. 
Let me start this off by saying I’m no expert at this stuff. I’m just an old guy who likes to tinker with stuff. Most of these upgrade ideas I got off of the YouTube.
So, I’ve had this gun for about 20 years. Way before I even knew what a PCP air gun was. Now that I’m back into airguns. I thought I dig it out and shoot it a little. Well it shoots pretty darn good. So I started researching upgrades. Once I heard of the steel breach I knew I wanted that. And I must say. It’s very reasonably priced. And simple to install. So while waiting for my steel breach to show up I started working on upgrades I could do myself. I’m a hobby machinist so it’s normal for me to try to make or improve parts rather than buy them. First up is trigger and sear pins. The factory pins are .125” Dia. Well a #30 drill is .128” Dia. That will help tighten up some trigger and sear slop. Here is the drill ruff cut then I grind to length.
Next I punched out some shims. I have a pretty good process for doing this. But that could be a whole thread by itself. I made two .010” shims for the sear. The trigger got two .010” and two .005”. .015” on both sides.
I also lightly polish all the mating surfaces. Trigger , sear and hammer.
Im still working on lighting the trigger spring. It’s still kinda heavy so I won’t cover that just yet.
Next I made a pin to replace the roll pin that holds the pump arm in place. I took a pice of .187” Dia stainless steel rod. Cut and ground to length. Then drilled and taped for 4-40 screws . You see here I have no lathe but it’s only one part so not that big a deal. Drill here.
.
Tapping here
.
An Allen head screw would look nicer. But this was all I had in the shop. It is however stainless.
.
Next I replace the screws that hold the trigger housing/ pistol grip on. Stainless steel socket head screws. Cut and ground to length .
.
Then I got the steel breach in. It was very simple to install. I’m pleased with it. For optics. I have a vintage Aimpoint 2000 red dot.
.
.
Now I just need to work on my pistol shooting skills. There are some of the first groups 10 yards with Crosman Premier 10.5 grn. @ 5 pumps. They look good but the groups have seemed to opened up. The trigger is still too heavy. No creep. But heavy. So I’ll need to work on that.
So that’s all for now. Hope this thread inspires someone to tune or rebuild an old 1377 or 1322.
Let me start this off by saying I’m no expert at this stuff. I’m just an old guy who likes to tinker with stuff. Most of these upgrade ideas I got off of the YouTube.
So, I’ve had this gun for about 20 years. Way before I even knew what a PCP air gun was. Now that I’m back into airguns. I thought I dig it out and shoot it a little. Well it shoots pretty darn good. So I started researching upgrades. Once I heard of the steel breach I knew I wanted that. And I must say. It’s very reasonably priced. And simple to install. So while waiting for my steel breach to show up I started working on upgrades I could do myself. I’m a hobby machinist so it’s normal for me to try to make or improve parts rather than buy them. First up is trigger and sear pins. The factory pins are .125” Dia. Well a #30 drill is .128” Dia. That will help tighten up some trigger and sear slop. Here is the drill ruff cut then I grind to length.
Next I punched out some shims. I have a pretty good process for doing this. But that could be a whole thread by itself. I made two .010” shims for the sear. The trigger got two .010” and two .005”. .015” on both sides.
I also lightly polish all the mating surfaces. Trigger , sear and hammer.
Im still working on lighting the trigger spring. It’s still kinda heavy so I won’t cover that just yet.
Next I made a pin to replace the roll pin that holds the pump arm in place. I took a pice of .187” Dia stainless steel rod. Cut and ground to length. Then drilled and taped for 4-40 screws . You see here I have no lathe but it’s only one part so not that big a deal. Drill here.
.
Tapping here
.
An Allen head screw would look nicer. But this was all I had in the shop. It is however stainless.
.
Next I replace the screws that hold the trigger housing/ pistol grip on. Stainless steel socket head screws. Cut and ground to length .
.
Then I got the steel breach in. It was very simple to install. I’m pleased with it. For optics. I have a vintage Aimpoint 2000 red dot.
.
.
Now I just need to work on my pistol shooting skills. There are some of the first groups 10 yards with Crosman Premier 10.5 grn. @ 5 pumps. They look good but the groups have seemed to opened up. The trigger is still too heavy. No creep. But heavy. So I’ll need to work on that.
So that’s all for now. Hope this thread inspires someone to tune or rebuild an old 1377 or 1322.
