How Do I "Bob" a Hammer for True DAO?

[November]

I have a 3" SP101 and I'd like to convert it to DAO. I'm okay with cutting off the hammer spur. I just need to know where the single action notch is on the SP-101 so I can remove it. Has anyone done this who can also photograph the hammer (removed from the gun) with this mod so I can compare it to my own? Thanks

 

[bountyhunter]

I believe the SP is a Ruger? I only work on SW's , but I would wager they are similar. If you can take the side plate off, remove the mainspring and operte the action. There should be a single action sear face near the bottom of the hammer that catches on the trigger nose when the gun is cocked SA. There should also be a face on the trigger nose that engaes the hammer when it is cocked SA. I believe the best way to get a DAO action is to grind the SA sear face off the hammer so the trigger nose can not engage it. ON SW guns, the DA action requires the underside surface of the SA "porch" be present because the trigger lifts the hammer by pushing up under it.

I believe if you can work the action with the side off it should become apparrent what material needs to be removed to prevent SA cocking. Before grinding, cycle it DA and make sure it is not part of the DA cycle.

On a SW hammer, the SA sear is a square area right near the bottom (as installed). It looks like it has two "steps", the upper one taller than the other. As you cock it SA, the trigger nose rides along that sear face. When you release the hammer, the trigger nose catches under the edge of the taller step. If you grind the taller step down level with the other, you should have a DAO gun that can not be cocked SA.

 

[Johnny Guest]

But, WHY?

http://www.thefiringline.com/forums/showthread.php?t=152352


Best,
Johnny

 

[November]

bountyhunter,
you are right that the sp101 is a ruger. The Ruger revolver design doesn't use sideplates. When you pull down on the trigger guard during disassembly, the trigger, cylinder hand, transfer bar, etc. all come out (kinda like stripping the guts out of a fish). Otherwise, the sideplate idea was a good one. After looking at the hammer and reading your description, I think the Ruger has a similar hammer design. Usually, I'd just buy a DAO hammer, but Ruger won't sell them. Either way, I'll figure it out eventually. Thanks for the assist.

 

[knzn]

But, WHY?

Arguments can be made for the conversion. One is that if the revolver is used in a self defense shooting. Cocking a revolver in a legitimate self defense situation has in the past been used against the good guy.

Lawyers for the bad guy have in the past made cocking look bad in that there is the possibility that in the stress of the moment that the gun fired not because the good guy wanted it to at that instant, but because it fired accidentally due to the short light pull required in single action.

 

[Jim March]

You can only "Bob" a hammer if you first name it "Robert".

 

[JohnKSa]

I'm in the "WHY?" crowd. I can see bobbing the hammer--that makes the gun more snag proof and perhaps lighter. Since you never intend to cock the gun there's no loss of function.

But why cut off the SA notch? If you don't want to cock it, just don't. There's no functional benefit to getting rid of the SA notch that I'm aware of. It doesn't hamper the DA pull in any way.

If you really feel it's important, you might call and explain to Ruger what you are doing and see if they'll send you a hammer with the SA notch already removed--or one that you could modify. Then you could keep your original hammer. If you ever sell the gun, it might be handy to be able to sell it in original condition.

If you go this route, DON'T modify the hammer currently in the gun. It's a fitted part and the second hammer might not work in SA without fitting. The DA portion is not so fiddly which is why I think Ruger might sell you one to modify if you let them know it's going to be for DA only.

 

[Jim March]

Seriously now: to properly and safely decock ANY DA revolver, esp. one with a frame-mounted firing pin and transfer bar so there's no firing pin on the hammer, you need to throw the pad of your thumb all the way over the hammer and down the forward face...putting your thumb in between hammer and frame. This is done with the barrel close to vertical in the outdoors, or with your wrist flipped and barrel downwards indoors.

This is far safer than the "thumbpad on hammer thumbrest" method. And it works regardless of whether or not the hammer has been "bobbed".

It does require at least medium-sized hands. If you can do this, and you do so on a regular basis with all your guns (which means not buying any firing-pin-on-hammer guns), then eliminating the SA notch on bobbed DA hammers isn't necessary. You can even hand-checker the top of the hammer for "some SA capability".

If you're NOT going to switch to this decocking method as your standard drill, then you need to remove the SA notch on bobbed DA hammers.

 

[JohnKSa]

Jim,

If I follow this right, you're saying that decocking a revolver with a bobbed hammer is tricky-- if one is not willing to practice the proper method the SA notch should be eliminated.

But I can't imagine a bobbed hammer revolver getting cocked by accident--is there some sort of failure mode in a DA revolver that could leave the hammer cocked?

Still asking why, I guess...

John

 

[popeye]

Murphy's law. And if you sell the gun will the cocking info be passed on down? Especially if it's sold 2-3 times. The third owner may not be so knowledgeable and wonder some day and say to himself " i wonder if I can cock this thing"?

Never happen? A friend of mine owns a gun store ( much to my bank accounts dismay) and he had sold a snub (standard spur hammer) to a lady one day. A month or so later she walks in his store and pulls the gun out of her purse cocked and loaded, carelessly pointing it around. She asks him " how do I make this thing with the pointy thing on the end go down" It keeps catching on things in my purse".

 

[Jim March]

John, once you have a "cockable bobbed hammer", you can still cock it and fire it SA. You need to start the hammer motion with the trigger is all .

This sort of configuration is for the EXPERIENCED SHOOTER ONLY!!!!!!!!!!!

Popeye has provided a graphic illustration why .

In very experienced hands, this sort of thing isn't dangerous, BUT I personally believe that even such an "experienced shooter" must switch completely to the de-cocking drill that works with hammers that don't have a firing pin on them (thumb down in front). Which means eschewing classic S&W DAs, true Colt SAAs and clones, etc. AND shooting a fair amount and doing enough dry-fire and handling drill that this decock method (thumb all the way in front of the hammer) is utterly ingrained.

That's my opinion.

I can recall one elderly gent at a range showing me his Taurus snubby with a home bob-job. I asked him if it was a true DAO conversion...he said yes. I confirmed the unloaded status, pointed it downrange, cocked it by starting it with the trigger. He was shocked, and didn't realize that was possible. I handed it to him, and he had no idea how to de-cock it. I showed him of course but this is a classic example of what happens and what people need to understand.

Another thing: say you take it all apart, figure out where the SA notch on the hammer is, and file it out to "finish the process". Cool. Are you *sure* you did that part right? Is there any possibility it could "hang up" back there with basically a 1/8th pound or so "seriously hair trigger"? I'm not a gunsmith, so I couldn't say for sure how likely this is, but at a guess it would appear to be at least possible. At a minimum, test the hell out of it, repeatedly trying to "cock it" with pressure on the hammer from various directions.

I'm not saying "don't modify your gun", not hardly. DO be aware of consequences and things to check for. Make a deliberate decision whether or not you want to leave a "minimal SA capability" in there with a bobbed hammer and if you do, understand how to handle such a beastie. Print up a warning on a 3x5 card explaining how this gun works and how to de-cock it, seal it up in clear packing tape so it'll last basically forever, and stash said card in with the gun's container. If you die, it won't end up killing a relative/descendent/purchaser.

 

[Mannlicher]

I sent my Model 65 back to S&W for this. The factory did a fine job, installing a factory bobbed hammer and DAO lockwork. I am sure there are a number of good gunsmiths that can do this work for your Ruger.
For a revolver that I will use strictly for CCW, it makes sense to me. Other than my SA revolvers, I do almost all of my revolver shooting double action anyway.

 

[Old Fuff]

I know of three cases where an individual managed to get a bobed hammer cocked because whoever did the work hadn't removed the S.A. notch on the hammer. When they tried to lower the hammer they slipped, and of course the revolver discharged. Fortunately no one got hurt or worse. Once the hammer was cocked they couldn't open the cylinder to unload it. In fairness to Jim's remarks these were all S&W or Colt revolvers with the firing pin mounted on the hammer nose, not in the frame.

I have always made it a practice to modify the hammer by removing the single action notch, as part of of a "bobbing the hammer" job. I presume the gun's owner/user will not intentionally try to shoot it in the single-action mode after this conversion has been made.

 

[Jim March]

Yup. I don't think this "sorta DAO" is safe if the hammer has a firing pin.

The safe way to decock such a "FrankenDAO" when there IS a hammer-mount firing pin involves use of a pen or pencil across the hammer, underneath the firing pin, sideways. Fire it onto that (IN A SAFE DIRECTION!), come off the trigger, pull the pencil/pen/etc out sideways.

The same basic thing with your pinkie is *possible* but you might get pinched hard enough to bleed depending on pinkie, gun, etc.

 

[bountyhunter]

Once the hammer was cocked they couldn't open the cylinder to unload it. In fairness to Jim's remarks these were all S&W or Colt revolvers with the firing pin mounted on the hammer nose, not in the frame.

FWIW, I believe the SW design is such that the cylinder CAN be swung out when the gun is cocked SA. The hand rises up and is flush with the breech face at that point (assuming it is correctly fitted). I am not sure about a Taurus.

 

[Old Fuff]

Bountyhunter:

In a S&W revolver the hand isn't an issue because it is on the right side of the ratchet, and the Cylinder swings out to the left.

However the Bolt (the part the Thumbpiece is attached to) and unlocks the Cylinder has a lug on the back. When the Hammer is cocked, contact between this lug and the back of the Hammer prevents the Bolt from moving forward far enough to unlatch the Cylinder.

At least this is the way things are supposed to work ...

If a S&W Hand Ejector revolver is available for your inspection, unload it and then see if I'm not correct.

I wouldn't press this issue except for the possibility that someone might get a loaded S&W revolver with a bobbed hammer cocked and then try to open the cylinder with negative (and possibly loud) repercussions.

 

[SLCDave]

Bountyhunter,

I have a Taurus 627 Tracker, and when the hammer is cocked, you cannot swing out the cylinder.

 

[fastball]

I don't think so'

Bountyhunter--- the cylinder on Smiths can not be opened with the hammer back SA. Just tried my formerly loaded ( unloaded to test) Mod 13 and Mod 15 to check this. --Think that would be likewise on most or all other mods.----Tom

 

[popeye]

On S&W's anyway, you can swing the cyl. out, push the cyl. release back, and cock the hammer. Perhaps therein lies the confusion.

 

[bountyhunter]

OK, maybe it's the other way? If the cylinder is out and you move the thumb bar to cock the hammer, then the cylinder can be closed with the hammer back. I never tried the other way, thought it worked the same.

 

[Old Fuff]

Oh boy ......

Yes, it is true that you can open the cylinder, pull or push the thumbpiece backwards, and then cock the hammer.

However be darn sure you lower the hammer before you try to close the cylinder. Doing otherwise could cause the ratchet to batter the hand.

Obviously revolver-fixer aren't going to end up like Maytag repairman ...

 

[deputy tom]

November,I have side stepped this post for five days,mainly 'cause I hate to start flame wars,but here goes.Removing the hammer spur was originally called "Bobbing" the hammer or De-Horning.Several years later some armchair commando decided to use the term " De-horning " to include all matters of smoothing out a firearms frame/edges/corners/etc.Neutering the firearm was a term used for removing the notch rendering the firearm capable of firing only in double action mode.Massad Ayoob was a big proponent of this procedure(neutering) for his new england reserve police department as a way(I believe) to keep their insurance premiums down.You can neuter the revolver without removing the hammer spur and you can remove the spur without neutering the revolver.Don't mix up the two terms.tom.

 

[November]

Popeye said it better than I could, but that's exactly why I want to go all the way and remove the thumbpad and sigle-action notch. I want to remove Murphy (risk of an AD by myself or anyone else) from the equation as much as possible.