Wednesday, February 4, 2009

Smith and Wesson Model 79G Disassembly, Part 1

A friend asked if I could try and reseal his S&W Model 79G pellet pistol for him. I used the article in Airgun Hobby magazine, Volume 2 Number 1, "Rebuild the Smith and Wesson 78G and 79G" by Peter Ruut, for a general guide of how to proceed with disassembly.

.177 caliber, CO2 powered.

The piercing cap was removed.

Then the grips.

The threaded plug at the front of the barrel was unscrewed.

And the power adjustment screw was unscrewed from the plug.

The adjusting rod and sleeve slipped out.

The small screw on the side was removed.

The "slide" springs up at this point.

The frame and the slide.

There's a small metal plate with a hole in it at the muzzle end.

I had trouble getting the sheet metal spring guide out, the pot metal of the frame had peened over on one corner. A tiny amount of filing freed it up to be removed.


The spring, cocking lever, plate and spring guide.

The trigger spring, prior to being fished out.

The trigger is removed by punching out the pin. I tried punching it from the other side but it wouldn't budge with gentle taps. Rather than break anything I tried this side. It came out easily.

The pin has a knurled end, so it can only go out one way.

More to come...

16 comments:

Jacques said...

Thanks for the amazing writeup and pictures. I bought my dad a 79g, but the seals are bad and I was trying to replace them, but I can't seem to get the "slide" off the frame. It pops up, but that's as far as I can get.

Do you just keep pulling up, or does the "slide" slide forward, or is there a pin ort something holding it in?

Felice Luftschein said...

It's hard to say without seeing it, on mine it did just come off but it may be that it's stuck somehow so forcing it would be a bad idea. Try removing any other parts you can and see if that helps getting the slide off?

Nick

dfdann said...

I just obtained a S&W 78G. It has an adjustable trigger but I have received opposite answers on which way to turn the set screw to lighten trigger. How do I adjust the trigger?
Thanks, Dan

Nick Carter said...

No idea how to adjust the trigger, don't have that one here anymore.
Nick

Anonymous said...

Fantastic blog. I have a model 79g with fractured "o" ring(s?). Your site has exactly what I needed. Thank you!. I am wondering if the "o" rings are unique to this product, or, more likely, a standard "o" ring which could be identified and easily obtained. I also appreciated the references to other articles and information.

Felice Luftschein said...

For o-rings I use Viton, although the professionals use polyurethane. You can get poly o-rings from Mac1 airguns. Viton you can get from most industrial suppliers. The cheap o-rings (Buna) don't work as well and often swell from the CO2.

joejeweler said...

Most of you might be as interested as i was on what mods can be done to these pistols, and would be especially useful in the similiar
.22 caliber Smith & Wesson 78G model.

Eric does a fine job at explaining what he currently offers on the
S&W 78G.

My pistol is currently being given
the full treatment of his stage 1 and 2 mods.

Two weeks is a LONG wait now! lol

http://houseofhomelite.proboards.com/index.cgi?board=wolf&action=display&thread=290

SACE/MRT said...

nick my sleeve was stuck/bound up. made an inside puller from a "RED HEAD" 5/16" x 2 1/2" hex sleeve anchor found at home depot or lowes. diameter was ~.31" (too big). turned down both expander and end of sleeve by spinning in drill motor up against a belt sander to ~.29". push in, tighten, pullout. blue tape around sleeve to protect 79G inside threads. the viton main seal on screw cap blisters, high pressure co2 permeates viton, after pressure drops off, seal starts popping. may try polyurathane seals.

Anonymous said...

where is the best place to get the orings for the 79G? How many o-rings are in this gun? Thanks for any info....

Nick Carter said...

For reseal kits, parts and service you can try Bryan and Associates, Mac1, Precision Pellet or JG airguns.
http://www.bryanandac.com/
http://www.mac1airgunstore.com/
http://www.airgunshop.net
http://www.jgairguns.biz/

In the UK: Lawrie Amatruda, lawrieandpat@talktalk.net
Chambers Gunmakers
http://www.gunspares.co.uk/shopdisplaycategories.asp?id=23960&cat=Airgun+spares

Tell them I sent you.

Anonymous said...

Do you HAVE to remove the trigger and spring to get the valve out?

Anonymous said...

The adjusting sleeve will not slide out any suggestions?

Nick Carter said...

http://anotherairgunblog.blogspot.com/2012/10/another-s-78g.html

Shows a tool I made to grab it internally.

Dennis Cotten II said...

I received 79g from my grandmother quite a while back. My parents put it up for me until I was old enough to use it. well by that time the piercing cap, (not sure if that it the name) it's the piece that screws into the handle and holds the co2. Sorry I really don't know much about these guns at all. but I am wondering where I might be able to get a replacement cap. All my searching on Google has so far come up short, might be because of my lack of knowledge on it.

ANY help would be appreciated. Also I would like an authentic replacement, not something that will "just work", but makes the gun look different then what it originally looked like. Thanks for your time. Hope to hear something from anyone.

Dennis Cotten II said...

Shot in the dark here, but I'm looking for a replacement piercing cap for my 79g. It has come up missing sometime in the last 20+ years and a few household moves later. Does anyone know where I might be able to find one? Also, I would like an original replacement to make it as authentic as possible.

ANY help would be appreciated, thanks.

Nick Carter said...

Your best bet is Ebay, Gunbroker and maybe JG Airguns. Asking around on the Yellow Airgun forum may yield a helpful seller as well.