Regulated M-Rod F & T Questions

[WNYBill]

I got this rifle used and have all the owners manuals. Couldn't be happier, shoot lights out. Nothing in the Owners Manual about the regulator, but there is a R in the model number. What is it set at and how many shots should I get? The meter has a GREEN area, should I refile when the needle goes out of the GREEN?

Manual leaves something to be desired. How much trouble to reduce the first stage to nearly 0 and lighten the 2nd stage.

Bill

 

[SqrlHntr]

Congrats on the rifle! What caliber are you shooting? My .177 FT in original form was getting about 70 shots around 870 fps, 10.5 gr pellets. The factory regulator is not supposed to be adjustable. It sits smack on the valve face with little or no plenum space, wedged against the gauge block. Only one marking on it and zero indication of setpoint. Hammer spring and striker throw can be adjusted, although my findings were the factory tune was best with the factory regulator. Trigger group is ealsily adjusted via the hex screws, link below for pics, theres also a lawyer spring that can be removed, clipped and retuned as a spacer. Fill pressures on marauder gauge are approximate at best so always confirm with your fill source, but the red line is 3000 and the yellow is 1000, mine was needing a refill at about 1300 psi. Hope it helps and happy shooting! 
https://www.airgunnation.com/topic/gen-2-marauder-25-setting-trigger-back-to-factory/#post-1162385

 

[WNYBill]

So, you are saying your regulator must be set a 1300psi if that is when you have to recharge. How do you know that? I find nothing in the owners manual about when to recharge. Maybe I don't understand what the regulator does. I thought it regulated the pressure so it was the same from shot to shot and your velocity would be constant. And at a certain level, your is 1300psi, it would start to drop and your velocity would start to decrease. Do I have that about right? Seems like you would refill when the pressure get down to the regulated pressure. .How do I find what mine is regulated at?

Bill

 

[SqrlHntr]

You are thinking correctly. Shooting over a chronograph, shot velocity on mine was starting dropping about 1300 psi so thats about where i figured the set point must be using 10.5 gr pellets and thats where I refilled. Much past 1200 and poi was dropping. Shot count also varies with pellet weight. The regulator from Crosman is not supposed to be user adjustable nor does it have marks to indicate any set point. Since theres no documentation, chrony numbers are your best bet and look for the drop in velocity. Its not like a Huma regulator thats easily adjusted or tested and has a bigger plenum. This one acts more like a restrictor. I made minor adjustments to the hammer spring to fine tune for a specific pellet with good results. On any marauder, some dry lube the hammer area and deburr/polishing the tube slots and hammer area will help reduce friction for a more consistent hammer strike. Compared to a normal marauder there is not much a factory regulated model needs or can be done in terms of the tuning without a regulator swap. Crosman did a pretty good job IMO setting up the gun’s tune. BUT all the factory settings are basically maxed out so again theres not much room for adjustment anyhow with the factory regulator.

If mine were still all factory, it would be sitting at the factory tune and I would be filling it to 3000 and shooting down to about 1300 psi or so before refilling. It was really a grab n shoot rifle out of the box good enough for FT competition without touching it.
Note: Remember that when searching and reading about marauder tuning the regulated model is different, majority of the marauder info out there is for stock versions and even may discuss or include a regulated tune but most likely not the Crosman installed one.

 

[WNYBill]

Tha makes sense, thank you. Yours is a 17 cal, would there be a difference for 22 cal?

Bill

 

[SqrlHntr]

Welcome! Besides the caliber specific parts, like bolt, breech o-ring, the transfer port may be larger on the 22, id have have to check, i have one in .22, havent shot it, but you are giving me a good reason to. The hammer, springs, striker and valve are the same though. The hammer, striker and velocity screw settings may be different, be sure to record your current settings if you tinker. The hammer adj has been known to come out of adjustment some after some longer use, just physics. If it does happen, readjust to the number of turns to what you recorded. Also best to make any hammer adjustments while the hammer is cocked. One more thing to mention about marauders, the shroud tension is important, if its shooting really well, I mark a matched point on the breech and the shroud for reference. Some like a tighter shroud actually touching the breech, some like finger tight, others like a slight gap even, each is kinda unique. Happy shooting!