MRod has new Huma reg - now what?

[GoneShootn]

About a year ago, I bought a Huma regulator with built-in gauge port for my Gen 2 Synrod .25, and I just got around to putting it in. I also bought a Hill lightweight hammer about the same time for no good reason other than I just wanted to try a lighter hammer. I couldn't use it at that time, however, based upon the gun's state of (un-)tune, but I still have it. I know there is lots of info about people who have tuned their Marauders, but that which I saw didn't really give me the direction that I need.

When I installed the reg, I put the hammer spring to zero and then went 3 turns in. The reg came set at 150 bar, and I didn't change it. The gun was filled to 3000 psi on the bottle gauge. The Marauder gauge showed about 2300 psi. The first string I ran, using JSB 25.4 pellets, gave me an average of 795 fps with a high of 804, a low of 785, and an ES of 19 over 16 shots. The gun came off the reg about shot 5-8 in the second mag. I kept shooting for a third mag down to 762 fps. The ending pressure on the MRod gauge was about 1950 psi after the 3 mags. That's where it stands right now.

I seem to remember reading in the past that a reg needs a certain number of shots to break in, but I don't remember either how many shots or how its behavior changes as it breaks in. I would like to get 40 fpe over at least two mags, or three, with an ultimate goal of 40/40, depending upon the cost to do it. That means an avg of 845 fps or so. I would very much appreciate any suggestions as to where to go from here.

[FuzzyGrub]

To obtain the results you are looking for, you need to modify the valve or use an aftermarket valve.  At a minimum, a 0.187" exhaust and transfer port.  If using a light hammer, a lighter poppet spring should be used. 

If you don't want to do any valve mods, and still want to get to 40fpe, make sure the velocity screw is wide open, and increase reg set point until you achieve the goal.  Shot count may not be that great, but hopefully get to 24 shots. 

The gauge is reading the plenum pressure.  As you are filling the gun and still below the reg set point compare your bottle and gun gauge.  The bottle gauge is usually more accurate. 

The reg break-in cycles is usually related to a higher than expected Es, not power/tune issues. 

[GoneShootn]

To obtain the results you are looking for, you need to modify the valve or use an aftermarket valve.  At a minimum, a 0.187" exhaust and transfer port.  If using a light hammer, a lighter poppet spring should be used. 

If you don't want to do any valve mods, and still want to get to 40fpe, make sure the velocity screw is wide open, and increase reg set point until you achieve the goal.  Shot count may not be that great, but hopefully get to 24 shots. 

The gauge is reading the plenum pressure.  As you are filling the gun and still below the reg set point compare your bottle and gun gauge.  The bottle gauge is usually more accurate. 

The reg break-in cycles is usually related to a higher than expected Es, not power/tune issues.

Thanks. I'm wondering if a decent valve mod can be done if you don't have a machine shop?

[Motorhead]

To obtain the results you are looking for, you need to modify the valve or use an aftermarket valve.  At a minimum, a 0.187" exhaust and transfer port.  If using a light hammer, a lighter poppet spring should be used. 

If you don't want to do any valve mods, and still want to get to 40fpe, make sure the velocity screw is wide open, and increase reg set point until you achieve the goal.  Shot count may not be that great, but hopefully get to 24 shots. 

The gauge is reading the plenum pressure.  As you are filling the gun and still below the reg set point compare your bottle and gun gauge.  The bottle gauge is usually more accurate. 

The reg break-in cycles is usually related to a higher than expected Es, not power/tune issues.

Thanks. I'm wondering if a decent valve mod can be done if you don't have a machine shop?

Drill press with a bolted on vise ... YES
Freehand i don't recommend it

[GoneShootn]

I have that, so I'm looking for a howto for a Gen 2 valve. If you have a reference handy, I would appreciate the tip. Thanks for the help.

[HunterWhite]

Have a look at this nice post from rstern. You can decide if you are up to it. The stock valve is like $30 I think.
"https://www.gatewaytoairguns.org/GTA/index.php?topic=111416.0"
hth

[HunterWhite]

Hello motorhead, do you do valve mods? I can understand why you wouldn't because you wouldn't have a good way to test it without the whole gun.

[Bigragu]

Goneshooting, by chance did you swap out your hammer spring to match up to that hill hammer?

I bought and installed his premium kit for my 25 synrod gen two, and for a string of around 26 to 28shots I was averaging about 847 FPS, with an extreme spread of around 14 FPS, going off of memory. My McMaster gage on the rifle reads about 2100 regulated(Audrius regulator) while the gage on my Airhog tank reads approx 3100 psi. This is with 2.5 turns clockwise on the hammer spring.

SD was in the low single digits

[GoneShootn]

Have a look at this nice post from rstern. You can decide if you are up to it. The stock valve is like $30 I think.
"https://www.gatewaytoairguns.org/GTA/index.php?topic=111416.0"
hth

I think that's a bit more than opening up the exhaust and transfer ports. I think I'll leave that kind of mod to Bob and others. :-)

[GoneShootn]

Goneshooting, by chance did you swap out your hammer spring to match up to that hill hammer?

I bought and installed his premium kit for my 25 synrod gen two, and for a string of around 26 to 28shots I was averaging about 847 FPS, with an extreme spread of around 14 FPS, going off of memory. My McMaster gage on the rifle reads about 2100 regulated(Audrius regulator) while the gage on my Airhog tank reads approx 3100 psi. This is with 2.5 turns clockwise on the hammer spring.

SD was in the low single digits

With no other mods, the light hammer couldn't deliver enough energy to the valve, so Tim was kind enough to send a heavier spring, but that wasn't what I wanted, either. So I reinstalled the stock hammer and saved the Hill one for another day.

[Motorhead]

Hello motorhead, do you do valve mods? I can understand why you wouldn't because you wouldn't have a good way to test it without the whole gun.

I do ... along with all the other options of possible work & parts to get it Very efficient.
AS A COMPLETE GUN sent in ... don't do piecemeal mods however.

[Tonykarter]

Listen to that man. Do what I did.  Play with it a while, pretend that you (I) are a tuner, that you are learning something and will figure it out eventually.  Waste a ton of time and about 2000 pellets and get ever worsening results.  Still, convince yourself that you are having fun. 

Then send the whole gun to Motorhead and let him work his magic on it.  Receive it back and experience the real potential of the gun.  Accept that in the time that you have remaining on this earth that you would have never gotten anywhere close to what Scott did in only an hour or two. 

Then, following my lead, resolve to stick to shooting, maybe change out a scope or two, and, most important (for me anyway), never again misconstrue what you do with a hollow ground tool set as "tuning" a gun.

I can build a scary LS engine, but I cannot tune it.  Neither can I tune a pellet gun.  I could probably neuter that cat over there though.  Some things are better left to the experts.

[GoneShootn]

Do what I did.  Play with it a while, pretend that you (I) are a tuner, that you are learning something and will figure it out eventually.  Waste a ton of time about 2000 pellets and get results all over the place.  Still, convince yourself that you are having fun. 

Then send it to Motorhead and let him work his magic on it.  Receive it back and experience what the real potential of the gun is.  Accept that in the time that you have remaining on this earth that you would have never gotten anywhere close to what Scott did in only an hour or two. 

Then, following my lead, resolve to stick to shooting, maybe change out a scope or two, but never again misconstrue what you do with a hollow ground tool set as "tuning" a gun.

Sounds like good advice. I'm afraid, though, that good advice is only useful to people smart enough to recognize it and take it. Thanks for the effort, though. :-)

[Tonykarter]

Hey, its a journey.  Enjoy it.  It's just more torturous and long for people like me.

[FuzzyGrub]

Have a look at this nice post from rstern. You can decide if you are up to it. The stock valve is like $30 I think.
"https://www.gatewaytoairguns.org/GTA/index.php?topic=111416.0"
hth

I think that's a bit more than opening up the exhaust and transfer ports. I think I'll leave that kind of mod to Bob and others. :-)

Those two ports, along with barrel port will do the most for getting toward your goal.   Even if you just took it to 0.160" from the stock 0.140" would help.   You can get 0.187" TPs from JSAR, but would still need to do exhaust and barrel. 

[Blue]

Not exactly apples to apples but here's what I did when I put a Lane reg in my .22 Gen 2 Mrod with the Hill lightweight hammer.

The Lane reg came with a 4 mm bit and instructions to open the valve exhaust, transfer port, and barrel port.  I was able to open up the valve and barrel with my drill press but couldn't manage to TP so I ended up getting Hill's .160 transfer port (close enough).  The reg also came with a spacer for the valve spring for use with a stock hammer, since I was using a lightweight hammer I left it out.  There were other instructions for drilling out the valve's interior but I was afraid I'd mess up the poppet seat so I skipped those too.  Make sure your valve metering screw is full open, you don't want to open your ports then strangle them inadvertantly.

I tried a few different springs and ran a bunch of shots over the chrony playing around with hammer spring tension and reg setpoints and ended up finding a combination of Hill's 262 spring (I wanted a Short Stiff Spring type setup) and a reg setting of 150 bar that fit my goals.

When I changed valves later and needed to retune I went about it in a better way.

I found an unregulated string that gave me the speed/energy I was looking for and then dialed the reg in from there.  I now find it much easier to eliminate the variable of the regulator and do an old school unregulated tune for a curve then use that data to start the regulated tune.  By recording pressure along the curve when you're tuning unregulated you'll be able to see what the pressure at the "knee" of the curve is and that will be the pressure to set the reg to start.  You may need to do some fine adjusting from there but you'll start a lot closer to where you want to be than jumping around between different pressures, tensions, springs like I did at first.

There are still a lot of spring and spring tension and hammer weight and striker length and... tests during the unregulated tune but I find it easier to zero in without the regulator "getting in my way".  You can also make a change when unregulated then fill to the pressure you think you'll set the reg at and test shots to see how they are at that possible setting. This lets you test setpoints without having to disassemble, adjust the reg, then refill to test (especially painful if you only have a hand pump like I do).

Blue

[GoneShootn]

Not exactly apples to apples but here's what I did when I put a Lane reg in my .22 Gen 2 Mrod with the Hill lightweight hammer.

The Lane reg came with a 4 mm bit and instructions to open the valve exhaust, transfer port, and barrel port.  I was able to open up the valve and barrel with my drill press but couldn't manage to TP so I ended up getting Hill's .160 transfer port (close enough).  The reg also came with a spacer for the valve spring for use with a stock hammer, since I was using a lightweight hammer I left it out.  There were other instructions for drilling out the valve's interior but I was afraid I'd mess up the poppet seat so I skipped those too.  Make sure your valve metering screw is full open, you don't want to open your ports then strangle them inadvertantly.

I tried a few different springs and ran a bunch of shots over the chrony playing around with hammer spring tension and reg setpoints and ended up finding a combination of Hill's 262 spring (I wanted a Short Stiff Spring type setup) and a reg setting of 150 bar that fit my goals.

When I changed valves later and needed to retune I went about it in a better way.

I found an unregulated string that gave me the speed/energy I was looking for and then dialed the reg in from there.  I now find it much easier to eliminate the variable of the regulator and do an old school unregulated tune for a curve then use that data to start the regulated tune.  By recording pressure along the curve when you're tuning unregulated you'll be able to see what the pressure at the "knee" of the curve is and that will be the pressure to set the reg to start.  You may need to do some fine adjusting from there but you'll start a lot closer to where you want to be than jumping around between different pressures, tensions, springs like I did at first.

There are still a lot of spring and spring tension and hammer weight and striker length and... tests during the unregulated tune but I find it easier to zero in without the regulator "getting in my way".  You can also make a change when unregulated then fill to the pressure you think you'll set the reg at and test shots to see how they are at that possible setting. This lets you test setpoints without having to disassemble, adjust the reg, then refill to test (especially painful if you only have a hand pump like I do).

Blue

Thanks for the info. I take it that you didn't change the poppet spring to a lighter one, so had to have a stiffer hammer spring with the light hammer?

[GoneShootn]

I had decided that I would just buy the valve, etc., and not have to fool around with it. Since, then, however, I have changed my mind, and I think I will have a go at opening the 3 ports. If that doesn't improve things enough, or if I screw the valve up, then I will just go with the JSAR system and be done with it. So that's the plan. Today, anyway.

[Blue]

Thanks for the info. I take it that you didn't change the poppet spring to a lighter one, so had to have a stiffer hammer spring with the light hammer?

Actually I kind of did go with a "lighter" valve spring than the reg recommended.

I was supposed to install the spacer which would have added preload and thus made the valve spring stiffer.  I figured if I was supposed to use a stiffer spring with the stock hammer (heavy) then I should at least omit the spacer to start and could possibly try an even lighter valve spring if I needed to.

The "Short Stiff Spring" is a part of an efficiency based tuning process that allows a small amount of "free flight" of the hammer to reduce hammer bounce against the poppet stem.  Similar in concept to Bob Sterne's SSG.  Less complicated to make at home but less tuning range than using a SSG.

Blue

[GoneShootn]

I figure if I'm going to work on the valve, I may as well make any adjustments/changes that I might want at the same time. So here's a question:  As I said, I have a Hill hammer. It weighs in at 23 grams with the set-screw striker that comes with it. If I were to want to use this hammer, what poppet spring and hammer spring would I use? Also, where could I get these springs in various weights?