THE MAGNUM VALVE BODY IS MACHINED FROM 7075 ALUMINUM, IT'S NOT A MODIFIED DISCOVERY VALVE
It doesn't fit Maximus models. For Maximus I suggest using the Marauder stem, ultra-light valve spring and upgrade valve screws I have listed. Those parts produce excellent performance and allow up to 2400 PSI. A Magnum Hammer Spring and Magnum Adjuster are also needed to balance the power curve at higher pressure. If you only use CO2 then the original Maximus valve stem seals better at low pressure. It's the same stem Crosman puts in their 13XX models.
There are quite a few versions of the Magnum Valve listed in the drop-down menu above. Each is for a specific application. The body itself (exhaust-port half in second photo) is a first of it's kind design that blends the Discovery and Marauder valves together with a large angled port. It's made of 7075 aluminum which is one of the strongest aluminum alloys. The port is .151" diameter and angled 26°. All of these valves include an ultra-light spring. This is the lightest, most versatile and most powerful valve on the market for small-bore models. It's designed to produce longer shot strings at the highest power levels but works very well at low power also. This is a direct-fit part, no modifications are necessary for it to fit your gun. Your original transfer sleeve (port) and gasket can be used or one of our custom sleeves. All of these Magnum Valves fit our custom valve screws for Discovery, PCP pistols and 22XX. Some Discovery chrony test results are posted at the bottom of this page.
The PCP and bulk-fill versions have a Marauder or 13XX valve-stem. Those stems have a smaller head and pin diameter than a Discovery valve stem. They open with much less hammer force which produces far more power and reduces vibration. The Marauder stem version is for pressures above 2000 PSI, the 13XX stem seals better at pressures below 2000 PSI. The short cap versions are for bulk-fill CO2 and Discovery with a pressure gauge in the original position. The bypass cap versions are for eliminating the tube-mounted gauge assembly on Discovery models. That's popular for those who don't want a pressure gauge at all or prefer one of our fill adapters with a gauge on it.
The 12 gram CO2 version is for standard CO2 cartridge models like the 2240, 2250, 2260, 2300 series and 2400KT. It produces an increase of 35-200 FPS depending on barrel length, caliber, pellet weight and temperature of the shooting environment. Co2 produces more FPS in warm temps, with longer barrels, with lighter pellets and in smaller calibers. Larger calibers produce more FPE but lower FPS. It includes one of our upgrade custom valve screws that fits the tube better and is a lot more stable than the standard factory screw.
The powerlet eliminator versions have a Marauder or 13XX stem. They don't work with 12 gram cartridges because they have no piercing pin. They're intended to be used with cartridge eliminator devices, HiPAC and dummy CO2 cartridges. The Marauder stem version is for pressures above 2000 PSI, the 13XX stem seals better at pressures below 2000 PSI.
The following chrony results were produced with an upgraded Discovery .22. It had a 26" Maximus barrel, wide-bore gauge port, 3500 PSI gauge, Magnum Hammer Spring, Magnum Adjuster set 2 turns back from full spring compression, 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. 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