little old 140.....time for a rebuild

[mac1911]

Picked this up a few weeks ago for the cost of shipping.
I like the 140/1400 pumpers
I will be going with a MAC1 updated pump seal head and maybe a few piston mods for a bit more air capacity internally...
https://imgur.com/a/CSVd9

[35 shooter]

Cool project. Keep the results posted.

[Multigunner]

Looking good. You can't go wrong with Mac 1 parts, the man really knows his stuff.
I ordered a Mac 1 Hot Valve for my S&W 78g restoration and It chronos at 467 FPS with a 14.3 grain pellet and 449 with a 17.2 grain pellet on the lowest power setting. That's about a 70+ fps improvement over factory specs.

I suspect my rebuilt Mk1 has a Hot Valve as well. It gets 440+ with a 14.3 which is 90 FPS over factory specs.

[melloairman]

I still have mine . It was a Christmas gift give to me in the early 60's . Resealed it about 10 years ago . It will be a winter project this winter again . The barrel is lose in the breech and rotates some . If I get that solved I will put a RD or a scope on it . The barrel mounts for a crosman pistol fit the barrel . I some times think I should have just left it in its broke state and looked at it every now and then . It was a used and abused rifle . Slayed more English sparrows in its day than I could ever count . Had to replace the stock .Because the butt had been shorted about 3 inch's so I could reach the trigger . Pump tube hole was so bad I had to drill it and the linkage to a larger size and use a larger drift pin . Then I re sealed it . Yours sure looks a lot better than mine .GL.Marvin

[mac1911]

So far it's cleaning up well. Some one at some point used a sharp object on the muzzle and scratched it up about a 1/8"-1/4" into the bore? I gave the crown a quick clean up. Parts should be here on the weekend.

[melloairman]

They are good shooters . I would rather have a 140 than any of the cheap springer's on the market . Marvin

[Multigunner]

These are fine looking guns.
How does the firing mechanism work with these, hammer and valve or air dump?

[melloairman]

These are fine looking guns.
How does the firing mechanism work with these, hammer and valve or air dump?

Not certain about your terminology it could mean different things to people . When you pull the trigger it pulls back the weight that is resting on the valve to keep it closed allowing the valve to dump air . The weight slides off the sear and closes the valve again . Here is a video that might help .Marvin
https://www.bing.com/videos/search?q...D1&FORM=VRDGAR

[mac1911]

the Mac1 updated pump piston is in and installed. The valve is next

[melloairman]

Looks good keep us posted .Marvin

[35 shooter]

That's a nice sturdy looking set up.

[mac1911]

That's a nice sturdy looking set up.

i have 2 of the upgraded Mac1 piston heads in 2 other pumpers. They work and are much easier to replace the Oring when worn than the old style pressed on cup style piston seal.

Received the rest of the seals monday. Although my eyes have degraded since the last reseal i did and now i need some sort of magnification help to see the small seal "quad" im trying to install in the exhaust valve.

[GBertolet]

I have an old 140 in need of an upgrade. Many fond memories from back in the 1960's. It now has a slow leakdown. Can anyone give me a link to the Mac1 website, for replacement/upgrade parts?

[melloairman]

I have an old 140 in need of an upgrade. Many fond memories from back in the 1960's. It now has a slow leakdown. Can anyone give me a link to the Mac1 website, for replacement/upgrade parts?

Try this .Marvin http://mac1airgun.com/

[mac1911]

Up and running first 8 shots walked off about 10 yards turned and shot. used 4 pumps for testing. Muzzle and a little inside the barrel is beat up. although I don't shoot much better than this with my target rifle! 8 pumps put a 14.3 grain JSB .399" into a 2x6 piece of pine. That's not to shabby and about par for these old pumpers.

[melloairman]

It is good to hear you have it shooting again . Try some different types of pellets as well . Mine was accurate until the barrel became lose in the breech . Marvin

[35 shooter]

Good to see you got it all together and working. Your penetration test sounds like it's squirrel ready!

[mac1911]

It is good to hear you have it shooting again . Try some different types of pellets as well . Mine was accurate until the barrel became lose in the breech . Marvin

The barrel has some issues I also cleaned the bejeez out of it. I found it takes a good 25-50 pellets through the bore before things settle down. If I can get it to hit soup cans at 25 yards I'm happy

[melloairman]

The barrel has some issues I also cleaned the bejeez out of it. I found it takes a good 25-50 pellets through the bore before things settle down. If I can get it to hit soup cans at 25 yards I'm happy

I think you will be a happy shooter then .Marvin

[Multigunner]

"Mine was accurate until the barrel became lose in the breech . Marvin"

Could the barrel be glass bedded into the receiver?