Ohhh nahh this just a junk marauder I had laying around that I kinda just practiced on for fun that breech doesn't work anyway. My good marauder .22 breech port hole is stock lol
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Benjamin Marauder .22 transfer port 1/4 tubing
- Thread starter anonymous_.457
- Start date
I opened up my barrel port to .166I am excited for you.I really want to see the results. I am using the full JSAR kit in one of my rifles and with Huma regulator and .196 porting (.25) I can get 24 shots at around 56 fpe. The JSAR balanced valve does not require a heavy spring.
What is your barrel porting?
I have given up trying to pull more than 60 fpe from an M-Rod, there is just not enough air capacity for a useful number of shots. I have also decided long ago that I did not like the heavy hammer springs and the wasteful hammer bounce of the factory hammer system which preloads the valve poppet stem and wastes air, bbrrrr--rrrr--rrppp.
For me, I am finding mid 50s fpe for my .25 rifles is about the limit to get a useful string and shot count, regulated or unregulated. And something in the upper 40s fpe is more practical. I just do not think at this juncture that heavy springs and greater than .161 flow paths are benificial to an unregulated rifle if trying to tune a Bell curve string, especially a .22.
I also have used the poly or nylon tubing but not currently. I heat the 1/4 tubing and expand it with a taper rod and let it cool. I then flame polish the ends after cutting to length and square. I have gotten okay results but as often get wasteful leaks. Such tubing can work though.
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That was just a old junk marauder I had laying around that I decided to just mess with lol. My normal marauder .22 the one I'm doing the mods too
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I chrongraph the marauder .22 with the valve port drilled out to 0.203 and polished and barrel port drilled out to .166 and it's shooting 15 grain pellets around 985-1000 fps on 3000 psi now I'm pretty confused because before opening the ports up it was doing around 1020 fps to 1045 fps with that same exact pellet the only thing I can think of is maybe humidity affecting fps and the transfer port is limiting it a ton
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Transfer port waste.
Wasted volume from poppet to pellet will reduce FPS as that causes undesired pressure loss.
You would need to either go full .196-.203" porting, or find a way to bring the valve porting back down from .203" to .166".
To go full .1965" porting on a .22 cal you would want to port oblong, so the width is no more than 80% or so of the caliber, say .175" and the length would be .218" for .1965" porting. This is to avoid pellet jam/loading issues as the pellet crosses the port into the rifling.
Also with 20-40 fps loss its likely a slight leak is present somewhere on your transfer port be it its seal on valve end or barrel end.
-Matt
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On my two unregulated M-Rod .25 rifles, I have found that too large of porting is detrimental. One in particular, this one:
JSB 34 grains pellets, avg. 826 fps, average energy 52 fpe. This rifle uses 9 shot magazines. I can increase the free flight gap and get more shots, up to 30 shots, at around 46 fpe average with 25.4 JSB pellets.
JSB 34 grain pellets, .161 nominal porting, FFH assembly with gap:
808 (3000)
815
820
832
837
839
844
842
846 (2500)
----------
832
838
837
828
818
822
815
810
802 (2000)
It has the Tim Hill valve set up with an AGR hammer assembly and AGR hybrid tube. With the barrel at .190 and the poly tube TP the velocity did go up for the first shots but dropped off a cliff. I removed the .190 ported barrel and installed it on one of my regulated rifles and went back to the Tim Hill .161 TP and a .161 ported barrel. Without touching anything else, I got a nice, flat Bell curve back and good power just over 50 fpe average. Again, just throwing in heavy springs and drilling ports up is not always the answer to a practical rifle. Just not that simple. If all that is wanted is two or three powerful shots, maybe so.
The problem (of several) with the M-Rod is the 210cc volume and only 3000 psi fill. I sit here drooling over an M4 and it's (up to) 160 shots and the 580cc bottle, huge plenum and 250 bar fill pressure that makes that possible. It is not going to happen with a M-Rod. This rifle, Huma regulated will pull 70+ fpe for 8 shots or I can run it around 55 to 60 fpe for 16+ shots on the reg and a few after on a mini Bell curve. Huma reg at 1900 psi, .196 porting, JSAR valve and hammer system, aluminum tube:
JSB 34 grains pellets, avg. 826 fps, average energy 52 fpe. This rifle uses 9 shot magazines. I can increase the free flight gap and get more shots, up to 30 shots, at around 46 fpe average with 25.4 JSB pellets.
JSB 34 grain pellets, .161 nominal porting, FFH assembly with gap:
808 (3000)
815
820
832
837
839
844
842
846 (2500)
----------
832
838
837
828
818
822
815
810
802 (2000)
It has the Tim Hill valve set up with an AGR hammer assembly and AGR hybrid tube. With the barrel at .190 and the poly tube TP the velocity did go up for the first shots but dropped off a cliff. I removed the .190 ported barrel and installed it on one of my regulated rifles and went back to the Tim Hill .161 TP and a .161 ported barrel. Without touching anything else, I got a nice, flat Bell curve back and good power just over 50 fpe average. Again, just throwing in heavy springs and drilling ports up is not always the answer to a practical rifle. Just not that simple. If all that is wanted is two or three powerful shots, maybe so.
The problem (of several) with the M-Rod is the 210cc volume and only 3000 psi fill. I sit here drooling over an M4 and it's (up to) 160 shots and the 580cc bottle, huge plenum and 250 bar fill pressure that makes that possible. It is not going to happen with a M-Rod. This rifle, Huma regulated will pull 70+ fpe for 8 shots or I can run it around 55 to 60 fpe for 16+ shots on the reg and a few after on a mini Bell curve. Huma reg at 1900 psi, .196 porting, JSAR valve and hammer system, aluminum tube:
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I drilled out the breech port hole for some hard tubing now I have blow by and feel air around the breech any suggestions?
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Would need pics and more details, could be a simple fix or one that requires a stick of gum, 3 nickels, a Popsicle stick and a tube of epoxy.
-Matt
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I'll get some pics here soon basically when I shoot it I feel air around the breech and it sounds like a machine gun going off
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My guess is you have two seperate issues. The air around the breech, if at the joint between tube and breech, is air leaking from the TP area. The machine gun hammer bounce is probably due to the 18 pounds spring whacking the valve so hard that the striker slams into the back side of the exhaust valve body flinging it rearward and repeating over and over.
You might try this, pull the striker fully into the hammer so that the back of the striker is flush to the face of the hammer. Install an O-ring or perhaps two on the backside of the exhaust valve that is slightly thicker than the striker protrusion from the face of the hammer. Much like the B Staley mod except for the purpose of absorbing hammer energy and preventing the striker from slamming into the rear of the exhaust valve. Or take the heavy hammer spring out. Even without the heavy hammer spring, the O-ring trick can be useful if not fully the answer. The answer is a FFH/SSG assembly.
You might try this, pull the striker fully into the hammer so that the back of the striker is flush to the face of the hammer. Install an O-ring or perhaps two on the backside of the exhaust valve that is slightly thicker than the striker protrusion from the face of the hammer. Much like the B Staley mod except for the purpose of absorbing hammer energy and preventing the striker from slamming into the rear of the exhaust valve. Or take the heavy hammer spring out. Even without the heavy hammer spring, the O-ring trick can be useful if not fully the answer. The answer is a FFH/SSG assembly.
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I have good news I got the trasnfer port to seal back in business! Just need to go get some more pellets lol
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And I still think you might get some benefit from a form of the BStaley modification as described. The machine gun brrr--rrrr--rrrpppp sound is extreme hammer bounce. You can stop the hammer from bouncing by using the O-ring trick or by using a FFH/SSG.
Another trick that may or may not be useful is to take one of those squishy ear plugs and squish it into a roll and stick it inside the hammer spring. If nothing else it will silence spring twang.
The BStaley mod uses #211 O rings stacked behind the exhaust valve as a hammer buffer. Typically three but for a partial fitting, a single O-ring can buffer the hammer just enough to stop bounce if the hammer striker is fully retracted flush. The O-ring being thicker than the striker thickness has the rim of the hammer strike the O-ring and absorb a lot of energy. If with a stock spring the hammer is not coming that far forward, then try two O-rings.
I battled hammer bounce until I finally said screw it and went down the FFH/SSG route which I am still exploring.
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When porting air passages on anything, bigger is not always better. There's a point where bigger port have less velocity, especially in small diameter ports like the .22 Marauder.
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I get the best velocity gains when porting and polishing the transfer ports by simply blending and radiusing the sharp drilled corners of the ports. High pressure air needs a smooth flow to increase velocity, so the air isn't going around a sharp 90° corner. I use a Dremel tool with small carbide ball shaped cutting bits to knock off the corner edges, to essentially create a curved pipe for the air to flow through.
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