Anybody know how much fpe a marauder .25 will have with a stock .22 mrod valve modded taking return spring out and end cap and using a 18lb heavy hammer spring with stock ports and hammer adjustment and air flow screw maxed out I plan on using Benjamin 28 grain dome pellets would like to push them at around 55-65fpe
Benjamin Benjamin marauder .25 power tune
- Thread starter anonymous_.457
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I do not think you can get there with the stock valve and a heavy spring that will make cocking difficult. I am going to say around 44 to 46 fpe is about maximum. The Marauder will like the JSB 34s a lot better than the Benjamin 28s. You will only get about 8 shots. It takes a lot of work, porting, FFH to prevent wasteful hammer bounce, modded or JSAR or Tim Hill valves.
I have now three working Marauder .25s, two are regulated one with mostly JSAR parts (60fpe@18 shots), another with a custom valve (54 fpe@24 shots) and the unregulated has a Tim Hill set up (52 fpe@27 shots).
Mostly stock as you describe but with a heavy spring I could get into the 50s with a steep bell curve, past about 54 fpe it was mostly just a declining curve. I was able to get 8 shots. There was a lot of hammer bounce and wasted air the more I pushed it.
I have not been able to shoot slugs accurately. The Marauder .25 barrel has a choke and so far just does not do well with slugs.
I have now three working Marauder .25s, two are regulated one with mostly JSAR parts (60fpe@18 shots), another with a custom valve (54 fpe@24 shots) and the unregulated has a Tim Hill set up (52 fpe@27 shots).
Mostly stock as you describe but with a heavy spring I could get into the 50s with a steep bell curve, past about 54 fpe it was mostly just a declining curve. I was able to get 8 shots. There was a lot of hammer bounce and wasted air the more I pushed it.
I have not been able to shoot slugs accurately. The Marauder .25 barrel has a choke and so far just does not do well with slugs.
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I don't know the answer to your specific question, but I doubt you will be able to get there without modifying the valve and porting through to the barrel. 55 FPE with 28 grains is over 940 FPS, and I never got close to that with mine before I swapped out the valve and increased the porting. Afterwards, no problem, but not without the work . . . that said, I did not try that stiff a hammer spring, but I do think it unlikely to get to even the bottom end of your range. You might get closer with 34 grain pellets.
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Maybe it's possible just have to Chrony it and see Florida bullfrog on YouTube was pushing like 940fps with jsb 33 grain slugs in his marauder .25
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If you really go down the rabbit hole,,,,, 98+ftlbs is possible with a .25 M-Rod. Be warned! It's hard to end the journey down that rabbit hole once you start!
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Either of these can make well over 60 fpe depending on the tune but not in the manner the OP suggested. One regulated the other not.
Thing is the heaviest commonly available pellet is the JSB 34 grain and it tends to become unstable somewhere above 900 or so fps which limits energy to about 60 fpe. Okay, maybe a little faster, say 940@66 fpe but accuracy begins to degrade beyond 900 fps. And the Marauder, at least none of mine yet, will shoot any slug I have tried with acceptable accuracy. I wish there was a JSB 40 grain pellet, then I could crank them up and burn some air.
Thing is the heaviest commonly available pellet is the JSB 34 grain and it tends to become unstable somewhere above 900 or so fps which limits energy to about 60 fpe. Okay, maybe a little faster, say 940@66 fpe but accuracy begins to degrade beyond 900 fps. And the Marauder, at least none of mine yet, will shoot any slug I have tried with acceptable accuracy. I wish there was a JSB 40 grain pellet, then I could crank them up and burn some air.
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Yeah, at a certain point I just had to call it quits before I started ordering slug barrels… I am edging close enough to the price of a nice FX or Taipan on mine, probably just should have started there.
That said, I wouldn’t have learned near as much, or probably had as much fun starting with the high-end stuff.
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Same here and with that said, I wouldn't be able to call out the high end rifle guys for a little LONG RANGE plinking.
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I have had mixed succss with water tube TPs. They mostly leak, some quite a bit. Negating their large bore advantage. And the barrel port needs to be drilled and reamed to .161 to .198 to match depending on ultimate goal. All of which is way beyond the OPs original question. And the valve flow path will need to be modded or replace the valve with a Tim Hill valve, JSAR valve or Cothran blow open valve.
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You might have learned some valuable lessons with the FX as well . It was my first regulated rifle and I had to change the pistons in 2 regs . The customer service was great at that time. The Taipan just feed and shoot. Both are fun .
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A honest question maybe ,"At what point is a M-rod no longer a Marauder?"
The rabbit hole was deep!
The rabbit hole was deep!
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You would need 1022 fps using 28 grain pellets to get to 65 fpe. Those pellets will not produce accurate results at that velocity. A more reasonable target is 50 fpe at 900 fps.
The AGR free flight hammer or home made versions of similar hammers produce a better result for me than the original configuration to eliminate hammer bounce.
And you have to have a useful shot string. The reservoir capacity of the M-Rod is fairly limited (215cc unregulated, about 190cc regulated) which means to get 16 shots at 60 fpe you will need some very sharp tuning and zero hammer bounce.
What you will see from a good M-Rod, mostly stock, is about 44 fpe at 890 fps with the 25.4 pellets. The Gen 1 in the photo, .161 porting, AGR free flight no bounce hammer will do 24 shots on a Bell curve averaging about 44 fpe. The side lever M-Rod on the bottom, GM barrel, Houma regulated, JSAR internals makes 60 fpe for 16+ shots with JSB 34s, 890 to 900 fps.
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Let me know if you need a valve. I got some that will definitely Amp up the power is yours a .25? With my valve in .22 I'm pushing 50 fpe
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