GTA
Gateway To Product Reviews => Air Gun Mods and Tunes => : speedturtle April 14, 2009, 06:05:25 AM
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Here is the result of my home tuned G-1 Extreme using all original parts. 10 yards indoors and elbows resting on table.
Speedturtle :)
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Looks very very good.
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Just swapped the GRT-III trigger on my G-1 and whoaa!!! much much much predictable trigger release! With the original trigger it would take me more than 15 seconds to set up my shots but with the GRT-III it's just a matter of keeping the cross-hairs on the target and pull the trigger. My only problem now is that it's too light and the safety lock is not locking properly. I might need to file away a small amount on the nose of the GRT-III to fully engage the safety lock. Another proof that the GRT-III is really a big improvement in shot confidence and a tuning is necessary to bring out the best in an airgun.
Speedturtle :)
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Congrats, - very nice indeed, ...
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Thanks. :cheers:
Speedturtle
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what all did you do to the gun? People say how big a difference the Trigger makes but I find the stock not that bad.. the pull on mine isn't bad if you pull it about 3/4 of the way then... set up and shoot. Thanx
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Here is what I did:
1. Honed the chamber part (below the slot of the chamber tube) with a home-made hone. I find this easier when done on a bucket filled with soap water (lukewarm) while honing and then rinsed with a clean tap water and dried with a clean highly absorbent cloth (similar to the one you use in cleaning a car) . If you did not totally let it dry it will easily accumulate rust but you are safe since you will be coating this part with silicone grease. Note: You can only do it this way of the barrel unit is already taken off from the receiver.
2. Deburred (to remove sharp edges) and semi-polished (using only 200 grit sandpaper so the moly will adhere to the surface) the upper part of the chamber (above the long slot of the chamber tube).
3. Deburred and cleaned the outside and inside of the piston (200 and 400 grit sandpaper).
4. Deburred and polished the top face of the piston and the surface where the piston seal is sitting.
5. Deburred and polished the top hat then coat it lightly with moly grease.
6. Degreased the piston spring (using paint thinner) then polished the top and bottom contact surface of the piston spring using 200 grit then 400 grit wet/dry sandpaper.
7. Deburred and polished the spring block (this is steel on the G-1 but plastic on the gamo) then coat it lightly with moly grease. (On the Crosman G-1 the inside part of the spring block has threads in it and I have no idea what is the purpose of the threading but when I disassembled the powerplant again after 200 shots I noticed that the long tube of the rear guide spring is scratched by these threads so I decided to sand this part (the internal part of the spring block) and the rear spring guide again.
8. Deburred and polished the rear spring guide then coat it lightly with moly grease.
9. Coat the outside surface of the piston spring with James Maccari heavy tar.
9a. Applied a light amount of silicone grease on the bottom surface of the piston seal before installing it to the piston. (The seal is a bit tricky to install, what I did was to dip it on a ceramic cup with hot water for about 10 -15 minutes and then install it (the way a tire mechanic installs a tire on the wheel hub).
10. Coat the outer perimeter of the piston seal with moly grease (light coating) and assembled the whole piston assembly - piston, piston seal, top hat, piston spring, spring block, and rear spring guide) and set it aside.
11. Coated the lower chamber with silicone grease (very light).
12. Coated the upper chamber with moly grease (light coat).
13. De-greased the whole trigger assembly.
14. Deburred and lightly polished the bottom contact point of the intermediate lever.
15. Sharpened (make the contact area perpendicular) the contact area of the upper intermediate lever that contacts the lower part of the seer lever.
16. Sharpened (make the contact are perpendicular) the contact area of the seer that catches the piston hole.
17. In my case the trigger pins are very coarse in texture so I decided to clean and polish them a little bit with a 400 grit sandpaper. When assembled I gained a very nice feel of the factory trigger.
18. Dipped the whole trigger assembly (except the contact point of the seer to the piston hole) on the moly grease/30WT synthetic oil and let it drip (take off the excess lube) for the whole night.
19. Cleaned the receiver washers and coated them with moly grease.
20. Polished the alive jam (the one locking the barrel to the receiver (below the breech area) and lightly coat it with moly grease (very very light).
20a. Assembled everything back into order.
21. After 200 shots I installed the GRT-III trigger.
That's it. Now I'm quite happy and satisfied with the way my G-1 is working. Smooth cocking cycle, Crispy click that you can hear when the seer engaged with the piston hole, light trigger pull (much lighter and crisper when compared to just simply dropping in the GRT-III trigger without deburring and cleaning some of the parts inside the trigger assembly. A big improvement when you drop in the GRT-III but you gain additional improvement when the internal trigger parts are cleaned and deburred), a perceived impression of like a "breaking glass" sound when the trigger is pulled (just one sharp sound, not loud but very crisp like breaking a piece of glass), less recoil, seems to give me better groupings after 500 pellets fired. Just one happy shooter now.
Next project would be to fabricate the new delrin spring guide and new top hat courtesy of a very accommodating friend. I decided not to immediately change the factory guides and top hat since I want to know what would be the changes to the gun when deburred and lubed before changing some of the major parts inside. The only part that I changed on the gun was the stock screws on the front. I changed it to a different screw with a locking washer so I will not always tighten it. It still holds well even after 500 shots and still tight.
This is how I did it. It may not work for others but this is how I did it on my own airgun and am satisfied with it.
Speedturtle
:)