M-Rod Tuning

[GadgetX]

I have read my manual several times.  From the factory M-Rod was set to Hammer Stroke full out, and the Preload was 5 turns.  The book says to increase striker CCW for more energy but it is maxed out already so I left it alone.  I tried to decrease the preload but i lost FPS.  I tried to increase to 6 turns (max) with no change in FPS after about 5 1/4 turns.  So I am guessing that I need to adjust metering screw if I want more energy.  Anyone know what the default for the metering screw is?  Can anyone direct me to the M-Rod tuning basics 101?

I have used 300 pellets already.  So I ordered 2800 more pellets today.  PCP is a lot of fun.  And of course there is no cost involved...   

Mike

[Motorhead]

This should help

[GadgetX]

THANKS !!  So do folks tell what settings work best for FPE?  I know every AG is different, but got to be a good starting point .  I am using JSB Exacts pellets, which most folks said work best for .25 MROD.

Mike

[Motorhead]

THANKS !!  So do folks tell what settings work best for FPE?  I know every AG is different, but got to be a good starting point .  I am using JSB Exacts pellets, which most folks said work best for .25 MROD.

Mike

Not a .25 cal user ... Hang tough for someone who is  or just use the sites SEARCH and use "M-rod .25cal Tuning" as a search criteria. ( or mix the words around )

[PakProtector]

hey-Hey!!!,
For the 25 cal, open the metering screw all the way. The passages are just not all that big. Put the travel about 3 turns CW from max and dial up preload. I assume you're looking for a two clip tune at 42-44 FPE. You're heading for a velocity of 840-850 from the first shot at a 3k fill. Velocity should increase to 860-870 and then back down to where you started from.
cheers,
Douglas

[GadgetX]

hey-Hey!!!,

Thank you !!


Mike

BTW - what is travel?

[PakProtector]

BTW - what is travel?

Hammer travel. Maximum is with the 1/8" allen screw at full CCW...so CCW 'til it stops and 3 turns CW.
cheers,
Douglas

[GadgetX]

Thank you sir.  Which way does the metering screw bottom.  CW or CCW?

I just noticed it is CW.  Sorry for the post.

Mike

[GadgetX]

This is exciting !!

Ok Metering Screw is at 4 turns.  Pre-load is at 5 1/2 turns. 

Why do we set stroke at 3 turns, when max is 0 Turns?

Mike

[Motorhead]

This is exciting !!

Ok Metering Screw is at 4 turns.  Pre-load is at 5 1/2 turns. 

Why do we set stroke at 3 turns, when max is 0 Turns?

Mike

Because we WISH to have guns tune more self regulating having a close velocity spread over enough shots to make POI consistent for a couple magazines.

Now if you just want MAXIMUM POWER and don't care about velocity consistency or air usage ? .... YUP full hammer travel, Max spring preload and a wide open port restriction setting 

[GadgetX]

But will it kill a BIG beaver?

Thanks I appreciate everyone on the this forum!!   At MAX power, how many shot full out?  What FPS can I expect?  Way cool !!

Mike

[Motorhead]

But will it kill a BIG beaver?

Thanks I appreciate everyone on the this forum!!   At MAX power, how many shot full out?  What FPS can I expect?  Way cool !!

Mike

Hit him in the azz or gut shoot em ... NO !!

[Bill G]

Wide open you can get 925-930fpe but they are all down hill from there.  When my rifle was all factory excluding the 10# spring and the B-staley tune method, I had a nice tune of 915-925 over 10 shots with JSB's.  Thats about 48 fpe.  If thats all I can get with factory parts and a upgraded spring, then I'd rather have the 6 extra shots over the 4-6 extra fpe.  Keep the range inside 30-40yrds and bust'em in the noggin.  I don't think that will be a problem at all. 

Bill

[GadgetX]

Thanks Bill !!

I think 850 - 900 FPS is plenty.  Going to find the best tune which maximizes the number of shots in that range.

The highest FPS so far with spring stoke (SS) at 0, pre-load (PL) at 5, meter screw (MS)at 3 (the way it came) was 832 fps at 2250 psi.

I'll get the chrony out and check the current settings at ss=0, pl=5, ms=4  this morning.

Mike

[PakProtector]

I think you'll do better with more preload. The A-team tuning guide makes mention of hammer bounce air wasting at low preload, and I have found similar. So I reduce travel 3-4 turns CW and dial up preload to get velocity I seek. It turned out this was enough to make installation of an HDD un-necessary; shot count did not go up, and it still gave me all the issues like difficult mag removal and grind-on-cocking they're famous( infamous? ) for.

At the 42-44 FPE level, 30-40 yards and noggin shots, the rifle is more than enough for yotes; beaver should pose no issue with a carful shot to their computer.
cheers,
Douglas

[GadgetX]

Do you have a link to the A-team tuning guide?   I have seen reference to it but all links are broken that I have tried.

Thanks,

Mike

[CitySniper]

This should help

In the picture The stroke adjustment is incorrect. (it should show counter-clockwise for hammer stroke MAX length

[rsterne]

Yeah, totally BACKWARDS on the hammer stroke on that diagram.... MAX is fully CCW until it stops turning.... I personally don't see why you would use anything else, and just adjust the hammer strike with the preload if you are going for anything other than a very mild, low pressure tune where you can't dial it down enough with just the preload.... However, I don't have an MRod, just lots of other PCPs, where I have found reducing the stroke redundant.... IMO the stroke adjustment on the MRod was to allow the gun to be tuned for low pressure (eg. 2000 psi) fills....

Bob

[Motorhead]

Funny ... That DIAGRAM is from Benjamin itself best I know 

Never really payed much attention being I knew what screws do what turned which ever way .... OUPS !!!

Good catch 

[ezman604]

Here it is...