Hey guys, I wanted to report my first impressions on the redesigned .22 cal JSB Monsters. I just got a tin from Pyramyd Air and was anxious to see how they fare.Firstly, a quick background note. I tried a tin of the orignal design back in 2012 and soon realized I would not need to buy another. They didn't group in any of my rifles then, and they never grouped in any rifle I've had in the intervening 5 years. Not one.So I began with a test group from the B51 using the originals:Yep, those are the Monsters I've come to know and loathe.And then a group with the redesigned Monsters:Now that's what I'm talking about A sub-MoA group right out of the gate.So if you're looking for a heavy hitting .22 pellet to buck the wind, it might be time to give these another try. I'm glad I did.
Pellets have another problem to deal with, Dynamic Stability, which causes the pellet to wobble, like a Gyroscope does.... This is called Precession and Nutation.... Since the forward velocity of the pellet decays more rapidly than the RPM, as the pellet travels downrange it acts like it was shot at a lower velocity with a faster twist rate.... This combination decreases the Dynamic Stablity, and can make the pellet corkscrew or spiral.... A pellet that shoots perfectly out to 50 yards may be useless at 100 yards for this reason.... and yet if you slow the muzzle velocity down a bit, it is fine.... I have never heard of a pellet that is sprialling get better with increased velocity.... IMO, when somebody sees an improvement in accuracy at a higher velocity, it is almost always due to improved barrel harmonics of THAT pellet in THAT barrel.... and has nothing to do with pellet stability....Bob
I do not believe that any pellet is likely to be better at higher velocities.... It makes no sense from everything I have read about Subsonic Ballistics.... either in terms of Gyroscopic Stability, or Dynamic Stability.... In fact both tend to decrease as you get closer to Mach 1.... here is a typical stability curve for a .22LR bullet.... This chart is particularly interesting, because it is in an 18" twist, not the usual 16" twist for a .22LR barrel....The "ideal" stability is about 1.5, like the bullet is when Supersonic.... Anything at 1.0 or below is unstable.... Note that just as the bullet drops through the speed of sound it goes unstable and will tumble.... THAT is why the .22LR uses a 16" twist, not an 18".... For airgun use, we seldom care about what happens below Mach 1, in fact usually we stay below 1000 fps.... Look at the shape of the stability curve there.... As the velocity drops, the stability INCREASES.... We are talking Gyroscopic Stability here - the resistance of the bullet to tumbling.... Airgun pellets follow the same trend, but because of their drag-stabilized (skirted) shape, they can get away with MUCH lower twist rates....Pellets have another problem to deal with, Dynamic Stability, which causes the pellet to wobble, like a Gyroscope does.... This is called Precession and Nutation.... Since the forward velocity of the pellet decays more rapidly than the RPM, as the pellet travels downrange it acts like it was shot at a lower velocity with a faster twist rate.... This combination decreases the Dynamic Stablity, and can make the pellet corkscrew or spiral.... A pellet that shoots perfectly out to 50 yards may be useless at 100 yards for this reason.... and yet if you slow the muzzle velocity down a bit, it is fine.... I have never heard of a pellet that is sprialling get better with increased velocity.... IMO, when somebody sees an improvement in accuracy at a higher velocity, it is almost always due to improved barrel harmonics of THAT pellet in THAT barrel.... and has nothing to do with pellet stability....Bob
At what speed Kevin?