Beeman Super 12 gets more adjustment travel for power adjuster

[PigButtons]

I have this awesome Beeman Super 12 (Theoben MK I) and it has a power adjuster that manages the power through hammer spring tension.

The gun itself


Here's the power adjuster (sorry about not having a pic before the process started, I didn't decide to share the project until after I was this far.)
The problem is that the adjuster only has room in the stock to turn 1 and 1/2 times. And as far as shot count goes it did nothing that I could tell. The air tube on the rifle is an aftermarket unit and is quite small. I had Martin at RAW build me a regulator that yields about 150 bar, so from a 200 bar fill I could only get about 12 shots before it would go off reg and POI drop. Great for hunting, not so great for plinking or target practice. Here is the pic of the adjuster in the stock.


So I drew a line on the stock where I wanted to remove the material so I could get more adjustment.


And then scribed it with a razor utility knife and made two small notches to be able to start the saw in, one on each side line.


Now using a small Japanese finishing saw, the two side lines were cut from the scribed line on top of the stock back to the scribed line at the bottom of the area to be removed.


The saw and the razor knife.


Then I proceeded to cut the rest of the area to be removed into segments just like the sides. I cut at an angle so that the saw met the line at the bottom of the removal area and the line on the top of the stock at the same time.


With a 1/4" mortising chisel I removed the bulk of the sawn area working slowly from the scribed line on the top of the stock to the bottom of the cut out.


Finally finishing up with a Marples 3/4" chisel to get the whole area flat and square.


Here is the final fitting. I now have 5 full turns of the adjuster. At low power I can get 40 shots from 200 down to 150 bar. The stock still prevents the adjuster from coming too far out of the action.

[grauhanen]

Nice work.  What power range does the gun have?

[PigButtons]

Nice work.  What power range does the gun have?

Thanks.
I don't own a chrony so I'm just guessing but maybe 10 to 30fpe. At the low end I can see the pellet flight in the scope; at the high end it will easily pass through a squirrel scull at 25 yards.

[PigButtons]

Got a chance to shoot a bit today. Really like the low power setting. First, it is nearly silent. The hammer strike is a muffled thud and the report is even quieter. Second, it now shoots Benjamin pellets as well as it does the JSPs, which will really save money. All is good.