JSB Monster ReDesign .22 Speed Question

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DrPutz

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Mar 18, 2017
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Ohio, United States
Do the JSB Monster ReDesign .22 (25.39 gr) and the Beasts (34 gr) require higher speeds to shoot accurately? Initially, I could not even hit my backstop, but once I got to higher speeds (> 950 fps), the groups tightened up. I could not get the Beasts above 860 fps and they were all over the place (most not on paper or even the dirt backstop).

Here is my final 70-yd group (Group #21) running 950 to 960 fps (137 bar Impact Mk0, TJ Barrel) - 5 shots within what would have been a .30 cal shot size of 0.3" CTC at 70 yards:

1588911057_18288307355eb4dbd1b842d7.94589072.jpg

 
The RDs seem to shoot accurately from around 920 up to 1000 FPS in the LW Poly barrel on a Red Wolf, but best in the 960 to 980 range. They need to be sorted for head size since it seems every tin has 10 or 15 runts 5.54mm or less.

The Beasts seem like they want to be accurate but every 4th or 5th shot is a flyer from RW at 935 FPS. Even if they were as accurate as the RDs, not sure it would be a benefit since I don’t know if the BC is better or not. 
 
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I have a powertuned cricket Charlie made for me with the goal of shooting the 25 grain at a higher speed. I'd does very well at 920 fps. I also tried them on my standard cricket it is set up for 18 grain at 890, they were very accurate in it at 40 yards but didn't check the speed on them . My quess would be 800 fps or less. All groups are 14 pellets.

1588949852_14803512265eb5735c8f56b2.38076307.jpg

 
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My Taipan Veteran in long configuration shoots the RD monsters at ~860 fps. Shoots amazing at 10 yards. Tried it at 120+ yards a few times and I may as well have been throwing rocks. 

Somewhere on the way to 120 yards they destabilize. Having a longer skirt then a traditional pellet, the CG is pushed more rearwards which I don't think is doing the pellet any favors in the stability department. Projectiles shot out of a barrel with a twist imparted on it travel in an elliptical motion. What I believe is happening with the RD monsters is that this elliptical pattern is really exasperated as it slows down, being more CG rearward, and as that ellipse opens up the problem is exasperated more, further "destabilizing" the pellet. 

By virtue of design, the .22 beasts will be even worse, destabilizing at a shorter range then the RD monsters. They will have to be pushed even faster to be consistent/stable to the same range as the RD monsters, but then you will be pushing up against the window of being supersonic, and I personally don't know how that pellet will handle the transition to subsonic, but I would surmise not well. 

Those that haven't seen the RD monsters destabilize just haven't shot them far enough. People say that you need 930+ fps to launch the RD monsters, but that velocity is not the whole key to unlocking the success of the RD monsters. The better question is, at what velocity do they fall apart? If the RD monsters fall apart/destabilize at 800 fps for example, you better hope they are traveling faster then that by the time they reach their intended target. What velocity they are at when they leave the muzzle doesn't really mean much. 930 fps may be great if you are shooting at 70 yards, but what if you are shooting at 150 yards? 

If you are at the ragged edge of stability at 100 yards, you better hope the environmentals don't change on you mid string. 

The 18 grain JSB's, a more standard diabolo design if you will, seems stable all the way through flight to 273 yards, farthest I've had to test them so far. They don't seem to have the same issue, but their CG would be much more forward, which makes sense on a ballistics standpoint for it's ability to stay stable. I think the RD monsters and beasts would benefit from a bi-metal design to place the CG more at the tip of the head.

I can easily test atwat velocity the RD monsters decay occurs at with my Taipan Veteran with the Donny FL speed dialer, perhaps I'll give it a test this week. 
 
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So I did some more testing over the weekend and tonight. I found that the MRD (monsters redesigned) shoot well all the way down to about 840 fps. At 70-yards the groups were 0.75" or less considering some wind effects. The breezes did push the pellet around more at the slower speeds. At 800 fps, they started to fall apart accuracy wise at 70 yards. Overall, the 950-940 fps was the most accurate range, I did not go above that speed so far. 

I got a few odd pooky-sounding shots during the shooting - so I went about measuring the head sizes - all were over 5.56mm, so that was not helpful. Then I weighed them - weights were from 25.0 to 26 grains. I weight sorted them in some groups and sized a few to 5.53. I shot the groups tonight and did not notice much difference in the speeds over the weight ranges. There was not much breeze tonight, so the groups were all tight. The 5.53 sized pellets weighting around 25.3gr seemed to have the best groups, but my paper was tearing a bunch (have to rebuild my shooting target), so not the best gauge of accuracy tonight. I had to shoot two target for the 25.1 gr, since it tore a big hole after the 3rd shot.

I did notice that my regulator was giving me higher speeds at higher pressure (225 bar) vs lower pressure (130 bar) (regulator set at 122 bar). I am hoping that this is just the new Huma regulator "breaking in", but my speeds started out around 951 and dropped to 937 fps by the end of the 45-shot string and bounced around a bit. POI did not change much until the speed fell into the 930's.

In the other thread on the MRD, I was speculating that the speeds were causing the accuracy issues - I am flipping that around, it was that the gun was shooting different speeds due to either an internal problem (regulator) or a pellet defect. A few 912's were noted, I put these off to a chrony issue, but now believe it was a pellet issue. So accuracy was not the issue - functioning was issue.

Sunday's Speed Test (70 yards) (speeds were lower due to low fill pressure - had to make air in the afternoon):

  • Max: - 935 fps
  • #5 - 915 fps
  • #4 - 880 fps
  • #3 - 876 fps
  • #2 - 842 fps
  • #1 - 800 fps



1589254733_9141228705eba1a4d2c6a81.93163607.jpg


Monday's Weight Test (70 Yards):

1589254782_13395220505eba1a7ec62a85.67097755.jpg





 
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