Disco SSG thread

[dpittman]

Do you think there is enuff room inside the Disco fro this to work. Or is that not a concern.

[mooseslayer]

Ok...I polished my hammer and hammer tube area to a mirror finish starting 320grit up to 1500 grit. I lubed with some powdered graphite I had. I also drilled out my endcap so no possible friction for SSG there. The 3/8 nut welded on endcap is holding SSG 3/8 bolt. I also drilled and tapped my valve to 10-32 and installed high tensile screws. Then I filled to 2300psi and shot first shot with no gap so SSG basically non existent...hit 930fps with 15.9 jsb and loud. I turned SSG so small gap  and shot some shots and the turned in another half turn, refilled to 2300 and shot a string down to about 1000.
Here is that string.

1 – 758      11 – 759   21 – 758   31 – 747
2 – 747      12 – 761   22 – 755   32 – 750
3 – 749      13 – 752   23 – 756   33 – 745
4 – 754      14 – 755   24 – 757   34 – 743
5 – 753      15 – 762   25 – 758   35 – 735
6 – 756      16 – 762   26 – 759   36 – 735
7 – 755      17 – 765   27 – 758   37 – 730
8 – 759      18 – 761   28 – 755   38 – 726
9 – 761      19 – 757   29 – 753   39 – 721
10 – 759   20 – 761   30 - 756

[dpittman]

I can barely get that with double tube Disco. Is your single tube. Those are awesome results. Imagine the shot string with SSG and double tube. My son could shoot all day.

[mooseslayer]

yes. single tube

[Dairyboy]

That's 36 shots under a 4% ES that's very good results.

[dpittman]

Anyone ever drill out Disco hammer. I am assuming it is very hard. Want to drill thru for an SSG attempt. Would that remove too much weight and render the ssg useless.

[Buldawg76]

dpittman
You can buy a crosman challenger hammer assy for 21.76 plus 4 bucks shipping from them that already has the hole for the stroke adjustment screw in it and then just drill out that hole and install the spring guide rod SSG adjustment screw and away you go. Just call them buy phone to get flat rate 4 buck shipping regardless of order size or cost.

The hammer is hardened on the surface and you will wear out several drill bits before you get it drilled out or end mills if you are going to use a mill. for 26 bucks it much easier to buy the Challenger/prod hammer and be done with it.

Mike

[dpittman]

Thanks Mike. Good to know. I was thinking same.

[Buldawg76]

dpittman
Not a problem

Mike

[ped]

it's fairly easy to drill a crosman hammer
all you need to do is remove the case hardening with a carbide rotary bit then it can be drilled or machined(remember to do both ends if drilling)

[Buldawg76]

That's true but not everyone has a grinder or carbide dremel tool bit plus I believe the challenger/prod hammer is a bit heavier than the stock 22xx/13xx hammer is so it will have more inertia.

Mike

[moorepower]

Can't it be heated up cherry red and air cooled to drill?

[Buldawg76]

Yea you could heat it cherry red but then you loose all temper in the metal and it could distort some as well so it would not be the exact same dimensions as before possibly. it would be better to oil cool it if you do it that way to retain some of the temper.

 

[ped]

it's made from low grade steel so to re harden you would have to use kasenite or similar
the carbide burrs are a few quid
just to see I took a stock disco hammer and drilled it m5 and a 8mm counter bore to sink the head of a m5 bolt iturned down to 7.5 mm
took about 15 mins to do

[Rivers3Plinker]

Anyone ever drill out Disco hammer. I am assuming it is very hard. Want to drill thru for an SSG attempt. Would that remove too much weight and render the ssg useless.

Someone else may have more information or correct me if I'm wrong but check this out.
The Prod hammer weight will work in a Discovery. This is what I'm using. You will need to clearance it at the top at the nose to clear the back breach screw. Norm at Discosrus sells these weights machined and ready to go for use with the Challenger trigger assembly for which they are required. Also required is a spacer for the trigger assembly.

That aside, the 2260 trigger in the disco might not work with a Prod hammer. I don't see how it could work actually since the sear engagement is different between the two and the Prod weight has no notch in the body. The sear is designed to engage the face of the weight with the triggers for this design.

Otherwise, as far as machining, I had a pretty easy time clearancing my prod hammer weight with a carbide end mill. I went slow and used cutting oil and it was a piece of cake. If you however take a HSS drill and try to cut this case hardened part, you will just destroy your bit.

I would want a lathe to drill a nice, straight, centered hole in that weight using a carbide tool.
As for weight difference with the SSG if you're using the design that has the SSG rod as part of the hammer weight ( internal design ) you are adding weight to it, not making it lighter.

[Buldawg76]

it's made from low grade steel so to re harden you would have to use kasenite or similar
the carbide burrs are a few quid
just to see I took a stock disco hammer and drilled it m5 and a 8mm counter bore to sink the head of a m5 bolt iturned down to 7.5 mm
took about 15 mins to do

Was that done by hand or in a mill

[ped]

in a lathe but I could have done it in a drill press nearly as easy

[Buldawg76]

Agreed that a drill press would be about as easy just not as precise as a lathe since you have much better control over speeds and feed rates in a lathe than a drill press as well as equipment tolerances.

Mike

[dpittman]

Ped, that is exactly what I want to do for an internal Disco SSG. That looks awesome. The only diff would be my bolt head would not fit inside the hammer face like yours. Great work. I was also wondering if you have to mod a challenger hammer fro how it cocks the gun. In other words does the challenger hammer drop right in or need mods.

[dpittman]

Steve, I just re-read your post and it looks like you have to have a MROD trigger for the challenger hammer to work in a Disco. Is that correct. I have the regular Disco trigger group.