View Full Version : Stevens Model 520

September 9, 2007, 02:39 PM
I have a Stevens model 520 in 12 gauge that belonged to my grandfather. It has the 2 step squared off receiver with "J. Stevens Arms Company" stamped on the left side and the safety located inside the trigger guard. S/N is 629XX

I've been searching for info on the slide unlocking mechanism. I obtained copies of Brownings original patent application that explains how the recoil operated slide unlocking mechanism works. However, the parts on my gun don't match the parts on the patent drawing. I understand that quite a few years have passed between when the patent was issued and when the gun was manufactured, but I've yet to find anything in any of the parts breakdowns I've seen that matches what's inside of this gun.

If anyone could provide a source for a manual, schematics or assembly / disassembly instructions I would greatly appreciate it.

James K
September 9, 2007, 07:44 PM
I used to own one of those that I bought from Letterkenny Army Depot for $17.50 many years ago. I sold it (at a small (?) profit) to a collector of military shotguns.

IIRC, there is no recoil operated slide lock on that gun. The slide unlocks when the hammer falls. Further, there is no disconnector; if the trigger is held back the hammer falls when the slide goes forward, so the gun will fire as fast as it can be pumped.

FWIW, patent drawings often don't look like the production item, since they are based on the inventor's model. The reason for a patent is to get some concept protected, not to produce engineering drawings. In addition, it was common practice at that time to put on as many patent dates as possible, even if the patented item was not used on that gun. I guess the idea was to impress the buyer and intimidate the competition.


September 10, 2007, 10:16 AM
Thanks for the reply.

I knew about the disconnector, but it never hurts to keep repeating it (no pun intended). Might just keep somebody from getting hurt.

My 520 definitely has a recoil operated slide lock. If you rack the slide and drop the hammer on an empty chamber (or snap cap) it won't unlock without using the manual unlock lever. But give the business end of the barrel a bump on the carpet and the action opens right up. I haven't tested this with live ammo because I'm reluctant to break something and the gun has a great deal of sentimental value to me.

I've attached some pics that show how I THINK it works. Plz forgive the quality.

Here's my theory:
When the slide is moved fully rearward it contacts the mystery part (for lack of a better term) pushing it back which then releases the slide lock and allows it to move up, thus locking the slide. During recoil the part moves forward and engages a pin on the slide lock moving it downward, disengaging the lock.

If anyone can correct my interpretation or add something I missed, it would be appreciated.

September 10, 2007, 07:39 PM
Up until a certain date, not sure exaclty when, but seems it was around 1910/1920, the patent dates for all applicable (claimed applicable, anyway) patents had to be on the item, or they were not covered.

James K
September 17, 2007, 12:55 AM
I admit the old memory isn't what it was, but that doesn't look like the gun I had. I recall a tang safety, and don't recall any "mystery part". Nor is anything like that shown in the parts in the GPC catalog, though it does show the trigger guard safety. (They list it as "old model".)

As I said, my gun had no recoil slide lock, and that one appears to be an "add on" improvement, though a clever and effective one.

In other words, just more confusion in the world of Savage-Stevens-Springfield.

Perhaps this is not right, but how about trying www.jouster.com which has a forum devoted to military shotguns. They would probably be better able to help.

BTW, great pictures!



September 17, 2007, 03:52 PM
I'll give your link a try. I hadn't thought of the military version. Good call.

I appreciate your taking the time to reply. If I find anything I'll be sure to share it.

September 17, 2007, 04:36 PM
Jim, your idea to chase the military line is starting to bear fruit. Nothing conclusive yet, but I think I'm on the right track.

C&P from www.subguns.com:

"...The earliest guns used an inertial weight to unlock the slide lock. My oldest one has a round button on the left side of the receiver to do this..." -John Browning's original design!
"...while a slightly newer one I had used a small lever jutting out from the bottom of the receiver, but it was still attached to an inertial system..." -Just like mine!
"...The later(after mabey 1906/08?) guns use a modern system where a spring extension rides in a slot on the side of the hammer. The falling of the hammer allows the spring to move the slide lock out of engagement with the slide, unlocking the gun for a quick reload..." -Posted By: Chuck Madurski (credit where credit's due)

September 17, 2007, 08:49 PM
I've got one of those with 1905 and 1907 patent dates. It only locks when it's cocked. Pull the trigger on an empty chamber and it unlocks.


k Squared
September 18, 2007, 04:25 AM
"If anyone could provide a source for a manual, schematics or assembly / disassembly instructions I would greatly appreciate it."
Try these sites:

> http://stevespages.com/page7b.htm
> http://www.biggerhammer.net/manuals/
> http://www.e-gunparts.com/aboutschematics.asp

September 18, 2007, 05:23 AM
Thanks K, that first link is awesome. I could spend days just looking at all those original manuals. No 520 though (rats!).

Nice pic Hawg. From all the searching I've been doing I think I may have actually learned something. I'm a long way from holding my own with anybody here, but there's hope.
From what I've been reading the top gun is a 520A? Squared receiver, shorter tangs with the safety mounted on the top tang.
Lower one looks just like mine except your forend is checkered, mine has vertical grooves. And of course, the evil inertial system.

Thanks guys, I really appreciate your input.

September 18, 2007, 05:57 PM
The top one is a Riverside(later bought by Stevens)made on the original Browning patent. Slide handles on both are original, stocks on both are replacements.

September 19, 2007, 07:27 PM
HAS EVERYTHING YOU WANT TO KNOW.pictures of assembly of each group.
Brownell 1959 edition.much more of pistols and rifles.big book.:):)

September 19, 2007, 10:50 PM
Reference to Riverside, Riverside was a Stevens " Store Brand " There was no Riverside Gun Co. per say.

September 20, 2007, 03:35 PM
Actually you're partially right. There was a Riverside Arms Co. which was acquired by Stevens in the early part of the 20th century. Stevens did continue to use the name until the 1940's.;)

September 20, 2007, 04:54 PM
Thanks Teddy. Funny you should mention it, I received my very own copy of the EOMF in the mail today. Very cool book.

The one shown there is the newer version with the hammer actuated slide unlock. At least I know how that one works now.

There's another detailed view of the 520-30 trigger/slide lock mechanism on pg. 191 thru 194, if that'll help anyone else.

September 20, 2007, 05:02 PM
There are some nice pics of the early version of the inertial slide unlock here:

I hope it's OK to post links here, I know some forums frown on that type of thing. Didn't see any prohibitions in the Forum Rules, so please let me know if it's uncool here.

April 14, 2010, 06:44 PM
I have one of these that was my Grandfathers. It doesn't fire when I hold the trigger and chamber a shelling the slide. If I hold the trigger & cycle the gun, it loads a shell and then I need to eject the loaded shell. What parts need to be replaced?

April 14, 2010, 09:03 PM
I helped a friend fix his 620a which is the same as the 520,but a rounded reciever and a tang.We ordered a schematic from numrich arms.

April 15, 2010, 10:06 AM
thanks. I will look at the schematics. Is this shotgun supposed to fire if I hold the trigger while cycling the action? I would think it was supposed to because I have heard & read that before. I guess I am looking for suggestions as to what parts typically needing replacing to make this work as designed. I know without looking at it it can be difficult, if not impossible to tell, but was hoping someone had this issue.

April 16, 2010, 09:29 AM
The original 520 did have a recoil operated action lock controlled by an "inertia bar" that rode in a groove milled in the left side of the trigger guard. It was soon replaced by the curved wire spring used by all subsequent models to unlock the action lock. You probably won't see this in any of the schematics. I used to have one with a missing bar that I milled out the triggerr guard to accept the more modern part and restored the function. Here endeth the lesson. Goatwhiskers the Elder

October 10, 2011, 09:46 AM
After lots and lots of hunting for info, the Wards Westernfield Model 35 (Stevens 520 20 ga. pump) was only made from 1903-1937. The humped receiver and safety on the trigger guard was stopped making in 1920. Straight receiver and safety on receiver is post 1920. Info is hard to find on this gun. I'm looking for a breakdown instructions if anyone can help. Just got the gun and it needs a good cleaning. Also, thanks for the info on the slide release. I thought mine was messed up.