Calling all 25 cal marauder REGULATED guns

[Dairyboy]

My gun has a leak and reg is creeping but here's my last string.  I took a couple shots to bring the regulated air down to normal pressures before starting string so no idea what starting pressure is.

01)  849.9                21)  837.4
02)  847.9                22)  849.6
03)  838.6                23)  847.6
04)  836.1                24)  848.9
05)  838.0                25)  837.0
06)  841.0                26)  842.8
07)  833.5                27)  845.3
08)  839.9                28)  832.7
09)  829.6                29)  832.6
10)  843.9                30)  853.4
11)  840.2                31)  843.2
12)  844.2                32)  841.2
13)  844.6                33)  844.3
14)  842.7                34)  846.2
15)  838.2                35)  841.5
16)  841.5                36)  844.8
17)  845.9                37)  838.9
18)  853.7                38)  838.1
19)  834.2                39)  831.6
20)  837.2                40)  828.3

That's looking great!!

[Ozarkairgunner]

My gun has a leak and reg is creeping but here's my last string.  I took a couple shots to bring the regulated air down to normal pressures before starting string so no idea what starting pressure is.

01)  849.9                21)  837.4
02)  847.9                22)  849.6
03)  838.6                23)  847.6
04)  836.1                24)  848.9
05)  838.0                25)  837.0
06)  841.0                26)  842.8
07)  833.5                27)  845.3
08)  839.9                28)  832.7
09)  829.6                29)  832.6
10)  843.9                30)  853.4
11)  840.2                31)  843.2
12)  844.2                32)  841.2
13)  844.6                33)  844.3
14)  842.7                34)  846.2
15)  838.2                35)  841.5
16)  841.5                36)  844.8
17)  845.9                37)  838.9
18)  853.7                38)  838.1
19)  834.2                39)  831.6
20)  837.2                40)  828.3

That's a great string, mind if I ask what pellet you were using

[David9862]

Sorry forgot to include some info.

JSB Kings 25.39
WAR Valve
WAR SSG with different spring for easy cocking
Huma reg without gauge port set to about 124 bar
Stock gauge block and hammer

Fill was less than 3k not sure since i had a leak and i had to take a couple shots to bring regulated pressure back down to normal.
String stopped at about 1700 psi.

Barrel drilled out to 0.1875 to match valve and transfer port.

[PBguns]

Dang that's with a stock gauge block & hammer!?!?!

Nice job David!!!!

[shorty]

Great work David!!!!

 Welcome to the club.

[shorty]

Mike,
I do believe doing some work on the bolt will make it better. The important thing to remember that it only really helps if the barrel port is .17" or greater.

Here's how I did mine:

[shorty]

Here's a few more things I did.

[shorty]

and this. Flush hammer throw and SSS.

[shorty]

I also did one other thing. Not sure if it helps with the "refilling" of the plenum but, I removed the tie off screw on the regulator.  You know, that screw that you would connect a piece of wire to so that you can pull the reg out.

I found a little trick when regging the 22 (no screw there either). To get the reg out with out pulling the valve out, all you have to do is put the degass tool in to open the valve and with your bolt closed, add shop air to muzzle of the barrel while holding your finger over the gauge port hole in the pressure tube. Popped right out for me.

[Motorhead]

I also did one other thing. Not sure if it helps with the "refilling" of the plenum but, I removed the tie off screw on the regulator.  You know, that screw that you would connect a piece of wire to so that you can pull the reg out.

I found a little trick when regging the 22 (no screw there either). To get the reg out with out pulling the valve out, all you have to do is put the degass tool in to open the valve and with your bolt closed, add shop air to muzzle of the barrel while holding your finger over the gauge port hole in the pressure tube. Popped right out for me.

That screw has a reason for being there ... FLOW DAMPER
Removing it speeds up the refill process while also INCREASING the seat impact speed.
You WILL GET far shorter life out of the seal disk and regulator that will suffer set-point creep a lot sooner than if screw was kept in place.

FYI ...

[David9862]

According to huma that screw is there to slow the flow of air into the plenum making the regulator more consistent.   There's a small groove underneath the label where i tied some fishing line to pull it out.

I think the stock gauge block is limiting my max fps to about 880 fps.  Increasing spring tensions won't raise velocity after that point.  So using an 8lb hammer spring is perfect for me right now at least until i figure out a way to open up the gauge block without a lathe or mill.

[Dairyboy]

According to huma that screw is there to slow the flow of air into the plenum making the regulator more consistent.   There's a small groove underneath the label where i tied some fishing line to pull it out.

I think the stock gauge block is limiting my max fps to about 880 fps.  Increasing spring tensions won't raise velocity after that point.  So using an 8lb hammer spring is perfect for me right now at least until i figure out a way to open up the gauge block without a lathe or mill.

Actually I believe your reg set point is what's causing you to max out there crank it up higher and should get more fps

[shorty]

Scott and David,
Thanks, for the heads up on that screw. I kind of thought it was "extra" parts and for the easy of pulling it out. Maybe that's one of the reasons for my gun having a little higher ES than others.

I am not sure about the gauge block needing to be hogged out either unless you think it's due to plenum size. Increasing that reg setting from 1800 psi to 1950/2000 psi sure should do the trick. I am not sure if you seen the pictures of the newly drilled barrel port with the shoulder pulled back vs stock. Big difference there.

I have a half-azzed  half hogged out gauge block from my .22 if you want to try it out. It ain't pretty man, and may need some TLC but should give you a little more plenum. Your more than welcome to have it.

[David9862]

I've tried the regulator set at 124, 131, 137, and 144 bar.  The difference between 124 and 144 bar was about 10 fps.  When the reg creep hit about 2400 psi, the gun shot 920 fps for 2 shots then dropped back down to 880 fps.  Figure the extra plenum volume cant hurt maybe get an extra shot or 2.  I saw a couple threads showing the newer huma reg with gauge port hitting 50 fpe at about 145 bar so i'm guessing there's more volume with that setup than the older style reg with stock gauge block and that's making a difference.  Either that or a heavier slower pellet is staying in the barrel longer making more muzzle energy.

Not sure about the barrel port picture got a link?

Thanks for the offer but i'm in no hurry to degas air tube again.

BTW hand pump tuning is a pain 

[Motorhead]

I have a half-azzed  half hogged out gauge block from my .22 if you want to try it out. It ain't pretty man, and may need some TLC but should give you a little more plenum. Your more than welcome to have it.

Done on BOTH ENDS  .... followed up with plunging a 1/2" end mill "OFF CENTER" to remove web material across from gauge mount area buys a lot more internal plenum space 

[shorty]

Acflier posted some of the pictures of the stock bolt vs modified bolt showing the difference.

http://www.gatewaytoairguns.org/GTA/index.php?topic=112722.msg1079967#msg1079967

[shorty]

Boring out that gauge block was the first time using a boring bar on the lathe (first time grinding a boring bit too). Didn't have a mill to finish it. I actually tried to off center the gauge block in the jaw to see if I can pull the webbing out with the boring bit but it looked and felt a little dangerous so I stopped and just bagged up the part.

[PBguns]

Some good posting and data today. Nice work guys!!

[rsterne]

If you want to see a really hogged out MRod gauge port.... look at Reply #42 in this thread.... http://www.gatewaytoairguns.org/GTA/index.php?topic=109718.40

Bob

[shorty]

With you guys that have done this 40/40 tune, some or most of you have mentioned that the gun has become a little more quite.

I have made absolutely no changes to the stock shroud and baffles and wanted to see if there is any correlation between doing the 40/40 mod vs straight up no reg.

I didn't do a sound comparison but, I just did a sound comparison between the 22 regulated (25fpe) vs the 25 cal 43 fpe. I used my computer using 8.1 windows and the free app for db numbers 3 to 4 ft away from the computer outside.

A hand clap at 3 ft away was 88 to 90 db for reference since I know this computer and app is bologna.

The 22 at 3ft away was 83db and the 25 at 3 ft away at 43 fpe was 86db.

Between the 2, the 22 won hands down but that 25 at almost twice the power was pretty neat to see the numbers and not bother the neighbors.

Pretty cool