Ruger Blackhawk - 2 Screw vs. 3 Screw


September 8, 2003, 11:37 AM
Could somebody please explain to me the difference between '2 screw' and '3 screw' Blackhawk revolvers? I am interested in when and why this change was made - a Google search seems to indicate it happened in 1973. What is this 'transfer bar' business all about?

Thanks! I may be a revolver owner soon.... I've got my eyes on a Blackhawk made in 1976 (marked with the "200 Years of Liberty" statement on barrel) chambered in .30 Carbine. Great balls of fire!



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September 8, 2003, 01:29 PM
The original blackhawk had the same safety system as the colt revolver it resembles, i.e. you leave an empty chamber under the hammer. Ruger publicized this in its manual. Lots of people still loaded six though and people were injured because of dropped guns that sheared the safety notch and fired, etc.

The transfer bar system was introduced to prevent these injures and make the gun truly drop-safe. I believe this was directly caused by Ruger losing a lawsuit from someone seriously injured with a blackhawk (who argued that Ruger calling the gun a "six-shooter" invalidated their actual loading recommendations in the gun's owners manual). Anyway, the transfer bar system works by using trigger motion to raise a bar which passes the impact of the hammer to the frame mounted firing pin. The gun is now completely drop-safe with 6 loaded chambers. Some Ruger shooters prefer the 3 screw system because the trigger is nicer and the mechanism is simpler (the transfer bar can break and cause problems). Some smiths will turn a modern Ruger into an old model, but many are hesitant because they may be held legally responsible for injuries which may occur.

Jim March
September 8, 2003, 01:35 PM
OK, there's actually several issues.

First, the transfer bar that started with the New Models (2 screw, 1973 and forward) is an automatic safety similar to what's found on modern DA wheelguns. In other words, you can load it six-up, drop it, and it won't go "boom".

Downsides: there's a slight boogering of the trigger feel as a result. Also, the loading sequence changed a lot: on a new model, you leave the hammer down, open the gate, and an interlink between gate and pawl allows the cylinder to spin. Problem: as you spin it, it clicks, but the clicks don't match up with the cylinder bores actually appearing in the loading gate window lined up ready to drop a round in. And since it can't spin backwards, spin it too far and you've gotta go all the way round to load that cylinder bore.

Which is why Power Custom sells buttloads of $35 "freewheel pawls" with good installation instructions - you can then spin the thing both ways with the loading gate open.

On an old model, you half-cock the hammer, then open the loading gate - at which point the bores line up with the gate on every click.

In other words, the "old model" (3 screw) is basically a Colt with improved metallurgy and coil springs instead of flat.

Still with me?

Good, it gets weirder :).

After 1973, Ruger realized they had a problem. By selling guns that had the safety, they had basically admitted that transfer bar guns ARE safer (they really are, in that idiots would sometimes FAIL to load old models five-up and lower the hammer on the empty). So their lawyers explained that they could be sued if some damnfool blew his foot off with a fully loaded old model.

So, sometime shortly after 1973, Ruger developed a transfer bar retrofit kit for old models, and did a free recall and upgrade program. It's still in effect - send them an old model, you'll get it back with a new hammer, trigger and other stuff in there and the old bits in a baggie. Said old bits CAN be re-installed, so the collector value of the gun is OK so long as you keep the baggie. Almost nobody does. And when an OM goes back for ANY repairs, or even re-bluing or whatever, it gets upgraded and they won't even listen if you tell 'em not to.

So most of the OMs you'll see out there HAVE a transfer bar. On a NM, pull the hammer about halfway back and jiggle the trigger (UNLOADED GUN, please!) and you'll see the transfer bar. It's a flat piece of metal. When the trigger is pulled, it rises. The hammer is then able to hit it, and it in turn hits the frame-mounted firing pin. The hammer is "stepped" such that when lowered and the transfer bar is down (trigger not pulled), the hammer can't hit the firing pin.

Now check the old model - if it's unmodified, the hammer face will be dead flat and there'll be no transfer bar. That gun is safe FIVE-UP ONLY, hammer on an empty. Pretend it's 1873. Modified, well, you'll see the diff.

The loading sequence is the same regardless of the safety present or otherwise - in other words, Old Models always load on the halfcock as described.

Next: all centerfire NMs are build on the same basic frame. It may have different sights, grips, barrel length, SuperBlackhawk Blackhawk, Bisley, Vaquero, whatever - doesn't matter, the primary frame IS capable of 44Magnum or stronger loads. Take that 30cal NM, swap barrel and cylinder (or re-bore both), and you've got another caliber up to 44Mag/45LC.

With the old models, there were two frame sizes. They're usually called the "357 frame" and the "SuperBlackhawk" frame. The latter is capable of 44Mag horsepower. The former is NOT. It's smaller, handles better, but isn't as grossly overbuilt as all NMs are.

I'm 95% sure the OM 30cal was built on the 357 frame.

So which to get?

The NM is stronger in many ways, and there's a lot more parts availability (esp. aftermarket). But OMs, esp. the ones on the 357 frame, have a near-cult following, many people swear by 'em. That frame is often rebuilt as a 44Spl and in theory could handle 45ACP. You COULD set it up for 45LC but most gunsmiths would quite properly refuse - you'd end up with a 45LC that could take "cowboy loads" or a bit stronger, but NOT the "Ruger ONLY!!!" 45LCs that are often hotter than 44Mags. Some of those such as the Bufallo Bore 325grain @ 1,300fps :eek: would probably blow an OM based on the 357 frame to Kingdom Come.

Hope this helps.

September 8, 2003, 02:28 PM
Thanks for the extremely detailed information.

Jim said,

Take that 30cal NM, swap barrel and cylinder (or re-bore both), and you've got another caliber up to 44Mag/45LC.

Can one really 'swap barrels' that easily? Man, this just gives me another exuse... I mean.... justification... I mean reason to buy this gun. "But... honey... it's really two guns in one... see?"

September 8, 2003, 04:32 PM
You can swap cylinders easily. IIRC Ruger still sells some NM conversions with 38/40 and .40S&W cylinders or .357/.38 and 9mm culinders. Some people like to have the .40S&W cylinders bored out a little so they can fire 10mm rounds. Swapping barrels would require a gunsmith to really do it right though.

4v50 Gary
September 8, 2003, 06:08 PM
As always, Jim March did one heckuva fine post.

Was told at the Ruger factory that after they designed the 3 screw, they were sued by someone who had an accident with the older 2 screw. They plaintiff used the 3 screw model to demonstrate that Ruger could have made the gun safer to begin with. :rolleyes:

The ony 3 screw that has remained in production is the Ruger Old Army. If you want to feel how the old Rugers felt, pick up one of those.

September 8, 2003, 06:41 PM
a couple of thoughts, I am one of the cult like followers of unconverted 3 screw (preferable flattop) small frame .357's blackhawks. of mine I have 2 that had their internal beauty done by bob munden and their external beauty done by doug turnbull. They are the last guns I would sell.

They are often sought out by fast draw competetors as the smaller lighter model is an edge.

When ruger converts they stamp the frame under the grip frame, an issue to some collectors.

Ruger will not even mail you a screw unless you tell them the serial number and they check to to see if it has been converted. Ask for parts for your old army (that you don't even really have to have) to get the right parts with out converting.

Flattop models are curio and relic eligable.

original boxes can go for 150 bucks

September 8, 2003, 07:24 PM
It's not Ruger, but if you want to see a diagram that shows a transfer bar safety, Taurus illustrates it on the details page of any of their revolvers. -

You can also read an article at Popular Mechanics ( which has a very nice picture ( of a Ruger Vaquero which shows the transfer bar very clearly.

Jim March
September 8, 2003, 08:42 PM
Re: barrel swaps: it's not that easy and I didn't intend to make it sound so.

The tricky part is getting the sight to line up with the top of the frame, while at the same time getting the torque on the threads right.

The situation is even more grim with stainless steel - the relatively fine threads sometimes don't survive being both unscrewed and then re-screwed.

September 8, 2003, 08:57 PM
Jim ..... excellent and detailed ''differences'' synoptic!

But, tell me ..... Which is why Power Custom sells buttloads of $35 "freewheel pawls" with good installation instructions - you can then spin the thing both ways with the loading gate open. is there a link you might have for this ... seems like I might well tweak my SBH to gain this advantage ... always gets me that if I rotate cyl just that tad too far ... then chamber too far round to load and have to go round again ..... irritating!!

Old Fuff
September 8, 2003, 11:51 PM
Just to nit-pick a little .......

Old Model Ruger Single Actions had three SCREWS - one for the hammer, one for the trigger and one for the cylinder bolt.

New Model Ruger's have two PINS (not screws) that do the same work three screws used too.

The .30 Carbine Blackhawk is built on the larger Old Model frame, as is the .41 Magnum and .45 Colt/45ACP. One can safely convert these to anything up to .45 Colt, but Jim is correct in saying that changing the .357 frame to the "big round" isn't adviseable, even though some have done it.

Last but not least, anyone that shoots the .30 Carbine round in a revolver better have good ear protection.

Jim March
September 9, 2003, 06:30 AM

There is a whole thread going on "Ruger SA hop-up bits" which includes notes on and links to the Power Custom parts. Note that the URL changed during the thread's life, and a correction has been posted:

(Even though it's a TFL thread, it's still alive - it continues here on THR :). That was one of two threads I did that with in the closing days of TFL, the other being the revolver checkout.)

Note that Power Custom (Ron Powers) has yet another mod, much more extensive, involving a hammer/trigger swap for all NM (2 screw/pin). This does three things:

1) Allows easy conversion to the Bisley hammer/trigger set yet in a form that drops in to ALL Ruger grip frames, not just the Bisley grip frame;

2) Give you BOTH the Ruger Old Model and New Model loading drills. Open the gate with the hammer down and it's like a new model. Half-cock it first, it's like an old.

3) Acts as a "user installable drop in high-end trigger job" equal to (typically) about $125 worth of gunsmithing. But since you're getting just a baggie of parts one-way plus good instructions, shipping costs (and risks) are peanuts. This must be countered against the cost - the Powers hammer/trigger/spring kit is about $175. I strongly recommend buying the matched set versus just the hammer and modifying your trigger; the matched sets are tuned to each other for the best possible (yet safe) trigger feel.

It's worth it for some people, esp. if you're doing a partial Bisley conversion on a non-Bisley grip frame.

It can also work in conjunction with the free-spin pawl.

When it's my gun involved, I'm going to go for the pawl alone plus a Belt Mountain Base Pin for about $25 to tighten the action. Those two very cheap mods help New Models a LOT.

Your only other costs: a GOOD screwdriver kit (Brownells has one for Ruger SAs for about $20) to avoid boogering the screws.

September 9, 2003, 08:49 AM
Excellent Jim ... and thank you Sir. I have archived the contents of both the TFL thread and the continuation here.

Now I need to find the time to do something about it!!:)

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