Hi All. I am new here and new to PCPs since I have always shot break barrels. A few weeks back I bought a used .25 cal M-Rod off a buddy who tried to tune it but gave up halfway. My idea is to pick up where he left off and try to get this thing shooting again. I currently have a hand pump he gave me but have a cheap Vevor compressor and chronograph on the way. Should I try to tune this rifle or try to get it back to the factory setting? Are all M-rods set the same at the factory? If so does anyone have the specs so I can reset it or how would you all recommend I go about this since he said he doesn't have that info anymore?
Benjamin Benjamin M-Rod Reset
- Thread starter vazsev
- Start date
Here are the O-rings:
Here are the factory settings:
Do yourself a favor and buy this:
www.airgunrevisions.com
And this:
www.airgunrevisions.com
With the AGR SSG hammer tuned per his instructions. I run my .25 M-Rod with the restrictor fully out, the SSG negates the other settings. The thumb rest makes cocking super easy and reduces double feeds. Short of a side lever it is the bees knees.
The AGR SSG (or any home made version similar) will stop hammer bounce and greatly increase your rifles performance and make it quieter also. If this is a Gen 1 M-Rod then a 1.25 or 1.5 inches bottle brush makes a great depinger, actually, the same for a Gen 2.
The M-Rod is a solid rifle, do not let people tell you it is not relevant, old fashioned, antique. The M-Rod is still being manufactured so it is hardly an antique. It is in some ways the Marlin 39A of the PCP world being one of the longest produced PCP rifles with few changes and very simple to work on, available parts a phone call away and most seals available at hardware stores or Harbor Freight kits.
I have four .25 M-Rods, two Huma regulated two are not regulated. Two are side lever, two remain bolt. I would recommend not regulating but I will recommend either the JSAR aluminum reservoir tube to knock the weight way down or the AGR hybrid tube to reduce weight and improve balance. If not handy with tools you might consider the Tim Hill short shroud kit (I cut the one above myself after purchasing one for another rifle).
Here are the factory settings:
Do yourself a favor and buy this:
Tuned SSG De-Bouncer Hammer Kit for Benjamin Marauder - Airgun Revisions
A complete drop in kit made from Stainless Steel and specifically tuned to give your gun a flatter shot string and up to 80% better shot count. Nylon button on adjusting screw keeps it in place from vibration without harming the threads and galling from a locking screw. Kit is…
www.airgunrevisions.com And this:
Marauder Thumb Rest - Airgun Revisions
Add a bit of comfort when cycling your charging handle with this AR exclusive Thumb Rest. Just screw into back of air tube. Rest your thumb on it while grabbing charging handle and squeeze your hand. Aids in smoother cocking as well bringing your index finger lower on bolt handle…
www.airgunrevisions.com With the AGR SSG hammer tuned per his instructions. I run my .25 M-Rod with the restrictor fully out, the SSG negates the other settings. The thumb rest makes cocking super easy and reduces double feeds. Short of a side lever it is the bees knees.
The AGR SSG (or any home made version similar) will stop hammer bounce and greatly increase your rifles performance and make it quieter also. If this is a Gen 1 M-Rod then a 1.25 or 1.5 inches bottle brush makes a great depinger, actually, the same for a Gen 2.
The M-Rod is a solid rifle, do not let people tell you it is not relevant, old fashioned, antique. The M-Rod is still being manufactured so it is hardly an antique. It is in some ways the Marlin 39A of the PCP world being one of the longest produced PCP rifles with few changes and very simple to work on, available parts a phone call away and most seals available at hardware stores or Harbor Freight kits.
I have four .25 M-Rods, two Huma regulated two are not regulated. Two are side lever, two remain bolt. I would recommend not regulating but I will recommend either the JSAR aluminum reservoir tube to knock the weight way down or the AGR hybrid tube to reduce weight and improve balance. If not handy with tools you might consider the Tim Hill short shroud kit (I cut the one above myself after purchasing one for another rifle).
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Here are the O-rings:
Here are the factory settings:
Do yourself a favor and buy this:
Tuned SSG De-Bouncer Hammer Kit for Benjamin Marauder - Airgun Revisions
A complete drop in kit made from Stainless Steel and specifically tuned to give your gun a flatter shot string and up to 80% better shot count. Nylon button on adjusting screw keeps it in place from vibration without harming the threads and galling from a locking screw. Kit is…
And this:
Marauder Thumb Rest - Airgun Revisions
Add a bit of comfort when cycling your charging handle with this AR exclusive Thumb Rest. Just screw into back of air tube. Rest your thumb on it while grabbing charging handle and squeeze your hand. Aids in smoother cocking as well bringing your index finger lower on bolt handle…
With the AGR SSG hammer set tune per his instructions. I run my .25 M-Rod with the restrictor fully out, the SSG negates the other settings. The thumb rest makes cocking super easy and reduces double feeds. Short of a side lever it is the bees knees.
The AGR SSG (or any home made version similar) will stop hammer bounce and greatly increase your rifles performance and make it quieter also. If this is a Gen 1 M-Rod then a 1.25 or 1.5 inches bottle brush makes a great depinger, actually, the same for a Gen 2.
The M-Rod is a solid rifle, do not let people tell you it is not relevant, old fashioned, antique. The M-Rod is still being manufactured so it is hardly an antique. It is in some ways the Marlin 39A of the PCP world being one of the longest produced PCP rifles with few changes and very simple to work on, available parts a phone call away and most seals available at hardware stores or Harbor Freight kits.
I have four .25 M-Rods, two Huma regulated two are not regulated. Two are side lever, two remain bolt. I would recommend not regulating but I will recommend either the JSAR aluminum reservoir tube to knock the weight way down or the AGR hybrid tube to reduce weight and improve balance. If not handy with tools you might consider the Tim Hill short shroud kit (I cut the one above my myself after purchasing one for another rifle).
Should I go ahead and replace all the o-rings and seals? Also is the designer necessary? All this stuff is somewhat new to me. I would ideally like to maximize the shot count and I assume the accuracy will increase with this naturally since fps should be more consistent between shots. As per the factory settings I am assuming if I were to install the AGR SSG I wouldn't need the factory setting anymore since I would be tuning for the SSG correct?
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Well, if you are going to go into the rifle then I would replace the seals or go ahead and buy a set (eBay, AGR, Crosman). If the rifle holds air and you are not going inside then just have the kit handy for when inevitably it will be needed.
A depinger is not required. It just makes the annoying -PING- sound considerably diminished. The ping is caused by a shock wave when the valve closes and the shock wave travels down the tube and hits the end cap making a ping or bell sound. It is harmless but annoying to some who want a quiet rifle.
Correct, if you install the AGR SSG hammer kit you will tune per the instructions he provides and it is super simple. So simple a caveman can do it, seriously, it is simple to install and simple to tune. And the owner of AGR, Rich, will talk your ear off and every bit of it will be helpful and friendly information. The thing about the AGR hammer is that it just works with no fuss, there are better designs, more expensive designs, homemade versions, just make it simple and get his, it is worth the money, I promise.
The stock M-Rod hammer is preloaded against the valve poppet. When the hammer hits the valve it will bounce back and forth wasting air and power and increasing wear and tear. The free flight SSG type hammers of any sort put a little gap in the system so that the hammer does not preload the valve poppet and therefore it does not bounce back and forth upon firing.
If you do a bottle brush depinger, you want the kind with a twisted center wire holding nylon bristles. Make sure there are no loose bristles. Cut most of the handle off and bend the twisted wire into a small hook so that you can reach down in the tube with a wire and hook it to pull the depinger out should you wish to. Shove the bottle brush down into the reservoir tube about midway.
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M-rods had a very bright time with much shared on there tuning and modification going back now 12-15 years. The .25 cal was honestly the exception being most who went the .25 route wanted POWER and used them for hunting or small / medium pesting duty. Most of the in-depth tuning and efficiency pursuits were with .177 and .22's .. tho some specific mods for .25's were shared as well.
Using such home created devises such as the Bestaly O-ring mod to buffer hammer lift & dwell, to custom valves, regulators, light hammers, SSG hammer debounce devices etc etc etc. There have "BEEN" aftermarket suppliers for parts & pieces over the years, but most have disappeared in the past 5 or so years.
If really interested in the Tech of this bygone time applied to the platform, your going to need to do some searching on line. The AG forum "Gateway to Airguns" was a hotbed of conversations back in the day and likely a vast amount of documented knowledge may still be in archived threads.
I'm not trying to be difficult here .. as one who contributed vast amounts of tuning / modification so many years ago ... It is not something I wish to go mining for it at this juncture, but much is still there if willing to research, read and weed threw the multitude of threads on M-rods.
Truly wishing you all the best
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Thanks Im mostly looking for recommendations and a push in the right direction. I'm not shying away from digging for the info just always thought it better to ask first and get started in the right direction. Appreciate you alls responses and time. Im going to go ahead and order the parts 3Crows suggested and start from there and might as well change out o-rings in the process.
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Okay, a heads up. Use a wooden dowel or appropriate size PVC pipe to push the innards out the front from the rear. Once the components are out of the way careful use of a jewelers file, hook deburr tool or a small dowel with 600 paper to deburr the inside edge of the hole through which the gauge installs. That hole will cut your new valve and gauge block O-rings nearly every time making a simple job into a two hours ordeal. Use only 100% silicone grease to lubricate the O-rings and put some in the tube as you slide the parts in from the front, not from the rear!
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Tim Hill, AGR, JSAR, Huma still support the Marauder platforms. It is true that many who were tuning and modding the M-Rod have moved on mostly to China stuff. Which after trying a Gauntlet and an Avenger I found them to be less than appealing. Right now the big thing is the Notos or spending $2,000+ on a M4 and then spending another near $2,000 to make it shoot straight. Of course, one of my essentailly parts built M-Rods probably cost me north of $1,200+ and it to be fair, it shoots like a $1,200+ rifle too and nobody has one exactly like it, so that works for me. I do not do this to get a return on investment. It is true though that many parts are NLA or at least not available at the moment to build a 6 pounds, 38 inches long, 60 fpe, superbly accurate side lever M-Rod .25, upper, like this one which does make me sad:
I have no problem spending money on esoteric things like air rifles. Yes, I want a M4 or that Ghost maybe better.
I have no problem spending money on esoteric things like air rifles. Yes, I want a M4 or that Ghost maybe better
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I got my parts in this week and went ahead and changed everything out including most of the o-rings. Thankfully I listened and ordered that service kit since when I went to air it up the first time the valve poppet shattered. I ended up ordering the SSG hammer from airgun revisions like mentioned and was able to find a "tuning guide" on their website which just states to tighten until air comes out then back off 1/8 turn is that it?
I have been reading up on tuning as much as I can and I think since I have installed this SSG hammer I don't have to mess around with Hammer tension and hammer stroke anymore and all the tuning I need to do moving forward is just open or close the transfer port to try to get my shot string as close together as I can. Is that correct?
I have been reading up on tuning as much as I can and I think since I have installed this SSG hammer I don't have to mess around with Hammer tension and hammer stroke anymore and all the tuning I need to do moving forward is just open or close the transfer port to try to get my shot string as close together as I can. Is that correct?
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Is your side lever a direct fit to the mrod still searching around for a used mrod synthetic stock in .22 . still using my model 48 break barrel
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I too have went down the marauder path. I don't regret it at all. Scott is right in telling you to snoop around on GTA. He has a very awesome b-rod. I'm glad to see some new people posting threads on them. The 25 armada was my first PCP and it's been a great rifle.
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The (AGR) SSG eliminates hammer stroke adjustment. The SSG assembly can be adjusted for length (tension) and it came with an extra stronger spring for higher power, however, the assembly comes pre-adjusted that should work well for most. The installation is to run the hammer in until you hear air begin to leak and then back it off 1/8 turn. Yep, that is it. This adjustment can be varied. A little more in gives more velocity and a little more out reduces velocity from this neutral postion. Do not, I repeat do not, with this type hammer, have the hammer ride the poppet with no free flight gap. You may get a machine gun! You can still use the restrictor to adjust your curve.
I love my .25 M-Rods and would not trade them for anything. I built them and they are mine and each is unique.
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I just got the .22 LW barrel model.I am going to use it for shooting 100 yards and see how I do.I am going to switch it to lefty and put the custom trigger in it ,I think I will do those other mods discussed also...
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I think I need to find time it. Was able to get it get some shots in this past weekend and can't get more than two maga in going from 3000 psi to 2000 psi. Chronoed at starting speed of 914 and ended up in the 830s but wasn't able to get a curve. It was declining shot after shot. Since I have the .25 cal I followed the instructions and switched out the spring in the SSG to the heavier one provided. I'm going to try backing up further than the 1/9 they suggest to see if I can start to develop an actual curve.The (AGR) SSG eliminates hammer stroke adjustment. The SSG assembly can be adjusted for length (tension) and it came with an extra stronger spring for higher power, however, the assembly comes pre-adjusted that should work well for most. The installation is to run the hammer in until you hear air begin to leak and then back it off 1/8 turn. Yep, that is it. This adjustment can be varied. A little more in gives more velocity and a little more out reduces velocity from this neutral postion. Do not, I repeat do not, with this type hammer, have the hammer ride the poppet with no free flight gap. You may get a machine gun! You can still use the restrictor to adjust your curve.
I love my .25 M-Rods and would not trade them for anything. I built them and they are mine and each is unique.
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I did not use the stronger spring with my two unregulated .25 rifles. I have three with the AGR hammer, two have the hammer kit you have but with the standard spring and one of my regulated rifles has his lightweight hammer with standard spring.
1) You might consider going back to the standard spring and the standard as delivered OAL for the assembly. Then vary your TP ID or use the valve restrictor to get a Bell curve. You should be able to get the velocity down in the mid 800s this way and get a curve. You may also consider going to a heavier pellet.
2) What is your TP ID? If it is .16 then go back to .14. Or keep the .16 if so and use the valve restrictor to try and get a curve.
My Gen 1 .25 has a pretty much stock Gen 2 valve. It has a .161 barrel port, .161 TP, AGR hammer with stock spring and OAL, valve restrictor is full out. Bottle brush depinger, AGR hybrid tube. I get up to 32 shots with a slightly skewed Bell curve. Average for 16 shots is 872 fps at 43 fpe, for 24 shots 41 fpe and for 32 shots avg 39 fpe. I am shooting the JSB 25.4 pellets. Peak velocity occurs at shot 14 and declines slowly until shot 22 falling below the initial shot 1 and then tails off but still good all the way to 32 shots and then it falls away steeply.
3) The neutral position for the AGR hammer is 1/8 turn out from valve leak. This adjustment is very sensitive. You might back off an additional 1/16 turn.
Being unregulated, at least for my two that are not regulated, I certainly do see vertical shot stringing as the velocity varies but out to about 30 yards I put the cross hair where I want it and it is good enough, out further, or as the string gets longer, I do compensate as the velocities decline, part of knowing your rifle. You should be able to get 24 good shots in the lower 40s for energy.
While talking, make sure you do not have a TP leak or a chamber O-ring leak at the bolt probe. Those things waste a lot of air and a TP leakage is hard to verify. I will rest my finger adjacent the TP and see if I feel anything or see oil blowing out there.
Okay, I am going to be cookbook. Do 3 first, then 1 and then 2 and if all that does not work then combinations thereof and if that does not work, call Rich at AGR and say HELP!
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Mine was easy. I backed out the restrictor and installed the SSG.
The adjustment doest take much.
Running 16 grain for 35 or so shots at 27pfe
The adjustment doest take much.
Running 16 grain for 35 or so shots at 27pfe
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I'll have to try stock spring. Since instructions said to use heavier spring for 25 I went ahead did out the get go. TP I am assuming is transfer port and I have it all the way open right now. As far as dimensions for it I have no idea I think it's a gen 1 marauder since buddy said he bought it 10-15 years ago.
I did back off the 1/8 turn as directed as well so I might try to back off a bit more as well see if that helps. I'll try to get some shots in this weekend see what works.
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