Definitive Answer on 1377 Rev 2 Modifications

[Rackhan]

Throwing my hands up here in exasperation.  I'm lost in the weeds on trying to figure out the "basic" modifications that will actually work (read that: be successful on my first attempt at hot rodding an airgun) for a 1377 pumper.  I've determined its a Rev 2 and my primary malfunction right now is trying to determine if you can put a Crosman over the counter steel breech on it or not. I read the vendors and Crosmans admonition "does not fit older model...sliding breech cover..." BUT, I thought I'd seen a comment or two and a youtube or two where they did a steel breech mod specifically on a Rev 2; along with a barrel change and a stock. But here's where the lost in the weeds comes in-I've lost track of what said who or how is where because I've done so much research but kept all the notes "in my head". Failed plan and my browser bookmarks now looks like a Family Circus path to nowhere, via everywhere.

Respectfully asking for help...can someone point me to the thread in this forum or other one-stop webpage or video that can tell me what will fly for the older model / Rev 2.  For calibration...I'd like to at least put on a steel breech to accommodate an optics upgrade, a longer barrel upgrade, and a stock...maybe a little trigger tickle...

My Ford reseal kit and I are just hanging out trying to figure this out right now and there is next to no shooting going on...which is kind of frustrating. Also, as an aside question, has anyone taken on of these little Frankensteins into any competitive arena? A "run what you brung" game? I would like to do that but not sure its a thing.

Thanks, Mike

[Mzq284]

I have one of those with a newer 22 caliber breech and barrel off of a new type 1322. They fit fine, but you're supposed to use a new type barrel that goes with the breech. They're not supposed to interchange between types and I haven't tried it, so don't know. Try it, at the worst you'll have to buy a barrel,  they're cheap from crosman.

[dan_house]

the "newer" steel breeches have the little screw hole (under the bolt) in a different location than the older breeches did

you didnt specifically say what issues your having, but Ive been tripped up by ^^^ this issue in previous builds

[threesuns]

Type 1 and 2 barrels have a much larger throat that will not seal with the steel breech probe. No problem if fitting a longer barrel.
Breech screw can be drilled and tap’d unless a rear screw location which will not work with the rear cocking hammer

[Mzq284]

the "newer" steel breeches have the little screw hole (under the bolt) in a different location than the older breeches did

You need to use the steel breech for the 13XXs, bolt right up, no worries

[Mzq284]

Here's a picture of the gun.

[bantam5s]

The new breech fits just fine, but only works with a modern barrel.

[Flex]

Here's a picture of the gun.

See pics in above reply.
Your pic seems to show a 2nd variant 13xx (rear cocking knob) with a “newer” plastic breech, (non-functioning ?) cocking bolt and likely, a “newer” barrel. I believe the OP is trying to install a Crosman steel breech but would agree that if the stock plastic breech and matching barrel fit, a steel breech and matching barrel, would too 🤔.
IMHO, the plastic breech on the newer 13xx pumpers seems a bit cheesy and all of my newer Crosman pumpers now sport steel breeches. My 1377 2nd variant with the rear cocking knob and sliding breech cover does have the plastic breech BUT it seems much less cheesy and way more sturdy than the newer plastic breeches, so I’m keeping it bone stock 😎. Sometimes it’s nice to keep a “classic” air gun in its OEM configuration. Just sayin’ 🙂

[Mzq284]

Here's a picture of the gun.

See pics in above reply.
Your pic seems to show a 2nd variant 13xx (rear cocking knob) with a “newer” plastic breech, (non-functioning ?) cocking bolt and likely, a “newer” barrel. I believe the OP is trying to install a Crosman steel breech but would agree that if the stock plastic breech and matching barrel fit, a steel breech and matching barrel, would too 🤔.
IMHO, the plastic breech on the newer 13xx pumpers seems a bit cheesy and all of my newer Crosman pumpers now sport steel breeches. My 1377 2nd variant with the rear cocking knob and sliding breech cover does have the plastic breech BUT it seems much less cheesy and way more sturdy than the newer plastic breeches, so I’m keeping it bone stock 😎. Sometimes it’s nice to keep a “classic” air gun in its OEM configuration. Just sayin’ 🙂

The whole point of the picture was to show that the breech screw holes in the old one and the new ones are in the same spots. The breech on that one was warped, that's why I got it free. The new breech and barrel got it up and running again, in 22. It functions just fine. Better to be used than sitting in a drawer.
I don't shoot much 177, except for my 1377 like the one in the picture. The plastic breech on that one warped, too, so I made a steel replacement cuz I like that design. Just sayin

[Flex]

Here's a picture of the gun.

See pics in above reply.
Your pic seems to show a 2nd variant 13xx (rear cocking knob) with a “newer” plastic breech, (non-functioning ?) cocking bolt and likely, a “newer” barrel. I believe the OP is trying to install a Crosman steel breech but would agree that if the stock plastic breech and matching barrel fit, a steel breech and matching barrel, would too 🤔.
IMHO, the plastic breech on the newer 13xx pumpers seems a bit cheesy and all of my newer Crosman pumpers now sport steel breeches. My 1377 2nd variant with the rear cocking knob and sliding breech cover does have the plastic breech BUT it seems much less cheesy and way more sturdy than the newer plastic breeches, so I’m keeping it bone stock 😎. Sometimes it’s nice to keep a “classic” air gun in its OEM configuration. Just sayin’ 🙂

The whole point of the picture was to show that the breech screw holes in the old one and the new ones are in the same spots. The breech on that one was warped, that's why I got it free. The new breech and barrel got it up and running again, in 22. It functions just fine. Better to be used than sitting in a drawer.
I don't shoot much 177, except for my 1377 like the one in the picture. The plastic breech on that one warped, too, so I made a steel replacement cuz I like that design. Just sayin

I wasn’t doubting anything about the pic but was hoping for a bit of a “back story” (which you provided) 🙂. I’m curious as to how the plastic breech gets warped? Mine shows not indication of that problem but I’d definitely like to avoid it 😉.

[Mzq284]

No worries, just explaining why I posted them,  a picture is worth a thousand words.
The plastic is thin under the screw, I don't think warped is the right term. The breech pushes up around the screw, maybe from the pressure from the transfer port? I made that steel one because my brother bought me the gun and I wanted to preserve it. Plus it's a shootin fool.
If yours does the same and you don't have the means to make one, you could scare up a steel breech from a 1300 Medalist and  drive the old barrel out and use the 1377 barrel. You might have to drill and counterbore for that miserable number 4 screw, I believe the 1300 doesn't have it. I would try to run it without it before I drilled it, it would load smoother. Hope that answers your question.
I don't like the plastic either, I would prefer aluminum or steel, but it's reality, what are you going to do?

[Flex]

No worries, just explaining why I posted them,  a picture is worth a thousand words.
The plastic is thin under the screw, I don't think warped is the right term. The breech pushes up around the screw, maybe from the pressure from the transfer port? I made that steel one because my brother bought me the gun and I wanted to preserve it. Plus it's a shootin fool.
If yours does the same and you don't have the means to make one, you could scare up a steel breech from a 1300 Medalist and  drive the old barrel out and use the 1377 barrel. You might have to drill and counterbore for that miserable number 4 screw, I believe the 1300 doesn't have it. I would try to run it without it before I drilled it, it would load smoother. Hope that answers your question.
I don't like the plastic either, I would prefer aluminum or steel, but it's reality, what are you going to do?

I’m somewhat confused RE: your posted pics🤔. Your first one shows a 1377 with the early rear cocking knob but also has the later plastic breech with cocking bolt (which I’m assuming is non functional). The second pic shows a 1377 in the early configuration with the rear cocking knob and sliding breech cover. Is this the one with the steel breech that you made? Is it the same gun?

[Mzq284]

They're the same model(version), but they're two different guns. You are spot on, the second one is the one with the steel breech, first one was a rescue, I saved it from the trash can. An extra, modern breech and barrel brought it back to life. Great guns.

[Flex]

They're the same model(version), but they're two different guns. You are spot on, the second one is the one with the steel breech, first one was a rescue, I saved it from the trash can. An extra, modern breech and barrel brought it back to life. Great guns.

Got it! Makes sense now 🙂. I agree that the Crosman 13xx series are fine air guns. None of my Crosman have been purchased in the past 10 years so I can’t address the attributes of those made since the acquisition by Daisy. Due to the packaging and marketing primarily in Big Box stores, I’m thinking that the general public views air guns as “toys” (even with the packaging stating otherwise) 🤔. True Crosman enthusiasts certainly know that’s just not the case 😎.
I am glad to know that if my older 1377 (2nd variant) ever needs “saving”, I have the parts to do the job!

[Mzq284]

Flex,
Since you like the older style Crosmans, go to the Vintage Gate, thread:
Crosman 147, Salvaged, or Savaged.
I just now found it, if you haven't seen it, I think you'll like it, it's a cool save on a junker.

[Flex]

Flex,
Since you like the older style Crosmans, go to the Vintage Gate, thread:
Crosman 147, Salvaged, or Savaged.
I just now found it, if you haven't seen it, I think you'll like it, it's a cool save on a junker.

Thanks for the Vintage Gate reference (I think 😉)! That collection of threads has serious “rabbit hole” potential 😜. Fortunately, I only have a few truly “vintage” air guns 🙄 but that doesn’t mean that I can’t be “hopeful” 😎.