My walk in the dark side... .25 cal Disco

[Matt15]

So I have been working on this project since September and I finally have it all together. I still need to paint the stock.

I used an Mrod .25 cal barrel that is 20" long. It was about 3 inches short from the end of the disco tube so I used a a .5 ID PVC pipe to "extend" the barrel.

Here is how the valve is modified.  http://www.network54.com/Forum/275684/thread/1473104144/last-1473123760/View+Thread

I have the 2600 psi screws from Magnum air power and his valve extension that eliminates the gauge block.   http://onlinestore.magnumairpower.com/products/extended-valve-cap-for-discovery-maximus-2260

I drilled the extension out to 3/8" from the front and back just before the grove for the trigger group screw. I drilled that section out to 5/16".

I shot a string over the chrony. I screwed the hammer spring in to coil bind and then backed it out 1 full turn. Here is what I got:

2600 psi fill with 25.4 grain JSB pellets.

   FPS       
1) 849
2) 851
3) 852
4) 858
5) 864
6) 864
7) 857
8( 848

8 shots at 40-42 FPE
End pressure 2000 psi
         

I am very happy with that string. I am now headed out to test accuracy at 50 yards.

[Ozarkairgunner]

That's pretty cool, how much does it weigh now? And what kind of groups do you get with it?

[Matt15]

That's pretty cool, how much does it weigh now? And what kind of groups do you get with it?

Just shot a group at 50 yards. It is about 2.5" wide and 1.5" tall. I shot it pretty fast so I think with a little practice I can get it down to 1". At 25 yards it stacks pellets.

I think it weighs around 5 pounds.

[Ozarkairgunner]

Sweet.

[Machinist]

848-864 looks good to me.  Don't know how many shots other guys get from 25 discos at that power level.  I wonder if a SSG would get another shot or 2 for you?

Nice Job
Steve

[Matt15]

848-864 looks good to me.  Don't know how many shots other guys get from 25 discos at that power level.  I wonder if a SSG would get another shot or 2 for you?

Nice Job
Steve

I plan to try an SSG in the future. Also, I will be drilling out the barrel port from .160" to .187" so that should gain me a few more FPS.

[moorepower]

I love that first string. If the ssg could gain a couple shots ...wow. Thats a nice little walking hunter. It would be fun to try a quad seal on the valve stem, and with the brass insert, it would be fairly easy.

[Matt15]

Thanks!!

What do you mean by quad seal?