Resized JSB King heavy mkI for my .25 Bobcat

[Patrick]

I started a post years ago with the tinbum pellet sizer from krale that I bought to resize the JSB King Heavy mkI. Now there are some accuracy results at 50m (5shots each) done with my good old FX Bobcat mkII .25. if the weather calms down I’ll do some test at 92m.

https://youtu.be/_166N70WekU





Regards

Patrick

 

[Enkey]

Hi my Friend

Very good precision with recalibrations. What size do you use? I use a LEE 257 But I'm thinking that a 258 would give me better results

Regards 

Enkey 

 

[Patrick]

Hi my Friend

Very good precision with recalibrations. What size do you use? I use a LEE 257 But I'm thinking that a 258 would give me better results

Regards 

Enkey

Hi bro!



yes absolutely, didn’t expect that out of such a cheap resizer.

in .25 they where only available at 6,35 when I bought it. don’t know if they have stocked up there sizer in .25.
ive measured with a cheap caliper, the originals are 6,66 and the resized ones are 6,35 now.

do u have a press for your sizer? Looks really professional.



Regards

Patrick

 

[Enkey]

Yes bro I have a Lee and a Lyman but better do it by hand do not buy a press is stupid I am an idiot LOL. With all brands you can get enough dimensions, if you can't find, LEE it is made to measure

 

[Patrick]

Haha, you are no idiot. If I had found this I would it buy too!

good to know, but right now I’ll stick with the TBT sizer. Next week I’ll be doing accuracy at 92m with my resized one, so let’s see what happens.



Regards

Patrick

 

[triggertreat]

Thanks Patrick! I just checked a bunch of my MKIIs. They are coming in at .251 (6.37mm to 6.38mm). I'll try sizing some with my NOE sizer and Lee press to see what happens. I think you said not to worry about the skirt also being sized down too, right?

 

[triggertreat]

I just did a quick sizing to 6.35mm with some 33.95 MKIIs. I then compared them to the un-sized over the chrono. Here is what I am seeing so far:

Un-sized and weight sorted straight from tin

1. 860
2. 864
3. 862
4. 865
5. 864
6. 860
   [/LIST=1]
   
   Sized to 6.35 (.250") in same mag following the un-sized.
   
   1. 869
   2. 873
   3. 871
   4. 872
   5. 872
   6. 872
      [/LIST=1]
      
      Clearly an increase in speed, also maybe consistency. I'll check for groups next....

 

[Patrick]

I just did a quick sizing to 6.35mm with some 33.95 MKIIs. I then compared them to the un-sized over the chrono. Here is what I am seeing so far:

Un-sized and weight sorted straight from tin

1. 860
2. 864
3. 862
4. 865
5. 864
6. 860
   [/LIST=1]
   
   Sized to 6.35 (.250") in same mag following the un-sized.
   
   1. 869
   2. 873
   3. 871
   4. 872
   5. 872
   6. 872
      [/LIST=1]
      
      Clearly an increase in speed, also maybe consistency. I'll check for groups next....
      

1. 1. 
      
      Hi, sry for the late reply!
      
      
      
      youre welcome, that’s the same That I have noticed at diameter. And cocking my Bobcat was really hard with the mkI‘s.
      
      i wasn’t worried about the skirts either cause the skirt was more issue when cocking than the Head. They really rubbed at the breech seal.
      
      
      
      the numbers u got are really good, got the same when I chronied them. The usized are between 826 to 844, with the resized I’m around 835 to 838.
      
      let me know what u get on groupings, my groups have improved drastically as u can see.
      
      
      
      Regards
      
      Patrick

 

[triggertreat]

The left row is all un-sized and the right is sized to 6.35mm. Nothing conclusive just yet. I had a hard time seeing the little black dot at 52 yards with the sun glaring right into my lens without a sun shade Plus, I got off target I see with my counts. I'll try again in better conditions. The winds were 6 MPH. I do like that I was able to drill one hole with sized MKIIs. That was when a cloud came over and gave me a break from the glare so I could see better, but still want to see more testing first. By the way, this is with a 600mm Impact stock barrel. The tune is above. Also may need to slow it down some or speed it up.

 

[Patrick]

The left row is all un-sized and the right is sized to 6.35mm. Nothing conclusive just yet. I had a hard time seeing the little black dot at 52 yards with the sun glaring right into my lens without a sun shade Plus, I got off target I see with my counts. I'll try again in better conditions. The winds were 6 MPH. I do like that I was able to drill one hole with sized MKIIs. That was when a cloud came over and gave me a break from the glare so I could see better, but still want to see more testing first. By the way, this is with a 600mm Impact stock barrel. The tune is above. Also may need to slow it down some or speed it up.

Doesn’t look that bad at that conditions. Maybe give it a try at a really calm day where everything is perfect. The mkII are really working good out of ur rifle as I can see!
speedwise u can do it just with the power wheel from min to max to see what works best. With my Bobcat it works at 835. Impact may be different.

 

[triggertreat]

Thanks! Hoping to get them as good as the Kings are, which are awesome and much better than the MKIIs so far. I believe I am picking up on the forums that the MKIs are better in the Impact. I don't currently have any of those to try.

 

[Patrick]

Wish u good luck to find that perfect tune for right pellet.
i forgot to say: when u are shooting the resized ones, shoot 1 or 2 mags of them before u count the grouping. STX barrels are working best with some lead buildup, and the resized ones are slightly smaller than the unsized. Cause of that there might be some shots able to built that up.

 

[triggertreat]

Looks like I am going to need a bit of luck with the MKIIs. These are three more groups each to finish off the tin with half un-sized on the left and half sized to 6.35mm on the right. 5-shots each this time, Lol with no sun glare on the scope at the same 52 yards. The individual quad squares are 1" for reference. I didn't change the tune. I just left it as it was from the first groups. I'll slow down now and focus more on the tune and the harmonic balance for these. I think these are the first of groups I have shot officially with the MKIIs out of this new-to-me gun of two weeks now. The 25.39's are shooting so well I didn't want to touch it, but those that know me know I can't leave my guns alone for long, and the reason I wanted an Impact. I'll post back once I get these MKIIs sorted out. The groups aren't horrible, but I believe I can get them a little better than this. I am also questioning this HC magazine. The pellets are clearly not lining up with the exit hole. I am gonna have to do Glem's mag mod he recently posted to fix this....I'll also let the barrel lead up a bit. I did just clean it before testing...Thanks!

 

[Patrick]

Looks bit better now.

Just try it, speed is the key and It doesn’t have to fast to be accurate. I think the whole design is fitted for the 25grain Kings, the cal .30 Impacts are also built for the lighter 44grains.

ive read that post with the mag, maybe it makes a difference. Let me know what u get when they’re sorted out.

 

[triggertreat]

I sized some MKIIs to 6.375mm (0.251"). I think that's the correct next test for my setup. The front bands definitely got touched a small amount. A small handful had significant resistance compared to most all as well. I just received my O-ring orders and want to go through the barrel O-rings and replace all being a one year old gun and not knowing where I stand with those. A new breech,TP and liner seals at least. It may be a few days with tuning, and maybe barrel timing, plus fishing schedule.

 

[Dairyboy]

Keith you got an Impact? Man where have I been?! Congrats on the new to you gun! 

 

[triggertreat]

Keith you got an Impact? Man where have I been?! Congrats on the new to you gun!

Ha ha...Thanks! Yes, I finally broke away from the Marauders and got something else to play with. I couldn't let you have all the fun. It's a little more to this one, at least starting out, so should keep me occupied for a while. I have seen it shoot well a few times, so there is hope, and I don't believe I have wasted my money so far. I'll get it sorted out and then it will be boring, Lol. You know the drill.

 

[Patrick]

I sized some MKIIs to 6.375mm (0.251"). I think that's the correct next test for my setup. The front bands definitely got touched a small amount. A small handful had significant resistance compared to most all as well. I just received my O-ring orders and want to go through the barrel O-rings and replace all being a one year old gun and not knowing where I stand with those. A new breech,TP and liner seals at least. It may be a few days with tuning, and maybe barrel timing, plus fishing schedule.

Well that could be really the right size for yours, cause I’m shooting them out of s Bobcat with a Standard ST Barrel. Spare orings are always great to have, if something’s feels weird change them and you’re ready to go again.

 

[triggertreat]

I also went ahead and sized the rest of the tin to 6.40mm (0.252"). The front bands were only touched in random areas with this size, and the skirts were touched the least of course. I am looking forward to testing these as only the heads and skirts were made concentric primarily. There were some that offered up more substantial resistance than most when sending through the bushing.

I also replaced the barrel and liner O-rings to start out with new and known O-ring conditions.

 

[Patrick]

I also went ahead and sized the rest of the tin to 6.40mm (0.252"). The front bands were only touched in random areas with this size, and the skirts were touched the least of course. I am looking forward to testing these as only the heads and skirts were made concentric primarily. There were some that offered up more substantial resistance than most when sending through the bushing.

I also replaced the barrel and liner O-rings to start out with new and known O-ring conditions.

That’s great!


concentric? Really?? that’s really not good, also the inconsistent resistance when sizing. There are some Produktion issues hm? With all the orings renewed your are on the safe side, so it only depends on the tuning and the pellets. Excited about the groups you get with them.