MAGNUM RIFLE ADJUSTERS for Discovery, Maximus & 2260
These adjusters are listed in 6061-T6 aluminum, black anodized 6061-T6 and 360 brass. The full-size version has a locking collar and tick marks on the back of the knob to help gauge and maintain adjustments. The compact adjuster has no knob or collar, it requires a 3/16 hex wrench or one of the ADJUSTER TOOLS I have listed separately. The striker spring can be removed by backing the adjuster knob/guide-screw all the way out. The adjustment range is wide enough to produce maximum power, maximum shot count or the precise level of performance you want anywhere in between. These will also fit 22XX, they are the same adjusters but include the shorter rear trigger frame screw described below.
Discovery, Maximus, 1760 and 2260 models require a shorter rear trigger frame screw. The original screw is too long and will hit the adjuster knob threads. A length of 3/8" works best. One 3/8" Phillips-head screw is included, it is black-oxide stainless steel.
The Maximus striker spring will not fit on these adjusters, a Discovery or Magnum striker spring should be used instead. I have those listed separately.
The following chrony test results compare a standard Discovery .22 to one modified with a combination of this and other custom parts I have listed. 14.3 Grain pellets were used for both tests. Testing was stopped at 100 FPS below peak power. Fallowing that are more dramatic results produced by replacing the original Discovery valve with a Magnum Valve.
The following chrony results were produced with an upgraded Discovery .22. It had a 26" Maximus barrel, wide-bore gauge port, 3500 PSI gauge, .045 Magnum Hammer Spring, Magnum Adjuster, Magnum Valve with a short cap and custom valve screws for higher pressure. The transfer sleeve and barrel port were both deburred and polished which enlarged each by about .003".
PSI PELLET FPS FPE
3200 10.03 g 1288 36.9
3200 14.3 g 1142 41.4
3200 18.21 g 1086 47.7
3200 25.39 g 1000 56.3
3200 33.95 g 905 61.7
The following chrony results were produced with the same gun as above but with the Custom Bypass Cap instead of the wide-bore gauge port. The adjuster was set 3.5 turns back from full spring compression. The starting pressure was 3200 PSI. JSB Jumbo Monster 25.39 and Jumbo Beast 33.95 produced the best consistency and groupings of about a dozen types and weights tested. Heavy pellets work best at these extreme power levels.
1) 817 FPS 33.95 g 50 FPE
7) 853 54 FPE
11) 816 50 FPE