The Power Maximo.

[Monkeydad1969]

So, a few of you know I have the Maximus Euro.  Well, as fun as it is, I was bored and curious.  It has that 26" threaded barrel, and my thought was---nice long range potential.  But the rifle is the 12fpe version, the tube is setup for a different valve retaining screw setup (more like the P-Rod valve), but it is basically a Disco.  What do you know, I have an extra Disco tube and my .22 carbine laying around.  I also bought a Cothran PowerHouse valve with the .180 exhaust.  BUT I AM EXTREMELY LAZY OR WHAT ONE WOULD CALL AN EXPERIENCED PROCRASTANATER.  But that all changed last night.  I took things apart and lego'd  2 new setups.  My .22 carbine got the Maximus complete tube, just a 1/4" vinyl tube TP.  The Maximus got the good stuff.  But before that, let me show you what a Maximus looks like on the inside.

Plastic TP---notice the difference between it and a Disco TP:





Then---the exhaust and valve differences.  Maximus valve is taller than a Disco.  Valve stems are different, and 1 o-ring instead of 2:





Gauge block is the stock Disco:


Bolt probes are the same except for finish:


Stock inlet:


I will add more to this thread.  Going to chrony...

...to be continued...

The Monkey

[Rob M]

subbed! i was hoping you connected the 2 tubes lengthwise and made a musket 4 feet long

[Machinist]

It's gonna be a BEAST!  Not too many shots, but the shots you get will have some bang.

Steve

[Monkeydad1969]

subbed! i was hoping you connected the 2 tubes lengthwise and made a musket 4 feet long

That would be crazy!

Joe

[nielsenammo]

OK Joe, you stop whining, here are your slugs for your .177 build.  13.7 grain HP with JSB 8.44 for reference. Send them out Monday.  They shoot great out of my Wolverine .177.

[Monkeydad1969]

WOOOOAAAAAAHHHHH!

GNOME-MMUNITION!

[Monkeydad1969]

Here are some groups I did today.  No tune as of yet.  Tanks are low...2300psi fills down to 1500psi.  All pertinent info is in the groups description.

Set: 21
Created: 02-18-2017 15:16:40
Description: Power Maximo .177
Notes 1: 2300-1500
Notes 2: Exact Monster Diabolo 13.43gr
Distance to Chrono (FT): 20.00
Ballistic Coefficient: 0.000
Bullet Weight (gr): 13.430
Altitude (FT): 0.0
Temp: 64 °F
BP: 29.52 inHG
Shots
#     FPS        FT-LBS     PF
12    910        24.70      12.22     
11    922        25.35      12.38     
10    929        25.74      12.48     
9     941        26.41      12.64     
8     948        26.80      12.73     
7     958        27.37      12.87     
6     963        27.66      12.93     
5     972        28.18      13.05     
4     979        28.59      13.15     
3     990        29.23      13.30     
2     992        29.35      13.32     
1     998        29.71      13.40     
Average: 958.50
StdDev: 29.03
Min: 910
Max: 998
Spread: 88
True MV: 960.68
Shots/sec: 0.06
Group Size (IN): 0.00

======================================================================================
Set: 22
Created: 02-18-2017 15:21:56
Description: Power Maximo .177
Notes 1: 2300-1500
Notes 2: Exact Beast Diabolo 16.20
Distance to Chrono (FT): 20.00
Ballistic Coefficient: 0.000
Bullet Weight (gr): 16.200
Altitude (FT): 0.0
Temp: 63 °F
BP: 29.52 inHG
Shots
#     FPS        FT-LBS     PF
12    875        27.55      14.18     
11    886        28.24      14.35     
10    893        28.69      14.47     
9     899        29.08      14.56     
8     908        29.66      14.71     
7     923        30.65      14.95     
6     925        30.78      14.99     
5     934        31.39      15.13     
4     945        32.13      15.31     
3     950        32.47      15.39     
2     959        33.09      15.54     
1     962        33.30      15.58     
Average: 921.58
StdDev: 29.40
Min: 875
Max: 962
Spread: 87
True MV: 923.68
Shots/sec: 0.07
Group Size (IN): 0.00

======================================================================================
Set: 23
Created: 02-18-2017 15:29:02
Description: Power Maximo .177
Notes 1: 2300-1500
Notes 2: H&N Piledriver 21gr
Distance to Chrono (FT): 20.00
Ballistic Coefficient: 0.000
Bullet Weight (gr): 21.000
Altitude (FT): 0.0
Temp: 63 °F
BP: 29.52 inHG
Shots
#     FPS        FT-LBS     PF
13    808        30.45      16.97     
12    817        31.13      17.16     
11    828        31.97      17.39     
10    835        32.52      17.53     
9     843        33.14      17.70     
8     851        33.77      17.87     
7     858        34.33      18.02     
6     866        34.98      18.19     
5     872        35.46      18.31     
4     880        36.12      18.48     
3     886        36.61      18.61     
2     895        37.36      18.80     
1     898        37.61      18.86     
Average: 856.69
StdDev: 29.38
Min: 808
Max: 898
Spread: 90
True MV: Infinity
Shots/sec: 0.06
Group Size (IN): 0.00

[dcorvino]

Excellent work Joe.
Looks like you built yourself a nice power house of a rifle.
Look forward to hearing more about the build.

Dave

[Monkeydad1969]

Shot this can for giggles.  Ruger 8gr HP.  Big ole hole.

[2K1TJ]

Curious about the valve differences...
Did you happen to measure the stems? Or wonder if it's the same diameter as the MRod now, making it possible to upgrade to an mrod poppet without having to sleeve?

And i wonder if you can combine the rear half of the Maximus valve with thexpected front of the Disco valve for more volume without too much trouble?

[Monkeydad1969]

No, didn't measure the stem.  But I believe you can put the bodies together.

[Machinist]

Are you really 20 feet from the chronograph? That seems kinda far.

According to Bob's calculations, it is theoretically possible to get almost 50 FPE from a .177 at 2000 psi.  I wonder if there is a choke point somewhere or if you need heavier projectiles.

Don't get me wrong, 30FPE is nothing to sneeze at.

Steve

My bad.... just read after posting, you have almost 38 FPE.  Very nice!

[Rob M]

A few years ago the record was set for fpe in 177, it was more than 50fpe But i dont recall an exact number.. It was done with eunjins and a 3 foot barrel.. on the yellow

[Machinist]

In the pic of the bolts, the Maximus probe looks like it is a larger diameter.  Are the probe diameters the same, and does the pellet get pushed past the barrel port?

Steve

[KnifeMaker]

The probe does look larger in Dia. for the Maximus.

Yes, in my stock maximus, the pellet is pushed Well past the port.

In the photo, it looks like the Maximus valve body is longer than the Disco. So no advantage in switching parts.

Never seen the plastic TP. In the .22 Max. I have, it is alu, with a red anodized finish.

I ported the valve body exhaust hole at 20 Deg forward to the port, and opened the port a little along with porting the barrel port hole. I beveled it, and elongated it. I then polished the port-hole to do away with any burs.
After mods, it went 34 fpe with 18 jsb's up from 24 fpe.

The guidance for this project was from B. Restern. Thanks Bob!

Knife

[FuzzyGrub]

When you mentioned "more like prod valve" were you only referring to the retaining screws?  or do you feel that dimensionally it is closer to prod valve, ie the port and two valve screws line up with prod valve?    It looks like it might, from the pictures. 

[anti-squirrel]

I've been thinking ".22 Maximus" but seeing this build is forcing me to re-think things.  I have a nice assortment of .177 pellets on hand, from featherweight WC to those meaty Eun Jin domes nothing shoots well.

Too many choices, not enough monies.

[rsterne]

i wonder if you can combine the rear half of the Maximus valve with thexpected front of the Disco valve for more volume without too much trouble?

No, the groove to clear the front trigger screw would then be in the wrong location....

Bob

[Monkeydad1969]

When you mentioned "more like prod valve" were you only referring to the retaining screws?  or do you feel that dimensionally it is closer to prod valve, ie the port and two valve screws line up with prod valve?    It looks like it might, from the pictures.

Yes, to the retaining screws.  I don't have a P-Rod valve on hand to compare the valves.

[Monkeydad1969]

So I did some expansion tests.  Not to shabby.






Yes I know those are Red Fires---ran out of Polymags and those were handy.

Joe