[munk]

a recent discussion about cylinder size has reminded me of a question I've always wanted answered:

Are the 45 Colt chambers in the Ruger Redhawk the same diameter range as those in their single actions? That is, oversize.


If you look at SAAMI specs for the Colt you'll find the chamber size is always going to be too large for todays warm loads and 452" bullets, but Ruger's are unneccesarily generous even by those standards.

I love my Ruger 45 Colt Single action. If the Ruger Redhawk was tighter I'd get one.

Anyone know? Any Redhawk fans?

munk

[Tom C.]

The Redhawk probably has chambers slightly tighter than the Blackhawk. The chambers are certainly better finished than any of the Blackhawks or Vaqueros I have. The Redhawk chamber throats seem to be .4515" as near as I can measure, which is a little larger than the Blackhawks. While I opened the throats on the Blackhawks and Vaqueros, and polished the chambers, I didn't do anything more than polish the star extracter on the Redhawk. Both actions respond to standard techniques for smoothing. Both ended up with nice trigger actions. For those who want to hotrod the .45 Colt, the Redhawk has a larger diameter cylinder with thicker chamber walls. Built like a tank.

[munk]

I had a 45 Colt Taurus briefly- probably a collector piece now- a Raging Bull. Its chambers were only ever so slightly tighter than the Rugers. I have a Marlin Cowboy in 45 Colt, and to my surprise, it's chambers are even larger than the Ruger's!

My heart just isn't into hot loads for the 45 Colt when the brass has to work overtime with a large chamber. Oh, I do it, but the joy is out of mudville.

I've always wanted a tight 45 and maybe the Freedom Arms or the BFR is the only way to go.



munk

[WebHobbit]

:confused:

OK you guys lost me. Since when are Ruger SAs known to have over-sized chambers?????????

I had a .45 Blackhawk and it's chambers were right on the money-- that is .451/.452 or so. Why would you want tighter than that when cast .45 is usually .452 and jacketed is usually .451?

I've heard of sloppy over-sized old Colt SAAs as well as cheap foreign clones but not Rugers.

[Majic]

The chambers are usually of the right dimensions, but the throats of Rugers are a little tight.

[munk]

If your chambers were .451, I'm not sure you could even put a round in. The cartridge is .480 Do you mean the chamber mouths? The funny thing, I thought chamber mouths on Rugers used to be too big and the factory took care of that. But I just read one poster saying they were too small. And majic just said they were tight. So Ruger has apparently gone from one extreme to another, but better too tight.

As for the chambers, Saami gives them a huge space. I don't have the number at my fingertips. If you'll notice, a resized case rattles down into the Ruger chamber. Compare it to a 357 or 41 you might own and you'll see what I mean. That's because both those modern rounds kept the same diameter bullets, and haven't changed. The Colt was larger around, and modern weapons are still cut fat for cartridges that don't exist. Chambers on the Colt may have been large for other reasons as well, like extraction. I don't know all the details. But almost all modern 45 Colt chambers are way too large.



munk

[Frohickey]

One article that I read from John Linebaugh (http://www.sixgunner.com/linebaugh/services.htm) is that the chambers on the Rugers are within spec, but on the large side of the spec. What this ends up doing is making cartridge cases expand more, and consequently, fail much quicker than otherwise.

Another is that the throats of the cylinders are smaller. Opening this up would give better accuracy since now, the bullet diameter is not decreased on its way to the barrel.

[munk]

Unfortunately, 'spec' on the 45Colt is is too large. I read the same Linebaugh, I'm sure.

Refresh my memory on something; wasn't an initial complaint of the 45 Colt single actions was that the chamber throats were too large? It was corrected by Ruger after enough people howled about it. Why they would be too small now is strange.

Is there any reason, mechanical or safety, that Ruger would do this?



munk

[Majic]

About 10 years ago my brother had a ss Ruger Blackhawk in .45Colt. I had heard that the throats might be tight and they were, one was as small as .4493". I recently bought the 5.5" Bisley and it also has small throats (from .4501" to .4496"). People recomended for me to contact ".45throatdoctor.com" as he does quick and quailty work. For a small fee they ream the throats, touch-up the blue on blue steel cylinders, and supply a spec sheet showing the before and after dimensions all in a 48hr turnaround time.
Alot of people have questioned why Ruger ream their .45Colt cylinder throats tight, but I have yet to see an answer. I wonder if they ream the throats of their .454's tight to, that's one cartridge I wouldn't want to raise the pressures on.

[munk]

Well, you just said it. I'm no smith, but raising pressures is the only thing I can think of it would do.



I'll go back and mic mine sometime today. I've had good luck with cast bullets with all my Rugers, but I never drive them faster than 1000fps.

munk

[J Miller]

My OM BH has max chambers. The Win 94 Trapper, and Rossi 92 also have max chambers. My S&W 25-5 is better.

Why they put such horrible chambers on otherwise fine guns I will never understand.

My Ruger had grosly undersized chamber throats, the S&W way oversized throats.
The Ruger was easily corrected by the .45ThroatDoctor. The S&W is looking for a new cylinder. I have read that at the same production point where they stopped using the pinned barrel, they reduced the chamber and chamber throat dimentions on the 25-5's.

As for the Redhawks chambers, I don't know. I've never loaded for one.

[munk]

The large chambers of the 45 Colt are an outrage. I'm guessing this helps control peak pressure. But I've another idea- they do it this way because of older guns and Saami and mostly, because they've always done it that way. Just because see- and no one can stop industrial malaise.

Hey; what is the 'throat doctor' ? Is that a reamer, or a man?


munk

[J Miller]

The .45 ThroatDoctor is a man. He lives in Norther IL. I believe he is a machinist by trade. I had him do the throats in the replacement cylinder for my BH. He left less tool marks than the factory had.
Here is his web site: http://45throatdoctor.com/
He has lots of good information in there. Well worth the read.

[munk]

just thinking out loud- i could just send him the cylinder and wouldnt have to pay that stupid shipping charge for a handgun.




munk

[Jim March]

Yes, that's what he recommends.

[Tom B]

The Throat Doctor presently has both cyls from my BH 45acp/45lc convertable to do.

[xtarheel]

That's me... I've done somewhere in the neighborhood 100 Ruger .45 throats in the past year and I would like to make a few observations if I may.

First of all the history as I understand it is that originally Ruger made their throats too big. People complained, and they over compensated by making them too small. When people complained again the official stance was, "You wanted them tighter, that is what we did". I honostly don't know exactly whan this change occured, but it was quite a few years ago.

What throat tightness does to accuracy: First of all the purpose of the throat is to convey the bullet into the forcing cone where the "funnel shape" centers the bullet in the bore and squeezes the bullet down to exactly the groove diameter. It the throat is tight, the bullet is "arrested" while pressure builds and then the bullet is squeezed down to pass through the throat and then it enters the forcing cone already smaller in diameter than the groove diameter of the barrel.

Another factor not mentioned above but just as important, is inconsistant throat diameters within the same cylinder. It is not at all unusual to see a cylinder with throat diameters varying from say .4497 to .4512 within the same cylinder! When I see a cylinder that has one throat significanly tighter than the others, I can pretty much predict that when that chamber fires it results in a 10:00 o'clock flier. That is because the recoil impulse begins before the bullet leaves the barrel. The tighter throat holds that bullet back just a small fraction of a second longer than the other throats so the bullet leaves the barrel later in the recoil cycle.

Why the inconsistancy? I don't know for sure but my guess is the factory uses a fixture that bores all six chambers at the same time. When one of the reamers in this fixture reaches some minimum specification it is replaced therefore you can have six different diameters within the same cylinder.

Throat roughness. There are a lot of tool marks in a Ruger throat. But in all fairness to Ruger, there is not a lot of finishing and smootheing done on the parts that are not normally visable. Ruger makes a finely engineered and very strong revolver at a very afordable price. They do this by keeping labor costs to a minimum, therefore minimal finishing. I have foung that if you disassemble their single actions and simply polish the internal parts it can make a big difference. If ruger did this for you, you could add a couple hundred dollars to the price tag.

[munk]

Doctor; my Ruger single action 45 shoots cast bullets fine- as long as I keep the velocity down- below 1000fps. The lead is only modestly hard. I'm thinking if I used very hard lead and drove them fast I would see more of a problem than I do now.

I just miked them, near as I can tell they are all pretty close at .452 Using calipers is a little of an art. If I press lightly they are .4515



munk

[xtarheel]

Munk: You are correct. The soft lead has a tendancy to obutrate (bump up) when entering the forcing cone to compensate for being too small. If you drive soft lead too fast, you get leading. Also, I would say your second reading is more accurate. The ideal throat size is .4525

[munk]

Tarheel, lets say your bullet diameter is .452 or 451 What will happen in a throat of .4525? Isn't that marginally too big?

To ask this another way- it is said when driving hard lead fast the bullet diameter must be very close, or slightly larger than the bore diameter. So I have a hard lead projectile of .451 What happens in your improved throat?


thanks,

munk

[xtarheel]

You are absolutely right. A hard cast bullet should be slightly larger so it adequately engages the rifling as it leaves the forcing cone. The tight throat makes this impossible. A slightly "oversized throat" however allows the bullet to be squeezed down in the forcing cone and properly fit the grooves. The throat on a Ruger Blackhawk is about .5 inches long. The average 250 grain bullet seats about .3 inches into the case. By the time the bullet leaves the mouth of the case it is entering the forcing cone. Any gasses that may pass between the side of the bullet and the walls of the throat during this brief period are very small in comparison with what is lost through the cylinder gap. With a larger throat, the same load will probably operate at a lower pressure.

[munk]

That's one thing I worried about- burning the side of the bullet. The bullet has engaged the throat nearly as it has left the case, has engaged the forcing cone of the barrel, therefore any degradation of the bullet is slight from gases slipping past it in the throat.

And if this lowers pressure, it also increases the amount of powder you could use safely. You might be able to increase top velocity a little?

Tarheel; should a bullet, even an oversized cast bullet, be able to slip out of the throat in any calibre revolver's cylinder, should there be slight or no resistance?

You should become a throat doctor for all calibres of revolver.

munk

[munk]

Tarheel, I haven't miked them yet, but three other of my Ruger revolvers seem to have tight throats, two double actions and one single. I dropped jacketed bullets down the chamber. Some of them had to be popped out.


munk

[WebHobbit]

One of rule of thumb me and my buddies have used for years is this:

"Drop a properly sized bullet (no case) down in each hole, if it does NOT fall out the other side than the chambers are not over-sized."

We never imagined any would be too tight!

:uhoh:

[xtarheel]

I would say one good rule of thumb is to not ask one part of a machine to do what another part is designed to do. The throat's job is to guide the bullet through the cylinder into the forcing cone where any diameter reduction takes place. I just took two bullets, a Speer .451 230gr fMJ and a speer .452 lead semi-wadcutter and dropped them through a cylinder that I just reamed out to .4525. As expected, the 451 easily drops through, the lead semi wad cutter is easily pushed through with a pencil eraser. If forcing a bullet through the throat results in diameter reduction, the throat is doing the forcing cone's job (maybe too much so) and the force required to push the bullet through is creating excess chamber pressure.

Whenever I send a cylinder back to a customer, I always ask for feedback. Reduction in group size and elimination of fliers are the most common comments, but apparent recoil reduction and elimination of leading are also common. I have no accurate way of measuring pressure, but I would surmise if throats are tight, opening them allows the same load to operate at lower pressure. I can push 325gr. LBT gas check bullets through my Bisley Blackhawk well in excess of 1,200 fps with no excessive pressure signs. The Starline brass drops right out with no stickeyness.

[WebHobbit]

ThroatDoc - That all sounds very reasonable but I know from personal experience that too large chamber mouths can cause tumbling so evidently their purpose is atleast in part to guide the bullet into the forcing cone straight.

[munk]

We need to define 'too large' .

And Tarheel, you need to set up for other calibres. ?? I've a 41 Bisley that might benefit.



munk

[WebHobbit]

I think we need an engineer to define "too large"!

[munk]

That's fine, webhobbit, though it was engineers who got us into this problem in the first place with too tight throats.

munk

[WebHobbit]

:)


LOL

True!

[xtarheel]

Well gentelmen, I am an engineer and part of the problem is that we are not dealing with a set of constanants. The variable is the diameter of the bullet, therefore everything becomes somewhat of a compromise, so we eliminate the variables that we can.

To get consistancy in where the bullet lands on the target, each bullet should experience the same pressures, constrictions, etc as it exits the muzzle as it would if fired from a single shot or autoloader which deal with a single chamber, throat, forcing cone and barrel.

Opening the throats makes sure that the bullet upon leaving the forcing cone is not smaller than the groove diameter.

Making the throats a consistent size, assures that each bullet enters the barrel with the same amount of pressure behind it and at the same time in the recoil cycle.

And yes, too big of a throat can also cause problems as seen on some pre-war Colts. Although in the example I gave earlier, with the .451 FMJ, you would be very hard pressed to see any light between the bullet and the wall of the throat, so it cannot tumble.

One final thought, for the best groups it is important that the shooter keep his eyes open when he pulls the trigger! ;)

[Majic]

Xtarheel,
The oversized throat will not case the bullet to tumble, but it will allow a bullet to cock slightly as it leaves the throat and hit the forcing cone at an angle. The bullet will straighten itself as that's one of the purposes of the forcing cone, but the initial hit of the bullet on just one side of the forcing cone creates a different harmonic in the barrel as opposed to a central hit in the forcing cone. That different harmonic can cause the bullet to be a flier.

[WebHobbit]

Majic -- that all depends on the bullet. I had Federal Nyclad .38 hollow-points that would tumble hitting the target sideways due to a POS Taurus with over-sized chambers.

[Majic]

Webhobbit,
You are right. Most likely the oversized chamber caused the forcing cone to deform the nose of the Nyclad (which is soft lead covered in a polymer) to the point it was not areodynamic and it tumbled.

[munk]

I for one am very glad Mr. McLeod has taken the time to answer our questions and explain some specifics.

The ideal size quoted is .4525 for 45 Colt throats. This is .0015 larger than a bullet of .451 and only .0005 larger than a bullet of .452 , representing the range of factory jacketed bullets.


I wonder if .41 would be best served by .4105 or .411 ?? A little narrower range because the bullets are more standardized.

munk

[WebHobbit]

for one am very glad Mr. McLeod has taken the time to answer our questions and explain some specifics

Agreed!

Good info to have.

[Majic]

Groove diameter of the .41mag is .409". The .410 bullets work fine in them. I size my cast bullets to .410 and get very good results with them.

[Tom C.]

Everything is a compromise. The .4525" throat is a compromise for lead and jacketed bullets. With the older guns which can have larger throats, .454 to .456", in addition to allowing the bullet to hit the barrel forcing cone at an angle, they also allow more gas blow-by which can damage the base of the bullet. The bullet then leaves the barrel with reduced stabilization due to damaged rear end. This can cause the bullet to fly in a helix which can cause interesting accuracy problems.

In addition to tight, consistent chamber throats, a uniform forcing cone also helps. I cut mine a little deeper than recommended. Works for me.

Another thing to look for in Rugers is "choking" of the barrel where it is screwed into the frame. The barrel diameter is reduced due to screwing the thin walled tube through the frame. It can be .0005” to .0015”. That will cause the bullet to be reduced below bore diameter just as it enters the barrel. Not good. You can remove it by “fire lapping” or, just shoot it a lot and it will probably be peened out. I tend to cut most of it out by deeply cutting the barrel forcing cone.

I have been opening my cylinders to .4515". A little tight, perhaps, but it seems to work.

[munk]

How do you do that, Tom? Do you just polish and keep miking until right, or is there a special bit?


I wonder if Throat Doctor can cut to the customers specs?



munk

[Tom C.]

Reamers are available from the vendors in any desired size, but the standard reamer from Brownell's is .4525". I use a chamber polishing brush, also from Brownell's. It probably doesn't do as good a job as the reamer, but I am satisfied. I check the diameter with an appropriate bullet that I measure with a good mike.
Someday, if I am feeling flush with cash, I may invest in a reamer myself.