Tuning the Marauder / Armada

[GCGS]

Out of the box, my .25 Armada is shooting Hades 26.54 grain pellets an average of 798 FPS at 37.43 FPE. I’d like to bump that up a bit. I see instruction and discussion everywhere on the 3-step process for tuning the Benjamin. The steps include:

Adjusting the Velocity Metering Screw
Adjusting the Hammer Stroke
Adjusting the Hammer Spring Pre-Load

My question is: Can one simply adjust ONE of these settings without adjusting the other 2, or MUST I make adjustments to all 3? In other words, is there a “balance” necessary when making adjustments in that all 3 need to be tuned together to be in sync? If the answer is no and I can or should make only one adjustment, which of the 3 should I start with to bump up my FPS and FPE?

 

[pnwairgunner]

First you should open the “velocity metering screw”. After removing the action from the stock, you’ll find there is a small brass screw on the right side of the reservoir below the breech that covers an even smaller screw. Completely remove the outer screw and lay it aside in a safe place. The smallest screw needs to be backed out (counter-clockwise) a couple turns to unobstruct the transfer port. Do not completely remove this screw. If this screw was adjusted in too far from the factory it would reduce your power output. Make sure you put the brass covering screw back on and snug it down. It doesn’t need to be Superman tight. Just snug.

Then you can use the hammer spring tension screw to increase power by turning it clockwise. I would recommend only adjusting a half turn at a time until you reach the velocity you are looking for. Increasing the tension on this spring will cause the valve to remain open longer and will increase power but it will also reduce the number of shots you get per fill. Increasing this spring tension will also make the rifle’s bolt harder to pull rearward.
Fine tuning is accomplished by making adjustments on all three screws but you can increase power by simply increasing pressure on the hammer tension.