The OTHER Marauder. Regulated .22 Initial Results

[n2omike]

Build:
.22 Synrod
Lane Regulator set to 130 Barr  (1885 psi)
Hill Valve
0.160 Transfer Port
MM Hammer Forged Barrel drilled to match TP
WAR TSS (stock outer spring, long inner spring...  same as the .25)
Rocker1 39.5 gram MDS Hammer

Gun is driving me crazy.  Started out with a even weaker outer hammer spring, with shorter inner and free play on both springs and a 0.144 TP.  Shot 840 fps.  Wanted to go around 880 fps, so I turned up some preload on the inner spring, and it did NOTHING. 
Okay...  Installed a 0.160" TP...  and still no change.
Okay...  Installed the stronger hammer springs, like are in the .25...  and still no change.
Okay...  Cranked up the preload on those, and still no change.

No matter what I do, it has hit a wall and won't go over 840 fps.
Every shot is within 5 fps or so, but I want that extra velocity...  and cannot figure out WHY it won't shoot any faster, no matter what I do! 

Any ideas?  It's like it's got a dang restrictor plate or something! 

Almost midnight.  I'm going to sleep on it for the night, and look at it tomorrow. 

Thanks for any input!

Mike

[Dairyboy]

Lol the wall your hitting is simply your setpoint on the reg. Took me alittle while to learn that also. Bump up the reg 100psi and I think you should hit your goal.

[rsterne]

What you are describing sounds to me what I call the "plateau velocity".... ie the max. possible with that combination of port size, pressure, and barrel length.... No matter how hard you hit the valve, you can't get any more, because the valve is open until the pellet exits the muzzle.... Adding more air after that just wastes air.... The easiest way to get more velocity is to add more pressure.... The only thing that doesn't fit is that you tried a larger transfer port and got no change.... but if your barrel port is smaller than the TP you had, that explains that.... It is also possible that for some reason your valve lift is restricted, and adding hammer strike just makes the hammer bounce off the back of the valve, without opening the valve stem further....  What pellet weight are you using, to give an idea of the FPE level at 1885 psi?....

Bob

[n2omike]

Thanks guys!

The gun is shooting 18.1 grain JSBs.  I drilled the barrel when I first got it to to match the 0.160" TP.
If anything, swapping in the larger TP and springs made the gun shoot a few FPS slower. 

I did notice that the valve spring in the 22's Hill valve was significantly stronger than the one in the 25's WAR valve...  but it seems, changing the hammer springs would have had an effect there. 

I'll try to play with it tomorrow.  Maybe bump up the regulator, and install a softer valve spring.  That, and check everything else out.

Thanks

[triggertreat]

Lol the wall your hitting is simply your setpoint on the reg. Took me alittle while to learn that also. Bump up the reg 100psi and I think you should hit your goal.

+1

[FuzzyGrub]

What is your plenum size?

As others, I suspect it is the psi/plenum size limit.  I will say, that on many reg builds using the hill valve, they all seem to get good results with the 6lb hill valve spring.   You might consider changing it while you are in there. 

[rockmike]

Our mods are very similar,I run a 26 gram MDS hammer and the hill 6lb poppet spring 1800 psi huma,.163 TP transfer port wide open.I can launch JSB 18.1's well over 950FPS if I tune to it... I shoot 18's @ 880-890 fps, MMHFB .22 is amazing,but slows the pellets down a bit....a good time was spent polishing the barrel with JB paste and I put a liberal amount of FP-10 lube on the pellets...now shoots a lil faster after the polish and lube.

My best mods where the light weight 26 gram MDS hammer and that 6lb poppet spring,gun was nice before but now its much better,very consistent.

I run the TSS stock outer spring, long inner.The tss brought more efficiency to the synrod 55 shots on reg 5 more good shots fallow then POI drops a bit.

 

[rsterne]

My 2260 HPA conversion cranks the 18 gr. JSBs out at 960 fps (37 FPE) on just 1600 psi (with efficiency > 1.4 FPE/CI).... but it has a huge plenum, I'm using the entire 2260 tube (65cc).... I would suspect your plenum volume is too small, creating a large pressure drop during the shot.... IF that is the case, either a larger plenum, or an increase in setpoint to compensate, may be necessary....

Bob

[n2omike]

The plenum on the .22 isn't much smaller than the plenum on the .25, and the .25 is attaining 53 FPE without a sweat...  so I'm not really sold on the small plenum yet.  (130 vs 155 Barr, Hill vs. WAR valve, 0.160" vs. 0.187" TP)

I DO want to change the valve spring.  The valve spring in the Hill valve (I did not plan on going regulated when I bought it) is a LOT stiffer than the WAR valve in the .25.  The WAR is very soft.  I'm not sure which rate spring was installed in the valve.  I do have some of the 'lighter' springs rated at 28 lbs, but am going to order a 6 lb spring.  The one in the .22 is AT LEAST the 28 lb unit. 

I'll be away for the next week, and will go over the gun and install the 6 lb spring sometime after coming back.  Hopefully, that will help free up some power.  Hammer weight is 39.5 grams.

What do you guys think?  Sound like a good move?  There is ZERO hammer bounce right now...  even at lower pressures as I was trying to shoot all the air out of it!  Took FOREVER!  lol  I think the valve spring is too strong.

Thanks for all previous and future input!!!

Mike

[rsterne]

That still doesn't tell me what the plenum volume is.... My reg'd 2560 gets 52 FPE with 25.4 gr. on only 1900 psi.... but again with a 65 cc Plenum.... Small plenums really limit the FPE potential.... or you have to up the setpoint to compensate....

Bob

[n2omike]

That still doesn't tell me what the plenum volume is.... My reg'd 2560 gets 52 FPE with 25.4 gr. on only 1900 psi.... but again with a 65 cc Plenum.... Small plenums really limit the FPE potential.... or you have to up the setpoint to compensate....

Bob

Sorry Bob.  I just put in the FPE, etc that I wanted, and he chose the pressures and did the sizing.  He didn't include the volume in the paper work.  Both plenums were a couple inches long or so, and the .22 unit was only around 3/8" shorter than the .25...  and it shot really hard, so I'm not really leaning toward insufficient volume.  When I do take it apart, I'll use my biuret and measure it. 

Here is how he chooses his pressures and plenum volumes.  It gets really technical.  But, also gives some guidelines.
https://drive.google.com/file/d/0BxDsz9IVH1pwczVuMnREb09UcWc/view

Here's one he sent me on how to adjust it.  The little ring is handy for retrieving the unit.  Too bad I forgot to install it.  lol
https://drive.google.com/file/d/0BxDsz9IVH1pwSGY5ZzhBdjFLeTg/view

[AlanMcD]

If you want a quick check on seeing if the lighter valve spring will do anything for you, you could throw the stock hammer back in and whack the valve good and hard with stiff springs in it.  If you don't get any more power out of the gun that way, you probably won't gain anything from a lighter valve spring . . .

[ackuric]

First and foremost, did you check for any leakage / air loss around the TP? You can easily lose 50-100+ fps if that area isn't sealed well. Can't believe no one mentioned this simple possibility! (I sure hope its just this tbh)

The .25 cal lane regulator plenum is approximately 18 CC's, I would guess your .22 cal is around 12-15 cc's, but that is a long shot.

I would suggest bumping up reg pressure as others have said around 100 psi if you find no other faults with the rifle.

1950-2k set point is pretty standard on a 19.45" barrel, the other guys commenting on making great power with less psi are using HUGE plenums and a 24" barrel, so don't let that insult your current #'s...

Your recommended plenum size for 30 FPE @ around a 1800-1900 set point is...18-19 CC's!

If you're @ 12-15 cc with plenum and the hill valve SHOULD have at least 4-5 cc's, that means your plenum size is fine...you should be running 29/31 FPE with 1800-1900 psi of air. Your ports are plenty big.

As you noticed, when you stop seeing increase in velocity regardless of spring / hammer weight, that means you hit the plateau for that current pressure/barrel/port arrangement. You either need to find any major air losses or increase set point/plenum although 1850/18cc should make 30 fpe all day on the mrod.

[n2omike]

Our mods are very similar,I run a 26 gram MDS hammer and the hill 6lb poppet spring 1800 psi huma,.163 TP transfer port wide open.I can launch JSB 18.1's well over 950FPS if I tune to it... I shoot 18's @ 880-890 fps, MMHFB .22 is amazing,but slows the pellets down a bit....a good time was spent polishing the barrel with JB paste and I put a liberal amount of FP-10 lube on the pellets...now shoots a lil faster after the polish and lube.

My best mods where the light weight 26 gram MDS hammer and that 6lb poppet spring,gun was nice before but now its much better,very consistent.

I run the TSS stock outer spring, long inner.The tss brought more efficiency to the synrod 55 shots on reg 5 more good shots fallow then POI drops a bit.

Nice!  What is the plenum size on your gun? 

Thanks!

[triggertreat]

The Hill valve with the Hill 6lb spring has a plenum space of 4.5cc total based on my water test.

[n2omike]

I took the gun all the way back down again, and adjusted the regulator for 135 Barr.  The plenum has a lot of excess aluminum and sharp edges around where the gauge screws in, so I got out the grinder and removed a LOT of aluminum, and rounded off the sharp corners.  I didn't do a fluid test, but the plenum itself, is exactly 2" long. 

I put it all together, and no matter where I adjust the inner spring on the TSS...  it shoots with the same velocity...  around 830 fps.

I guess I'm going to wait until the 6lb valve spring gets here, and try it again.  The one that's in it is advertised at 28 lbs. 

This thing has me scratching my head! 

The .25 was awesome...  3 mags of 33.95 grain JSB's at 840 fps.  (53 ft-lbs)
This one won't 'open up' no matter what I do! 

I guess we wait on the valve spring. 
Getting a lot of practice taking this thing apart!  Too much!  lol

Maybe I'll go put a heavy, stock hammer and the biggest spring I can find in it, and see what happens....

[n2omike]

Put a heavy hammer in it, adjusted to full spring pressure...  Same exact results as before.  I don't know WHAT to do with this thing!

830
823
825
828
825
822
823
826
826
824

[rsterne]

Gun doesn't by any chance have an O-ring or two sitting behind the valve.... ala Bstaley mod.... does it?.... or anything else stopping the hammer from moving further as you increase the power behind it?....

Bob

[triggertreat]

Has the poppet head mushroomed down into the valve seat causing flow restriction and less lift with said hammer energy?  What about the seals leaking at the TP and barrel?  You can let a little air out using a degas tool while placing your finger over the barrel tip.  Should be plenty of pressure on barrel exit with no air leaks audible from the seals.

[pcp_Dave]

It sounds like you may have a velocity regulator in the barrel......