2289 pumping / power....

[Trigg603]

I have a 2289 with stock piston and valve.  Is it safe and / or beneficial to pump it more than ten times to get more power?  I have installed a steel breech and 18" barrel and for some reason it seems to have less power than before.  I don't have a chronograph so I have no way to confirm this.....It's just something I sense.

Thanks in advance for any advice!!!

[Steeb86]

I'm having this exact problem, minus the 18" barrel.  Before my breech swap I was getting 480fps at 10 pumps with 14.3 cpum.  Now I get 419 with the same pellet...I'm quite perturbed as I paid good money for that breech to give me better accuracy and now I get less power and erratic groups from a bench...I checked the alignment of the barrel hole and breech hole and everything has lined up.

[Bentong]

With stock piston and valve and pumping it more will just build up heat until seal or piston fails. Longer barrel does increase speed. Make sure when you swapped up breeches, you have no leak in the TP and verify the pellet is pass fwd of the TP. Load a pellet then pull the barrel out and look at the TP hole and  pellet should not be halfway in. If that happens, you need a longer probe. Do a penetration test as longer barrel is more quit than stubby.

[Steeb86]

I found my problem, I had reinstalled the little port nipple backward and had the short end going into my breech instead of the long end. Whoops!  I'm back up to 460-470 at 10 pumps   Check yours also, you may have done what I did. 

[Monkeydad1969]

I found my problem, I had reinstalled the little port nipple backward and had the short end going into my breech instead of the long end. Whoops!  I'm back up to 460-470 at 10 pumps   Check yours also, you may have done what I did.

 

[rsterne]

Another common problem when installing the steel breech is not shortening the rear screw and having it bind on the hammer spring....

You may think yoru gun is less powerful because it is quieter with the longer barrel.... RE pumping more than 10 times, yes, it will increase the power, but slowly with a stock piston.... You are better off to use a flat-topped piston and valve to increase the compression ratio....

Bob

[oldnamvet]

I found my problem, I had reinstalled the little port nipple backward and had the short end going into my breech instead of the long end. Whoops!  I'm back up to 460-470 at 10 pumps   Check yours also, you may have done what I did.

I seem to remember someone replacing that part with a piece of vinyl tubing?

[Trigg603]

I made sure I put the long end of the port pointing upward into the breech / barrel.  I used a screw that came with the breech that is a little bit shorter than the one used to keep the sight and stock breech.  I also have a Disco bolt that is pushing the pellet just past the transfer port.  I forgot to mention that.

This just MAY be perception on my part.  I need a chrono....for sure!!!

[Trigg603]

Oh yeah, I almost forgot.....Thanks, gentlemen!!!