Ruger Blackhawk with huge cylinder throats

[Chill Wills]

In about 1977 or ‘78 I got the bug for a short-barreled Ruger Blackhawk Convertible in 45 Colt and 45ACP.
It and I walked out of the gun shop and straight out to the river to put some rounds through it. The second cylinder of 45 Colt, the sound of the “boom” had a twang to it. It clearly did not sound right. I stopped shooting and starting looking. Nothing to see from the outside, I pulled the cylinder out. It looked good and something caught my eye in the frame. The forcing cone really, at 6 0’clock, there was a big crack in the cone. Long story short, I ended up with a new replacement and the first one went back to Ruger. The gun shop was kind enough to trade it out and deal with the bad one.
I shot the new one putting thousands of rounds through it. Accuracy was lousy! The 45ACP was hopelessly worse. All kinds of loads were tried. About 10 to 15 years later, when I was on the phone with Veral Smith about something rifle related, and the poor accuracy of this handgun came up. He mentioned the throats might be off. I did not have pin gauges in those days. I pushed soft lead slugs through the cylinders and found they were running 0.456” and a few 0.457” in both the 45 Colt and 45 ACP. Veral made a large diameter 4-cavity mold that cast a copy of the factory bullet weighing 255grains. That helped a bit but the large bullet and small barrel diameter wasn’t a great set-up for accuracy. I could not even get the large bullets loaded into the 45ACP case to fit into the cylinders.

My interest in the revolver dropped off.

On a side note, in addition to the cylinder problems, the backstrap fit the cylinder frame crooked, which left a very sharp edge and corner on the left side that drew blood if I shot more than a few cylinders through it.

Recently, I bought a used Ruger Security Six as a gift for my youngest son. It arrived with a light hammer strike and lots of FTF. I called Ruger to see if they would look at it. …No parts or service on the Security Six. That is another story. While on the phone, I asked if they would look at the Blackhawk. Yes! $45 for FedEx to send it to Ruger and the late 1970’s Blackhawk went to have the cylinders checked.
It took a month to get it back, which I think is very good.

Ruger agreed with me. Both oversized cylinders were replaced! The first thing I did was get out the pin gauges. All 12 holes run a loose pass on the 0.451” ZZ and almost pass the 0.452”. I don’t have half sizes. This is as close as I can check. The work sheet that came back with the revolver only stated the cylinder work BUT they either replaced or maybe reworked and refinished the gripframe/back strap. Now it fits straight and smooth! Thanks Ruger!!! That is a bonus!
It went on the say, they did clean, lube, time and perform a function check with test firing.

Here, on Cast Boolets, I read that Revolver BC gaps should be 0.004 to 0.008”. With feeler gauges, I cheeked the gap on both cylinders and also on a few other revolvers I had close at hand. My new cylinders on the Blackhawk pass 0.011” and hold 0.012”. This is on the large size but the revolver is NOT going back. I will live with it and smile.
Other revolvers measured 0.003” on the Ruger Security Six, and I have since resolved the FTF problem, it goes bang every time now too. A S&W 586 measures 0.009” and a S&W M-67 measures 0.004”.

[cwtebay]

Glad to hear that you have a shooter now!
Sucks it took the better part of 40 years to make it happen though!

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[376Steyr]

I seem to recall that the hammer spring for the Security Six was the same as the one used in the 10/22 rifle. Maybe a spring swap would help.

[Uncle Grinch]

I recently picked up another Ruger NMBH in 45 Colt. This one was very used, but it was the 4 5/8” barrel with only one cylinder. I sent it back to Ruger due to the .012+ gap. They replaced my cylinder for me but it cost $192. Now it gaps at .004.

[DougGuy]

IF you call their CS and tell them that the replacement cylinders that THEY fitted to the gun are spitting bits of bullet material out of the b/c gap (don't say LEAD) after the cylinder replacement, and that the gun came back from having the cylinders replaced with .012" b/c gap. This was an oversight on the part of Ruger, it poses a considerable safety risk, they will fix it.

Tell them how great their customer service is, they are the best in the industry, and they sent the gun back like that, they just may send the brown truck to pick it up on their dime.

[castmiester]

So all along I was right, Ruger just carries a name. Even though I have a cylinder with throats a little loose but still can be worked with, without sending it back, isn't bad. Years ago a barrel blew off a gun , they sent a new one out with an extra smaller piece as a courtesy, to a guy I knew at a gun range I belonged to. Th eguy didn't need to send anything back. Those days are long gone. Didn't need the service of any extra work from outsiders either, which can be just as bad if not worse.

[Chill Wills]

IF you call their CS and tell them that the replacement cylinders that THEY fitted to the gun are spitting bits of bullet material out of the b/c gap (don't say LEAD) after the cylinder replacement, and that the gun came back from having the cylinders replaced with .012" b/c gap. This was an oversight on the part of Ruger, it poses a considerable safety risk, they will fix it.

Tell them how great their customer service is, they are the best in the industry, and they sent the gun back like that, they just may send the brown truck to pick it up on their dime.

That is good advice. I will shoot it some to get and idea of what is getting out the sides. Maybe shoot it near a sheet of cardboard 6" or 12" to the side to catch what ever it puts out. I may do the same with the Ruger Security Six as well as a control or test with the known small 0.003" gap.

Any idea or data on a revolvers velocity loss verses each 0.001" BC gap? Is that info that is out there?

[rintinglen]

Rule of thumb for "special velocities" (think 750-850 FPS) is that you lose about 10 fps for each additional .001 over .006, but that is a very rough guesstimate. Personally, I prefer .003-.005 on a new gun, because I know it will get bigger over time. Anything over .010 is too darned big in my book, though I have seen a bunch of new guns that crowd that figure out of the box.

[castmiester]

That is good advice. I will shoot it some to get and idea of what is getting out the sides. Maybe shoot it near a sheet of cardboard 6" or 12" to the side to catch what ever it puts out. I may do the same with the Ruger Security Six as well as a control or test with the known small 0.003" gap.

Any idea or data on a revolvers velocity loss verses each 0.001" BC gap? Is that info that is out there?

How about velocity loss from a cast not filling a throat, verses....

The forcing cone is not to "funnel" the boolit into the bore, it will push and rotate the cylinder into the alignment that offers the least resistance, that's it's job.

Why fill a throat if the cone takes up the slack ? it makes sense to fill the throat to seal the heal of the bullet. I see gas cutting the sides of the bullet, maybe not the base with a gas check. Am I wrong ?

[cwtebay]

How about velocity loss from a cast not filling a throat, verses....



Why fill a throat if the cone takes up the slack ? it makes sense to fill the throat to seal the heal of the bullet. I see gas cutting the sides of the bullet, maybe not the base with a gas check. Am I wrong ?

That's what's called "choke". I believe that dougguy has spoken about that at length

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[castmiester]

That's what's called "choke". I believe that dougguy has spoken about that at length

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He talks about alot of stuff.. hard to take it all in. I read about him mentioning fire lapping, but nothing at length.

you talking about where the barrel and frame meet I take it ?

[higgins]

I had one of those early .45 convertibles that had .45 Colt throats that slugged about .456. It shot pretty well with .454 cast bullets. Maybe I just got lucky; the gun did not have any faults other than the large throats.

[gc45]

Happy this worked out to the OP's satifaction although I could not except .011 gap. I will never understand why Ruger sends out guns with large throats, wide cylinder gaps and crooked backstraps. This is just poor quality control IMO and Ruger expects buyers to just take it as is and live with it with most guns never going back for warrentee then the owner sells it to someone else. The OP sent his gun in for repair, he got it back with the cylinder changed out and throats better than before but now has .011 clearances in the gap..This is not good service, it is poor quality control and why I take pin gauges and feller gauges along when looking at any and all revolvers. Of course the Internet stops buyers from knowing exactly what they are getting. I got lucky some time back when buying a Ruger 44 Spec flat top, the seller said he 100% stood behind his gun and if I found something off or wrong he would take it back..Gun measured up perfect and the seller turned out to be a good friend as well selling me two more guns...I do like Rugers, especially my 1990 45C that was about perfect out of the box other than undersized throats which I quickly opened up to .45225. I feel very lucky the have bought two Rugers with minimal issues that I could fix myself..

[Tatume]

My new cylinders on the Blackhawk pass 0.011” and hold 0.012”.

This is within Ruger specifications. They won't change it. A barrel/cylinder gap of 0.012" won't affect accuracy, may cause slightly lower velocities (for which you can easily compensate), and reduces top strap flame cutting when high pressure cartridges are fired. I prefer the reliability and longevity of the Ruger spec gaps.

[Chill Wills]

This is within Ruger specifications. They won't change it. A barrel/cylinder gap of 0.012" won't affect accuracy, may cause slightly lower velocities (for which you can easily compensate), and reduces top strap flame cutting when high pressure cartridges are fired. I prefer the reliability and longevity of the Ruger spec gaps.

Can you tell me what the Ruger specifications are?
Thanks.

[Tatume]

Iowegan, the person who wrote the IBOK on Ruger revolvers, is quoted below. If you don't have a copy of the IBOK you should get one. The one for the GP100 is available as a PDF free. It can be found by searching on "Iowegan ibok ruger." He wrote another for the single actions, but I've not been able to find a PDF, and hard copies are hard to find.

Some people worry about stuff that really doesn't matter much. B/C gap is one of those things that is way overstated ... probably because it has become a measurement to judge the quality of a revolver due to urban legends .... not actual performance. I know for sure .... Ruger doesn't consider .010" B/C gap to be excessive.

Revolver companies won't divulge this specification. I once called Ruger and asked about a new Blackhawk that had a 0.011" BC gap. They told me it was within factory specifications and not to return it.

[Chill Wills]

Tatume, thanks for the reply.
I just took the time, as it is a nice day for here, and put three cylinders full of the 45ACP and two cylinders full of 45 Colt onto paper targets at 25 yards. I am really happy with the new cylinders. Very accurate. This is a huge step in the right direction. More later for anyone that is interested.

[Kestrel4k]

I know that if I was manufacturing revolvers with 0.011" cylinder gaps, I would /certainly/ state that 0.010" gaps were not excessive.

[Tatume]

I know that if I was manufacturing revolvers with 0.011" cylinder gaps, I would /certainly/ state that 0.010" gaps were not excessive.

One of the worst guns I ever owned was a Freedom Arms M83 in 454 Casull. It had a 0.002" BC gap. At the same time I owned (and still do own) a SRH, also in 454 Casull. The Ruger was more accurate than the FA. Further, the FA developed a fracture. Since it was the Premier Grade I sent it back. They told me it would cost $1000 to fix. I protested that the Premier Grade has a lifetime warranty. They shrugged. I sold the gun to someone who was willing to have it fixed.

That wasn't my only experience with FA either. I also had a model 97 in 41 Rem Mag, and at the same time had (and still have) a Ruger Blackhawk in 41 Rem Mag. The Ruger was the more accurate of the two. Not by much, but enough to make me sell one and keep the other. The one I kept has a larger BC gap than the one I sold on.

BC gap doesn't mean much by itself.

[gc45]

This is within Ruger specifications. They won't change it. A barrel/cylinder gap of 0.012" won't affect accuracy, may cause slightly lower velocities (for which you can easily compensate), and reduces top strap flame cutting when high pressure cartridges are fired. I prefer the reliability and longevity of the Ruger spec gaps.

I disagree. Poor gap clearance has been an issue with revolvers since they were invented and why 1000's of guns have been fixed for this problem. I know of no compensation for large cylinder gaps that give longer jump for the bullet to contact the forcing cone and barrel Lands and it's akin to freebore in rifle barrels where both get reduced accuracy. Longer gaps reduce pressure somewhat and why Ruger won't change it so they say it is within their specs. So I ask you, why does all revolver makers not do the same as Ruger? Ruger makes the strongest revolver we can buy then they screw up accuracy with large gaps and poor cylinder throat size. As to gas cutting, I doubt it makes any measurable change with a larger gap. Please inlighten us to your claim.