What size reamer for .44 cal cylinder throats?

[Deep Six]

Hi all,

I am getting ready to buy a reamer to clean/open up the throats on my 44s. Rather than going with the expensive Brownell's kit ($130 per caliber), I was just going to buy a carbide chucking reamer and use the beartoothbullets.com method of piloting it. My option on reamer size is 0.4310, 0.4320, 11mm (0.4331), and 7/16 (0.4375), all with about a +0.0005/-0.0000 tolerance. I currently have three 44's, which have the following dimensions:

1. Ruger Redhawk 44 mag Blue 7.5": Barrel slug measures 0.4305", boolits sized to 0.431 go through the cylinder with light pressure. Shoots 0.4315 boolits accurately with minimal leading.

2. Ruger Flattop Blackhawk 44 spl Blue 4-5/8": Barrel slug measures 0.4300", boolits sized to 0.431 go though the cylinder with light pressure. Shoots 0.4315 boolits accurately with almost zero leading.

3. Smith & Wesson 629 44 mag Stainless 4": Barrel slug measures 0.4315, only bullet I can get through the cylinder is 0.4290 jacketed - even a 0.430 jacketed wont even start into the cylinder. I've only shot this one once but it leaded up pretty bad over the coarse of 100 rds of my usual 0.4315 boolits. Accuracy was very good none the less.

I'm thinking I should go with the 0.4320 reamer. This would seem to be the minimum to fit the Smith's barrel without going too large on the Rugers. Opinions?

[DougGuy]

.432" and some tap magic would work. It should finish near .4325" which would allow for .432" boolits to fit through the throats with a light drag fit. Couldn't ask for better. The money you save on the reamer would just about pay for the forcing cone cutter kit should you decide to get it.

[Larry Gibson]

I wouldn't get a reamer. I would result that S&W. A .431+ is quite large for a S&W barrel. The 2 Rugers aren't broken so no sense "fixing" them. If anything get a .431 reamer and do the S&W only. Then your .431 sized bullets will fit all 3 revolvers.

Larry Gibson

[R.M.]

Are you sure you need carbide? Seems to me a high speed reamer would do the trick at a much lower cost.

[leftiye]

Get the .431 reamer like Larry says. If it still doesn't shoot or leads up, open it up another thou (at a time) with a dowel with wet or dry 400 grit taped to it (by hand or in a drill).

[white eagle]

there are also expandable reamers that maybe in the size and quality you are looking for

[Larry in MT]

My 629-4 cylinder throats are just like yours. However, I haven't experienced much leading with 280 grain .431WFNGC BearTooths and accuracy is excellent. Why should I enlarge them? (asked respectfully).

[Old School Big Bore]

I have the opposite situation. My 29 has .432 throats & I'm considering getting a 57/58 cylinder rechambered.

[Char-Gar]

Whoa! You gave us some numbers that may or may not be accurate, but you didn't tell us what kind of groups the handguns shoot. How well they shoot is all that matters. These theories of barrel groove and cylinder throats are not like the law of gravity. Sometimes you need to modify a cylinder but most often you don't.

You state your Smith and Wesson shoots well in spite of the numbers, but is leading. I would not jump to the conclusion the leading was caused by the cylinder throats. There could be a number of other causes and once the metal is gone it is gone.

Your Smith and Wesson barrel groove does sound large, but I once had one that large and it shot quite well with cast bullets.

[Deep Six]

I haven't shot the S&W at paper yet. However it rang the gong just as good as the Rugers at 50 yards. The flattop shoots 1.5" at 25 yards while the Redhawk is good for an honest 3" at 50 yards. The Smith had a LOT of lead in the barrel after 100 rounds. These are high quality 250 Keith boolits of probably 15 bhn alloy, sized to 0.4315, lubed with Ben's Red, and crimped with an RCBS seater die. They don't really lead at all in the Rugers.

I know the Smith needs it's cylinders opened up because the barrel slug won't even start into the cylinder holes. The barrel slugs from the Rugers go though the cylinder holes without much resistance. There's no way the Smith isn't going to lead with it's barrel/cylinder relationship.

[Char-Gar]

I haven't shot the S&W at paper yet. There's no way the Smith isn't going to lead with it's barrel/cylinder relationship.

"It ain't necessarily so!"....Cab Calloway

Ream on! I would not want to stand in the way of a man pursuing truth as he knows it to be, and a lead free barrel.

[MtGun44]

Never ream a gun that you are not 100% certain has a problem. I would not touch the Rugers.
Since you have not shot the S&W, you don't know, it may work fine.

No need for a carbide reamer for this. I used a tool steel reamer from MSC, with the reamer in
a mill (drill press will do as well if square to the table) and turn the chuck by hand, with cyl in
a V block in a FREE TO FLOAT mill vise on an oiled table. Let it center itself, you are just holding
the reamer square to the cyl. Also, I would ream .001 smaller than I want an then polish the last
.001 to get what you want. At this point, you may be just as well to polish from .429 to
. 430 and call it good -- AFTER shooting proves that there is a problem.

At this point, I don't think you know whether you have a problem or not.

"I know the Smith needs it's cylinders opened up because the barrel slug won't even start
into the cylinder holes."
Nope, while it PROBABLY needs reaming, but you do not KNOW it if you haven't shot lead and found
an actual accuracy or leading problem. You may decrease the accuracy by reaming, so be
certain that there is an actual problem, not just measurement (possibly erroneous) that you
think are not correct.

Bill

[Deep Six]

I think you missed where I said I shot it and it leaded up pretty bad over 100 rounds of ammo that does not lead in the Rugers and should not lead in a revolver with properly barrel/cylinder relationship.

You guys do make a good point though: I should go shoot the 629 several more times using a variety of different loads and put it on paper (as opposed to just gong ringing) before I start removing material. I will heed your advice and get some more experience with it before I touch it.

Also, I was planning on the carbide reamer because I see some stainless Rugers 44s in my future. I know from experience that the stainless material Ruger is currently using for their revolvers can't be machined using standard tools. I'm pretty sure it's close to the same alloy that we use in critical parts of our reactor coolant pumps at work (I work as an engineer at a nuclear power plant). I tried to file off a casting mark on the side of the hammer of my stainless 45 Blackhawk. The hammer won the match with the file. That is some seriously hard material and even if a HSS reamer would cut it, I doubt it would last for six holes while maintaining tolerance.

[9.3X62AL]

I would be inclined to leave the Rugers alone, and would do some more shooting with that S&W before taking tools to the throats. My lazy streak kicks in by itself, and I loathe doing more work on a gun than it absolutely needs. I own and have owned MANY revolvers, and have only done throat surgery on one example--a BisHawk in 45 Colt from Ruger's Celebrated Blue Period of backwards dimensioning. Taking the throats out to .453" for its .452" grooves from the OEM .448"-.449" throating made a definite improvement. I shot the Ruger 45 Colt for close to 3 years before I ran the reamer through it and polished out the throats. I don't jump into things, and let them REALLY annoy me before resolving them at times.

[MT Gianni]

I would leave the Rugers as found and try three different lubes before reconsidering a throat re-ream. If it shot well I would clean it well after a session and consider it the price of ownership before reaming throats. If it did not group well I would toss a coin for a ream or sell.

[Deep Six]

I'm not lazy and I like tinkering. I really don't mind reaming and I don't see how opening it up to 0.431+ could possibly hurt a thing, given its 0.431 barrel. I will shoot it some more to confirm that it needs it first.

[MtGun44]

Same exact situation as Al - lots of revolvers, only reamed a Ruger BH conv in .45 Colt/.45 ACP with VERY
undersized throats, the demonstrated consistent 3 in a group with 2 fliers for a 5 shot group with
either cyl.

Most of my revolvers are fine as they come from the factory, and I will be
VERY, VERY certain before I remove any of the metal in critical parts.

For the small amount you need to remove, and if the cyls will be hard, I'd buy a brass lap
from MSC for about $25 or less and get it dead nuts right on the diam you need by lapping.
Perfectly round, goes slowly so you can control the diam well, and leaves a very
smooth finish.

Bill

[Char-Gar]

I can understand if a fellow has a couple of Rugers that don't lead and then has a Smith that will, he settles in on the cylinder throats as the cause. But the leading issue may come from a different cause, such as a bad forcing cone or a barrel that is loaded with ultra fine micro machine hickies.

Over the years I have had three Smith and Wesson sixguns that leaded no matter how much magic I worked on the cast bullets and loads. The dimensions had nothing to do with the problem. The leading did not go away until I polished out the micro-hickies and that cured the problem.

Due to difference in manufacturing methods Ruger sixgun tend to have quite smooth bores that are no prone to lead. I have one of the new Lipsey 45 Flatops that has the smoothest bore I have even found in a sixgun barrel. I own four more Ruger sixguns that while not that ultra smooth have never given me leading issues. Neither have the Colts I own and have owned. But the occasional Smith and Wesson can prove a booger in this area due to poor inside barrel finish.

This is based on my considerable experience with most makes of sixguns.

I might add that trying to push jacketed bullet through a cylinder throat does not give any idea of the diameter of the cylinder throat. Cylinder throats are not perfectly round and jacketed bullets are not either. Throw in the stack up of those number, plus the fact that many cylinders tend to have a constriction on the front edge of the charge holes and you can see how zero useful information is gained that way.

I use Starrett expandable machinist hole gages to measure cylinder throats and this is very precise. I have noted at some time, you get different measurements if you insert and expand the gage from the front of the cylinder and if you insert and expand the gage from the back of the cylinder. There will be a .001 to .002 edge on the front lip of the charge hole. I have always assumed this is a little burr thrown up when the front of the cylinder was milled. Whatever the reason, this little unseen lip can cause issues with measuring from the front of the cylinder and trying to push bullets or slugs through the cylinder throats. Whatever this little micro-hickie is, it will come off after enough rounds are fired.

I have never seen this issue discussed, but I have seen it multiple times over the year and it is worse on Smith and Wesson cylinder of certain vintages. I have seen it enough to know it is real and not an occasional flunk with the use of the tools.

Like others, I feel the reaming of cylinder throats is way overdone. Folks tend to start removing metal before they are absolutely certain it needs to be done. Cylinders most often are reamed based on theory rather than facts and proof.

It would take me a long time to count up the number of sixguns I have had and used over the years, but it would be in the hundreds. I have 60 or so now. In all of those years I had had to ream two Ruger BHs in 45 Colt. I have also never "fire lapped" a sixgun. Other than these two, all issues could be resolved through handloading, recutting the forcing cone or polishing the barrels to take out the micro-hickies.

I have never tried fire lapping as the notion of firing abrasive grit coated bullet down a barrel just give me the willies. I have not found it necessary to do it.

I do know this flies in the face of standard internet dictum in the post-LBT world. But I was doing this stuff long before the Internet and LBT ever existed. I am in favor of progress and learning, but not in favor of hokum. There is a saying here in Texas..."Don't whiz down my back and tell me it is raining".

[leftiye]

I'd ream the chamber mouths. The fact that someone's friend's cousin's guns worked fine with .005" undersized boolits is anecdotal at best, and bucking the probability that yours will work better blueprinted to proper sizes and clearances. Fer shore it wouldn't be smart to bet the other direction.

Though I am biased - I do almost all of mine (any that need it). Even more than .001, up to .002", up to 003"even usually work fine, whereas the same sized mouths/grooves and smaller chamber mouths are the ones we hear about having the problems.

[Deep Six]

I understand about removing steel as a last resort, and I will go shoot it some more before doing anything else. I'll also put a few hundred rounds of jacketed through it to smooth out whatever machining marks it may have. However, I'm just wondering how much damage could possibly be done running a 0.4310 reamer through the throats? All it's going to do is give me a set of 6 perfectly round, uniform throats polished out at probably 0.4315". How could that possibly be any worse than what I've got now?

[MtGun44]

Lapping will give you far better throats than reaming, and you can do whatever
diameters you want.

Bill

[cbrick]

1. Ruger Redhawk 44 mag Blue 7.5": Shoots 0.4315 boolits accurately with minimal leading.

2. Ruger Flattop Blackhawk 44 spl Blue 4-5/8": Shoots 0.4315 boolits accurately with almost zero leading.


I wouldn't touch those Ruger's, your already pooping in tall cotton. From your own post . . . Just what is it you wish to . . . "FIX"?

I've also like Char-Gar never fire lapped a bore, just the thought is like the sound of finger nails on a blackboard. For the Smith I would take a long, hard look at the forcing cone before I did any cutting on the throats. Also after cleaning all lead from the Smith start shooting cast again but pay attention to any possible lead build up on the forcing cone. If there is leading is it uniform all the way around the forcing cone or starting on one side or the other? Waiting until 100 rounds are fired won't tell you where the lead is starting and that could be key to what causes it. Any leading in the cylinder?

Rick

[9.3X62AL]

I understand about removing steel as a last resort, and I will go shoot it some more before doing anything else. I'll also put a few hundred rounds of jacketed through it to smooth out whatever machining marks it may have. However, I'm just wondering how much damage could possibly be done running a 0.4310 reamer through the throats? All it's going to do is give me a set of 6 perfectly round, uniform throats polished out at probably 0.4315". How could that possibly be any worse than what I've got now?

Assuming good craftsmanship, I would say the likelihood of causing further damage or a worsening of conditions is rather remote. There remains a chance of no improvement, in the event that your barrel has the finish imperfections cited by Char-Gar. There is also a reasonable chance of improving performance and ameliorating the barrel leading by proceeding with the contemplated throat surgery. You have to make yourself happy in this hobby field, and if contentment lies in opening those throats--it is your revolver, and the choice is yours to make. I think the consensus view from this thread is to "make haste slowly".

As far as the barrel's interior surface is concerned, clean it well, then run a cotton ball down the barrel on your patch jag. See how many (if any) of those tiny cotton fibers get grabbed by micro-monsters living within same.

[Silverboolit]

I just reamed my Ruger GP100 this afternoon. It has a .3565-.357 groove and the cylinders were .356. I got the reamer from 4D rentals for 35.00. Includes 7 bushings and works very well. I'll have to see if it made a difference at the range tomorrow.

[DougGuy]

I had a really nice shooting 1978yr 7 1/2" SBH that everybody here said LEAVE IT ALONE, it shot j words perfectly, put many times it's own weight in my freezer year after year, couldn't fault it. THEN I decided I wanted to bring it over to shooting cast boolits, which are a bit harder and a bit larger diameter than the factory j words.

It had 3 different throat diameters in the cylinder. I bought a .431" Manson reamer (which I still have) and it fell through two throats, cleared two more by twisting it with my fingers, and needed chucked up in a t handle to clean out the two tight throats.

At this point, it was fine to take a "sample" cast boolit that I planned to shoot, .432" diameter, and use it as a feeler gage for the throats. It had a light drag fit in the two largest throats, and I used a 3/8" slotted dowel and some 280grit cloth abrasive to very gently hone all the throats to the same light drag fit on the sample boolit, all the way around. Took me a few times per hole as I was going slow and keeping the hone square with the cylinder.

Know what? After all the nay saying, and the "it's good enough" rhetoric and the "if it ain't broke don't fix it" I took it out to my bud's range and shot it after reaming/finish honing the cylinder. Holy smoke! This gun has NEVER grouped so well in it's LIFE and I have had it going on 30yrs! NO leading to speak of, and I can say for a fact that those slight differences in cylinder throat roundness and diameter CAN and WILL make differences in point of impact. The more consistent those diameters are, the more even fit the boolit has in the throat, the better your groups will be.

There really isn't anything at all fundamentally WRONG with evening out the cylinder throat dimensions on an already good shooting Ruger, trust me you AIN'T gonna hurt it by doing it!

PS I did also recut the forcing cone to 11° and it turned out beautiful and shiny, about 5/16" down into the bore before the rifling is it's full height, and I suppose this would also help matters since the factory cone was short and had tool marks all in it and it did spit some. With me shooting long cast boolits, this type forcing cone gives the boolit a lot more free jump from the cylinder and a lot less chance of it swiping the side off of it before it gets started good in the bore.

[MtGun44]

You will never know what did it if you change multiple factors
at the same time.

Bill

[cbrick]

DougGuy, The OP said his Ruger throats are uniform and shoots really well. The "don't fix it if it ain't broke" comments are in regards to the Ruger's. The other revolver may well benefit from uniforming the throats. When the OP says how uniform the throats are and how well it shoots (really well) I don't think the advice to him should be to start removing metal.

Rick

[DougGuy]

Actually, that was my experience with my own .44 and not any specific advice to remove metal. If he has two Rugers and they are both real even in throat diameters, he has not one but two flukes of the production line. Two rarities I would say!

[9.3X62AL]

I'm not going to be a hypocrite and say DON'T DO IT after going and doing it (once) and having a MARKED performance improvement post-surgery. I just should emphasize that my Ruger 45 Colt revo was GROSSLY out-of-spec, and was a one-boolit-wonder with castings before taking tools to the throats. My other Rugers (2 Blackhawks and a Redhawk) have excellent throat/bore relationships right from the git-go, so maybe I'm luckier than most. I have yet to mod a forcing cone in any fashion; my revos shoot well enough and do not leave lead deposits laying around. If it ain't broke, don't take monkey wrenches to it, says I.

[cbrick]

Actually, that was my experience with my own .44 and not any specific advice to remove metal. If he has two Rugers and they are both real even in throat diameters, he has not one but two flukes of the production line. Two rarities I would say!

I guess my Ruger 45 Colt would be the third, the throats are within tenths of a thousand. My OMBH 44 would be the fourth, throats are all within .0005". Sounds like Al has 5th, 6th, 7th etc.

Rick

[9.3X62AL]

Wednesday guns, most likely.

Most recent Ruger, BH in 30 Carbine, bought Jan. 2012. Bore is .3000", grooves .3080"-.3082", throats are all .3085" or .0001" either side of that spec. That is well-nigh perfection in a production revolver. Lee Soup Cans sized at .309" (confirmed) shoot LIGHTS OUT, as do Lyman #311316 at that same dimension. Off hand/standing, I hit a 100-yard iron coyote cut-out 10 for 10 repeatedly, full-tilt loadings (1450 FPS). It out-shoots every M1 Carbine I've ever fired at 50 and 100 yards, and meets or beats the now-departed Marlin 62's work with several bullets. Needless to say, this Ruger won't have tools taken to it! This kind of work pretty much eliminates the need for a 327 Federal, too--though I am a 32 caliber handgun addict of the first order. The 327 would be superfluous.

[cbrick]

Al, have you tried 311410 HP in that 30 Carbine?

What weight is the LEE your using and what load?

Are you sure you don't want to ream the throats? [smilie=1:

Rick

[Hickok]

Not making any recommendations as what to do, but here are my real world results with my three .44 magnums.

Smith Model 29 6" Barrel. Cylinder throats= .4333"

Smith Model 629 4" Barrel. Cylinder throats= .4286"

Ruger SBH Stainless 7.5 " Barrel. Cylinder throats= .4316"

Measured by driving a lubed .454" lead round ball through and miked with Mitoyu 1"mic. It ain't perfect but it is the way I did it.

I use a ACWW Lyman #429421 boolit with round lube grooves, over 20 gr. 2400 powder that gives about 1200-1260fps depending on which barrel length. Boolits sized .431". Same load used in all three revolvers, because of convenience and safety. I don't want different ammo that could be mixed up.

These three revolvers will shoot consistent 2 inch groups with this standard load. The Super Blackhawk will out shoot all them, with 1-1.5" groups being common, but it has a longer barrel and the boolit more closely fits the cylinder demensions. The older M-29 will get some very slight leading at the start of the forcing cone after alot of rounds, but it cleans out easily, not a problem. The "tight demensioned" Model 629 doesn't lead, and neither does the SBH.

Don't know what the bore demensions are, nor do I know if the barrels are constricted where they are threaded into the frame, I just never checked.

It is not a perfect solution, but I think the ww alloy is doing a very good job of obturating to fit the different cylinder diameters, and all three revolvers are as accurate as I need them to be, and all three have dropped deer.

Not being a "know it all" just some results to help in making a decision.

[9.3X62AL]

Al, have you tried 311410 HP in that 30 Carbine?

What weight is the LEE your using and what load?

Are you sure you don't want to ream the throats? [smilie=1:

Rick

Rick, I have not tried #311440 in any form in any firearm chambered in 30 Carbine. Buckshot and others have sung the praises of this boolit for the application, and this might be a good addition to the fleet--I do have a number of 30/31 caliber war toys laying around the place.

The Lee Soup Can is their nominal 113 grain 30 caliber flatpoint, and with Hornady GC and lube grooves filled it scales 116 grains in 92/6/2 alloy. 12.5 grains of 2400 is its usual loading, but WC-820 and IMR-4227 have made guest appearances too. All are louder than Hell's Drum Line when fired.

No, the ONLY things running through those throats and barrel will be projectiles! Taking tools to such a machine would be like using spray paint on The Sistine Chapel.

[cbrick]

Rick, I have not tried #311440 in any form in any firearm chambered in 30 Carbine. Buckshot and others have sung the praises of this boolit for the application, and this might be a good addition to the fleet--in 92/6/2 alloy.12.5 grains of 2400 is its usual loading, but WC-820 and IMR-4227 have made guest appearances too. All are louder than Hell's Drum Line when fired.

Not 311440, it's 311410.

Wanna try some to help decide if you want the mold? I have this boolit in MP 4 cavs in both PB and GC. I haven't done anything yet with the gas check boolit yet just cause the PB is doing just fine. Naked they are 130 gr. Both of my molds cast at .3105". The prime difference between the Lyman and the MP 311410 is that the MP has a front driving band ahead of the crimp groove where the Lyman does not.

It can be a loud sucker. I tamed the noise a bunch by using a lighter load at a bit over 1000 Fps with 10.0 gr SR 4759 & standard primer & this load does quite the number on them CA ground squirrels that like to dig up the range. Haven't bothered to crimp it yet & haven't had any issues.

Send me a PM if you want some, I have some of both PB and GC cast up.

Rick

[Deep Six]

Had both the S&W and the flattop out shooting yesterday. I shot paper this time. Tried several loads in the Smith (mag, special, cast, jacketed). Most turned in 10"+ groups at 25 yards. The best was my pet load of the Lee 430-240-RN tumbled in 50/50 LLA/JPW over 7.5 Unique in special brass (for some reason this load works great in just about any gun I try it in). The Smith turned in a 4" group at 25 with this load.

The Flattop was shooting its usual 2" or so group at 25 yards with its favorite load of a 250 Keith on top of 15.0 #2400 with Ben's Red. I've always thought this was pretty outstanding performance from a $450 gun with a 4" class barrel. Then I tried an experiment: shoot a group using only one cylinder hole. I only had 3 rounds left at this point, but they were all touching at 25 yards.

I am going to buy the 0.4310" reamer. The prospect of a gun capable of 1" groups at 25 yards is too much to resist. If I somehow manage to ruin the gun (not sure how this would even be possible), $450 replacements are readily available. If it works good on the flattop, the Smith is next.

[MtGun44]

If you intend to have .431 throats, buy a .430 reamer and polish the last .001.
Reamers leave a pretty rough surface finish, you will want to polish with a
split dowel and 240 grit Wet or Dry silicon carbide paper and some light
oil

Bill

[Deep Six]

Yeah I haven't found a 429 bore yet so I was thinking a .4310 reamer and end up with throats of about 4315 after polishing. I already size my boolits to 4315.

[MtGun44]

I'd go .430 and plan on polishing .0015. Much easier to polish off another .0005 or so than
to add it back. Also, with a new reamer, drill and ream a hole or two in some steel before
you use it. A very sharp, new reamer tends to be rougher and cut a hair larger the first
hole or two - or at least, my MSC reamer did. Thankfully we were reaming something else
before we did my cyl with it. It was about .0005 larger on the first couple holes than on
later holes. I figure just a tiny bit of burrs from sharpening.

Bill

[Deep Six]

Interesting. I'm just afraid that removing 0.0015 with sandpaper is going to take too much time/effort versus just doing the last half thousandth or so. That and a 0.430 bullet will fit through the Ruger cylinders so I'm not sure a 0.430 reamer will actually touch them. I was hoping to get the throats nice and uniform with a reamer and then just polish them out with sandpaper.

I have a Bisley 45 convertible on which I tried lapping throats of the 45 acp cylinder with sandpaper on a dowel rod. They were about 0.451 when I started and I was just trying to fit a standard 0.452 bullet through them without using a hammer. It took probably 20 minutes per hole starting with 80 grit paper (I tried finer grades first but they didn't produce any measurable enlargement). I did finally get it so that I could push a 0.452 bullet through each hole with a dowel rod, but it took forever and I gave up on doing the 45 Colt cylinder. That Ruger stainless alloy is tuff stuff! The 45 acp cylinder does shoot really well now.

Then again I've lapped out a couple Lee bullet sizer dies and 2 thousandths went pretty quick on those. I guess it just depends on the hardness of the metal one is trying to lap.

[Deep Six]

Now I see that I can get a 0.4305 reamer. That will allow me to split the difference perfectly!

[R.M.]

80 grit???? Might as well use a rat-tail file.

[leftiye]

Were you turning the dowel by hand? I'd use a drill motor. All you need is 400 grit wet or dry. It will wear down and polish too. Select your sandpaper strip length to fit as tight as possible to get into chamber mouth. Enter from the rear to minimize beveling at the front, and to help with staying straight on. Another thing that will help - the finish of most cutting processes (to include reaming) leaves a surface that abrades comparatively quickly at first, then more slowly as the surface becomes smoother. Due to this, a thou. is removed fairly quickly.

[Deep Six]

That was being spun in a drill. Like I said, I started with something like 400 grit and worked my way down to 80 before I was able to accomplish anything. Of course then I had to work back up to 600 to get a good finish. It still took forever just remove a thousandth like this. I suspect a S&W or blued Ruger would be different. But that Ruger stainless alloy is a real *****.

[Mal Paso]

I've used the Manson Reamer on several guns. I made a centering sleeve to use along with the pilot bushing and cut from the rear. The little bit tooling marks are 90 degrees to the bore and don't hurt a thing. I would rather have the throats strait and aligned than rounded from polishing. Cylinder Smith said pretty much the same thing.

S&W and others are cutting the throats small to improve Jacket performance. A lead boolit sized down to .4285 by a modern S&W 629 is still a lot larger than the .429 groove, bore. Almost half the bore is .01" to .014" smaller when you consider the rifling land. That .4285" boolit will still be sized down a minimum of .004" in the barrel. Another .001"-.002" may put you over the top in getting that good gas seal but that might not be your leading problem. That said I like throats .001"-.002" over groove for BOOLITS.

[Fluxed]

I've used the Manson Reamer on several guns. I made a centering sleeve to use along with the pilot bushing and cut from the rear. The little bit tooling marks are 90 degrees to the bore and don't hurt a thing. I would rather have the throats strait and aligned than rounded from polishing. Cylinder Smith said pretty much the same thing.

S&W and others are cutting the throats small to improve Jacket performance. A lead boolit sized down to .4285 by a modern S&W 629 is still a lot larger than the .429 groove, bore. Almost half the bore is .01" to .014" smaller when you consider the rifling land. That .4285" boolit will still be sized down a minimum of .004" in the barrel. Another .001"-.002" may put you over the top in getting that good gas seal but that might not be your leading problem. That said I like throats .001"-.002" over groove for BOOLITS.

^THIS^

Good post.

[Deep Six]

S&W and others are cutting the throats small to improve Jacket performance.

If S&W's goal is good jacketed performance, they failed miserably on my 629. The jacketed 44 mag load I tried (225 FTX over 12.5 HS-6) shot the worst out of any load I tried. My 12ga 870 might have patterned better at 25 yards. I know the gun isn't totally whacked though because it did manage the 4" group at 25 with the 240/7.5 Unique 44 spl load.

[at_liberty]

I have had some gun's cylinder throats reamed and have a few more at the gunsmith, all to address a real leading problem and to make the guns compatible with typical lead bullets. Admittedly, some guns have throats smaller than they should be regardless, or the throats are not consistent in diameter.

My standard has been whether a jacketed bullet of standard diameter will go through the throat without too much force or deformation. Basically, I can push it through freehand. Then the lead bullet, measuring a grunt larger, will offer resistance but can be tapped through freely with a squib rod and light hammer, the bullet still measuring true on the other side.

Yes, this size retention matters more for harder bullets, but I buy bullets up on the hardness scale and have a lead supply rated at Lyman #2. What I hope to achieve is normal obturation in the barrel, rather than expecting a harder bullet to recover from being squeezed through a narrow throat. Meanwhile, my gun's accuracy with jacketed bullets will hopefully not be undermined.

I will have think about the forcing cone dimension and discuss that with the gunsmith.

[Deep Six]

I ordered 0.4310 and 0.4525 reamers a couple days ago. I ended up going with HSS as I figure I can just buy another if I manage to wear one out. Now for the interesting part: I knew today was delivery day, so I had everything ready to go for surgery on the flattop. I got the sleeve pilot system all rigged up and cutting oil out only to find that the 0.4310 reamer was a pretty much perfect fit in all six holes. It would just barely spin through without catching on all six holes which were remarkably consistent. So I guess I'm not going to improve the throats on this gun. It will usually shoot 2" and under at 25 yards with a good load. Perhaps I can improve on that with further load development. My goal is to get it shooting 6 touching holes at 25 yards. If I can't get there with load development I may give fire lapping a try.

I tried setting the reamer in the 629 and there is definitely some material to remove there - looks like about 3 thou. I'm just a little leery about learning on a brand new $800 gun. My Bisley 45 is also a little tight so maybe I'll try reaming that one first. I need to do a lot more load development before I'm ready to ream that one. Still waiting to get my mold from the Mihec 45-270-SAA group buy so load development is on hold for that one at the moment.

Just the way it goes sometimes I guess!

[DougGuy]

Find some Tap Magic and use it instead of cutting oil. BIG difference in surface finish, AND the effort it takes to use the reamer. Also, I use a sleeve made out of a spent case and metallic duct tape to make the back of the reamer fit snugly in the rear of the cylinder. It works along with the pilot kit to assure the reamer is straight and centered.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/DSC01943_zpsa39d251d.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/DSC01943_zpsa39d251d.jpg.html)

With your .44 if you can push the boolits into the cylinder throats with your fingers, it's at least half thou over the boolit diameter. If you can't then the dowel hone works great. I sized one of my SBH cylinders with a .432" cast boolit, and a slotted dowel/180grit hone until all 6 holes had the same amount of drag fit to the boolit and it is wanting to cloverleaf a one hole group now, if I do my part.

The .431" reamer fell right through two throats, took finger pressure to twist it through two more, and the remaining two needed a good cut taken out of them. I had 3 different sized throats in one cylinder. I sized them all to how snug the boolit felt in the two largest ones, so now they all are pretty dang close to each other, and the groups certainly show it.

I think the 50/50+2% alloy has something to do with it too, that alloy is soft enough to scratch with a thumbnail, and I am running it out the muzzle about 1175f/s or thereabout, I doubt hard cast boolits would group as well as these do so that is another thing to consider also. Might not seem like much but the alloy is just as much a part of the right combination as any of the other components, powder, primer, crimp, cylinder throats and forcing cone angle included.

[Deep Six]

With your .44 if you can push the boolits into the cylinder throats with your fingers, it's at least half thou over the boolit diameter. If you can't then the dowel hone works great. I sized one of my SBH cylinders with a .432" cast boolit, and a slotted dowel/180grit hone until all 6 holes had the same amount of drag fit to the boolit and it is wanting to cloverleaf a one hole group now, if I do my part.

I did try a bullet through each throat after I found the reamer wasn't going to cut anything. I was using a bullet that measured 0.4310-0.4315 with calipers and it was snug fit that I could push through with a wooden dowel. All 6 holes were very consistent. Like I said, if I want further accuracy gains out of this gun, I'll need to look elsewhere. I did start experimenting with powder coated bullets the other day. We'll see where that gets me. I also noticed that the little of leading I do get with this gun starts imediately after the forcing cone on the 3:00 side of the barrel. Perhaps I should look at getting the 11-degree cutter tool or maybe some sort of forcing cone lapping tool.

[DougGuy]

The 11° cutter might ease the transition through the forcing cone, it will make it longer. Rugers can be difficult to time, if yours is leading one side of the bore it usually means the cylinder is either early or late in lockup and the boolit is hitting the forcing cone more on one side than the other. It is possible to correct it if it isn't too bad by using shims on the side of the cylinder latch where the trigger pivot pin goes through it. There is usually enough space there to move the latch to one side or the other and if moving it aligns the cylinder throats better then the shim will hold it aligned when it locks up.

On the other hand, their customer service is exemplary, and if you can get them on the phone and tell them it is leading the barrel on one side after the forcing cone, they may just email you a prepaid shipping label and fix it, including shipping both ways, on their dime!

Other than that, it sounds like there is basically nothing wrong with your gun!

[Deep Six]

Yeah 2" at 25 yards is nothing to complain about and certaintly not worth calling Ruger over in my book. That's a good tip about the shims though. While sighting down the bore with the action cocked, there is no visible misallignment. I check out the shim idea anyways.

[MtGun44]

"measured with calipers"------ This is really a bad idea for this kind
of work. Calipers are absolutely not accurate enough for this work.

You need a micrometer that reads to .0001" to know what is actually
going on.

Bill

[leftiye]

Yeah 2" at 25 yards is nothing to complain about and certaintly not worth calling Ruger over in my book. That's a good tip about the shims though. While sighting down the bore with the action cocked, there is no visible misallignment. I check out the shim idea anyways.

It should be - action cocked and trigger held as far to rear as it will go (hammer falls, yup). Sighting down the bore seems good to me. I've got range rods, but after studying them, I don't think they can work. Maybe I should "read the instructions" (don't understand them correctly), I don't know.

If they look well centered with the trigger wired back, and if there's a little wiggle room both ways (centered wiggle room too - rock solid tight actually isn't good), then the boolit will center purty good - enough to shoot well.

[GP100man]

What material did ya use to slug the bore ???, if anything other than pure the alloys will make it spring back a bit!

Measure 3 times cut/lap once.

[Deep Six]

"measured with calipers"------ This is really a bad idea for this kind
of work. Calipers are absolutely not accurate enough for this work.

You need a micrometer that reads to .0001" to know what is actually
going on.

Bill

Usually I would agree with you, but the precise size of the bullet wasn't important here. I was trying to state that the same bullet fit very well in all six holes. I measured the bullet just to get an idea of it's size. The measurement of 0.4310-0.4315 compares well with the fact that the 0.4310 reamer just barely fit through the holes without cutting.

[Deep Six]

I did go inspect the gun again and now that I look closer, it is just a wee little bit out of time when cocked. There is more than enough play in the lockup to achieve perfect timing so I will cut some shims and fit them to the cylinder latch bolt mechanism to get it in perfect timing. Then we'll see how it shoots. I've also got some powder coated boolits made up so I can test accuracy of my pet load with Ben's Red vs. Powder coat.

The 45 Bisley is going to be the first one to get cut, but that won't be for a while.

[MtGun44]

Do you understand that you WANT a bit of slop from side to side in the
cylinder when shooting? You do not want the cylinder held absolutely
rigidly. There is always a touch of misalignment in the cylinder holes
to the barrel, so this tiny slop lets the boolit actually move the cylinder
a hair to get perfect alignment as the boolit jumps the gap to the barrel.

Bill

[cbrick]

Do you understand that you WANT a bit of slop from side to side in the cylinder when shooting? You do not want the cylinder held absolutely rigidly. There is always a touch of misalignment in the cylinder holes to the barrel, so this tiny slop lets the boolit actually move the cylinder a hair to get perfect alignment as the boolit jumps the gap to the barrel. Bill

Not always Bill. My 357 and my 22 revolvers have zero "slop". When cocked the cylinder is locked tight with no movement. The FA revolver cylinders are line bored and the chambers line up perfectly so no need for "slop". But except for line bored guns you are correct.

Rick

[DougGuy]

I agree, especially with a Ruger SA. The longer 11° forcing cone helps that too, as it lets more of the boolit out of the throat so it doesn't work the cylinder notches and latch so hard. The OP's pistol by his account may be improved by shimming the latch to shift lockup more in line with the bore, but yeah you don't want it tight as a drum, all it will do is beat itself to death.

[Deep Six]

I did the shimming job yesterday. I didn't have any shim stock handy so I drilled and cut up a 0.005 feeler gauge. I ended up needing three 0.005 shim washers as there was quite a bit of slop in it (more than my other Rugers I now realize). All three went between the bolt and trigger. Now the cylinder holes are much more centered when it's cocked. And don't worry, there is still some wiggle left in it - I know Rugers aren't supposed to be locked up tight as a drum. This one just had a lot of slop. Now it's more like some of the tighter Rugers I've picked up.

I was going to shoot it today but the weather was too perfect so I ended up using all my free time doing some spring cleaning around the house/yard/barn. Hopefully I'll get out to test it tomorrow.

[Deep Six]

I picked up a new t-handle and some tapping fluid this evening. I couldn't control myself (I'm like a little kid) so I took the reamer to the cylinder on the 45 Bisley. I cut off a piece of brass and fit it around the reamer. This was within a thousandth of the cylinder so there was no need for taping it. The chucking reamer worked perfectly like this. If it didn't cut straight due to lack of a front pilot I can't tell. Everything measures perfectly now. I finished it off with some 400 grit paper to get a nicer finish. 0.4525 boolits slide through with thumb pressure and all 6 are consistent. Can't wait to go shoot it!