need to grind it, a file worked fine. I screwed up and got my flat a few degrees off vertical, but it should be okay. I figger I reduced the impact area by 50% or more, which should make for a sharper strike, right?

Did this on a spare pin; put the one that was in the unit and "working" (most of the time) aside to fall back on if need be.

My light strike problem only surfaced in the last box or two of Dynapoints, so it might be a slightly bad run of the ammo. Up to then it had fired them 100%, no problems of any kind at all. The funny thing is that I might get a misfire somewhere else in the mag once in eight or ten mags worth of ammo, but the first round would misfire maybe half the time. I would even check the bolt after loading the first round to make sure it was fully closed. When I ejected round #1 and let the handle fly forward on round #2, that one would fire no problem. Odd.

"My light strike problem only surfaced in the last box or two of Dynapoints, so it might be a slightly bad run of the ammo. Up to then it had fired them 100%, no problems of any kind at all. The funny thing is that I might get a misfire somewhere else in the mag once in eight or ten mags worth of ammo, but the first round would misfire maybe half the time. I would even check the bolt after loading the first round to make sure it was fully closed. When I ejected round #1 and let the handle fly forward on round #2, that one would fire no problem. Odd. "

Listen to yourself.  a box or two? 100rds of problems and you mod it?   I hope it works, but I wouldn't jump so fast to screw with it.  

Contact Frank White at Compass Lake.  He was making replacement firing pins for the M261 kits because a number of them were breaking.   I received a replacement and have never had a problem of any kind since.