Recent content by Scotchmo

Your conclusion was based on a faulty comparison. Use the same airgun and keep all settings the same, including pressure and hammer weight. Same projectile. Swap barrels for the comparison. Compare the 27.5” barrel with 33.5” barrel.

1:19 is unlikely to adequately stabilize the 80-100gr slugs that you are looking for.

Long slugs typically require a faster twist rate. Otherwise, accuracy can suffer. Do you know what your twist rate is?

For airguns, over 100yds is often considered ELR. The Oregon match consisted of the following: 140yd, 2in square, 5 shots 166yd 3in square, 5 shots 187yd 4in square, 5 shots 250yd 5in square, 5 shots 300yd 7in square, 5 shots Cameron had a 68% hit rate. There were no warm up or practice shots...

When we used to hold GP matches at the Morro Bay course, we did not use general timers for everyone, even at the 2021 National, no timers. I always gave the threat of putting a timer on any squad that had empty lanes in front of them, and had squads backing up behind them. But usually not...

I go as far as .0005 to .001 under groove diameter. The lands will usually bulge/squeeze the lead out just enough to seal the groove areas.

Best that you make the distinction between lb weight and lbm. A slug is 32.17405 lbm. There are 7000 grains in a lbm. 7000 x 32.17405‎ = 225,218 There are 225,218 grains in a slug mass. So, either way you look at, when velocity is in fps and mass is grains, the kinetic energy formula: 1/2 x...

If we were on a planet with 1/2 the gravity of earth, would an airgun’s kinetic energy be 1/2 what it was on earth? Answer: no Muzzle energy of a projectile is kinetic energy and is not affected by gravity. I don’t need the acceleration of gravity to calculate kinetic energy. The kinetic...

I 3D printed a snug fitting holder for my talking timer and pellet box. They just happened to be the same dimensions. I look at the timer every time I grab a pellet. Gives me a good feel for time progress.

I’ve been using talking countdown timers in competition since 2015 when another competitor gave me one at an IHMSA match. Great for timed FT matches.

1:40 twist is intended for pellets. Unlikely that 1:40 will work well with slugs. Maybe try a very short (43gr?) conventional slug like NSA offers. Go with the faster twist for slugs.

What would the muzzle energy formula be if it were calculated in deep space, where there is no gravity? Ok. I already know the answer. And the actual muzzle energy is the same on the earth as it is in space, and gravity has nothing to do with it. If you use weight and the estimated acceleration...

A piston gun use the inertia of the piston to hold the compressed air forward momentarily before that piston is forced back (piston bounce) by the compressed air. Ideally, the projectile leaves the barrel before the piston reverses direction significantly, thereby maximizing use of the...

My similar Coltri had similar symptoms. It was at the connection on the end of the lower (4th stage) cylinder. I used a 1-1/6” open end wrench to snug it down. Leak stopped. A little bit of vapor out of the intake after shutting down is normal for mine.

In the living room. 0n the floor. If someone wants to try it: Practice in your living room. Try the yoga “easy pose”, and then lean forward to have your elbows on your knees. It’s a very stable position and it’s possible to be very relaxed. If you need it, have a stool/chair/couch near by to...