The 13XX Cabin Fever Build

[Turbinator]

Thanks for the idea.  I have been using o-rings from my HF kit to help seal up the transfer port area.  Unfortunately what I think I'm observing is that the plastic breech on my Phase 2 is flexing ever so slightly such that the transfer port + o-ring solution I have in place isn't sealing up well enough to contain the pressure.

Using GTA, I researched converting to a steel breech, but it seems that requires enough mods to a Phase 2 to make it not worthwhile.

I have some irrigation tubing here, similar to the refrigerator water line routine.  I might give that a try, as I can cut them a little longer to perhaps offer a better seal.

The transfer port design on the Phase 2 1377 unfortunately seems to be a bit of a weak link in the system.

Turby

[TheOtherSprocket]

Turby - you can use a steel breech and retain the PH2 bolt - or just get a PH3 bolt and pin for about $20 shipped.

If you're spending $40 for the breech, the extra $20 for the bolt/pin is worth it.

That said, your TP seal issue is fixable.

Also, check the barrel and chamber for burrs - they might be cutting your O rings.  Your chasing something very small a this point - keep at  - you'll find it

[Turbinator]

Turby - you can use a steel breech and retain the PH2 bolt - or just get a PH3 bolt and pin for about $20 shipped.
If you're spending $40 for the breech, the extra $20 for the bolt/pin is worth it.
That said, your TP seal issue is fixable.
Also, check the barrel and chamber for burrs - they might be cutting your O rings.  Your chasing something very small a this point - keep at  - you'll find it

Thank you for the words of encouragement!  Just did another take-down, and I noticed there was a very subtle misalignment between the valve exit port and the transfer port, so I re-aligned it -- though that didn't fix the air leak problem (still fails the tissue test).  I did check for burrs, everything is nice and smooth - thanks for suggesting that.

Just trying 1 thing at a time to try to isolate the issue..

For the steel breech + Phase 2 tube, I thought I'd also need to replace the barrel to use the newer steel breech?  Saw another thread where a guy suggested that it's not worth it to convert a Phase 2 gun, says you're better off just buying a Phase 3 and starting from there.  Guess it's a matter of opinion.

Will think about what to try next.  Will report in later this week.

Turby

[Turbinator]

Sorry - double post!

[TheOtherSprocket]

Oh yeah - the barrel - I forgot that - easily sourced from Mr Mellon and would be a chance to add length.  Just start with a PH3 gun for that fun.

Personally - I like your commitment to the PH2 set up.  It's got to be something you're overlooking somehow.  Or seriously drastic like the PH2 bolt doesn't fit the PH1 barrel quite right...not probable but possible.

The German barrel band does not interfere with my PH2 pumping but it's a close tolerance fit.  The China band does not interfere with a B&R Plumper Pumper forearm - I did have to file a lot off the band to fit the pump linkage though.  I think it's an older ink compared to the newer ones.  The other linkage I have fits fine in the other band, no issues...

[Turbinator]

Yup, I could buy all the necessary top end parts to go Phase 3, but as you say (and as others have noted), might as well buy a brand new Phase 3 as a starting platform.

Personally - I like your commitment to the PH2 set up.  It's got to be something you're overlooking somehow.  Or seriously drastic like the PH2 bolt doesn't fit the PH1 barrel quite right...not probable but possible.

Thanks!!  I’m determined, maybe even stubborn, because I truly believe that it can be fixed.  It’s got to be something so simple and straightforward, I agree.  I’ll keep at it.  I do have another 1377 I’m working on as well, so I can swap parts back and forth for comparison.

Another reason for me really fighting hard to keep the Phase 2 as a Phase 2 is for the nostalgia of it all.  I’ve had these for decades and I’d love to keep them operating as designed.

The German barrel band does not interfere with my PH2 pumping but it's a close tolerance fit.  The China band does not interfere with a B&R Plumper Pumper forearm - I did have to file a lot off the band to fit the pump linkage though.  I think it's an older ink compared to the newer ones.  The other linkage I have fits fine in the other band, no issues...

How interesting that neither of the bands were problematic for your forearms - I wouldn’t have thought that the general fit would vary this much across the population of 1377’s, but maybe I’m wrong there…

Turby

[TheOtherSprocket]

Looking at the top of the page - if your breech is moving, there's the issue.  Something isn't fitting quite right.  If you can break it down a dry fit things to make sure the seals are in good shape, etc. Are the screws tightened properly?  The rear one with the sight and the small one inside the breech - thinking out loud, if the barrel is lined up on the TP seal, things should just be flat on the tube...

Does everything line up right without the barrel?  You've got a PH1 barrel right?  Is it fitting in the breech well?  The breech and barrel band keep the barrel on the TP seal.  Is the seal too long and keeping things misaligned?

I have some PH2 parts from one I tore down and re-used for learning.  If you need something let me know and we can sort out something.  I've got a working PH2 as well - I need to check accuracy to see if any rifling is left.  The parts barrel has a shadow of rifling from the use of BB's...

[Turbinator]

Thank you for the continued ideas -- and the offer to provide parts if needed.  So kind!  (That's why I really like this forum, I see a lot of help, and pretty much zero drama.)

I am back from a short business trip, and was looking again at the problematic 1377.  I'm starting to think that the problem is the bolt probe.  I actually used a slightly oversized o-ring on it, it's a HF 006, but in other threads I read that the right size is either a 004 or a 005.  I have some 005's on the way and was planning on swapping out to an 005 to see if that helps.  I feel that the bolt probe might be the issue because I am pretty sure I feel air leaking out of the breech cover when I dry fire (with a wadded up sock at the muzzle to help build up back pressure).  I'm going to try swapping the bolt probe today to see if that resolves the problem.

I'm somewhat convinced that the TP seal is pretty good, though I am willing to test that assumption further as well.

Turby

[TheOtherSprocket]

Can you pull the cover off the bolt and use a screw to cycle the bolt?  This would help ID things visually.
And a really dumb Q - Is the barrel a 177 vs 22?  The 177 bolt on a 22 barrel would definitely leak at that point I reckon...

[Turbinator]

Can you pull the cover off the bolt and use a screw to cycle the bolt?  This would help ID things visually.
And a really dumb Q - Is the barrel a 177 vs 22?  The 177 bolt on a 22 barrel would definitely leak at that point I reckon...

The barrel is a .177.

I don't need to cycle the bolt to cock the 1377, since it's a PH2 model.  It is a rear cocker.

I swapped with a good bolt probe that still has the original factory o-ring and I'm still seeing the tissue test fail.  Going to go back to focusing on the TP...

Turby

[TheOtherSprocket]

Well at this point I'd tear it all down and swap out the TP seal and check the barrel/breech fit.

Be careful on the reassembly - someone here talked about clamping the breech and then installing the screws...  Also, I've found that if I install the seal, then the TP on the tube - then loosely drop the barrel/breech onto the tube and wiggle the barrel onto the TP, it all kinda drops into place - then I press the breech firmly and start with the rear screw - then the screw at the bolt.  It's fussy so take your time.  I pooched a TP by not taking care.

[Underdog]

I'm reading this thread with interest as I've recently upgraded my Ph 2 - 1322 with an Alchemy RP valve, trigger shoe, stainless pin, and adjustable sear spring.
I also cold-blued the barrel, breech, and pump tube while I had it apart. I also polished and painted the aluminum grip frame with some High Heat paint from Ace while I was at it. That paint doesn't hold up well, so I'm looking for a better alternative. But it LOOKS a lot better than it did.

Previously I'd replaced the plastic breech with a steel breech that I got for the price of shipping from a guy (Eric) on the Crosman pistol forum. It didn't have the front small screw hole in it, so I milled a new hole and installed the old screw after carefully grinding down the head. I sanded down the breech end of the barrel (on my lathe) until it fits pretty tight in the breech. I have to use a transfer punch to get it back out. I'm afraid to do that much more as it's marring the bevel seat area where the bolt probe o-ring seats... I need a custom punch...

The new 25% transfer port didn't fit any of the holes, so I just recut some vinyl tubing for the port. Another reason I went this route was that the ports in the RP valve and the barrel don't line up right with the breech hole and the pump tube holes. If I pull the barrel out just .020" then the ports line up, but then the barrel isn't fully seated in the breech, and there's a gap that pellets tend to hang up in.
I wonder if I can dremel or file out the barrel hole so that the holes line up a bit better, and fully seat the barrel. And maybe the transfer port would actually fit? I was wondering if I enlarged the RP valve hole whether it would line up better too. Even getting it lined up then tightening the screw doesn't make it stay in place.
Think that'd be a mistake?

I think I'm still getting another 20fps out of it which puts it around 450 fps @10 pumps, 500 fps @15 pumps, and 515-520 fps @20 pumps.
Do you think I could get any more fps out of this thing?

I'm wondering where to get a barrel band for this thing as I've cracked the original plastic one when removing the barrel/breech the last time.

And also the rear plastic sight base is horrible. It's not long enough, so it doesn't seat correctly on the front edge of the flat. More importantly, it moves so easily it's a wonder that I can hit anything with it. Is there some replacement for that as well?

[Turbinator]

Well at this point I'd tear it all down and swap out the TP seal and check the barrel/breech fit.

Be careful on the reassembly - someone here talked about clamping the breech and then installing the screws...  Also, I've found that if I install the seal, then the TP on the tube - then loosely drop the barrel/breech onto the tube and wiggle the barrel onto the TP, it all kinda drops into place - then I press the breech firmly and start with the rear screw - then the screw at the bolt.  It's fussy so take your time.  I pooched a TP by not taking care.

Thanks!

Well - SUCCESS!

Here's what I did -- TP has 2 o-rings, 006's, to help create a good seal.  One on top, one on bottom.  I am not using the factory TP seal any longer.  Bolt probe has the new 005 o-ring installed now.  Much nicer fit than the 006 o-ring.

Firing a pellet, the 1377 passes the tissue test no problem now.  Nice!!  I'm happy.

Thanks to you & all who gave suggestions and stayed with me during this adventure!

Now onto my 3rd 1377..... hah hah

Turby

[Turbinator]

I'm wondering where to get a barrel band for this thing as I've cracked the original plastic one when removing the barrel/breech the last time.

I can't help you with the TP port misalignment (I thought I saw the same problem with mine) but I went for this barrel band here:

https://www.ebay.com/itm/115471291600

3 available as of this writing.  Ships from Germany.  Nice solid aluminum plus gives you the ability to mount a 1/2-20 standard UNF LDC.

The only downside is, no front sight, but I found a random correctly threaded screw fits to serve the purpose for now.

Turby

[Turbinator]

By the way - I had run into some bad info online about what the right size o-rings are for the 1377.  Here is the correct batch I used for my 1377:

.177 bolt probe = 005
Inner valve o-ring = 012
Outer valve o-ring = 111

And my 3rd 1377 was just rebuilt tonight, compresses great, all back together and passes the tissue test.

Turby

[TheOtherSprocket]

We're probably bidding against each other on some of those...

[Turbinator]

We're probably bidding against each other on some of those...

Hah hah!  Probably not!  My 1377's are vintage from 1990, 1991 -- for 2 of them, I am the first & original owner.  For the 3rd one, it came from a friend who was the first and original owner.  I have not purchased any 2nd hand or any new 1377's since these purchases were made '90 / '91.

Good luck on your buying!

Turby