What does your buffer hammer weigh? I ask because the one I received didn't have a brass insert and wasn't heavy enough to make any hunting power with. I am not sure what your HS rating is either. I am just wondering if you have enough overall hammer energy to make good power is all.
Quote from: triggertreat on August 17, 2022, 06:38:22 PMWhat does your buffer hammer weigh? I ask because the one I received didn't have a brass insert and wasn't heavy enough to make any hunting power with. I am not sure what your HS rating is either. I am just wondering if you have enough overall hammer energy to make good power is all.The JSAR Super hammer I am using is the third below, 49.2 g:TH Hammer (Peet striker) = 22.5 gOE Hammer and striker = 74.2 gJSAR MDS Hammer (w/OE striker) = 49.2 g ( https://www.jsairrifles.com/2022-MarauderArmada-Super-Hammer_p_23.html)I wanted 50 fpe for at least one magazine and that is what I am getting now. The TH hammer came with the TH valve as a matched set and it is considerably lighter than the JSAR Super Hammer though both are lighter than the OE hammer. If the TH valve needed more weight why would he make a "matched" set with a light weight hammer? The only reason I am not using the light weight TH hammer that came with the TH valve is that I have an aluminum air tube and the advice is to use a plastic hammer with aluminum air tubes.The set up on my rifle now, anything much below 1800 psi the velocity goes off a cliff. It seems to like the 3000 to 2000 range for the eight-shot string I posted previously. I note also using the 34 grain JSB pellets the rifle makes a loud, sharp Ka-Pow for the entire shot string. Shooting the JSB 25 grain pellets, especially once below 2600 psi, the rifle makes a Bla---ahhaaat sound. Good information, thank you,James
It could be that there is a light valve spring being used if the tune is dropping with each shot. This would also indicate too much hammer energy for the valve resistance. The TH kit I thought was for a regulated system which may be part of this, but I am not sure about his parts/designs. The noises also sound like this is what is going on. It all boils down to having the parts balanced against the pressure. You also should get at least two mags as well so sounds like a lot of wasted air from being too out of balance. Make sure also that the TP is not leaking. If you are careful, you can block the end of the shroud while cracking the valve open ever so slightly to see if it is leaking. You would need the Crosman degas tool to do this though. It's a trick I use. There should be back pressure at the muzzle end and no noises of air leaking with a properly sealed shroud.
That's a great group but only at 25 yards. 50 yards and so forth is more telling of course.As far as shot count two mags is certainly possible, but you have to eliminate any hammer bounce/wasted air to have a chance at that power level. The other thing is to tune the valve to be very efficient. A way to go about this in addition to balanced parts is to find your peak velocity without using more hammer energy than is needed and then backing off of that peak velocity with the hammer energy by 3% to 5% so you are tuned just below the knee of the peak or bell curve. This will ensure you are not overdriving the valve and also is making sure the valve is closed before the pellet exits the muzzle, so no air gets wasted. This also helps with accuracy, so the wasted air doesn't skew the pellet skirt on exit.While you are checking for leaks, I would also pop in a new breech seal O-ring. You can get a bag of those and the other O-rings cheapest at the O-ring Store online. Just order the minimum quantities allowed. These are quality O-rings. Having a good breech O-ring is key to achieving a low ES and good shot count.Attached are some of my .25 cal tunes with shot counts, FPE and ES using the MKIIs. Some are better than others while learning how to tune with different springs, hammers and valves. It just depends on what range you want to shoot as to what ES you can tolerate for shot count.