1377 American classic, HELP!

[SwampHunter]

 Hey guys n gals, I recently got an older 1377 from a friend that he has had since we were kids. I don't know anything about these so I need some advice.
    I want to fix it up to be a target plinker, it's in pretty rough shape though. I was thinking about ordering a 1300kt and thought this would be a fun project and if I like it , I will order the 1300.
    The bad, seems like the seals are shot. You have to pump it fast to get it to build any air pressure, also when shot it blows air out of the breech area. Overall it's in rough shape, but it's meant to be a fun project. Also he has shot mostly bb's out of it so it will probably need a new barrel. With any type of bump the forearm will open also.
   So what do you guys think? Where to start? I would like to put a scope on it eventually, not sure how hard it would be to swap out a steel breech though? I was thinking of a 14" barrel, possibly converting to .22? Not sure really, just want some opinions and need some help. Would like to be able to shoot small game with it if possible.

[c_m_shooter]

Mellon Air flat top piston and valve and one of his prepped barrels should get you where you want to be.  The steel breech is an easy swap except for that hidden .050 breech screw can be a challenge if it is stuck. 

[Stinger177]

I'll second what Cliff said with one additional suggestion - the breech seal, also called the transfer port. It's a small tube between the top of the tube and the barrel. On all 13xx's, that small tube also has inside it a tiny metal port. On your older gun it may look like a top hat and be buried inside the old black plastic tube- easy to overlook and throw away - don't do that. With the newer style valve such as a Mellon Air, and a new barrel, the metal port will be different. Don't know how to describe it except that instead of having a flange on one side only, it has a flange around the middle. The metal part is the transfer port, the tube is the seal. You will also need a new bolt o-ring. Those two places are most likely where yours is leaking in breech area.

In the diagram below, those parts are numbers 1322AO26, 130-036 and 397-062.




Installing a steel breech is a good idea if your goal is to make it a nicer shooting plinker, or even reasonable target gun.

If you call Crosman for parts, be sure to have the part numbers in hand, as they will not look them up for you. Aside from the Mellon valve and piston (which are half the price of competitors), Crosman has the best prices for all other parts, including the steel breech.

For barrels, I start with a Discovery barrel from Crosman (around $26) and cut it to length, usually around 14.5"

Topped off with a 6.5" TKO, it will be a great little gun, but that will put you into the $110 investment range. Minus the TKO, you're looking at around $50, maybe more.

I have one 1377 with all of the above mod's, plus a MagnumAir trigger and Super Sear. I also have three older 1389's with the same mods. They all shoot great!

[Stinger177]

I just remembered a couple more things about these older Crosmans.

If you stick with the original breech, I'm not sure you can change the barrel. As far as I know (and I have a 1300 which is similar) the barrel and breech are pretty much one unit. Maybe someone else here knows if they can be separated.

Also, if you remove the breech from the main tube, which you will have to do to change the transfer port and seal, be sure to remove the upper rear sight screw before you remove the rear lower grip screw. On my 1300, that upper sight screw actually threads into the lower screw and it will shear off if not done in the order I just described. Replacements are non-existent.

[SwampHunter]

Thanks guys, I am following pretty good so far but have a couple questions.
 When converting to a steel breach, I have been looking at a few post and am confused on which one to use, I would like to do away with the rear cock if possible, not a deal breaker though. Seems to be some confusion about which particular breech to order, pertaining to breech screw location?
  The TP you describe replacing the old one with sounds like a standard disco type?

[SwampHunter]

Also, I have a Maximus barrel, and a variety of bolts for the disco style breech that are .22 Cal, would those work with the barrel shortened?

[c_m_shooter]

The disco parts will work.  I haven't worked on a rear cocker in awhile, the hammer may need to be drilled for the pin that goes up behind the bolt handle or swapped for a disco hammer if you already have one.

[SwampHunter]

The 13xx tube and disco tube are the same diameter? I have a disco hammer bit didn't think it would fit.

[Stinger177]

I'm at work right now so I'll have to make this brief for the moment.

Yes, there are two different locations for the breech screw. Open the bolt as if to load a pellet. If you see a screw hole in there it's the newer more forward location. If not, it's under the bolt more rearward.

TP  parts should be as I described above.

Ridding of the rear cocker involves new hammer, hammer spring and rear cap, along with a hammer pin (the one that the bolt pulls on to move the hammer back) and, a new sear. The rear cocker sears are shorter. By the time you do all that you may as well buy a new 1377.

Don't know anything about Disco parts other than the barrel.

Will add more tonight if necessary.

Good luck.

[SwampHunter]

It has the screw that you can see towards the front of the loading gate. So a standard steel breech should fit correct?  If I understand correctly I can swap a steel breech and the .22 bolt and barrel I have, the only difference is it will retain the rear cock feature?

[Stinger177]

It has the screw that you can see towards the front of the loading gate. So a standard steel breech should fit correct?  If I understand correctly I can swap a steel breech and the .22 bolt and barrel I have, the only difference is it will retain the rear cock feature?

Yes, that is all correct. You can hold your .22 breech right up next to the 1377 A/C and compare just to make sure, but the difference in screw location is not minute. it will be obvious if they are different. You will notice that when you remove the original breech, the barrel is very firmly (if not permanently) attached to it. The diagram I posted above is for the newer version. This image shows the sliding breech cover style that you have. In it you can see that part #63 (1300-11) comes as one unit - barrel and breech. Replacing it with your .22 breech and barrel should not be a problem. This diagram is for an older 130, but they are the same design.



That forward breech screw is a .05 inch allen (or hex) head screw. That size allen is actually not that uncommon. I found it on the Husky brand Allen combo (SAE) set from Home Depot or Kobalt brand from Lowes (the smaller version combo, not the larger). It is not uncommon for the hex wrench to strip out the inside of that screw. I would advise using a clamping force to press the barrel tight to the main tube before trying to loosen the .05 screw. I use a wood clamp. Some people advise using a Torx (#6 I think?) instead of the .05 as it gives a better bite. Magnum Airpower sells a replacement torx screw just for that reason.

Also, if your .22 barrel happens to be longer than the 1377, you can drill out the front sight/barrel band (7/16" diameter) all the way through.

I should correct something I said earlier. The rear upper sight screw on this gun does NOT screw into the lower bolt. That is for a 1300 self-cocker as in the diagram in this post. Sorry for that misleading information.

There are so many variations of these Crosmans using the same parts in one place (i.e. the single-unit breech/barrel) and either a self cocking arrangement or rear/pull cocker it's hard to describe them.

What you will be building is yet another hybrid with a rear cocker and a lever/bolt breech. It's not unheard of, and I've seen it done before, although I have not done it myself. I'm also not so sure that Crosman themselves did not make a gun with that arrangement, but if they did, I don't know what model that is.

Hope this helps.

[SwampHunter]

Ok,  thank you very much for your help!

[Stinger177]

No problem Travis.

I'm not pretending to know everything there is to know about Crosman 13xx's. It's just that I went through all of this just last Fall so I thought I'd try to help out while I still remember. 

[SwampHunter]

You have definitely been a big help! I started on the disco platform and know just about enough about it to get myself into trouble now LMBO.

[mav72]

Great suggestions. This is what I know about my rear cocker 1377. If you are planning on getting rid of the rear cocking knob, it’s best to get a whole new 1377 because you are going to be changing out most of the parts.

I kept the rear cocker and just converted to the steel breech and left mostly everything else stock. To do that, you just need a breech, a new transfer port, and a new barrel. You’ll probably need a reseal kit. If you find that you have a brass valve stem, don’t throw it out. You can rebuild it for later use. As for the pump tube, you can take the rust and bluing off with CLR. Soak a paper towel and role the pump tube, and let it sit. From there, you can reblue, polish, or paint it.

You can go flat top with these but you have less tuning options compared to the newer design.

[SwampHunter]

Yes, I think I am going to buy another and put this on the back burner until I come up with something lol.

[Stinger177]

The great thing about a 1300KT from Crosman's Custom Shop is the pricing. Although I have yet to buy anything from them, it appears that they give back some price break for parts upgrading.

A 1300KT with the rear stock, 14" LW barrel (too bad they don't have an LW in .22, if that's your choice) and a steel breech for $141 and change is a really great deal.

TIP - for 5 bucks or so, get a trigger shoe. I think they're great and if you don't like it, take it off. Don't get the muzzle brake. Save the money toward a TKO - you won't regret doing that!

I just love spending other peoples money!!   

[SwampHunter]

The great thing about a 1300KT from Crosman's Custom Shop is the pricing. Although I have yet to buy anything from them, it appears that they give back some price break for parts upgrading.

A 1300KT with the rear stock, 14" LW barrel (too bad they don't have an LW in .22, if that's your choice) and a steel breech for $141 and change is a really great deal.

TIP - for 5 bucks or so, get a trigger shoe. I think they're great and if you don't like it, take it off. Don't get the muzzle brake. Save the money toward a TKO - you won't regret doing that!

I just love spending other peoples money!!   

I was disappointed that they don't have a .22 lw option. I was under the impression that they did at one time. It is an option on the Co2 models but not the pumper. If I decide to order one I am going to call and talk with them beforehand.

[mav72]

The great thing about a 1300KT from Crosman's Custom Shop is the pricing. Although I have yet to buy anything from them, it appears that they give back some price break for parts upgrading.

A 1300KT with the rear stock, 14" LW barrel (too bad they don't have an LW in .22, if that's your choice) and a steel breech for $141 and change is a really great deal.

TIP - for 5 bucks or so, get a trigger shoe. I think they're great and if you don't like it, take it off. Don't get the muzzle brake. Save the money toward a TKO - you won't regret doing that!

I just love spending other peoples money!!   

I was disappointed that they don't have a .22 lw option. I was under the impression that they did at one time. It is an option on the Co2 models but not the pumper. If I decide to order one I am going to call and talk with them beforehand.

At one point, I thought they did. Maybe it’s a barrel satabilization issue with these guns. The platic barrel bands maybe move too much.

[rangerfredbob]

The disco tube and 13XX tube are different sizes just to throw that out there... so hammers are different.

To fix that one really all you need from what you explain is a new pump cup ($1.15 from Crosman parts), while there I would get a new valve stem ($1.15 again) and take the probe O ring to a hardware store and get a new one. That'll get it back to working again. While there I think the carbine stock is like $12 if you want one...