New AV 46M FPS Adjustment

[Timberwerks]

As mentioned in my previous thread I ordered a AV 46M to help get me back into the sport. It arrived yesterday and I took the first 10 shots from it. I'm at 415 fps with 7.0 gr Meisterkugeln. I've read & seen photos on how to adjust the piston TDC. I'll do this myself vs sending the pistol back. My question is, is it to early to make this adjustment or will the seal break in and add fps after a few hundred shots or so?

Thanks,

[Gwhite]

I wouldn't mess with it right away. The adjustment is a bit of a pain, and if you overdo it trying to get a few extra FPS, you can stress the mechanism and eventually break things.

[Rover]

Use it for a tin of pellets or so. Also put in a couple of drops of oil on the pistol ring. It might be a little dry from hanging around.

[kevinweiho]

The piston will break in with use and a drop of oil will help to seal and increase velocity a bit, but for you to reach 480 fps, you'll need to carefully adjust the piston stroke.

[Timberwerks]

Well, while drinking my coffee I decided to go ahead and raise the TDC of the piston. The process only took 15 minutes or so and I'm now at 445 fps with my first 10 shots after. I increased TDC by 2 clicks = 1/2 turn on the piston. I'm going to leave it here since there is no binding at the end of the compression stroke and I don't want to push it by adding one more click at this time. Maybe after 1000 shots I'll add that extra click and perhaps even the rubber band in the seal groove and see if I can get to 500 fps.

So far very pleased with this pistol!

[Timberwerks]

Just one last update. I decided to go ahead and make one more adjustment to the piston. I advanced TDC another 2 clicks, this make one full turn in total. I'm now at a fairly consistent 485 FPS with a random 488 or 490. There is still no binding at the end of the charging stroke but I do feel the bit more effort it takes. I will leave the pistol as is now and focus on shooting.

[kevinweiho]

Good, that extra oomph is music to one's ears when the pellet smacks against the steel plate. I can hear the difference in the ping sound when I hit a 10 or 6.

[seamaster]

Enjoy your higher velocity. But stay away from the temptation and joy of going higher.

I had adjusted my velocity to match LP10 years back. Wonderful sharp beast, until one day, the lever circular piston hinge just cracked.

A hairline fracture. Velocity dropped, pellet would not even make it out of barrel.

Had a machinist friend welded it back. Enjoyed it for a year, then hairline fracture recurred. He welded it to three times the original thickness the second visit.

I doubt it will ever have hairline crack again. I have chrono it to shoot at 460 fps now. I am happy with that velocity.

I am sure the welded back three x thickness can handle up to 515. BUT it is guaranteed to have fracture at some OTHER spot.

I am not willing to revisit hairline fracture elsewhere just to have 515.

460 is plenty good enough. 46M is just a simple joy at that velocity .

[PeeWeeDaddy]

My old IZH46M (about 22,000 shots so far).
Of course the Crosman pellets are VERY tight:

[Timberwerks]

I'm happy with the 480 - 485 range and will keep it there. No need to go higher, pumping is still easy so I think I'm at it's sweet spot.