0.177 MROD tune w/ JSB Beast 16.20 gr. pellets

[WKV]

I have been shooting the JSB Monster 13.43 gr. pellets in my stock 0.177 MROD (1st Gen) with good results against the dreaded North American Tree Rat. I recently found that JSB has a 16.2 gr. version and decided to try and tune for this pellet. Here are my results so far:

Spring Pre-load Turns 2.00
Hammer Throw Turns 2.00
Transfer Port Turns 3.00
JSB 0.177 Exact Beast Diablo 16.20 grains
Start Pressure = 3250 PSI
End Pressure = 2000 PSI
31.25 psi used per shot

Shot#/FPS/ft.-lbs.
1/822/24.3
2/820/24.2
3/816/24.0
4/828/24.7
5/833/25.0
6/830/24.8
7/832/24.9
8/831/24.8
9/837/25.2
10/838/25.3
11/826/24.5
12/838/25.3
13/838/25.3
14/844/25.6
15/839/25.3
16/845/25.7
17/838/25.3
18/845/25.7
19/840/25.4
20/844/25.6
21/845/25.7
22/851/26.1
23/850/26.0
24/848/25.9
25/848/25.9
26/855/26.3
27/848/25.9
28/853/26.2
29/852/26.1
30/846/25.8
31/849/25.9
32/848/25.9
33/846/25.8
34/846/25.8
35/839/25.3
36/839/25.3
37/834/25.0
38/832/24.9
39/828/24.7
40/825/24.5
41/stop

Does this look reasonable, or should I continue to tweak? I would appreciate feedback.

WKV
Newbie and 1st time poster.

[RayK]

Looks great! You're done (as long as accuracy is good). Go shoot more squirrels.


Ray

[WKV]

Thanks for the feedback, Ray.

It has been wet outside, so I have not been able to verify accuracy. I am hoping the jsb 16.20 grain pellet follows the example set by its 13.43 grain brother. I will follow up with more info as the weather allows.

I have been reading the posts here for many months, and really appreciate the knowledge everyone so freely shares. I would never have attempted this tune without the information provided on this forum.

FYI - In am using a recently purchased Combro CB-625 chronic and it seems to be accurate (or at least repeatable) and easy to use - also inexpensive. I am able to shoot at my workbench into a pellet trap while it rains outside! Anyone else using this chrony?