Tuesday, August 21, 2012

Master Lock #3 Padlock teardown and the Peterson Silver Bullet Bypass

I don't own many bypass tools. To be exact I own two, one of my own making and the Peterson Silver Bullet for Master Lock Padlocks.
I picked up the Silver Bullet at Defcon from the Merch area, it looked deceptively simple from the example lock and demonstration. I just so happened to have a #3 padlock I had brought with me so I bought it.

I spent the next several days trying to figure out how in the hell to use the damned things. I read the directions a few hundred times, I looked online and all I saw was a lot of videos showing how easy it was and descriptions of "you just slide this one in, press down, then slide the other one in and press down".

I could not get it to work.

Furthermore there was nothing online that showed exactly how it worked, what it moved, and what the lock looks like inside.

So I decided to tear my lock apart and take a look for myself and see exactly what the hell I was supposed to be doing in there.
It's a #3 it got a bit ground off
So these here are the bypass tools, one marked A (shorter) and one marked B (longer). I've added a bit of heat shrink as a make shift grip because these are very thin and are hard to hold onto if your fingers are sweaty, also after a few hours of trying to get these to open the lock my fingers were getting sore from the edges of the metal.
Peterson Silver Bullet Bypass w/ "custom" grips

Here's the lock with the face and the unimportant plates removed.

This is what the "unimportant" plates look like. The inside shape is identical on all of them. The ones near the bottom (where you insert the key) of the lock are smaller on the outside to accommodate the blue plastic "Master" wrap the locks have on them.

This is the lock cylinder. Nothing fancy, just a 4 pin setup with no security pins. The back has a protrusion that when the sheer point is reached and the plug turned interacts with a post that moves the locking plates and releases the shackle.

This is the padlock without the plug. Finally I was able to see what was going on in there.
Outlined in Yellow are the locking plates, Red is the post that rotates to move the plates and release the shackle
                                     Here's a larger picture of the internals of the padlock.

                                               This is what the locking plates look like

You can see the scratches where I've been using the bypass on this one.

                                               So this is how the bypass actually works
This is with the A bypass inserted. Now normally you would slide this in while pressing the pins up in the lock to be able to access this, then you have to find where the locking plate contacts the post and press, it will move out of the way without a lot of pressure.

This is with both A and B bypass tools in their proper position. Bypass B tool has to reach the second locking plate which is about 2 plates further down than the first locking plate. Once the A tool is inserted properly it moves the locking plate which also reduces the opening available to get the B tool into it's proper position.

                     Here's some more pictures of the locking mechanism and post.

Post, there is a 3 stamped in the the middle

Side View, when turned the sides contact the locking plates and press them against the springs

Top, furthest from where key is inserted into the lock.

Lock with Top Plate removed, this is the locking plate that the B tool interacts with
Lock with Top Plates removed, this is the plate the A tool interacts with

Here are the 4 plates that make up the locking mechanism for the shackle

So that's it. The mystery of how the Silver Bullet Bypass tool actually works is solved.


  1. Hi dude, really nice article, with good picts ! Love it, was searching infos about silver bullet and in one of the better I found all over the net !

    I wonder if I send you my email, can you send me a pict of the picks with something to see the size, or the template of these ?
    Want to homemade one : )
    Hope it's possible

    PS : I make nice picks, maybe can send you a little gift for that ; )

    1. Sure thing. Take the first word in the address of my blog, add an _ between the k and h and send it to yahoo. The last character is a zero.


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