I have started to have failure to fire issues with my newish PSA 9mm.  I thought it might be the Timmney Trigger I put in so I replaced it with the original PSA GI type trigger.  This actually seems to have helped a little, but I still have a failure to ignite the primer ever 5 shots or so.  Looking at the mechanism it seems that the hammer may be hitting the last round hold open before  the hammer fully strikes the firing pin??  I suppose I could change to Fed'l primers which are said to be softer, or try to get a longer firing pin.  I should say that I have two bolt groups a PSA and a Spinta, both are prone to the misfires, but the PSA seems slightly worse, although both are unacceptable.  

My question is, have others had problems with the PSA lowers bolt hold open latch stopping the hammer from delivering full force to the firing pin??  If so how have you fixed this?  It looks like the easiest way is to remove the hammer and file a few hundreds off of the face that contacts the bolt hold open.  A better solution would be to remove the bolt hold open and file the same off the face that contacts the hammer, thus making it GTG with all hammers??

I would appreciate any guidance here, I have a PCC match this Sun and can't see going if I can't get this problem solved.

I don't have the PSA, but some earlier threads mentioned the bolt dragging on the ejector and not always going completely into battery. Thus, appearing to be a light hammer strike.

Thank you for your reply, I will check to see that the ejector isnot dragging on the bolts, I did have to adjust it to get the empties to eject reliably.  I am about to trim the surface of the bolt hold open where it makes contact with the hammer.  will let everyone know how it goes. This is really frustrating, as I have a match I'm signed up for this sun and have to travel or not depending on how this goes in the next two days.

OK, tentatively the problem is solved.  I filed back both the hammer where it makes contact with the bolt hold open and the face of the bolt hold open itself.  Therefore not sure if it was neccesary to cut back the bolt hold opn, the hammer face is easier to address, so I'd have been well advised to pull the hammer and trim it back and then try before dissembling the bolt hold open!

I had two failure to fires, but both turned out to be 8x18 Makarov caases that had mysteriously gotten into my Luger brass.  Interestingly that has happened before and my CZ will fire them.  I surmise that the extractor on the CZ is hooking the rim of the ;brass and holding the short brass tight enough to the bolt for the firing pin to work????  I do not like the look of the extractor, looks to be  a bent piece of spring steel, much as a cheap .22 would have.  Both the Spinta and the PSA have that type of extractor, does anyone make a bolt with a AR15 type extractor?

so it now looks like I'll be going to my match Sun after-all.  Now if I can get the Timney trigger to also work  I may actually be able to hit something, or not.

I have a Spikes 9mm with a factory mag adapter. If the adapter isn't seated in exactly the correct place it drags on the bolt. I've also notice that rifle loves oil. I use Mobile 1 on the bolt.