N/A Hy-score 819

[vintageairguncollector@gm]

I bought Hy-score 819 (Diana model 10) at an estate auction. Auctioneers' picture showed no accessories, paperwork or box. Auction fever spiked and I felt buyer's remorse thinking I overpaid.

I was surprised when the airgun arrived it had an ugly brown vinyl case with 70's orange foam. The Vintage Airgun Gallery confirmed it is a factory cased set Hy-score 819 (Diana Model 10). The original receipt, manual, tools, pellets and even the 2 case keys too. Seems to shoot fine

Mine has the eccentric sleeve b/c the serial # is 32xx. Can someone explain the purpose of the eccentric sleeve to me please?

 

[marflow 777]

so, in the owner manual it tells you so i will post that
now the million dollar question when was it rebuilt and or has it been rebuilt
now i own several of these 4 to be exact but never rebuilt one but i have rebuilt 7 model 6's of different forms
if you do not know the answer you can look at the gear cover screws and the rear cap screw and if they have no marks at all there could be two things in play one it has never been opened up, two it has been opened up but by a very skilled smith
another way is the breech Oring if it is new looking it could have been change at the time of the rebuild if it looks very old and crushed and dirty you may have bought a pistol that is going to need some work
if you can see which hard into the transfer port and see small bit of debris that could well be your old front piston seal that has disintegrating
now this is just a heads up because you DO NOT want to fire this pistol with bad seals and i say seals but the front one is your concern i have never seen a rear seal with much damage at all
so you have a great pistol and again this is just a heads up for any buyer of a Model 6 and 10 Diana
old pistols have old seals and that mean you have money to spend

 

[beerthief]

so, in the owner manual it tells you so i will post that
now the million dollar question when was it rebuilt and or has it been rebuilt
now i own several of these 4 to be exact but never rebuilt one but i have rebuilt 7 model 6's of different forms
if you do not know the answer you can look at the gear cover screws and the rear cap screw and if they have no marks at all there could be two things in play one it has never been opened up, two it has been opened up but by a very skilled smith
another way is the breech Oring if it is new looking it could have been change at the time of the rebuild if it looks very old and crushed and dirty you may have bought a pistol that is going to need some work
if you can see which hard into the transfer port and see small bit of debris that could well be your old front piston seal that has disintegrating
now this is just a heads up because you DO NOT want to fire this pistol with bad seals and i say seals but the front one is your concern i have never seen a rear seal with much damage at all
so you have a great pistol and again this is just a heads up for any buyer of a Model 6 and 10 Diana
old pistols have old seals and that mean you have money to spend View attachment 512340
View attachment 512337View attachment 512338

the op said "seems to shoot fine "

 

[marflow 777]

seems to shoot fine means what they cocked it and dry fired it they heard noise and they said to themself good to go
i had a seller of a 6m say that it shot fine and i asked the normal questions and he on his own started test firing the pistol got to about 25 shots and that was it
my point as always is
if you looking to buy a Giss System gun and the seller cannot tell you when if ever it has been rebuilt then you are in the position of spennd too much money for the gun
if you can do the work yourself that is one thing but to ship a say model 10 out for service shipping two ways 30.00 to 50.00 service plus parts 120.00 to 140.00
now the model 10 pistol is one i have not done and from all the reading i have seen it is hard not the resealing it but as with the model 75 you have to take so much apart to get the pistol apart and it falls into the old story
do not take the clock apart unless you can put it back together and in this case the clock is the model 10 pistol
you break a part loose a part you could be done before you start

ads for gun are a mix of fact and fantasy and the gun in your hand and how it works is reality and see we live in reality buyer beware

 

[Compressorguy]

Congrats on your new pistol! That looks like a really fine specimen! I have the twin to it as well. Really good shooter. Not sure how many times you’ve shot it but you should know within a dozen of so shots if the seals are good or going. I’ve seen this several times with these with failing seals. First few shots may seem good then the seal starts to disintegrate. Shoot it (with a pellet of course) into balled up paper towels and look for pieces of seal or oily grimy crumbly residue. It should also chrono at @ 400 to 450fps. This is what total breakdown of the seal looks like (like it dissolved/melted) or some times break into tiny crumbly pieces. Rest of the seal goo was stuck down in the compression tube by the breech end.

Rear cap disc (actually a shim to set preload) and new green buffer disc, new rear dummy piston seal and new compression seal, crumbled leftovers of old seal. (They usually either crumble or turn to goo)

 

[marflow 777]

for those who care about the rear cap filler
as us that have been inside these know the hardest part can be getting the rear cap screw to line back up
they make three different sizes of filler 2.0-2.5-3.0 mm but if you are do just one rebuild you will not have all three
so, i went to using Teflon sheet goods in .3mm and .5mm can cut circle with scissors
now with those two sizes i can come up with any thickness i want
i had a hot chocolate plastic top and it is .6mm, i will put in 5 pieces in as filler to test and if too much, 4 will be used and that is 2.4mm and this for testing
now i will take the Teflon pieces and build up the filler
so say the 2.5 will close but the 3.0 will not make the filler 2.8 and it should be hard to turn the cap to position but also that it gets there filler has been made

so, why is this important
the filler pushes the stepped washer tight against the tube and at that point there is no pressure on the gears you are in a neutral position

it is what i do and i have many part the average guy would not have because i am a Diana model 6 hoarder
and it is an idea no more no less

 

[Compressorguy]

“Can someone explain the purpose of the eccentric sleeve to me please?”

Rotating the eccentric would apply more downward force to the top web of the thumb and index finger for tighter fit of the hand to the grip.

In later models this eccentric feature was done away with and the sleeve became cylindrical and non adjustable. It’s an easy way to distinguish the two. Also, the “early” models have no provision for an under barrel weight (no screw holes)

 

[jccams]

“Can someone explain the purpose of the eccentric sleeve to me please?”

In later models this eccentric feature was done away with and the sleeve became cylindrical. It’s an easy way to distinguish the two. Also, the “older” models have no provision for an under barrel weight (no screw holes)

Are you referring to the barrel sleeve? If so, it is there to protect your hand from the sharp front sight when cocking.

 

[Compressorguy]

This is the eccentric sleeve the OP and I am referring to. On later models it is cylindrical.

 

[Compressorguy]

OP be sure to look under the foam (if) it will lift up for any hidden goodies. That’s where I found the extra sight blade in its original wrapper. Also found a homemade aluminum cleaning rod. Alas, no case keys though.


Congrats again on a great find!