Newbie question on pumping 1377

[Maury]

Tried to post here for the first time yesterday and must have done something wrong, so trying again: Hello to all!

I am brand new to this entire pursuit: got my first 1377 a few months ago and have been hooked ever since.  Gun is vintage 1994 and originally belonged to a relative; I doubt that it has ever been serviced and definitely never modified, but seems to be quite sound.  After many hours of YouTube-ing videos on the subject, I have managed to replace the plastic trigger with a metal one (polished and buffed it, too!) and replaced the sere spring. No big deal for most of you guys, but I am pretty proud!

Anyway, I do have a  question in regard to pumping.  I am in pretty good shape, but I noticed that after 2 pumps, I need to work lots harder for a third pump.  Seems like over 4 pumps would be putting much too much strain on the components.  I tried replacing the pivot pin with a well-fitted machine screw and that seemed to make it a tad easier, but I still hesitate to pump it more than 3 times.

So is this to be expected and not a worry or an indication that there is something that needs to be done?

Thanks!

[foxwalker]

That's a tough one because it's an older model..but I would pump it 5 times shoot it into a peace of wood..them pump it 10 times  shoot it and see if the pellet go's deeper...or you can dry fire it .just listen to the sound ..you did not mention oil..I hope your oiling it with pellet gun oil or 30 non detergent motor oil...just pump it your not going to hurt it 

[Maury]

Thanks for the reply.  You also mentioned oil for my gun.  I do not have any of the Crosman brand right now, but I do have Tuf-Glide liquid and a small container marked 'silicone grease' that I got on line specifically for flashlight o-rings.  Would you recommend either of those?

[foxwalker]

Well , No .. the parts are designed for a certain type of oil with the right viscosity.. Walmart should have it cheap .you can order it on Amazon cheap or you can get some non detergent 30 W motor oil ...the gun has not seen oil in a long time I would put 6 drop in front of the pump cup to get it all over the valve and seals , then dry fire it a 5/6 time to get the excess oil out,then clean the barrel.... it will get much easier to pump....if you don't have anything to clean the barrel with you can shoot some q tips lol..it works.... or you could just shoot the hell out of it ......it will start shooting better. Eventually    but not ass good without a cleaning....good luck 

[foxwalker]

Also  the wrong oil can eat the rubber plunger  and gum up..ask me how I know 

[Multigunner]

When I first got my 1377 it had been in a storeroom for years and I found it extremely difficult to pump even a few times. Not knowing about Pellgun oil I tried silicone spray lube I'd used on air soft guns with little effect. I then tried pure medical grade mineral oil, which softened the rubber cup a bit. I then tried Transmission fluid, which some recommend. Transmission fluid does renew old dried out O-rings and pump cups but provides little in the way of lubrication.

It seemed more than anything else that the inlet valve was just not opening fully or was partly blocked in some way.
The gun, since converted to a .22 carbine, now pumps normally to ten pumps or more.
I don't recommend over pumping but we all do it sooner or later. I normally use 12 pumps as this seems to give the best accuracy and with the 24" barrel I'm using the extra impulse is not wasted. At ten pumps I get 535 FPS with a 14.3 gr .22 pellet ,at 12pumps  565 FPS IIRC.

With an unmodified 1377 rather than going for higher velocity going for higher energy by using a 10.5 gr pellet would be more productive.

For target practice only six pumps should be plenty.

These guns are plenty over built. I've seldom heard of anyone breaking one unless they just deliberately abused it.

Don't worry though, by the time you've been here for awhile you'll be investing in upgrades to push the limits of the design.

[Maury]

First off, thanks to all: replies and info most appreciated!  Just checked prices on line and it seems lots cheaper to order a quart of non-detergent 30 weight oil.  That should last me a bit anyway.  Also have some heavier pellets on the way. Somewhat of a relief to know that I am not in danger of damaging the gun right now. 

Biggest potential danger (as I check out posts, photos of some of those over the top modified guns and YouTube videos), seems to be to my bank account!. Maybe there ought to be a warning label here someplace!

[Multigunner]

I think Pellgun Oil is most useful for CO2 powered guns due to the extreme temperature ranges and erosive and corrosive nature of CO2 under high pressure. The Monolec additive isn't really necessary for pumpers and spring guns.

In older manuals for some pre WW2 Crosman air pistols they state that no oil should be used because it degraded the seals but I expect the materials used then were quite different than what we are used to.
The manuals did not state what lubricants if any were safe to use.

Oils with Monolec were only available for use in high performance aircraft engines of the day and some heavy duty marine diesel engines.

[rangerfredbob]

I normally just use air tool oil, but I've had a quart of that around for several years anyway... some ATF would probably be fine too

One thing to note, on the machine screw you used for the pivot, I would look at that again and see if there are threads riding on the pump linkage part, that is fairly hard on the pivot if there are threads contacting the pivot area, that increases the forces applied to that area a lot and will cause more wear... When I can I just re use the factory roll pin just making sure the seam points away from the grip. I made one replacement pin but it hasn't been a big enough of an issue with the stock roll pins to deal with making more. I might make something for my newly acquired 1322 but it is an older model with a snap ring holding a shouldered pin in...

[Maury]

I did try replacing that pin with a machine screw as per a YouTube video and although it seemed to make a bit of difference, the fit was not close enough and I ended up putting that original part back.  I will check on where the seam is: thanks for that tip.  Have a feeling that proper bit of lube – for the first time in 25 years! - should make more of a difference.   Currently waiting for a quart of non-detergent 30 oil to arrive.  Just under $5 on eBay, so I could not resist.  Will probably also be using that for a long time.....!