I was wondering what's the biggest size you can drill the valve and barrel port out in a marauder .25 I was thinking drilling the mrod .25 valve port to 0.250 and the barrel port to 0.218 are those sizes too big?
Benjamin Marauder .25 ports drilling size
- Thread starter anonymous_.457
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Hill makes 7075 aluminum port i installed the entire kit tons of power new valve port hammer everything
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Yeah so I was actually wondering about his big .161 trasnfer port for the mrod rifle vs the 1/4 tubing the 1/4 tubing is .170 is the 0.9 difference gonna make that much difference in power? I can modify my stock valve to make a ton of power I have a marauder .22 that's doing over 40 fpe with 15 grain pellets valve port drilled and polished to 0.205 and barrel port drilled out to .166 and breech port drilled out and polished my .22 mrod actually uses a piece of tubing with the trasnfer port inside of that. I know the tubing seals good but not as good as the metal trasnfer port with the 2 o rings. My plan was to build a 100 fpe .25 marauder drill the stock valve out to 0.250 and barrel port to 0.220 and use the .161 hill trasnfer port I believe a stock .25 mrod trasnfer port is .140. Also I'm going to machine down the bolt probe in the .22 and .25 the bolt probe covers up about 60% of the air flow when you machine it down you'll gain about 50-60 fps extra also I run my valves with no return spring and no end cap. Also will be getting a 18 pound heavy hammer spring for my .22 and .25 and the air stripper will be drilled out bigger in both of them too it makes it way quieter.
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I tried them all and they worked great i just liked the aluminum one because it was aluminum and i had so much power anyway 100 fpe shooting slugs it was good enough for me i even dialed back a little
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Simple and direct ... NO !!
Stock valve @ .160" on transfer exit and valve won't flow more with its throat size/stem limitations.
It goes much deeper than this & just drilling stuff w/o knowing what your doing is only going to cost you parts & $$
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The Hill Teflon TP does work. It has about as large an ID as possible (well, not entirely). It is a single use item as it may not seal up a second time. It may take a number of shots for the TH TP to form and seal. Maybe 20 or 30 shots with heavy pellets.
A .161 port is probably not going to get you to 100 fpe and who knows what projectile you are planning to use? That would be around 1200 fps with the JSB 34 pellet!
Unless you are oblonging the ports some where around .196 or perhaps a little more is the limit without having the pellet try to drop through.
All you guys wanting stock numbers, here:
A .161 port is probably not going to get you to 100 fpe and who knows what projectile you are planning to use? That would be around 1200 fps with the JSB 34 pellet!
Unless you are oblonging the ports some where around .196 or perhaps a little more is the limit without having the pellet try to drop through.
All you guys wanting stock numbers, here:
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I planned on opening the valve port around 0.210 and barrel port around 0.200The Hill Teflon TP does work. It has about as large an ID as possible (well, not entirely). It is a single use item as it may not seal up a second time. It may take a number of shots for the TH TP to form and seal. Maybe 20 or 30 shots with heavy pellets.
A .161 port is probably not going to get you to 100 fpe and who knows what projectile you are planning to use? That would be around 1200 fps with the JSB 34 pellet!
Unless you are oblonging the ports some where around .196 or perhaps a little more is the limit without having the pellet try to drop through.
All you guys wanting stock numbers, here:
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My Mrod pistol 357 only has .275" porting and gets 3 shots at 130 fpe out of a 16.5" barrel. It has a Don Cothran powerhouse valve though.
The limiting factor with a poppet type valve like these guns have, is the throat area. Doesn't matter how big before or after the ports are, if it has to get funneled into the barrel. The diameter of the poppet head also plays a big roll in getting that air into the throat.
The limiting factor with a poppet type valve like these guns have, is the throat area. Doesn't matter how big before or after the ports are, if it has to get funneled into the barrel. The diameter of the poppet head also plays a big roll in getting that air into the throat.
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Niceee! Currently my marauder .22 is doing around 45 fpe with 15 grain pellets I'm gonna modify the bolt probe for more air flow and get the 18 lb heavy hammer spring I'm filling around 3850 psi. I'm gonna be getting a .25 marauder soon and plan to power build it and get a .251 50 grain noe mold for it
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I seem to get a lot more power out of my stock modified valve I take the return spring out and end cap out the valve and on my .22 mrod the valve porting is 0.203 barrel port is .166 I'm getting no valve lock on 3800 psi with stock spring which is where a lot of the power is coming from. The spring and hammer is maxed out settings wise and the valve vms screw is maxed out. It should be making around 50 fpe with the 18lb spring and bolt probe mod.
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Careful with those higher pressures. Have you upgraded your valve screws yet?
Mine is running on a standard 3K psi fill.
I bought a talontunes air tube extension to bring it up to 6 mx power shots, and am swapping it over to a rifle trigger/boyds stock here soon. I don't like plastic/tactical guns. Only ones I have are powder burners, and those are for 2 legged critters anymore.
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