We found a video of someone firing different rounds point-blank into a barrel filled with rubber mulch. This seems like the worst-case depth of mulch you’d need in a backstop for different bullet types (i.e. there would be less energy if you were firing from ten meters or a hundred meters, so there would be less penetration). I wanted to record the round types and approximate depth
22 long — 10″
9mm — 14-15″
40 cal — 18″
300AAC — 20″
The third Avenger arrived today — pumped it up and we’ll see if this one manages to hold air!
We tested various regulator pressure and hammer spring combinations to see where we get the best accuracy. Using 19.91 grain H&N Barracuda Green pellets. Looks like 1200 psi with the hammer spring two turns in wins.
1200 psi:
Hammer spring at 1 turn:
Left side of top right target has hammer spring at 2 turns.
Right side of top right target has hammer spring at 3 turns.
1400 psi:
Hammer spring at 2 turns.
Hammer spring at 3 turns
1800 psi:
Hammer spring at 1 turn
The second gun arrived and seems to be a refurbished / used gun. Scuffed up, worn o-rings. Pumped it up and lost a couple hundred psi overnight. Better, but not good. Sigh … hopefully our third attempt arrives in a few days.
Our Avenger has been a bummer — one of the two cartridges didn’t work out of the box. It doesn’t advance after a shot. You can disassemble the cartridge and tension the spring. Unfortunately, the gun loses about 500 psi overnight! There are a few other problems too — front rail wobbles even when tightened, the barrel shroud slid forward about 1/8″ and has oil leaking from it. We’ll be getting a replacement early next week.
Our new gun arrived today! Ordered a 25 caliber Air Venturi Avenger on Monday. It had a bit of a side trip heading east, but a really helpful fellow at FedEx seems to have gotten us sorted and our package resumed its westward journey.
We added a brick of putty to the stock since it’s incredibly front-heavy otherwise. One of the two cartridges seems to have a spring issue — it doesn’t advance unless you remove and re-insert the cartridge. Luckily, it comes with two … so we’ve got a functional one. It’s assembled, pumped up, and we got fourteen shots in before it was too dark. We’ll finish getting it sited in tomorrow.
To fix a nock right by yoke tuning, you shorten the right yoke legs and lengthen the left.
Adding one twist and removing the same amount from the other side (right lower / left lower, for instance) should maintain the cam timing. Not 100% true because the amount of take-up per twist changes compared to previous twists. But it’ll be close.
Make sure to check cam timing — may have timing check hole drilled into cam so you can verify cams are in the same place at a point in your draw. Or draw and ensure stops hit cam at the same time.
Found an article on tuning at https://www.gohunt.com/read/skills/what-does-it-really-mean-to-tune-your-bow