I have decided I want to play airsoft. But I have no airsoft guns, so what can I do? Well, I just happen to have a pellet revolver but it is .177 cal and I need it to be 6mm for airsoft.
So basically what I am undertaking now is to convert my Gamo R-77 combat revolver from .177 to 6mm.
This will not be easy.
However, the most difficult part will be boring out the existing crappy stainless steel rifled barrel to make way for the new 6mm aluminium barrel.
So lets look over what I am going to do:
-Replace existing .177 cal barrel with 6mm barrel
-modify the cylinders from .177 to 6mm
-Use a much longer barrel when replacing old one
-Extend gun to be as long as the barrel
(using epoxy putty)
-Extend top weaver rail to be as long as gun
-Add bottom weaver rail
-Add some sort of seal between the valve and the cylinders
(possably adding orings around each cylinder)
-Fix 12gram seal on valve
Ok, doesn't seem so hard, lets look at what I already have

Yep, most of what I need. All I need to get is more rails and a BB 6mm barrel, which I will get from my freind, I already have a barrel but that only is long enough to replace the cylinders. I also need epoxy putty, which I will get from the shop.
First of all, Replacing the .177 cylinders.
Now, this will be fairly easy and straight forward. This is because of the actual cylinders. It isn't one piece, its two, a piece which holds all the cylinders and a piece that fits over it like a shroud.

First thing to do is cut the cylinders off the plastic back piece, so they are flush with it, then bore out the existing holes on that to make room for the new cylinders ( about 8mm in diameter). Then Drill bigger holes in the shroud, here are some pics to make it more clear:
Back piece with cylinders

Shroud:

So, thats done, now the hard part.
Boring out the existing barrel. This will be tricky, and I don't think I can do it cleanly myself so I am thinking of sending it to my freinds dad, who is a machinist and have him bore out the old barrel to 8mm. So I can insert and glue in the new barrel.
I will replace the old barrel with a fairly long barrel, maybe about 20cm or so, about 17'' I think. Then the barrel will be sticking out like this:

Which is not going to be very astetically pleasing, so I will mold epoxy putty around the new barrel, extening the lines of the gun and adding weaver rails to the top and bottom. I might just not stick to the lines of the gun and add a little more meat to make it look more agressive. The epoxy putty is very very strong, I do not have to worry about it breaking.
That should just take a lot of sanding to get right, I already have plans. Then I will strip the gun, sand it and add a kick ass black paintjob.
The weaver rails will make it possable to add a lot of accesories.
Another thing I would like to try do is add hop up. This will be tricky but I think I have a simple solution that will serve two purposes. I will add strip good quality tape of some sort to that inside of the cylinders at the furthest most point away from the middle of the cylinders or in other words, at the top. The tape will hold the rounds in place when they are in the cylinder and induce hop up when the bb is fired.
Since the revolver was 290fps with .177 pellets and a very short barrel I am hoping for velocities of around 400fps.
This should be a fun project. If anyone has any imput it would be appreciated. I should start this project this week or the week after. I don't want to mess up so if missed anything completely ovious, let me know
