Alot of hard work but...

[1377x]

i dont know what you are aimimng for .
i did build my LS13XX from a 140/1400 tube and pump linkage.
the 140/1400 conversion is the simplest to do
the gripframe mount right up all the ports line up with a 1377 valve.breech lines up,needs a breech screw hole drilled and tapped
all you have to do is shorten the rear of the tube so you can use a 1377 end cap.i havent done that yet im using a phase1/2 modified end cap.for the barrel band i drilled out a 1400 barrel band or you need a custom made one.this one is worth the effort.i get 730fps 10 pumps cphp .22
rsterne's uber carbine is highly modified i have the plans to build one.got them from rsterne.you need a mill or the skills to do what a mill does.after asking several people if they could do the mill work for me with no takers i gave up on that project.sold the 2100 tube metal piston and pump linkage
a 760 the pump tube is the same length as the 1377.not worth the effort
heres a pic of mine its almost complete


http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=3349.0

[millipede]

heres a video on youtube of the 760 internals..  i had to watch this one a lot when i was messing with mine 

[youtube]https://www.youtube.com/watch?v=OeOLKDYnGoE#]Crosman 760 Pumpmaster assembly[/url]

i have an older model that had a brass valve. my 760 has been sitting in pieces for a while now so i sent the valve to AC and had him drill and tap a hole for the grip frame screw and put it in my 1322. the reason is because the valve has a nice sunken hole where the transfer port is and it fits some plastic refigerator tube PERFECTLY. so i had him do a poly tube mod on the valve and barrel also...  it works great

im still thinking of doing some power mods to the 760 since it has a smooth barrel. i want to test my theory that you could make a survival gun out of this. the point being that with a smooth bore and if in a survival situation you might be able to use objects from your surroundings as projectiles if you dont have bb's or pellets.

so far the only mod ive done to mine is cut the barrel down right to the barrel band. i dont really know why. it just looks really cool that way  someday ill get around to re-building it

[Plasticman]

I did the tube with out a mill. I used a drillpress, dremmel and files took my time and it worked fine. Had a bit of a problem getting the proper tap for the breech screw  and had to special order it.

[1377x]

I did the tube with out a mill. I used a drillpress, dremmel and files took my time and it worked fine. Had a bit of a problem getting the proper tap for the breech screw  and had to special order it.

you made an uber carbine or a 140/1400 conversion??

[AZAG]

Why do many of these have a band around the breech and tube.

[1377x]

Why do many of these have a band around the breech and tube.

i have the band around my gun because i didnt drill and tap a breech screw hole.i used this same set up on my disco pistol for the best possible transfer port seal.believe me the dinky breech screw could use some improvement.i dont bother with the breech screw in high powered guns,go straight to the hose clamp.
on the 2100 set up it used to mount the gripframe.if you make a hole for the front gripframe screw the tube will leak,the valve is short

[millipede]

so thats just an ordinary hose clamp? ive had the same idea a while ago after seeing a guy who made his own clamp with a mill that fit perfectly. i figured a hose clamp would work, just not as classy. i hate the breech screw too. ive often thought about drilling a bigger hole for it and using a bigger screw but im not sure what would happen on the inside of the tube if i did that.. have you tried it before?

[Joshua A]

It would and should wook just fine, the only problem is that a bigger screw has a bigger and thicker head... that head needs to be sitting in a countersunk seat drilled into the bottom of the breech, so that the bolt can pass over it without obstruction... thats the problem. I've thought about doing this before too, and actually tried it.. the bottom wall of most breech's arent thick enough to allow for a countersink deep enough to use a bigger screw, and still allow for unobstructed bolt movement. sucks!

J.Austin

[1377x]

it has been done not by me i ran across posts with pics when looking to see if anyone else did it
the hose clamp is tacky if you ask some .im not into bling just power
there is a guy in canada that used to make the band on the uber carbine.

[Joshua A]

 Yeah I'm sure it can be done, but It would need to be done precisely and either the screw would need to have a low profile head on it, the breech floor would need to be thick enough to have a deep enough countersink. the You know, I talked to Roy Weid one time and he told me that one of the problems that comes up with crosman guns that are bulk filled to over 2500 psi is that that little breech screw rips out after so many shots do to the repeated massive bursts of air coming through the TP. So he said that the screw needs to be replaced with something beefier, and the barrel band needs to be pulled back so it is right in front of the breech, so I know that it can, and has been done before. You's probly have to use a countersunk style screw with the v-shaped bottom on the head, and a flat on top. this way the counter sink wouldnt have to be flat at the bottom for a panhead style screw. When it comes time for me to build a pcp pistol or carbine someday, I will be looking into this more, because I AM into bling. I'm more into power too, lol, but I am into bling as well. I bet if someone started making those bands they'd make a killing!

[arkmaker †]

i hate the breech screw too. ive often thought about drilling a bigger hole for it and using a bigger screw but im not sure what would happen on the inside of the tube if i did that.. have you tried it before?

You still end up with only a .060" wall thickness for the screw to hold on to. The fine threads on that little breech screw actually provide a lot of holding power. So, if you try a larger screw, you still need to use a screw with very very fine threads, otherwise you will end up with it loosening up on you. What come to mind is the screws that hold the closure on my screen door, which which is a very coarse thread sheet metal screw. I seem to be re-tightening those every 3 months or so.

Also, if you have the new breech screw location, you need to watch for the screw hitting the hammer.

Rich

[Madkoifish]

Since this has drifted to the breech screw has not anyone considered metric screws? You would need to turn down the head to clear the dai and the height. but the size of the allen should still allow for enough meat to grab. The metric would be a bit bigger in dai and have a slightly tighter thread count.

Nest solution is likely one of those bands. Only issue is clearance from the pump arm unless it is a long tube build. (thinking stock 1377s)