The 398 tune. #25 barrel, 1-1/8" preload spacer, home made air tube, abutment seal reamed out for oversized air tube.
412 tune. 499 barrel, everything else the same as above.
The air tube has the inlet slot through both sides. Slot is allowing max air in possible. Went longer until no improvement.
Got it. You know, to be honest if I could get 375-ish fps and the gun didn’t feel stressed like mine did at 350 fps, I'd be happy. But 400-plus is sure tempting.
The stock air tube is limited to a 7/64" drill. I believe we maxed at around 378.
Was 378 w/a 3/4" spacer? Did you open both sides of the stock drilled air tube? If not, what was the best you got using a 7/64" air tube and 3/4" spacer? That is, if you ever used that combo.
I was only able to get a single air tube drilled to 7/64”. I couldn’t tell you which gun it’s in at the moment, but I need to find it so I can use it in a gun w/more spacer and a ‘level’ spring anchor to see what I can get.
The 1-1/8" spacer is milled on the retainer end to compensate for the retainer angle. I believe this is important.
I'm starting to believe it is, too. At first I ignored the slight misalignment but your results didn't fall from thin air (ha). I'm making a new spring anchor that will contact the spring squarely, as this is easier for me to do w/the materials and tools I have available.
On the rail. I would like to cut it off. I also plan to lower it some. That will require a notch to clear the sight.
Would a red dot mount to the rear like the scope? Or would it need to be mounted more forward, requiring some of the length? Same question for the leapers "bug buster". Input appreciated!
Thx!
FWIW the original Bill Brice scope mount used a notch, too. Should work even better with your rail, seeing as it’s thicker.
Lowering the rail might help w/the ‘cheek weld’; if the optic is too high the head is unsupported by the stock and many find that way harder to aim steadily. This also depends on the stock and how high the comb is.
A red dot is very flexible for eye relief in my experience. I tend to mount mine where the least amount of head movement is needed to see the dot when I shoulder the gun w/eyes closed, and then open them. This includes the red dot height as well as how far forward/rearward it is mounted.
THIS short article covers other aspects pretty well.
The Bug Buster will work best w/the eye relief set to no more than 3" (my BB is set at about 2-3/4"), but you'll want to try it to see where you like it best.
I’m seriously considering relocating the trigger screw to increase the stroke. I need to see how far I can go and that will depend on if there’s any “extra” finished compression tube behind where the plunger sits now when the gun’s cocked. And if the lever can accommodate this extra distance needed to set the trigger.