I recently bought some JSB Heavys from Jeff at TrenierOutdoors.
When I opened up a tin to see,
I also ended up with MK2's.
Jeff said shoot em, and he'll refund if they don't work.
Jeff also emailed JSB's reply to him about this whole Heavy vs Mk2 ordeal.
I will shoot them next wknd, and see if they shoot as good as the Heavys out of my Taipans and Huben.
I've enclosed his email below.
"Hello Terry,
Yes, there is some confusion as of recent with the MKI and MKII. Below is the message from JSB. I will call a bit later, but figured it was easier to relay the written message rather than try to explain on the phone. I’m glad to hear they thickened the skirt for less damage issues.
It seems there is a misunderstanding among our customers about the difference between the MKI and MKII. The only difference between the two pellets is the outer diameter of the skirt. This dimension on the original MKI pellets are 6.68 - 6.70 mm while the MKII pellets measure 6.58 - 6.60 mm.
We made this change because the original MKI pellets would not fit some of the rifle`s magazines.
The thickness of the skirt or the inner skirt shape cannot be used as a guide to identify MKI or MKII pellets. There can be batches of thinner and thicker skirts in both types. Some time ago it was an identifiable visual and people would tell the difference by the skirt thickness, but now both skirts are thick, (in the MKI and MKII (because the thicker skirts are much less easy to damage.
Best regards,
Pavel
Thanks,
Jeff
Trenier Outdoors
16626 Hawk Rd
Sparta, WI 54656
www.trenieroutdoors.com"
Good on Jeff at TrenierOutdoors,
Bad on JSB.