1377 backpacker clone

[WILBA]

Well i managed to finish my 1377 attempt at cloning my backpacker but with a few upgrades. Bought a steel crosman breech off jsr which by the way i will say is better than the gmach offering i have on my backpacker at present. Fitted a oversize cocking bolt i had made by an engineer in work for me. A 17" barrel, crosman stock, walnut backpacker cloned pump handle that i stained black to match the stock . I also fitted a brass silencer adapter i drilled out to fit the 17" barrel. Only thing left to do is fit the gmac brass trigger and its all done not as powerful as the backpacker but still fun for plinking.

[Shed tuner]

good work. I really like the crosman steel breech too. Did you get the hidden screw version (screw sits under the bolt so as not to interupt pellet feed) ?

On power - it should be just as good. Does your valve have any nasty bleed holes ? You replaced the TP with some tube that actually seals I assume ?

I'm making an alli end plug/barrel band for mine when I get home, and switching it back to .177. I figure for plinking fps-per-pump will be better in .177 so I can get away with 4 pumps Power not really a consideration.

Rgds,
JB

[WILBA]

good work. I really like the crosman steel breech too. Did you get the hidden screw version (screw sits under the bolt so as not to interupt pellet feed) ?

On power - it should be just as good. Does your valve have any nasty bleed holes ? You replaced the TP with some tube that actually seals I assume ?

I'm making an alli end plug/barrel band for mine when I get home, and switching it back to .177. I figure for plinking fps-per-pump will be better in .177 so I can get away with 4 pumps Power not really a consideration.

Rgds,
JB

The only version jsr had was the front screw placement type jon but are much better than the gmac version. The blacking on the breech is better also. I fitted a fast flow port to it with seals both sides as when i left the seal out barrel side it must have leaked air out down the breech along barrel as power dropped so bad pellets bounced off wood rather than stuck in. . I will look at changing the valve next as it is the modern type with blow off holes. But to be fair concidering its.. 22cal the power aint bad. I went for a.. 22cal breech purerly because i had a . 22cal barrel spare off the backpacker when i converted it to.. 177cal last year so seemed a waste not to use up the barrel. Chris

[ratbuster2240]

These do make great rifles and certainly the lightest out there especially when you consider the power to weight they can offer. Like the 22XX series they are also very addictive but a great way to start learning about how airguns work.

[TonyL]

These do make great rifles and certainly the lightest out there especially when you consider the power to weight they can offer. Like the 22XX series they are also very addictive but a great way to start learning about how airguns work.

That's lovely.

[Shed tuner]

I will look at changing the valve next as it is the modern type with blow off holes.

perfect, it'll make a big difference. You could possibly plug with jb weld or something similar.

[TonyL]

My 1377 "mini-carbine" is based on a 2009 version. Just the Crosman steel breech, shoulder stock and 4x32 scope. Left on standard barrel as it's only for short range use at home. Pellet on pellet accuracy. Love it. Wouldn't mind building a longer barrelled higher power version, but always been a little hesitant due to pistol origins....some say it's okay, some say, "once a pistol, always a pistol".

Always also fancied trying a flat top piston, mainly for the efficiency but also because the rod part is more heavy duty?

JB, what tubing do you normally use to ensure better TP sealing?

[ratbuster2240]

I see you've also discovered how accurate these are as carbines.

Just by Adding a 14.5 inch .22 Ratcatcher barrel makes a big difference in power. Then you can use the Ratcatcher in summer and Back Packer in winter.



Having said that a 1377 at short ranges is effective too. The only issue I have with flat top pistons is that the orings seem to wear very quickly, the standard cup holds up much better.

My 1377 "mini-carbine" is based on a 2009 version. Just the Crosman steel breech, shoulder stock and 4x32 scope. Left on standard barrel as it's only for short range use at home. Pellet on pellet accuracy. Love it. Wouldn't mind building a longer barrelled higher power version, but always been a little hesitant due to pistol origins....some say it's okay, some say, "once a pistol, always a pistol".

Always also fancied trying a flat top piston, mainly for the efficiency but also because the rod part is more heavy duty?

JB, what tubing do you normally use to ensure better TP sealing?

[harvey_s]

good work. I really like the crosman steel breech too. Did you get the hidden screw version (screw sits under the bolt so as not to interupt pellet feed) ?

On power - it should be just as good. Does your valve have any nasty bleed holes ? You replaced the TP with some tube that actually seals I assume ?

I'm making an alli end plug/barrel band for mine when I get home, and switching it back to .177. I figure for plinking fps-per-pump will be better in .177 so I can get away with 4 pumps Power not really a consideration.

Rgds,
JB

This may help... http://www.airgunbbs.com/showthread....ow-to-fix-them

[WILBA]

How do you remove the valve on these guns anyway? Do tbey come out front end or out the rear? What do you have to remove to get the valve out?

[ratbuster2240]

They come out the front because there's a raised lip inside the tube preventing the valve moving backwards under pressure.

How do you remove the valve on these guns anyway? Do tbey come out front end or out the rear? What do you have to remove to get the valve out?

[ratbuster2240]

https://m.youtube.com/watch?v=xVI5owkEPAc