P 64 fail to fire

[kbstenberg]

I have a new to me P64 and am having trouble with the trigger not letting the hammer fall. I have never tried to fire any factory rounds in it. I'm too cheep. All the brass has been trimmed to speck from 9mm luger. All loaded rounds are .005 under book length, and 90 + 100gr round nose bullets.
Yes the hammer will fall like it should on about every 4th or 5th round when hand operation of the slide. On the times that the gun will fire like it should. As the trigger is pulled I can feel when the weight of the hammer release will activate the hammer. When the trigger does not fire that additional weight is not felt.
If I hand close the slide on an empty chamber or have an empty fired case in the chamber. The trigger will activate the hammer EVERY time. I just tried this last night. So I am thinking even though LOAL length is below book I may have to shorten it more. I can't do the plunk test. Because the base of the case sits about 3/16's above the rear of the barrel. I checked that already.
When the trigger will not connect to the hammer. The trigger spring acts like normal an the trigger returns to its normal position. If I keep repeatedly pulling the trigger eventually ( after 8 or 10 pulls) the gun will fire. And when it does operate as it should I can feel the additional weight being added to the trigger pull.
I have tried shaking the gun, hitting the top of the slide with my hand, even shooting it gang style (sideways) Nothing so far helps.
If you look at the rear of the gun where the hammer drops into. On the right side lower area. You can see the transfer bar. When the gun will not fire that bar will be floppy loose. As the trigger is pulled when it woun't connect to the hammer you can see it jump in place. When the gun will fire it is steady and not jumping. Which mite be a symptom of too long of a round.
I have completely striped the gun to clean and look for broken missing parts. Everything is there and working.
Sorry for the book length post. If you have experience with the P64 please help! Kevin
After posting I got an idea. I redid the plunk test with an empty case. The case base was .126 above the barrel base. A loaded round measured .135 above the barrel. So hopefully my loaded cases have to be shorter. I will se latter today.

[kbstenberg]

Well I think I have found the prob. The loaded length was too long by a bunch. 2 books say .970 loaded length. Well I found out after the hunch I had above. I started from scratch. The longest my rounds can be with a round tip bullet is .912. And at that length the trigger will operate the hammer.

[OptimusPanda]

So the slide was held out of battery by a cartridge longer than .912"?

[kbstenberg]

Yes Even at .912 I had the occasional hammer hangup. I had to go down to .906 to get a constant hammer contact.