.25 JSB Heavy quick review.

I like the mk 2, 34's in my fx, especially in a breeze. I've tried um at 75 & 100 yd and will shoot um at ebr.

I just got five tins of mk1 for ebr shooting. My condor no mag problems!

I just got 5 tins of mk1 s for ebr cant wait!!!!

I shot the MK-Is through my .25 Marauder and other than they dropped more than the 25.4grain pellets they were fine. Once I adjusted for the drop they were pretty darned accurate. Now that I have a chrono I think that I'm going to spend some time playing with the power settings on my gun. I'd like to set it for power and accuracy. I'm not too concerned about shot count. I just want to stretch it and see what happens pushing the Heavies at distance. AJShoots is probably going to dread the onslaught of messages from me...

LOL! Maybe but he keeps offering to help anyone who asks!

Ok I got out the digital calipers. I measured 3 of each to get an average.

Original (Mk1) Mk2
inch/mm inch/mm
Head dia: .250/6.35 .250/6.35
Waist dia: .200/5.08 .200/5.08
skirt dia: .262/6.65 .259/6.58
height: .353/8.96 .345/8.76

The mk2's are shorter and the skirt is narrower. I don't have a scale so no weight data.

I updated my post with the photos so the info is all in one place.
Cheers!

My pleasure! I have learned so much from this and other forums. Glad I can contribute something useful.

"PlanB"I like the mk 2, 34's in my fx, especially in a breeze. I've tried um at 75 & 100 yd and will shoot um at ebr.

Click to expand...

Would you kindly elaborate? Which FX ? Are you saying the MK11's are working well in the standard FX .25 magazine or are you single loading? I'm quite interested in these for my MK1 Bobcat .25, especially with Ted's facebook tease. Do you, or anyone else that might care to comment feel the added load/weight will prematurely compromise the seals for FX 25's platforms given they were designed around a lighter pellet? 

Thanks in advance, 

ClearedHot

The Mk2 were designed to solve the to tight in the mag issue of the originals and as far as I know they have succeeded. I wonder if they will or have discontinued the 1st ones. Anyone heard? There should not be any problem with seals. The only seal would be the breach to probe. Usually just a ten cent o-ring. I don't have an FX yet but my RAW does not use a soft seal at all. Just tight tolerance bolt probe to breach fit. Nothing to be damaged. These guns are adjustable for power and are frequently tuned for more power than stock. A heavier pellet is just like turning up the power a bit, as far as the seal is concerned.

Thanks 30 Cal, good points all. I still want to firm up on the FX magazines for the MK11's. before ordering several tins. 

For you folks that have the JSB 25 Heavy and MKII versions:

Can you give a short chrony string from the same gun of the the two (2) Heavy pellets? If you have the Exact kings do that one also if you don't mind.

THANKS
.....I would my self but apparently I did not add a tin of the MKII to my shopping cart..... :s

Ronin001 As a matter of fact I just did this very test this weekend. I used it to get a base line for adjusting the regulator on my RAW HM1000x for a little more power.

Ten shot groups preformed back to back on the same day:
JSB King 25 gr. AV- 833 fps
JSB King Heavy 34 gr. AV- 728 fps
JSB King Heavy mk2 AV- 739 fps

The mk 2's are not as tight in the barrel and therefore are eleven fps faster, at least in this gun.

For those who may be interested I achieved these results after tuning:
JSB King 25 gr. AV- 953 fps
JSB Heavy mk2 AV- 866 fps @ 56.55 FPE

Here is a video of that I did a while back. Hope it helps.

http://youtu.be/Zq60Fuv3N0o

AJ I have not compared them for accuracy yet. I will try to get to that this coming weekend. Really want to see how they do at the new higher velocity.