Modding the 1077 :) .

[DavidS]

I am going to order a Crosman 1077 and do some power mods to it, then convert it to HPA.
Decided to do this for now as I am with out enough money to get an FD-PCP for a while.

This thread will be kept up to date with the progress on this project.

The mods list (this list will grow):

• 1:  [WIP] Order a Crosman 1077.
• 2:  [TODO] Clean and oil my new Crosman 1077.
• 3:  [TODO] Shoot a few clips, enough to get a good baseline .
• 4:  [TODO] Recrown barrel.
• 5:  [TODO] Stableize the barrel.
• 6:  [TODO] Shoot a bit to see how it is doing .
• 7:  [TODO] Add mass to the hammer.
• 8:  [TODO] Lighten the trigger spring.
• 9:  [TODO] Smooth Flashing on the magizine to clip contact areas.
• 10: [TODO] Shoot a bunch to see where it stands
• 11: [TODO] In valve: Polish the front bolt, seating area, and rear pin.
• 12: [TODO] Install O-Ring on plunger in Detent Body (black on front of valve body).
• 13: [TODO] Install a stronger spring in the Detent Body.
• 14: [TODO] Shoot shoot shoot, see where we are
• 15: [TODO] Make a custom valve housing to allow for greater internal volume, thus alowing for greater power.
• 16: [TODO] Make and add tube plugs for tube bulking.
• 17: [TODO] Add a fill niple in the new end plug.
• 18: [TODO] Shoot for a good while to see how she is doing.
• 19: [TODO] .. More power modes to be inserted, as determioned. ..
• 20: [TODO] Shoot for a few, shoot some more and enjoy seeing where she sits .
• 21: [TODO] Tube bulk Air with 1200PSI, and a regulator bringing it to 850PSI before the valve front.
• 22: [TODO] Shoot till the crows chase the cows home
• 23: [TODO][IF NEEDED] Reverse back to CO2 bulk if and only if it does not do well on HPA
• 24: [TODO] Shoot, shoot, shoot, shoot, and shoot a bit more .

And I may spend a little time shooting mine .

[tkerrigan]

I tried using hpa using a Powermax-Hypac tube and never got over 300fps no matter what pressure. Bulk filled with CO2 and shoots at about 625fps.  Regards, Tom

[DavidS]

I tried using hpa using a Powermax-Hypac tube and never got over 300fps no matter what pressure. Bulk filled with CO2 and shoots at about 625fps.  Regards, Tom

Did you increase the effecteve valve volume, with mods to dump the added volume?

the valve pressure in my 2289 at 12 pumps is only about 1050PSI.

[DavidS]

I tried using hpa using a Powermax-Hypac tube and never got over 300fps no matter what pressure. Bulk filled with CO2 and shoots at about 625fps.  Regards, Tom

I will likely go CO2 bulk first and then experiment with HPA in a reversable fashion.

[Yarp]

The 20 bucks off a hundo for Crosman products at Amazon has me looking at the 1077 as well.
It will be very interesting to follow your mods.

[DavidS]

Well I have some time today to take care of the first step:
[WIP] Order a Crosman 1077.

I will look in all of the local stores again, and if I can get one localy do so, otherwise I will order one from walmart, as a ship to store item.

Then we will be able to have some fun.

Also I am going to add a couple of items to the list today.

[tkerrigan]

I tried using hpa using a Powermax-Hypac tube and never got over 300fps no matter what pressure. Bulk filled with CO2 and shoots at about 625fps.  Regards, Tom

Did you increase the effecteve valve volume, with mods to dump the added volume?

the valve pressure in my 2289 at 12 pumps is only about 1050PSI.

I just tried the air, didn't go into the gun at all.  Regards, Tom

[DavidS]

I have not found one localy yet.   Will be checking Cabelas and go from there.   I realy want to find a Crosman 1077 that I do not have to wait for shipping.

The solution, to a few problems:
It is easy enough to make a better valve housing, that will fit in place and have greater internal volume.   Thus I added this to the list.

With a greater internal valve volume it should be possible to get a decent level of power out of 850PSI Air .   And no worry about damage as 850PSI is a good lower than CO2 in the spring or summer.

[BillK]

You probably have already checked out these sites on the 1077 but, here ya go:
http://www.network54.com/Forum/246966/
http://airgunner.org/?p=538
http://www.airgunhome.com/agforum/viewtopic.php?t=176
http://www.network54.com/Forum/246966/thread/1129215586/Acuraccy+modification+and+its+very+cheap
HPA Sports sells a nice barrel stabilizer. 
GMAC also has parts.
http://www.gmaccustomparts.com/epages/BT3197.sf/en_GB/?ObjectPath=/Shops/BT3197/Categories/%22All%20Crosman_1077%22
Have fun....

[DavidS]

Well the Crosman 1077 is ordered, though it is going to be a while.   I will likely pick it up next time I go to town in 4 or 5 weeks, already spent to much gasoline for now.

I did grab another Daisy 880 while running around.  what can I say I have fallen in love with the Daisy Powerline MSP's.  Still need to get a Daisy 953, though enough OT.