Retaining air

[Matchstickshooter]

 Don't know how or why but my 1377RC now seems to be retaining air.
 I''ll shoot, then go to pump it up again and it seemed harder.
 So after I shot, I cocked it again, and it went off again!

 Now each time I dry fire after taking my shot. What's going on?

[ER00z]

Striker (hammer) spring getting weak, possibly excessive oil in valve (reducing volume, increasing pressure) or slight wear in tube where the striker moves, causing higher friction (doesn't hit valve stem as hard)... Or combination of these. Well, that's the best I can figure. I'm sure others will chime in.

By any chance, have you replaced the transfer port with icemaker tubing? If collapsed (being too long) it could possibly choke airflow and cause valve to retain air.

[Matchstickshooter]

 Zack, I'm thinking  you guessed it.   I have new transfer port, and know the striker/hammer is polished smooth.

Being a Rear Cocker I think the spring is getting weak.  See no way of changing it yet.
 Got my thinking cap on now.
 Thanks!

[Matchstickshooter]

 No way of changing the hammer spring.
Guess I'll put a lighter one in the valve.

[Back_Roads]

 Compressing the valve spring to coils touch sometimes does the trick.

[ER00z]

Compressing the valve spring to coils touch sometimes does the trick.

Mrs. R has a micro torch for projects I sometimes barrow for spring modification. Handy little thing. Using it I've collapsed a coil or two and/or used to close the end of a spring I've clipped. For valve springs in pumpers, I haven't been too aggressive, just clipping one or maybe one and a half coils off then closing the end... By heating a coil bend red hot then pressing closed/flat with pliers. 

[Matchstickshooter]

 Had a chance to tackle it today and went a different route.
 Found a washer the same size as the hammer plug, made a slot in it to fit over the hammer stem.
Greased it and put it between plug and hammer spring for pre-load. 
  Read up on doing it this morning.     Also there is a YT video out there about doing it. (he used a plastic washer, I used metal)
  Works fine!