Author Topic: Modding new to me .25 SynRod Gen 2  (Read 949 times)

Norcal

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Modding new to me .25 SynRod Gen 2
« on: October 06, 2017, 08:45:50 PM »
So, haven't done anything to my new 25 SynRod G2 besides putting a Scope, Sling, and Bipod on & start killing Ground Squirrels. Am reasonably handy with tools and think I should hopefully be able to learn to maintain/mod my rifle with a little help. What I hope/plan to do mod-wise as I can afford it is to install a Huma Regulator and one of Travis's new ART/SS Valves. Initially just looking to double my shot count at around 40 FPE

Just received a MDS Hammer from Travis @ A.R.T. but received no install instructions. I assume that's because he figures 99% of folks pretty much already know their way around a Marauder but I guess I'm one of the 1% that doesn't. Have watched Travis's video on knocking down the burrs in the Air Tube Slots and using a 1" Ball Hone to get the inside nice and smooth but have some general Novice questions.

1 - What are the differences in Gen 1 and Gen 2 Marauder disassembly? I can't seem to be able to find a Gen 2 disassembly tutorial/video - are they similar enough that I can use a Gen 1 guide? Links if any would be much appreciated.

2 - When doing work like on the Hammer or Action/Trigger, is it best to degas the Air Cylinder or is that not necessary with proper caution? Is a Benjamin Degassing Tool required for the process if I need to degas?

3 - I don't have a Ball Hone yet, should I wait to install my MDS Hammer until after I've worked that area of the tube over?

Thanks in advance for helping another n00b out - wish me well on my journey down the Rabbit Hole!


  • Windsor, Kalifornistan

Alan

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Re: Modding new to me .25 SynRod Gen 2
« Reply #1 on: October 07, 2017, 03:09:52 AM »
Just to replace the hammer, you don't need to degas the Marauder. However, there are a couple of other things you might do.

First, there are after market transfer ports which are a bit larger than the stock one. If memory serves, the (new) size was (is) .162 inches. This will allow for a bit more velocity (50 to 100 fps depending on the pellet), while saving a bit or air in the process. This equates to more shots per fill, and a bit less muzzle report. And don't go crazy with velocity. If you're shooting the 25.4 grainers, about 880 to 900 is good enough. Much more than this, and the accuracy suffers.

Download the parts manual from Benjamin's site. Note that two o-rings are used on the transfer port. Order a few! While you're ordering from Crosman, buy a few breach o-rings and barrel position o-rings too as sooner or later you'll need one. Buy a set of allen wrenches if you don't have one already. Buy some silicon grease to lube the o-rings. DO NOT use and petroleum-based lube—PERIOD! Remove the scope. Remove the stock of the unloaded and uncocked gun but removing the stock bolt. Remove the barrel assembly screws (4 in total). Be careful not to lose the o-rings on the transfer port. Move the power adjustment screw the pressure tube cap all the way out. The instructions for doing so are in the downloadable manual. Remove the rear trigger screw which holds the pressure tube cap. Be careful, there still may be spring pressure pushing on it. Remover the allen-headed screw which holds the hammer in the rear of the tube. The hammer can now be removed by removing the allen-headed screw. That is the one in the slot (sort of evident which one). Clean the inside of the air tube carefully with a shop rag. The new hammer (VERY lightly lubed with silicon grease) and supplied spring can be installed, and everything put back in place in reverse order using a dab of the silicon grease on the o-rings.

I trust I haven't missed anything, but if I have, others will correct me. You'll have time too, because it will take Crosman about 10 days to get the o-rings sent to you. The silicon grease can be bought from Amazon with a large bottle that will last a lifetime, selling for less than $10. I trust you have a nice workbench to do the work on? A few shop towels? Above all, take you time.
  • Roswell, New Mexico
Alan

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Steelhead

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Re: Modding new to me .25 SynRod Gen 2
« Reply #2 on: October 07, 2017, 07:20:58 AM »
Or you could just call Mike!  :D
  • Petaluma, CA
Airforce Texan .308
Benjamin Armada .25
Benjamin Prowler .177
FX Streamline .25
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Norcal

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Re: Modding new to me .25 SynRod Gen 2
« Reply #3 on: October 07, 2017, 08:14:15 AM »
Or you could just call Mike!  :D

Who's this Mike you speaketh of?
  • Windsor, Kalifornistan

Steelhead

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Re: Modding new to me .25 SynRod Gen 2
« Reply #4 on: October 07, 2017, 05:27:26 PM »
I'll be honest...when I replied I thought I was responding to SteveO because your threads were so similar. All three of us met up a few weeks ago and worked on my Armada. Mike is one the guys here that's really good with Marauders. Not sure if he'd be into working on your gun, but you never know.

his handle is Int3man
  • Petaluma, CA
Airforce Texan .308
Benjamin Armada .25
Benjamin Prowler .177
FX Streamline .25
Air Venturi compressor

triggertreat

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Re: Modding new to me .25 SynRod Gen 2
« Reply #5 on: November 11, 2017, 10:27:56 AM »
You really don't need to hone the air tube if you are installing the MDS hammer since it removes any galling issues you have.

You do have a good plan in place with waiting a bit and installing the new SS valve from A.R.T. (Travis).  I have a prototype SS valve that I have been testing for Travis in my .25 Synrod and it is absolutely the best valve I have ever tried.  It is easy to tune a gun with it because all you have to do is adjust the hammer spring.  You don't have to use a large/heavy spring or a lot of preload on the spring either to get good power because it is a balanced valve and not a typical stock spring valve.  This makes for easy stock like cocking.  For only 40 FPE you are going to get a boat load of shots with it because it is a very efficient valve. 

I have only ran a partial string at the 40 FPE level as I prefer more power, but I got 24 shots using the heavier 34gr JSBs.  That was on a 2800 psi fill shot down to 2200 psi. The string averaged 40.82 FPE and the efficiency was a whopping 2.14 FPE/CI.  The regulator was set on 1600 PSI.  The ES (extreme spread) was 1.62% or a 12 FPS spread for the 24 shots.

If installing a regulator you will need to do your part and open up the ports/flow path to the pellet skirt like has already been mentioned previously by Alan.  Otherwise you will be chocking the valve and performance will suffer.

Pray for Travis's quick recovery as he is dealing with back surgery, but hopefully will be back in action soon to release the new A.R.T. SS balanced valve. It is definitely worth waiting for.  My gun has never shot so quietly with so much more power.  I am currently averaging 56.62 FPE for 16 shots with an ES of 1.15% (10 FPS spread) and an efficiency of 1.49 FPE/CI and it is still with easy cocking.  It is just awesome!!!
  • Nashville, TN
Romans 8:1-11

22 Synrod Unregulated. Tuned using JSB 18.13gr:
30 Shots @ 31.02 FPE Avg., 1.36% ES (12 FPS), 1.58 FPE/CI
Mods: ART TSS & MDS hammer, MMHF barrel, Stock 25 cal. Valve spring, (w/Stock .22 TP, Valve & Porting)

25 Synrod Regulated. Tuned using JSB MKIIs:
24 Shots @ 55.92 FPE Avg., 2.08% ES (18 FPS), 1.45 FPE/CI
Mods: ART SS valve, TSS & MDS hammer, Hill Gauge port, Huma reg., .220 Porting