Tumbling JSB Heavy Ultra Shocks

[pbft]

I've been trying different pellets in my .177 Hatsan AT44 Long. It loves the Crosman Premier Heavy at 10.5 gr and the JSB Exact Heavy at 10.34 gr. Both shoot groups around .7" at 50 yards.

I'm looking for a hollowpoint, so I tried the JSB Heavy Ultra Shock at 10.3 gr. Shock is the right word. They gave me a group of over 6.5 inches! The pellets are clearly tumbling, as two of them hit the target sideways. Has anyone else seen this behavior?

All these pellets are around 1020 fps muzzle velocity. After the wild group with the ultrashocks, I tried a set of Crosman Premier Lights at 7.9 grains. They're clearly supersonic at almost 1200 fps at the muzzle, but managed a group of about 1.5" anyway.

[nervoustrigger]

Well I thought the .177 Ultrashocks were a failure for me but apparently they were fantastic by comparison.

Honestly though, I wouldn’t be surprised if that’s just too fast for what is essentially a wadcutter profile, but don’t expect slowing them down to reveal greatness.

[Habanero69er]

Bill, slow your rifle down to 900-950fps & see what kind of accuracy you get.

[Monkeydad1969]

I shoot them at 850-900 depending on rifle.  But you are definitely shooting them to fast.  I don't think you'll be able to slow that AT44 down.  Shoot .177 slugs.  Talk to d-rig on here. He's the owner of VarmintKnocker slugs.  They shoot great at high speeds.

Joe

[pbft]

I shoot them at 850-900 depending on rifle.  But you are definitely shooting them to fast.  I don't think you'll be able to slow that AT44 down.  Shoot .177 slugs.  Talk to d-rig on here. He's the owner of VarmintKnocker slugs.  They shoot great at high speeds.

Joe

I will talk to d-rig - thanks for the tip. I have some NSA slugs already, and a sampler pack of Griffin slugs on the way. I'm making the simple mod to allow hammer spring adjustment, so I should be able to fine-tune velocity on the AT44.

I've never seen a pellet tumble before, and there are a few folks here who report pretty good results for the ultrashock.

Besides the slugs, any otther suggestions for hollowpoint pellets that might work well in this gun?

[anti-squirrel]

You're going WAYYYY over 750 FPS with a JSB Ultra Shock and complaining about a 6" group?

I've shot Ultra Shocks extensively in all my .22 and .177 airguns.  Keep 'em under 750 FPS and they show superior grouping.  Push over 800 and you'll be sad.  Over 900... LOL...  these are hollow-point tubular sorta-wadcutters, dude.  Seriously, you wanna shoot hollow-points over 1000 FPS? 

If you want to get good groups, you need to match the pellet shape to the desired speed range.  Wadcutters and mostly-cylindrical hollow-points like staying under 750 FPS.  I've shot 10-shot 30 yard groups with my .177 PP700 using Ultra Shocks using a fixed 4x crossbow scope you could cover with a dime.  The pistol was shooting 620 FPS and I've used that exact combination to kill a lot of HOSPs and squirrels.  A diabolo-shaped HP like the H&N Crow Magnum will handle a little more velocity, but the superlative barrels for my Leshiy can't make fast hollowpoint pellets work.  HP slugs are likely another story, but I'm too cheap to buy those.

As long as you're shooting over 800, you're not going to get decent groups with any hollowpoint pellet I'm aware of.  My Leshiy was shooting 800 FPS with .22 JSB Ultra Shocks and I could not even get on target at 40 yards.  I dropped the speed to 740 FPS and started shooting 3" groups- freehand- unbraced- with a 2x red-dot.  Temper your expectations for the type of pellets.  You might be able to squeak past 800 FPS with the Crow Magnum hollowpoints, but I've yet to have any luck over 780 FPS.  My Leshiy is tuned right at 780 FPS using Crow Magnums with a 350mm .22 barrel.  Any faster and groups suffer.  I use the Crow Mags as my baseline for chrono testing.

Now- there is one distinct ppssibility that may work: the JSB .22 Hades.  Chances are they will still be going too fast in your Hatsan for reasonable accuracy, but maybe you have a unicorn barrel and it can make them work.  If I was in your shoes, I'd be dropping the speed to ~ 880 to 910 FPS and enjoying tight groups; especially with the Hades.  My girlfriend shoots the .25 Hades in her Lelya and it is pushing right around 845-ish FPS and accuracy is outstanding.  We can crank the velocity faster but efficiency suffers and we end up with just under 4 magazines.

[pbft]

Good insight. I hadn't realized that hollowpoints were so velocity-sensitive.

The Cro-mags work pretty well in my R9 at 800fps. The Cro-mags are over 1100 fps in the AT44 with factory settings. Haven't bothered to test them at 50 yards, but they're only good for a 3/8" group at 10 yards.

Until my long-shank 4mm Allen wrench shows up, I can't adjust the AT44 to bring the velocity down.