I might be getting ahead of myself since I dont own an M-Rod yet but I am doing some research before that big day.

How do you tune an M-Rod? From what I have been told, the best speed for a 177 is around 885 to 915 ftps. I know this is not written in stone but a good starting point. I plan on getting a bunch of different pellets in different weights. I think I will try to push the heaviest pellets in that 885 to 915 ftps speed range. When I start working with a specific pellet, do I use the built in Port Restrictor to adjust the pellet speed? Is there anything else to adjust in the gun?

Stepping it up a notch. If I install an after market Regulator I suspect the process of tuning the M-Rod becomes harder since you have more things to adjust. I suspect you have to adjust to the Regulator to provide a consistent pressure to the face of the valve at the low end of your fill pressure. For example, the fill pressure goes up to 2800 psi and you set the Regulator to provide a consistent value pressure of 2000 psi. I would think that might limit the pellet speed to the best speed that can be attained by 2000psi. Will using a Regulator make it impossible to reach my target 885 to 915 ftps speed with heavy pellets?

Would you recommend getting a Regulator for the M-Rod 177?

How long do Regulators last before needing to be swaped out?

Im going to use the gun for Hunter Class Field Targets.

Thanks for any and all your responses!
Eric

http://ateam.alotspace.com/ateamh/A_Team_PCP_Tuning_Procedures.pdf

Also, the regulator (assuming it's reliable) actually makes things easier. They come pre-adjusted for a particular output pressure - usually anywhere from 80-bar to 130-bar. 2000 psi won't limit your pellet speed at all, should be fine. Sometimes they can last years, other times they are finicky...just comes with the territory.

If you are new to airguns and PCPs and have the time, use the linked tuning document without a reg and just give it a go.



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CASA Member - California Airgun Shooters Association: http://socasa.org

Thanks for pointing me to the article.

I read the article and the Benjamin Marauder Owners Manual.

The owners manual seems to indicate that the Hammer Spring Preload (tension) and Hammer Stroke (distance) are used to tune the gun for different fill tank pressures. The metering screw is used to tune the pellet velocity.

The article indicates that the Hammer Spring Tension and the Hammer Stroke Adapter are used to tune the pellet velocity. The Transfer Port (Marauder metering screw) to fine tune the velocity. But the article seems to indicate you adjust the Transfer Port more to make your gun efficient than to adjust the pellet speed. If the Transfer Port is not adjusted properly, you will lose speed so in essence you adjust the port to an inefficient setting to slow your pellet down. Of course this costs more air and less consistent shots in a string (I would guess).

Is each Marauder unique in how it should be tuned? It seems their should be some research that provides good setting for Marauders as a general rule. For example, I want to shoot my Marauder from 10 to 55 yards using heavy pellets. I am only interested in the guns accuracy. It would seem that, that profile is shared by most owners so a tuning solution for one would probably be good for all. That is, unless every gun performs a little different. Then the question is, how much different.

I would guess putting a regulator in a Marauder does not have an affect on the tuning mentioned above. The regulator would just make the input pressure on the Hammer Spring Preload consistent. So if I were to set the regulator to 2000 psi, I would set the Hammer Spring Preload tension and the Hammer Stroke distance to a value that works best for 2000psi. Without a regulator, I would set the Hammer Spring Preload tension and Hammer Stroke distance to a value that is a little over half the distance between the fill tank stating and ending pressure. For example if I fill to 3000psi and run it down to 2000psi I would tune the gun as if it were at a consistent 2600psi.

Do I seem to have it right?

I think you have a .22 but take a look at these settings. They give you an idea of settings and pressures to use to achieve various goals (power, shot count, quiet etc). Might give you a good starting point for hammer stroke, tension and transfer port adjustment.

As for the tuning I would follow the A-team document over the user manual.

Casey




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CASA Member - California Airgun Shooters Association: http://socasa.org

Have been using a regulator in the m-rod for about a month now ... Gun is a .22, but also have a .177 cal upper receiver conversion set as well.

Sadly with guns tune established WITHOUT REGULATION .... Adding the Reg the tune changes !!
Why ? ... because in the stock gun valve is subject too the volume and pressure of the entire air chamber. Regulated the "Downstream" volume within valve and space within gauge manifold in MUCH reduced. The Reg provides no additional air during the shot so the VOLUME of regulated air becomes paramount !!

On another site it has been greatly discussed WHAT volume is required to get the power out of a Regged Gun close to an Un-Regged gun ?
* Optimum DOWNSTREAM volume between Valve & Reg is @ 1cc per Ft-Lb of desired/design power.
More volume does little to find more, however LESS starts taking power away exponentially.

Personally have done near EVERY valve mod one can, transfer tube and barrel / bolt mods etc ...
In .22 can get to @ 32lb lbs for 23 GREAT shots with an ES of 7-8 fps ( Jsb 18.1 @ 900 FPS )
Efficiency at that power lever is fair at best.
Dead nuts accurate holding sub dime 50 yard groupings, but less shots that factory tune, yet MORE accurate. Yup a trade off indeed.

The .177 barrel is LESS efficient and shot count a few less, tho again VERY accurate being better than factory tune.

With all the reading and research about regulators, I am getting NO WHERE near the efficiency numbers some state should be there ? ... Power level I need/want likely the reason why.

Just some FYI on my state of regulation tuning at this time ....

Scott