Tuning Pair of Marauders - HDD and dialing down power.

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5thumbs

5thumbs

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Aug 3, 2019
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I have a pair of Marauders. I've been trying to weed through a decade of post to find a decent source of information.

Marauder 1. Gen 1 from initial production. Still has factory settings and I would like to dial down the power, perhaps change some of the o-rings and install an HDD. My objective with the HDD is more to keep the rifle as quiet as possible as opposed to getting more shots.

Marauder 2. .177 Gen 2 and regulated from Crosman custom shop. Want to keep the power that came from the factory, but want to install an HDD. Again, primary objective is to keep the rifle as quiet as possible.

I know much of this information is available and I've been weeding through it and some seems to be contradictory.

Recommended HDD

Opinion of HDD on regulated Marauder. Effectivness

Tutorial on tuning (reducing power) and swapping o-rings on the Gen 1 rifle.

Thanks in advance. I'm also looking into perhaps having a tuner do the Gen 1 Marauder but figure it is worth a try to see if I can do it.



Regards,

5thumbs
 
5thumbs,

I'm not too familiar with the regulated Gen 2 version, so someone else might be able to chime in on that one. 

For the Gen 1 Marauder, this is what i would do, if it hasn't been touched, and the factory settings are on the gun now.

First, before tinkering with anything, record all the factory settings in a notebook. This way, if whatever you decide to do doesn't work out, at least you can put it back where it was.

Put an Allen key in the hammer stroke adjustment, i believe that it's a 1/8" key. Back the screw counterclockwise, counting the amount of turns, and fractions of turns, until it stops. Record your results. 

Put an Allen key in the hammer spring adjustment, i believe that is 1/4". Do the same procedure as above.

When I went to get lower power from my Gen 1 Marauder, I used a Hill valve, Hill transfer port, and Hill hammer. 

Now, you have to remember, the Hill hammer is not adjustable, and the Hill valve does not have the valve metering screw at all....it doesn't exist. Some people do not like that, but if you are looking at lower power, it's the way to go. I look at it in the way that it's 2 more adjustments that I don't have to worry about adjusting, or going out of adjustment themselves. Now in order to tune it for lower power, I would go to a good hardware store that has a wide array of springs. Bring the original hammer spring, and the valve spring of whatever valve you decide to go with. Get a bunch of springs lighter than the hammer spring.

If you are going to go with the Hill valve, take that spring, and get a bunch of springs heavier than the Hill, you won't need lighter, because it's pretty light in the first place. 

If you are going to use the original factory valve, get all springs you can that are lighter than the factory hammer, no need to get a stiffer one, because the factory one is pretty strong, and you won't be needing a spring heavier than that.

If you go with all Hill stuff, all adjustments are done with the valve spring, and the hammer spring. You may, but not necessarily have to swap to your original hammer as well.

If you would like to see a complete rebuild using Hill parts, here's a video that I did a while back on mine.

https://youtu.be/60JdCRPTIlg

Hope this helps,

Tom Holland 

Field Target Tech 


 
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Take Tom's advice. He lead me through installing a regulator in my Marauder Gen II, new springs from hill, and a new transfer port. Through some extensive tuning, I tuned the power down to about 22FPE and got the shot count up to 55 before it fell off the regulator. Now, I just fill 5 magazines, shoot, and refill.

I think the important part is to install the regulator, then buy the Hill parts so you can rebalance the springs with the regulator and do a completely unique setup. The factory springs are designed to give performance in about a 1000 PSI range. With a regulator you can get springs that work well at a single pressure. In my case, it's about 1800 PSI. Makes tuning easier.

Good luck, I sure like the consistency my gun now has.

If I remember, I installed:

  • Regulator
  • Lighter hill hammer spring
  • Hill Transfer Port (basically it's a wide open plastic tube)
  • Hill hammer, though I kept the Crosman Striker

Then I burned through tons of air while tuning. To save a couple bucks, I bought Crosman Premier Hollow Points from Walmart for about $6.50 per 500. Then just figured out what the speed difference between the Crosnam and the JSB 15.89 grain pellets. The Crosman pellets were 1/3 the cost of the JSB's and since accuracy didn't matter, worked great.

Also, Crosman punches the holes in the air tube for the trigger, screws and the rest. Take some time and some 1000 or 2000 grit sand paper and polish the barrel. The burrs from the punches will tear up any new o-rings you try to install. No fun.

Expect take time, lots of air and have fun doing it. I sure did!


 
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The B Staley o-ring stack mod reduces velocity and adds a cheap but effective HDD to a bone stock gun for both of your cases if you want to try it and safe a lot of money. May be worth giving it a try before deciding to spend more money in case you can possibly be content with such a simple and cheap quick DIY mod. Who knows?

After this simple mod you can follow TOM HOLLAND's suggestions if you decide to go all-in. Just mentioning this cheap option because though Hill's parts are first rate, it gets rather expensive when they all add up.

Their regulator is only $71.98 and that's pretty darn cheap for a regulator and would be worth looking into (not replacing your other regulator though its for your other unregulated gun) plus the B Staley o-ring mod could be enough.

https://hillairgun.com/product/regulator-for-your-benjamin-marauder-rifle-or-armada-rifle-all-calibers/

You could also do a low pressure start fill tune (unregulated) 2400-2500psi as-is too since you want lower power anyway you should get a decent amount of shots especially when done with the B Staley o- ring mod.

Reason I mention this is another rifle such as an AA S400/410 (preowned of course possibly even a later transitional side lever model) for example could be cheaper in the end even with a HUMA regulator and aftermarket LDC installed. The Marauders do have better triggers and are inherently more quieter as-is tthough. OR a preowned Daystate Regal XL in the $700 range unregulated or $800-ish regulated whether factory regulated or added on/in DIY.

Coming from a 22 Benjamin Armada $1250+ investment here and thinking back what I could have bought instead thats all...

Recently bought a RAW HM1000X chassis edition en route and the $1250+ Armada kinda haunts me now... 
 
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I have a Gen 1 .22 Marauder. I wanted reasonable power and a lot of fills from a SCUBA tank. So after some research I set my transfer port to two turns, the hammer spring preload to 3 turns and the hammer stroke to 6 turns. Filling to 2500 psi I get about 40 shots at 720 fps with Crosman CPHP 14.3 pellets. This gives me 16+ fps. Plenty for any squirrel that I can hit at the ranges that shoot.
 
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5thumbs,

If you go with the stock OEM parts, and modify them, that will get you to your goal as well.

I personally don't use the B Staley oring mod, after some length of time you will get velocity changes, usually higher, as the o rings get squished and wear out over time. I've tried several anti bounce devices, and were not too happy with them.

What I did find, is, if you use a hammer spring that is too short, but powerful enough to send the hammer to the valve, you can eliminate hammer bounce. This serves 2 purposes. 

Again, save all original springs, so you can always go back to where it was. 

The hammer has a recess in it, that holds the hammer spring. What you want to do, is cut a spring down, so when all the parts are together in the tube, there is about a half inch of play, with everything at rest. So before you cock the bolt, and you shake the tube, you'll hear the hammer sloshing around. 

When the gun is cocked, the hammer compresses the spring, and the hammer catches on the trigger sear, holding the hammer back, until fired. When the hammer goes forward after the trigger is pulled, it goes and whacks the valve stem. After the hammer nails the valve stem, the pressure from the air within the valve, along with the lighter valve spring, forces the hammer to the rear. It quickly forces the hammer rearward, but being the hammer has play in it, and the strength of the hammer spring is much stiffer than the valve spring, the inertia is not enough to compress the hammer spring enough to send it forward again with any force to reopen the valve.

So, it serves as a bounce reduction device when balanced with the valve spring in that manner.

The second benefit is that, when a light valve spring is used, and you have a medium to strong hammer spring, that is left at full length, at lower pressures that are used with lower powered tunes, it may have a tendency to exhale all of the air in the gun, because the hammer spring will overpower the valve spring, holding it open. This usually happens when trying to squeak higher power from these guns. How many times do you hear of someone who can't fill their gun, unless they cock the hammer back? A lot. With a much lighter valve spring, the above scenarios are a possibility, but with a shortened hammer spring, giving the hammer zero preload, this will never happen.

You just need to polish up the inside of the tube, where the hammer travels, along with the hammer. The pluses are springs are cheap, so get a lot for testing, you'll be cutting, swapping and mixing them for this project. The above would apply to either valve, and either hammer, or any combination of those parts.

Keep us posted, 

Tom Holland 

Field Target Tech 


 
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