.25 JSB Heavy quick review.

That's great to hear AJ. I have both the 1st gen and MK2's coming as well as the standard kings. Looking forward to testing them in my RAW soon. I also have some 27.8 gr Benjamin domes, 31 gr Baracuda's and Air Arms 25.4 gr to test out in it.
I will tune the gun to shoot the heaver ones at 950 or more to see how their accuracy holds up.

I've been waiting to get my hands on these for some time now. Importing takes time. I wonder if the first to land here will be the original heavies or the MK2 heavies. And I wonder if the difference in BC will have any impact on accuracy. Anyone who gets their hands on both, please do post a comparison for us. Excitingly interesting experiment. Yay I am happy. 

I shoot the King Heavy 33.95gr JSBs out of my Hatsan BT65 at about 940 FPS. At that speed, I did experience some occasional spiraling, but most shots were very accurate. The spiraling could be attributed to the large skirt diameter. I am still very impressed by the accuracy and the energy produced by these pellets. I have the King Heavy MKIIs arriving tomorrow, so I will test them to see if there is a difference. I am going to tune them to run at 930 FPS. Should be a very accurate and deadly combination.

1:16 Twist rate.

Barrel Length - 22.8

"hunterone"I shoot the King Heavy 33.95gr JSBs out of my Hatsan BT65 at about 940 FPS. At that speed, I did experience some occasional spiraling, but most shots were very accurate. The spiraling could be attributed to the large skirt diameter. I am still very impressed by the accuracy and the energy produced by these pellets. I have the King Heavy MKIIs arriving tomorrow, so I will test them to see if there is a difference. I am going to tune them to run at 930 FPS. Should be a very accurate and deadly combination.

Click to expand...

Neat. Can't wait to see the difference in performance between the longer and shorter MK 2 Skirts

Well if they just trimmed the length which would be also reduce the diameter and be the easiest thing to do then it could be both shorter and narrower. Maybe?

Are the MK-I and MK-II versions the same mass? If they made them shorter, they'd need to alter the shape of the skirt to fit more material in, right? Pretty soon, it will be less a pellet and more of a slug.

That's true they would have to change the shape to maintain the same weight. I would like to see an extra heavy .25 like the .22 monster. That's almost a slug.

On a side note my mk1 JSB's .25 heavies just finally shipped today from PA after being back ordered almost 2 months!

Well, I just got in from trying the mk II heavies that FedEx Dumbpost finally got to the post office (they got there too late to be delivered today and I had to run down and pick them up myself). As I described in another thread the mk I's were dynamite in my Cricket carbine, shooting 2 5 shot groups under 3/4 of an inch at 100 yards in a row, something I've never come close to with any other pellet or air rifle that I have. So I had high hopes for the mk II's..............to no avail. I was lucky to keep them close to 3/4" at 50 yards, and the 100 yard attempt was pathetic. Conditions weren't ideal, I was shooting into the sun and there was an intermittent light breeze, so I tried a 5 shot group with the JSB King "lights" at 50 and it was probably under 1/2 inch c-c. I will try them again next week early in the morning when things are still and the light is from my back, but I don't have much hope for them.

Moses in PA

I would give them another chance before writing them off Moses. Another day with a cleaner barrel perhaps. 

That's too bad. I hope your results get better. So far so good for me. Will see how they perform on the hunt.

Just got back in from shooting the new MK 2's, in a .25 Cricket. I had great results with the first variety. Yesterday I set spinners up at ranges from 50- 82 yards, and the 2's were performing great for a hunting situation. At 20X 3 mildot hold on the top of the smaller center spinner. It was hit 75% by two different shooters at the longest range, and one miss in ten at the 50 yard firing strait out. Today riding the nursery roads with the landowners son. There was a woodchuck convention, grass was cut and with a couple of chilly nights they were all over. As I was telling him the range and to wait for the chuck to stop, he took a mature male at 25 yards with a quartering away slow walking shot. The shot hit the shoulder, and exited in front of the ear on the opposite side. A couple more at 35-40 yards, also body pass thru on smaller females. The finish for the day he spotted a brown lump in the row, and got out of the truck, we both climbed into the bed, I spotted it as it moved further away. I now ranged it at 73 yards, it was laying flat facing away. using a bag of peet moss for a rest perched atop the truck cab, the chuck moves further away then stands up providing a full back shot. I'm guessing 85 yards and I call 3 dots top of head, he says got it bang. The chuck dropped a lower head shot, and pass thru the throat. The newer version appears to be slightly shorter, the skirt is noticeably heavier, and the indentation is shallower than the earlier ones. Sorry I misplaced the calipers, for my use at 880 fps they work pretty well. I will try an actual group on paper with both.