Probably a good idea to break this up a little- that's a lot to wade through on the other thread...
Finally got some replacement o-rings in for the fill yoke on my 3K tube, on the 20-78.
Tore into the gun tonight, and found that the rough valve stem was binding up pretty badly. The dancing valve spring probably didn't help matters... Thanks Todd! (Spent 2 hrs lookin for my replacement valve- I had put it in the factory 20-78 tube so it wouldn't get lost )
At any rate, I pulled a Todd, and rebated the brass base of the valve stem enough to tightly seat the end of a new spring. Did side-cuts again on the valve front- not as long as the first- I left enough at the front to engage the first couple of spring coils. I opened up the former piercing pin hole to 5/16" to compensate.
Back to the 16.1 gr Predator, as I'm almost out of the Heavy Exacts.
1800 PSI:
1.) 743.0
2.) 742.5
3.) 755.0
4.) 744.0
5.) 749.8
6.) 747.3
7.) 744.6
8.) 738.4
9.) 732.3
10.) 721.4
I think I found the sweet spot, right off the bat, for a gun with an un-modified hammer.
I'm not going to type all this one- it's too long:
2000 PSI:
1.) 684.7
5.) 707.1
10.) 731.3
15.) 739.7
20.) 717.8
Fastest on that string was shot # 12 @ 741.1 Un-modified hammer strike becomes apparent here.
2200 PSI:
1.) 567.0
2.) 653.3
7.) 656.7
10.) 677.6
15.) 723.9
20.) 746.3
25.) 727.7
30.) 697.8
Fastest on this string was shot #19 @ 749.4 fps.
I don't think I'll be taking it over 2200 PSI- shot #1 sounded like a long bbl'd .177 @ 500 fps
Now to investigate shimming the hammer spring. This gun is loaded with potential.
I'd still be scratching my head, if it wasn't for the input of Todd and Bob and all you other contributors. I owe you guys a cold one- and I don't even drink Doors always open if you end up at the home of the Jets!
Regards,
Doc Sharptail