Cylinder reaming = accuracy

[Larry Gibson]

Doug

Please don't get me wrong. I am not criticizing you or the work you do. From what I've seen it is first rate. What I am trying to do is determine if it will benefit any of my revolvers. If i can determine it might be then you'll, no doubt, get some work from me. The problem is I see little, if any documentation of benefit other than "golly gee whiz, it really shoots better now", or some such.

I have gone through a lot of revolvers in my life. Besides many of my own through the years I was an advanced firearms instructor for the Oregon Board of Police Standards and Training (BPST). Besides being the firearms instructor for my own agency I also instructed agencies in 2 other counties plus assisting with instruction at the basic LEO training at the academy. The revolvers were used 99.9% of the time back then being S&W, Colt and Rugers. Many times, when a student wasn't shooting well the excuse was always "something must be wrong with the gun". Another instructor or I would then use that "gun" and shoot 12 shots standing, two handed holding on the X ring of a B-27 target at 25 yards. I never saw any that would not shoot 2" at 25 yards. The student then realized it was not "the gun" and began listening to instruction and began to shoot better almost immediately. That was "back in the day" when I could shoot a lot better than I do now.

I have 15 good revolvers of S&W, Ruger, Colt and Uberti make from 32 S&WL up through 45 Colt. They all with shoot 2" or less with 12 shot groups at 25 yards from a rest [elbows resting on bench with wrists resting on sandbag]. For example, here is the 12 shot group of the first 12 shots through my 50th Anniversary Ruger FTBH 44 Magnum. Load was the RCBS 44-250-KT cast of COWW + 2& tin, sized .430 and lubed with Javelina loaded over 8.5 gr Unique. The cylinder throats pin gauge out at .431.



Of the 15 revolvers 3 of them have cylinder throats the same as the nominal groove diameter of the barrels; A M9S&W 357, a Ruger Vaquero (OM) 44-40 and a Colt Anaconda 44 Magnum. All three of those are the most accurate revolvers I have. However, I have one revolver, an original run Ruger SS 32 H&R that has a .312 groove diameter barrel with cylinder throats there a .312 pin gauge will almost go through but stopping about 1/16" shot. A .311 gauge will go all the way through. Thus, I consider it "undersize but this is how it shoots at 25 yards [6 shots with a TL90 gr SWC sized .312 over 3 gr Bullseye [specific load info on target];



Both of those targets are about as good as I can do these days with iron sights. Thus is my quandary, I've yet to see enough "proof" if you will, to convince me honing any of those revolver's throats would do any good? Again, no criticism intended or implied on you or your work.

[Bazoo]

What about gas cutting Larry? If you don’t size to throat diameter you get gas cutting, which equals leading, according to Doug, and many. Do you not see any leading?

[Larry Gibson]

What about gas cutting Larry? If you don’t size to throat diameter you get gas cutting, which equals leading, according to Doug, and many. Do you not see any leading?

Only time I get leading is when testing other's bullets or using commercial hard lubed bullets. Even with commercial cast 44/45s if I properly lube them with LLA leading is very minimal.

For several years I shot Lyman 429421s cast of COWWs, sized .429, lubed with Javelina loaded over 23 gr H4227 or 22 gr 2400 [I kept the primer carton lid and stopped counting at 5,000 primers] loaded with a Lee loader. I was pretty poor back then and the only handgun I had was a Hawes Western Marshal 44 magnum. The cylinder throats pin gauge at .434. Never had any leading and had excellent accuracy. My eyes were good, and my hands were steady back then and I shot many a 1" 6 shot group with most being 1 1/2" or less. Then I read about "fit"....got a GB mould that cast .435 - .546 "Keith" bullets and a .434 sizer. Accuracy promptly went to 6" +/-. Tried .430 sized bullets and accuracy is back to less than 2". I've relegated the old girl to 44 SPL loads these days as the barrel/cylinder gap is close to .012" and the ratchet has set back a bit in the recoil shield. Using the 240 gr Lee TL cast of whatever left over alloy may be around, sized .430, lubed with BAC or NRA 50/5-0 and over 5 gr Bullseye in 44 SPL cases will give a bit of "flash" leading in the throats but still no leading in the barrel. If loaded in magnum cases, it does not even "flash" the throats. That load shoots as good as I can hold any more and since I've 500+ 44 SPL cases I use that load in the semi-retired Hawes.

[DougGuy]

Larry explained it right there. It is a combination of factors that make a load a keeper or a waste of time. I cannot explain why it is as accurate with boolits .003" smaller than the throats, and this is one where they say "let the gun tell you what it wants" and there is a lot of truth in that statement.

I would say there are very few shooters that size smaller than the throats and have good luck with it. I am dead nut certain the hardness of the alloy AND the lube are a BIG part of why something that isn't supposed to work, works.

[Bluerock2000]

Larry, I tried a number of loads in the 32 using both cast and jacketed boolits prior to sending to Doug. I still have the targets with load data on them, so I’ll load a few of them up and report back.

Brady

[DougGuy]

Hawes Western Marshal 44 magnum. The cylinder throats pin gauge at .434. Never had any leading and had excellent accuracy.

I shot Lyman 429421s cast of COWWs, sized .429, lubed with Javelina loaded over 23 gr H4227 or 22 gr 2400

Tried .430 sized bullets and accuracy is back to less than 2".

Ok let me ask this. In lieu of any noticeable leading in the throats, would you attribute this to maybe the boolit obturated and filled the throat, preventing gas cutting and consequently leading?

[Larry Gibson]

Not sure of that Doug but years ago I was dabbling/shooting M1917 S&Ws and Colts. Numerous of them went through my hands back then (early '70s +). I wasn't pin gauging back then but slugging several of them, both chamber and Cylinder throats, I found the throats generally ran .454+. I had read a bit of Elemer about them. He said cast for the m1917s needed to be hard because of the shallow rifling(?) or something to that effect. As the only sizer I had at the time was a .452 I did find that WQ'd COWW and linotype cast bullets of that size were the most accurate. I also found out an old Ideal 454190 that dropped bullets as cast a .455 shot dismally in all of them. But once those 454190s were sized .452 they shot very well, about 2" at 25 yards. That was born out testing several with a ransom rest. Lyman 452460s cast of linotype, sized .452 over 7.5 gr Unique would hold 2" at 50 yards in the ransom rest in both a M25 S&W I had and a M1917/25 [M1917 with a M25 target barrel] with the throats being .454. I still have the M1917/25.

As to the Hawes. I got it new for my 21st BD in '68. I only had a single cavity Lyman 311410 HP, a Lyman 5 lb cast iron pot, Lyman dipper and a Lyman 450 though that I had got for Christmas in '67 with a .309 H&I for the only rifle I had at the time, a M1 Carbine. I got the .429 H&I die and a single cavity 429421 mould for the Hawes as I didn't know any better other than .44 bullets for the magnum were .429. I was loading for the Carbine using a Lee wack a mole loaders [had learned how to use one a few years earlier for a M94 30-30] so i got a Lee loader for the 44 Magnum to. Still have both Lee loaders. Anyways, it wasn't until I had put 5k+ rounds through the Hawes and many more through the M1 carbine that I got a loading press and regular dies. Almost all the bullets I cast in those early days were with COWWs and were AC'd. I would think it's very possible the bullet may have obturated some(?) but I don't know. May have been the bullets from the old COWWs (much closer to 94/3/3 alloy than the COWWs of the last 30+ years) have been hard enough not to and simply performed well like the 45 ACP hard cast in the M1917s(?). Again, simply conjecture at this time.

[DougGuy]

I haven't shot the Uberti with .4565" throats with anything other than the 454190 cast in 50/50+2% lubed with SPG sized .456" over 9.0gr Herco. This one is pretty dang accurate at 10yds I didn't have a 25yd lane or a shooting bench, just two hand standing.

I guess I could run some through the LAM2 with the .452" die and load them over the same charge just for grins..

[lar45]

Remember you can Beagle the mold to increase diameter.
Get some Aluminum duct tape, cut a few thin straps and shim the sides of the mold open.
Start with 1 or 2 strips on each side, cast some, measure and add another if needed...

[Bird]

I have a new uberti revolver in 38/357mag. The throats are at 0.367'' and bore of 0.357''. I may be just able to fit 0.360'' or even 0.361'' bullets if I can find a mold large enough, and still be able to chamber them. It would be interesting to see what others have experienced with way oversized throats.

[Larry Gibson]

Wow! .367.....never ever seen any that large........I'd be sending it back to the importer.

[DougGuy]

Wow! .367.....never ever seen any that large........I'd be sending it back to the importer.

Exactly b/c about the biggest boolit you can fit in a 357 is .360" as the chamber itself behind the throats is only .381" so you subtract two thicknesses of case wall at the mouth, and that's all the boolit that cylinder will chamber. Brass .011" like standard Starline, .381" - .022" = .359"

Maybe someone is measuring with calipers?

[Bazoo]

When I got a mic it opened my eyes. It confirmed that my feel and technique was spot on for my calipers and if I measured .430 it was right on.

[DougGuy]

Doug

Please don't get me wrong. I am not criticizing you or the work you do. From what I've seen it is first rate. What I am trying to do is determine if it will benefit any of my revolvers. If i can determine it might be then you'll, no doubt, get some work from me.

I have 15 good revolvers of S&W, Ruger, Colt and Uberti make from 32 S&WL up through 45 Colt. They all with shoot 2" or less with 12 shot groups at 25 yards from a rest [elbows resting on bench with wrists resting on sandbag]. For example, here is the 12 shot group of the first 12 shots through my 50th Anniversary Ruger FTBH 44 Magnum. Load was the RCBS 44-250-KT cast of COWW + 2& tin, sized .430 and lubed with Javelina loaded over 8.5 gr Unique. The cylinder throats pin gauge out at .431.



Of the 15 revolvers 3 of them have cylinder throats the same as the nominal groove diameter of the barrels; A M9S&W 357, a Ruger Vaquero (OM) 44-40 and a Colt Anaconda 44 Magnum. All three of those are the most accurate revolvers I have. However, I have one revolver, an original run Ruger SS 32 H&R that has a .312 groove diameter barrel with cylinder throats there a .312 pin gauge will almost go through but stopping about 1/16" shot. A .311 gauge will go all the way through. Thus, I consider it "undersize but this is how it shoots at 25 yards [6 shots with a TL90 gr SWC sized .312 over 3 gr Bullseye [specific load info on target];



Both of those targets are about as good as I can do these days with iron sights. Thus is my quandary, I've yet to see enough "proof" if you will, to convince me honing any of those revolver's throats would do any good? Again, no criticism intended or implied on you or your work.

Ok I thought about this today, while my hands were busy honing cylinders. I thought about your groups, which are considerably good groups, and I thought you are probably an exceptional shot with a handgun, and I thought well, those are factory stock Rugers, which means the throats in yours are NO different than the throats in the cylinders I get in for honing. They have the same anomalies that all of them have. Some likely have inconsistent throat diameters, same as everyone else's, and I have honed enough of them now to say with a good deal of confidence that VERY FEW of them are not without issues!

I get them and when they first go on the Sunnen hone, if they aren't really round they jump around quite a lot, which equates to the hone torquing against them less and then harder when the stone is crossing over the bottom of the "egg" and fairly soon it calms down and evens out once the stone has honed the egg out of the throats. I get them with belled throats where the throat is bigger at the front of the cylinder than it is at the end of the chamber, I get them with 32 flat areas arranged into a circle, those actually vibrate eerily until the stone smooths them out, some of the flats are straight, others are sorta angled, so they come in with throats uneven 17 ways from Sunday.

Many of these odd shaped throats would be difficult to measure, but the Sunnen is a precision tool that will tell you RIGHT NOW what kind of geometry is in the throat you are honing. Overall S&W are better and more consistent than Rugers but the titanium S&W cylinders? OMG unbelievably misformed.

Anyway.. As good as you shoot, and as inconsistent as the few thousand cylinders I have reamed or honed by now, unless you got SO lucky that most of your revolvers are the cream of the crop, there IS room for improvement. Your 2 1/2" groups may make some of us jump for joy, me included, but if I am right in my assumptions that some of your revolvers' cylinders probably suffer the same inconsistencies as thousands of others, you may see your own super nice groups made even better.

I would include addressing the height of the hammer pad as well as cylinder throats, it doesn't reduce trigger pull, it just reduces the amount of travel the trigger makes before the shot breaks, and I often suggest the use of a Wolff 30pz. trigger return spring. This makes holding the sights motionless while firing, a TON easier to do. If you practice dry fire with the creepy trigger and stock spring, it can be difficult to hold the sights dead still while the hammer falls. After reducing the hammer pad and changing the spring, it's not just a little bit easier to hold the sights still, it's night and day easier.

These are the things that will cut groups on average by half. I just wonder if as good as yours are, there isn't the same room for improvement, because you are shooting the same revolvers as the ones I work on and the folks that take advantage of that work are generally VERY happy with the improvement(s).

[Forrest r]

Myself, I've never did well with any revolver that had 2/1000th's" or more difference between the cylinder holes and the bbl diameter. Just seemed to be a lot pickier about the bullet selection & a lot smaller pressure windows to work with.

Start sizing bullets down 2/1000th's" in the bbl and bad things start to happen.

[Bazoo]

Well today I fired 6 or 7 cylinders of a load I’ve been tweaking. RCBS 44-250-k 50/50 ww/pb+Sn 4.4 bullseye. Previously I had used .431 sized bullets and gotten okay results. Minor leading and okay accuracy. Today I used .430 sized bullets and leading and accuracy was improved. After 6 cylinders full, what was minor leading after the first cylinder was really only fouling. Accuracy was as good as I can hold, rested off the top of my tracker at 15 yards, 2” or so. It wasn’t the best light for my eyes as I was shooting at sundown.

So in this instance, sizing closer to groove than throat dimensions is better for accuracy and leading.

[alfadan]

Shoot, I may pay for Larry to send in his cylinder. As much as he's contributed to the forum, a small price to pay.

[murf205]

Larry, I believe that the reason we don't see the before and after groups is because the "before's" usually look terrible, therefore no photo's to be proud enough to save. THEN...when the cylinder, throat, forcing cone or whatever work has been done and it produces good results,we are elated enough to photograph them-justified- I might add. I agree that the scientific way to do it is as you suggested but in all my years of shooting groups, I never wanted to save or photograph those that looked like a chicken squatted on a target but keep the bugholes (rare) plastered everywhere. You have given me thought though, that when I get a gun that is giving me trouble, it would be wise to start documenting the good vs bad results.
btw, alfadan is correct, you have steered more than a few in the right direction, thanks.