Needed an HPA day

[Ribbonstone]

Not every experiment goes quite the way you plan it and yesterday was quite frustrating.  That evil tempered gun is sitting in a corner, punished; will pick it up and try again sometime off in the future.

What I needed was a session with an old friend.  This simple HPA conversion sold me on the idea, and while several much more expensive/nicer  PCP's have entered the safe, it is still a go-to gun for days like today.

5mm barrel blank from MAC 1 (which taught me a lot about rebarreling), QB78 converted with a QB79 tank block, LDC, 13ci 850PSI output bottle, cheap scope, and a lot of tuning.


Got up this AM, filddled with it a bit to try for 12 foot pounds (I missed by 8/10ths of a foot pound), filled it to 3K and shot 100 shots.

Chrono readings:

Unsorted Benjamin Cylindrical  14.3gr. Pellets:

Shot #1 – 10 = 632.7fps average  8fps variation
Shot #45-55 = 631.7fps average  7fps variation
Shot #90 – 100 = 637.4fps average  6fps variation.

(Aim point was the center of the bullseye...point of impact set for the small white square)


To get a better Idea of the target size.  The cneter white square is running right a .21”.


Tank is still at 1050-100PSI, so with an 850 put put tank, should still be +20 shots before going off reg.  Call it 120shots.  While I only chronographed 30 of the above 100 shots and there could have been an occasional wild velocity in the string, it does seem that 120 shots/ 12.8foot pounds/ and an overall vel. variation of less than 20fps is what I'm getting.

May not be fancy, and it looks a little like a plumber built it, but having what basically is a quiet  Sheridan C that shoots for 120 shots before refilling certainly gets a whole lot of use.

[pjw]

 How far away was the target?

[Ribbonstone]

That has become my default distance.  It's how fat it is from my little shed/shop (which has AC for the summer and heat for the winter) and my test backstop.

[Ribbonstone]

Factory wood, stripped and refinished.

Just never know what is under that toe-nail-polish type finish.  This one turned out to be reasonably pretty...others are butt ugly.

That's my oldest HPA conversion...still running just fine and the finish has held up quite well considering all the use the gun has had.