I'VE READ THAT revolvers often have varied chamber sizes...really?

[mozeppa]

i have a

s&w 44 mag
ruger black hawk 45/45 LC
ruger 38/357

should i slug each chamber and each barrel?
or is ignorance bliss?

haven't noticed anything ......yet.

but i want these to be as near perfect as i can get.

[Outpost75]

Depending how the cylinder are machined you will either have two, or three different dimensions, depending on tool variations. Older Claussen drill presses did two opposite Chambers and indexed three times, modern Hitachi machines do three alternating Chambers and index only once. Chambering is done in multiplesteps,usually core drill, rough ream and finish ream. DA revolvers are usually honed or roller.burnished to ease simultaneous ejection.

If the manufacturer is doing a good job in selectingand setting up tooling, youshouldnot see anyvariation,butit is possible. That is what pin gages are for.

[500MAG]

I don't automatically slug the barrel of my firearms. I size to appropriate size and go from there. I have been pretty lucky with my firearms in those calibers and not had leading due to size issues.

[Beagle333]

If it shoots well... ignorance is bliss. I got one slightly bigger chamber on my BH. The only way I could tell it was to drop 6 boolits in the chambers and push them snug with a pencil.... and one booilt sticks out almost to the point of coming out the end. It used to bother me, but it doesn't lead and I marked it with a Sharpie and fired several rounds of shots without looking at which cylinder it was, until after I had fired all 6, and the target never picked it out. So I cleaned off the Sharpie mark and now it doesn't bother me. :cool:

[fredj338]

It's very diff to put a Tool into a piece of steel, 6x, polish & have them all identical. Then do that a dozens of times before changing the cutting tool. Variation always exists. Sometimes what you don't know won't hurt you.

[Piedmont]

mozeppa, You are using the word chamber but you mean cylinder throat.

[mdi]

Mebbe I'm just a curious ex-machinest/mechanic, but I like to know all about my guns. I have slugged every barrel of all my firearms except an old .25 ACP Iver Johnson and my rimfires. I have pin gauges for my revolvers and have checked them all. No, it ain't necessary, but I like to know just like I know the tire sizes on my truck...

In measuring my revolvers from Ruger, S&W, Taurus, and Dan Wesson, there isn't a noticeable difference in cylinder dimensions from chamber to chamber to detect with .001" difference pin gauges.

[44man]

Usually not enough to worry about, I use all chambers when I shoot. Did all the tests with each chamber, waste of time.

[NVScouter]

mozeppa, You are using the word chamber but you mean cylinder throat.

Exactly what I was thinking. Like 500MAG I usually size to what a normal size should be and give it a go. Only if it becomes trouble to I investigate and go through all the hoops. Now if I had to drive 1.5hours to shoot a 10" 50y group and be done for the day I'd put more time before the range trip.

[jmort]

I used to be more concerned until I read Glen E. Fryxell's article from the LASC site and he sizes his .357 boolits at .357" for his guns, S&W as I recollect.That went against everything I had read here/elsewhere and got me to thinking, everything says go bigger. Now I just go .001" over and if there are no problems, I go with that. When I have more time, I will probably, with my .357 Blackhawk, for example, try .357, .358, .359, .360, kind of like a load work-up, and see what works best. For now, don't have the time or inclination.

[C. Latch]

It's pretty common for ruger . 45 Blackhawks to vary. One of my holes shoots outside of the rest, so I never load it. It's the one at the feet of the man engraved on the cylinder.

[Animal]

I've read that it is possible to get a good throat measurement by measuring the inner diameter of a fired case. So far, I'll say this is probably the way to go because I've noticed very consistent measurements when compared to the outer diameter of my lead slugs. I would imagine that case wall thickness would account for some variation though. But, as a disclaimer... I'm no gunsmith, or even an experienced reloader.

[Pilgrim]

Just as most of the rifle manufacturers cleaned up their rifle barrel mfgr to produce consistently good barrels, so to have the revolver manufacturers improved their cylinder chambering. 15 years ago or so, I figured I would have to replace roughly 1/3 of my Ruger #1 barrels to get acceptable (to me) accuracy. My .223 and 6mm #1's both wear new barrels. The 7X57, .270, and .338 barrels are still Ruger. My S&W revolvers (again 15 or more years ago) had terrible throats. A model 25 .45 Colt had throats that were .455, .457, and .458 between the 6 holes. None of them were close to .452. I do not know what current revolver mfgrs tolerances are, but given the improvement in the 1911's, I suspect current revolver mfgrs cylinder throats are much closer to the desired dimensions. FWIW Pilgrim

[DougGuy]

Ruger has really cleaned up their act with the New Model medium frame guns, BUT the cylinder throats, as beautiful and smooth as they are rolling them out now, are still undersized. I do half a dozen Ruger cylinders a week, every week, ream and hone the throats and get them perfectly round and all even with one another. I use a .4505" pilot on the .45 ACP cylinders almost as a rule, and a .451" pilot for the .45 Colt cylinders. Almost all of them have at least one throat that is oval or egg shaped, some have more than one. You can use a pin gage on these and see it hitting 2 places and see light coming through on one or both sides of the pin gage.

The large framed Bisleys, in stainless, with the rollmarked unfluted cylinders have been some of the tightest with many of those only accepting a .4500" pilot on the reamer. .44 and .45 cylinders made in the 80s are the ones that have 3 pairs of throats, 3 different sizes, those vary greatly depending on when Ruger replaced the reamers because they seem to have never replaced all 3 at once, they replaced them as they wore so the new reamers cut bigger throats and the worn ones cut smaller throats.

Most shooters would not be able to tell an oval cylinder throat from a round one by shooting off a bench or a pistol perch. It's likely you could zero in on how much effect tight vs. loose throats have by using a Ransom rest, and carefully assembled ammo. However, the average shooter can and will notice an improvement in group sizes from having the throats sized .0005" to .001" above boolit diameter, and having all of the throats EVEN in size with one another. It gets better if they have a nice long 11° forcing cone and are using smooth sided boolits because they transition into the rifled bore easier than a Keith type boolit with it's very pronounced driving band.

Considering the cost of cylinder throat reaming being about half the cost of even a mundane pair of grips these days, bang for the buck, getting the cylinder throats reamed is one heck of a good bargain, you only have to do it once and the gun shoots better from that point onward.

[Harter66]

I was able to lap both a Sec6 357 and RBH 45 to all match. The 6 had 1 throat at 3565 and 1just under 358 ,2 at 3575 an 2 at 3572 . The issue is of course the nice square 357 groove, they're as close as I can measure to 358 now the result is that the groups are 3'' field rested at 25yd instead of 1 dead at point of hold 4 w/in 4'' and 1 out there someplace. The BH was the same except 4515-4545, w/all but 1 454+- .0002 it holds 4'' at 50 yd w/best loads from field rests instead of 6'' at 25 w/1 over there.

[h8dirt]

My recently purchased S/S Bisley convertible had throats of 0.450" in the 45 Colt cylinder and the ACP was 0.451". All six chambers were remarkably consistent. It also had a bore restriction due to thread crush just forward of the forcing cone that I had to fire lap out (ughhh). I opened up the throats to 0.4525" and have since been able to regularly shoot 5-shot, 25 yard rested groups under 2" with both cylinders.

[JonB_in_Glencoe]

When I started casting my own, the first revolver I had problems with was a late 1970's S&W mod 25 (a dash 3 I believe ?) in 45 colt, when I got it, it's looked NIB.

I had lead fouling issues, when I slugged all the cylinders, they varied by .003"
I don't recall that actual numbers, but they were all larger than the Groove dia of the barrel, but the barrel had a thread constriction causing my problem.

[Kansas Ed]

Worst one I ever owned was a brand new Colt SAA. Groove was .401 and the throats were anywhere from .396-.398. A half hour on a Sunnen hone with pin gauges took care of that. Shoots great now.

Ed