Speeds that You see in that video are not out-of-the-box speeds.
Out of the box speed for JSB Exact monster RD was average 873fps (11 shots, spread 11, STD 3.0). No internals de-burred, cleaned, hammer spring was maxed out. Barrel cleaned before shooting the gun.
Then I took gun apart and de-burred barrel lead, pellet probe and pretty much every hole in the gun. Remover sharp edges where there should not be sharp edges.
Changed few O-rings that were damaged during assembly in factory due to those sharp edges. For example, transfer port hole in main block.
Then polished hammer, because machining marks on hammer were too obvious and perpendicular to hammer movement.
The cocking mechanism was stiff and binding wen moving cocking handle forward, last 10-15mm (~0.5"). Got that moving very smoothly and with no restrictions other than hammer cocking.
After that took a closer look at the barrel. Crown was looking like someone did it with drill and drill bit with an angle of 90 degrees, and drill bit chattering. And it was deep. Doing all that I was so into it that forgot to take before picture of that crown. Anyway did a new crown. Did 11 degree crown protective face and little 45 degree crown.
Also did open up transfer port in barrel, from 3.0mm to 3.5mm. Transfer in block is 5mm. Then de-burred and polished barrel lead.
Polished barrel inside.
Putting gun back together I left hammer spring tension screw flush with the back of the block. From factory HS tension screw was turned in all the way, bottomed out.
Trigger and air cylinder remained untouched. But intend to lighten trigger pull a bit.
Closest picture of the crown that I found from internet (mine was cut 2 times deeper):
And crown made by me:
Then did that in-shroud moderator upgrade.
Comparison in speeds between out of the box and after fiddling with the gun.
Out of the box:
1. JSB Hades .177, 10.34gr - 11 shot average 889fps
2. JSB KO slugs .177, 10.03gr - 11 shot average 881fps
After fiddling:
1. JSB Hades .177, 10.34gr - 11 shot average 971fps - gain in speed 82fps
2. JSB KO slugs .177, 10.03gr - 11 shot average 949fps - gain in speed 68fps
Bare in mind that HS tensioner was backed out, flush with the block in that after fiddling test.
Well I'm impressed.
To find the most accurate pellet/slug for this setup, is ongoing process at the moment. What I've managed to accomplish at the moment is at the end of the video in previous post.
May be in need of a softer HS... to shoot those .177 Hades...
