Discovery receiver- here gooooo

[tinbender]

I won't talk about disassembly/ assembly as others here have covered that very well. If you have trouble please ask and I will try to help:) I'm going to try to do this without the lathe for the benefit of those who might not have one.

goals:

1- increase the length of the bolt slot 1\4" to the rear and remove material from rear of bolt to gain bolt nose clearance in breach area of receiver.

2- radius sharp cornersand polish up a bit

3- remove material from front of bolt and install 1/16 piano wire probe to push pellet clear of the transfer port in bottom of barrel. This can be seen with barrel off receiver, pellet loaded and bolt pushed in to O-ring seat. Only want to clear the port and not push it farther and make more headspace behind the pellet than needed. This is from testing done on the crosman forum and I will go with that. Will not do this until I get a chronograph to compare velocity.

4- the transfer port seal I have not decided what to try yet, suggestions welcome :) Did not find any Delrin seals for sale, this was my first thought.

Doctors appt. gotta go

Dave

[melloroadman]

Dave at this point I thank God for small hands and fingers . Keep us posted .Marvin

[Timmyj1959@yahoo.com]

Dave,, are you using a scope on your Disco.??  Tim.

[tinbender]

I was starting to think tweezers Marvin LOL

[tinbender]

Yes Tim,

Have CenterPoint 6x compact with one offset and one std.  mount and they are both on the rear of the breech. I wanted to keep the rifle as a compact hunter so that's why the short scope. The end bell is not helpping the loading at all :)

[tinbender]

Sorry folks,

Tried to squeeze in a post when there wasn't enough time. to continue:

5- slot the dreaded .050 Allen head screw before it strips:)

6- light trigger group polish and may try the lower link pivot mod.

7- power adjuster with provision for degasser screw

If there are any other suggested items please let me know and I might give it a shot.

Thanks Tinbendin' Dave

[normal]

Dave, have you made progress on your list of mods?  I made a power adjuster for my .177 Disco.  Mainly I wanted to shut it up for backyard plinking.  Works.  Main issue is that the relative calibration of the hammer and the valve springs changes a lot.  At minimum hammer tension, shots start at "pfft" and about 550 fps rising as pressure in the tank drops to 700s fps and loud by the time the gauge reaches the bottom of the green zone.  Didn't bother with degasser provision so adjuster is an allen screw.  Did the trigger with some polishing, a much lighter coil spring and lightening the main trigger spring by doing some bending.  Excellent result.

[tinbender]

Howdy Norm :)

Yes I have been working on the rifle in small bits. Can't seem to get enough time and energy at one time to be  thorough. Did not change the mousetrap spring, but did try different diameter pins in place of the safety cylinder and none at all. If there is not enough tension here it will make huge changes to the amount of gas released by the valve. Try and pull the trigger very hard and see if there is a change.

Yes the balance of striker weight/striker spring power VS valve spring power/ gas pressure can be fussy work. Too little of the first gives you valve lock until the gas pressure decreases. Too much and noise will increase, gas usage will increase and valve lock will happen at higher gas pressure. I'm not any kind of expert on this but perhaps others can provide more specific information.

Being fortunate enough to squeak 20 yards indoors to shoot I have been looking for info on co2 fill to lower the noise.

Hope you're having fun with it Norm :)

Dave

[normal]

Dave:
Yup, fun. Simple mechanisms entertain me no end.
More specifically, with the adjuster applying no pressure to the hammer spring, I get at least 50 550-600 fps shots as the pressure drops from 2000 to 1500 psi with the noise level remaining very low. Muzzle report is less than the thwack in my steel bullet trap. Very nice for indoors. I made my adapter so the stock hammer spring sits just at its natural length with the adjuster all the way out.
Attempting to attach picture with sketch of what I did.

Norm

[tinbender]

I'm going to save that drawing Norm,

Adjuster looks good. I had a little differ ant approach in mind, perhaps a picture will come along latter. One other thing you might want to play with is a dual spring one inside the other. With different lengths and spring rates the possible combinations are mind boggling :)

Dave