Very interesting. I wonder if the gain will be more or less than increasing the amount the valve opens? Or fitting a stiffer hammer spring? Or best when combined with one of the other mods? Or both?
I’m trying to get some good FPS 600 + with 7-8 pumps using 10.5 gr pellets. I’m taking a hopeful look at 8 pumps, ~ 600+ with 10.5 gr pellets :-)
Quote from: wll2506 on December 08, 2018, 07:44:20 PMI’m trying to get some good FPS 600 + with 7-8 pumps using 10.5 gr pellets. I’m taking a hopeful look at 8 pumps, ~ 600+ with 10.5 gr pellets :-)Dang, you're moving the target. I thought it was 575 fps with 7 pumps? But I'll play along - I just went down to my basement and tried 8 pumps ........ 605 fps with the 10.5 gr pellets.So, your goal is realistic.
The one thing I do know is to get the velocity your getting I don't want to turn my Daisy Powerline into a gym machine, 8 pumps is the max, It will be a bit disappointing if it takes 9 pumps to get what I want. I plan for pest to use 10.6 gr CP's in the velocity area you are getting ... The CPHP are for messing around, I will use the # of pumps needed to shoot in the 600's with those pellets, it will probably be around 7 pumps, I don't know.In a hunting situation, or maybe a log range plinking situation (~35-45yds) with a multi pump gun, I would think most folks want the power to do the job with the least amount of pumping, at least I do.wll
What have you done to that gun, and is it the new style aluminum tube valve body or a brass tube?
To my way of thinking, the valve spring is pretty strong and takes quite a bit of force to open the valve port. The hammer arm and the hammer spring side of the pivot point are fairly close in length. The spring side has no major leverage advantageI think the less valve spring tension you have fighting the hammer spring to open up the transfer port valve, the faster that port will open and the faster the air dump will be, increasing velocity. We are talking fractions of a second here, but how much air is wasted (leaked) before the explosion of air comes through the port. This whole scenario takes fractions of a second, but in those fractions of a second how much pressure has been wasted ? Also now that the spring is gone around the valve head collar, that can be tapered down to improve air flow ; - )I removed the factory spring, put in a ball point pen spring (the ink cartridge is almost exactly the size of the valve stem) and re assembled the valve assembly. I might very well add, this job was a PITA, that clip is a son of a gun to get out and you will just about ruin it doing so. I will buy some clips from McMaster-Carr should this make a big enough difference for me.difference in velocity.The new gun I received from my buddy will have the bottom valve installed (pen spring) ... What do you guys think ?wll