Ruger 45 colt cylinder throat reaming

[2shot]

Measured the throats on my Bisley 45 colt and found three different throat sizes. .448, .449 and .450, these were measured with a set of MINUS plug gauges so they're a tad smaller that this. I'm going to ream them with a Manson .4525 reamer and was wondering what kind of accuracy improvment if any to expect from doing this? I also have the constrction in the barrel where it is screwed into the frame and I'm planing to fire lap that also. Now before fire lapping the barrel constriction measuers .451 with it being looser in the middle of the barrel and it seems that there is a constriction at the muzzle also but not as bad as where the barrel goes into the frame. It's a shame that Ruger can't get this right, it's a nice looking and handling gun but just doesn't shoot as well as I had expected it to.

2shot

[softpoint]

I had my 4⅝ black hawk reamed and the forcing cone re-cut at the same time. That gun regularly shot around 2" or so at 25 yards. After having the work done, the gun will occasionally go into an inch ,so you could say the improvement was near 100%:smile:

[Charlie Sometimes]

It will shoot better than you can hold it, and maybe see! Mine does now that I had the same work done as you are considering. I want to get a SS Bisley in 45 Colt and do the same to it for hunting. Love the Rugers! I won't own anything else- unless they don't make it.

[Changeling]

Measured the throats on my Bisley 45 colt and found three different throat sizes. .448, .449 and .450, these were measured with a set of MINUS plug gauges so they're a tad smaller that this. I'm going to ream them with a Manson .4525 reamer and was wondering what kind of accuracy improvment if any to expect from doing this? I also have the constrction in the barrel where it is screwed into the frame and I'm planing to fire lap that also. Now before fire lapping the barrel constriction measuers .451 with it being looser in the middle of the barrel and it seems that there is a constriction at the muzzle also but not as bad as where the barrel goes into the frame. It's a shame that Ruger can't get this right, it's a nice looking and handling gun but just doesn't shoot as well as I had expected it to.

2shot

First of 2shot I am not an expert on revolvers (rifles I know about). I'm answering because I believe something is wrong with your measuring. Either the tool or your procedure, not sure because you didn't specify.
You need to clean the barrel and cylinders spotless before you take measurements that will equate to changing the metal sizes of your revolver. Your measurements just don't make sense, it would be possible, but not normal or probable.

Get the barrel spotless inside (soak and clean till no residue) and then do a "slugging " of the barrel and cylinder throats for exact measurements. What tool are you using for measuring ?

Almost forgot, What bullets (brand and weight) have you been shooting?

[Dale53]

Before I reamed my SS Bisley Convertible .45 Colt/.45 ACP, i had leading with the Colt cylinder. The accuracy deteriorated as I shot. I couldn't even load the .45 ACP with cast bullet SWC's.

After reaming, I get NO leading and the accuracy is maintained as long as I shoot (five shots to several hundred). The .45 ACP cylinder now allows me to load my "loaded for the 1911" target loads and shoots as well as anything I have. That is to say, VERY well indeed.

I see no downside to reaming (if it is done in a professional manner) and certainly in my case (and that of two of my friends) the accuracy was much improved and leading ELIMINATED.

FWIW
Dale53

[2shot]

Scrubbed and cleaned the throats and measured with plug gauges (minus). There is no fouling or lead in the cylinder throads and those are the correct measuements. One at .450 three at .449 and one at .498.

Been shooting RCBA 270 SAA mostly and some Remington 255 grain lead. Tried Cor-Bon WFN freight trains and some jacketed 300 grain Hornady. Nothing shot much better that 3" at 25 yards.

This gun was bought when the Bisleys first came out so it's over 10 years old. I don't know if Ruger ahs improved their machining or not since mine was manufactured.

2shot

[NHlever]

The measurements you got are possible because Ruger used to machine the chambers with a three spindle multiple drill head. Three chambers were cut ( in stages, of course), and then the cylinder was indexed , and the other three cut. The final throat sizing was done from the muzzle end. Now all that machining is done on CNC machines, and I believe that everything is done from one end. I think that change took place a couple of years ago. Between all the indexing going on, and using three different tools at a time, the tolerances you saw are not out of the question.

[Dale53]

2shot;
I wouldn't presume to tell you what to do. However, this was my second Ruger .45 Colt that I reamed and I'll tell you, without reservation, that both of my revolvers (as well as my two friends revolvers) now shoot at NRA Match levels with my cast bullets.

If you don't have the machine shop experience to ream them, you can send cylinders only to Cylinder Smith for proper reaming and quick turn around for a small charge. That will be the best value you'll have in revolver smithing...

FWIW
Dale53

[stubshaft]

2shot:
Rest assured thast Ruger is NOT the only manufacturer that has this problem. S&W was even worse when they used to pin the barrels to the frame and I have a couple of SAA Colts that also show a slight restriction in the forcing cone.

[MtGun44]

My 45 convertible had .449 on one cyl and .450 on the other. Reamed both to .452 then
polished to .453. Reduced fliers, I presume the remaining fliers are my fault.
No leading, very good accy.

Bill

[azrednek]

I just had my Blackhawk Convertibles cylinders reamed to .452 by member JIMinPHX. Mine is a little more than a year old. It was a 2008 Christmas gift. My measurements were all over the place with the smallest being .448 and the largest .451. I'm no professional machinist like Jim but I believe he got similar measurements with his high quality tools. Jim also noticed the throats were slightly tapered.

I was going to have the throats reamed a short time after I got it but a member here or the Handloads group suggested I contact Ruger first. I sent Ruger targets comparing the group size using the same ACP loads in my S&W 25-2 and detailed the measurements of each of the cylinder's throats. Ruger just sent me a form letter saying I could return it to the factory for testing.

I decided to wait until the NRA Convention here in Phoenix this past summer and talk directly to a Ruger rep and see if I couldn't get them to ream it for me. The Ruger rep told me they would test fire it with factory jacketed ammo and if it was determined to be safe they would just return it to me. The rep was aware of the problem and mentioned he was a lead slinger but unfortunately they wouldn't ream it. The rep I'm sure following the advice from Ruger's legal dept, warned me, very politely but somewhat sternly that I could void the warranty if I altered it.

Hopefully I'll get a chance tomorrow to shoot it and see how much improvement there is. When I slugged the bore in Jim's work shop I could feel a slight restriction in the barrel right under the strap. If I don't get a major accuracy improvement, guess I'll have to have the forcing cone lapped. It is really a shame Ruger can't (or wont) ream the cylinders to a consistent .452.

It is bad enough that Ruger sends them out under sized but one would think they could at least get all the throats the same size.

[mtgrs737]

I had my New Vaquero throats reamed to .452" then hand polished to .453" so I could shoot cast without leading. I sent it off to the cylindersmith along with two others that were undersized, it was money well spent as I shoot lead only in most of them.

[2shot]

OK, I reamed my cylinder throats last night and now I at least have the same diameters on all the throats. I had two that were tapered and three different size throats on the same cylinder but that's all in the past now.

Now I have to check to see about the constriction in the barrel where it screws into the frame. I may do as Softpoint did and re-cut the forcing cone with an 11 degree cutter and see if that eliminates the constriction. The constriction isn't very long so the re-cutting just may do it. If re-cutting the forcing cone doesn't do the trick I'm back to fire lapping.

Stubshaft pointed out that there are other guns that are just as bad about cylinder throats. The good news about the Ruger is that there is enough metal left in the throats so that this can be corrected fairly easily. I like others find it strange that Ruger somehow can't get this right and maybe with their newer CNC machines they will.

2shot

[Dale53]

2shot;
Ruger tests their guns with jacketed bullets. Most manufacturers do NOT cater to reloaders (some of them think reloaders are sub-standard - and in some cases, no doubt, they are right). A jacketed bullet will shoot well with undersized chamber throats and a cast bullet will not.

Personally, I am almost thankful that my cylinder throats were undersized - it allowed me to custom ream them for best results. I had access to a reamer kit. If a person does not, then a quick trip of the cylinder or cylinders (discount for more than one at a time) to:

http://www.cylindersmith.com/

will solve that problem for you at minimal cost. I have been able to do my own, but I hear rave reviews about cylindersmith constantly. He has a reputation for excellent work and fast turn-around.

FWIW
Dale53

[Shiloh]

What dale said.

This guy has the tools, experience, and a stellar reputation.
It'll be done right.

http://www.cylindersmith.com/

Shiloh

[2shot]

Thanks for the link guys but I already reamer the throats in my Ruger. Did it last night with a Manson reamer that I borrowed from a guy that I shoot NRA Bulleye with. Now I have .4525 throats in 6 chambers.

Now I jst have to do something with the constriction in the barrel and I'll see how it shoots.

2shot

[Wireman134]

2shot;
I wouldn't presume to tell you what to do. However, this was my second Ruger .45 Colt that I reamed and I'll tell you, without reservation, that both of my revolvers (as well as my two friends revolvers) now shoot at NRA Match levels with my cast bullets.

If you don't have the machine shop experience to ream them, you can send cylinders only to Cylinder Smith for proper reaming and quick turn around for a small charge. That will be the best value you'll have in revolver smithing...

FWIW
Dale53

+1 What Dale53 says. 10% of the 45 job goes to a good cause. :drinks:

[9.3X62AL]

Changeling et al--

WAY too many Ruger 45 Colt Blackhawks have the undersized throat problem to call the original poster's issue anything but a "product characteristic". Mine was similarly dimensioned, and after reaming and polishing out the throats to .453" (groove is .452"), .454" boolits of all descriptions shoot VERY well in the revolver. Prior to the 'operation', the revolver was a "One Boolit Wonder", only shooting decently with Lyman #454490, a SWC/GC design.

A 45 Colt owner should NOT require either a gas-check boolit design OR a jacketed bullet to obtain decent accuracy at 1873 load levels--but those were the requirements in the OEM Ruger I have. As for factory warrantee.......I don't give a rat's aspirations about a warrantee that only covers revolvers in poorly-dimensioned OEM condition, and goes void when someone does things right in the aftermarket.

[Railbuggy]

I bought a bearly used RugerBH in 45lc thurday.I googled the gun for info,then calapered my throats.All looked to be .449.# showed it was made in 93.Guess Ill be sending cylindersmith a email.:cbpour:

[Dale53]

John Taffin said something (I believe on Lee Martin's Single Action Forum) that kind of caught my interest. He stated (or words to that effect) that he doesn't even slug the barrel. He has little interest in what the barrel measures. HIS emphasis is the cylinder throats. THAT he slugs and measures carefully and takes appropriate action (that's EXACTLY what we have discussed here).

I have been doing the same for many, many years. Then, I do serious accuracy tests. You can test with a Ransom Rest (I have access to a Ransom Rest) or over sandbags. I do initial testing at 25 yards then move to 50 yards. If it is a hunting handgun, I move to 100 yards for final acceptance.

If you are shooting with sandbags, it is very helpful to use a scope or Red Dot sight. If you have good eyes, however, you can do VERY good work with issue iron sights. Personally, because of vision problems, I have to struggle with iron sights. I can still shoot them, but it IS a struggle. Mostly, I now use Red Dots (primarily) or a scope.

The purpose of this post is to suggest that before you get EXTREME with lapping or firelapping the barrel, you might want to seriously try accuracy tests. I'm betting that lapping or fire lapping will not be required. I am still a bit leary of lapping or firelapping. I fully understand the theory but it is MUCH harder to lap what needs to be lapped and not damage what does NOT than to ream the cylinders with a good kit like the Manson reamer kit.

Just a thought or two...

Dale53

[pdawg_shooter]

I would say your Ruger is a little better than average! I have never seen a factory Blackhawk 45 that measured any better. After being a FFL dealer and gunsmith for over 25 years I came to hate selling a Ruger. Most comebacks of any brand by far.

[2shot]

John Taffin said something (I believe on Lee Martin's Single Action Forum) that kind of caught my interest. He stated (or words to that effect) that he doesn't even slug the barrel. He has little interest in what the barrel measures. HIS emphasis is the cylinder throats. THAT he slugs and measures carefully and takes appropriate action (that's EXACTLY what we have discussed here).

I have been doing the same for many, many years. Then, I do serious accuracy tests. You can test with a Ransom Rest (I have access to a Ransom Rest) or over sandbags. I do initial testing at 25 yards then move to 50 yards. If it is a hunting handgun, I move to 100 yards for final acceptance.

If you are shooting with sandbags, it is very helpful to use a scope or Red Dot sight. If you have good eyes, however, you can do VERY good work with issue iron sights. Personally, because of vision problems, I have to struggle with iron sights. I can still shoot them, but it IS a struggle. Mostly, I now use Red Dots (primarily) or a scope.

The purpose of this post is to suggest that before you get EXTREME with lapping or firelapping the barrel, you might want to seriously try accuracy tests. I'm betting that lapping or fire lapping will not be required. I am still a bit leary of lapping or firelapping. I fully understand the theory but it is MUCH harder to lap what needs to be lapped and not damage what does NOT than to ream the cylinders with a good kit like the Manson reamer kit.

Just a thought or two...

Dale53


I agree Dale 53. I was going to see how it shoots now with the throats reamed before I tried fire lapping. To tell the truth fire lapping kind of scares me. That's why I said I may see if re-cutting the forcing cone in the barrel might be an option. Still though I don't see a barrel that has a constriction just in front of the forcing cone is going to give the gun it's best possible accuracy but then again it just may.

I just reamed the throats this last Saturday night but haven't had a chance to get to the range.

2shot

[Rick459]

okay so after reading this thread i got out my digital calipers and measured my blackhawk (purchased in 1975) and measured the mouths on the cylinder. five measure at .456.5 and one is .457. the pistol shoots well but compared to what everyone here is reaming out their cylinders to, doe this put me at a disadvantage?
Rick

[Bucks Owin]

okay so after reading this thread i got out my digital calipers and measured my blackhawk (purchased in 1975) and measured the mouths on the cylinder. five measure at .456.5 and one is .457. the pistol shoots well but compared to what everyone here is reaming out their cylinders to, doe this put me at a disadvantage?
Rick Our Rugers are pretty much identical, I too have a pre warning NMBH 7.5". .456" throats w/ .452 groove. I believe the biggest problem a lot of folks have, with that vintage anyway, is shooting "1873 level" loads that don't bump in the fat throats. Accuracy is lousy and leading is too. Put enough POWDER in the case (H110/W296, NOT Unique in the 8-900 fps range), a .454" water dropped WW bullet and watch it shoot 1.5" all day long! Old Rugers, too fat, new Rugers too small, ALL with oversize charge holes! :roll: Good thing they don't cost $2,000 huh? :wink: I'll just have to resign myself to 1.5" groups @ 25 yds I guess. I don't feel "too" disadvantaged....Dennis ;-) (Who has found that in regard to the .45 Ruger, Linebaugh knows best! 8-))

[Rodfac]

Plus 1 to what Dale says. Shoot it a bunch for grouping before you resort to lapping. I've got two revolvers that show signs of restriction in the forcing cone area but shoot wonderful groups. Like sub-2" at 25 yds, sitting with 63 yo eyes doing the steering...in a few words...if it ain't broken, don't try fixin' it!! JMHO, Rodfac

[geargnasher]

The New Vaquero .45 Colt I purchased toward the end of last year has a pretty good cylinder, .453" mostly but a few elliptical throats, not great but not terrible, either. It has been CNC cut, doesn't have the burrs and marks internally that the gang-cut cylinders typically had.

Now, it DOES have a .0015" choke at the forcing cone and a .0008" restriction from the front sight blade and .0005" restriction from the wonderful little encylopaedia the ***tards think they have to roll into the side of such an otherwise shiney, pretty barrel.

If anyone has real experience getting rid of at least the throat restriction, please let me know! I have had a devil of a time getting this gun to stop leading after the forcing cone. I have done it, but it only works with one load and I want to use different boolits.

Gear

[azrednek]

I bought a bearly used RugerBH in 45lc thurday.I googled the gun for info,then calapered my throats.All looked to be .449.# showed it was made in 93.Guess Ill be sending cylindersmith a email.:cbpour:

I believe it was cylindersmith's website or another doing the cylinder reaming recommended that you don't rely on measuring the cylinder's throat with calipers. The website suggests that you slug the cylinder and take the measurement from the slug. A real statement of his honesty. He claims to return many cylinders that do not need reaming and refunds the payment.

[Wireman134]

Yes, do slug your barrel. My groves were .4515" with .450" throats. The accuracy was quite good with jacketed heavy bullet loads I attempted to do a home throat job. After taking a little metal out of a few holes. I decided reaming with the proper tool was the only way to have a square true throat. I did discus this with Cylindersmith prior to shipping to him. Now I have square true throats at .4525" and all loads should be easier on the cylinder.

[Changeling]

I agree Dale 53. I was going to see how it shoots now with the throats reamed before I tried fire lapping. To tell the truth fire lapping kind of scares me. That's why I said I may see if re-cutting the forcing cone in the barrel might be an option. Still though I don't see a barrel that has a constriction just in front of the forcing cone is going to give the gun it's best possible accuracy but then again it just may.

I just reamed the throats this last Saturday night but haven't had a chance to get to the range.

2shot


Afterthought: Keep in mind that fire lapping will also increase the groove diameter.
I do not have a bore scope so I can't tell you if it has an adverse effect on the original angles in the groove vs bore diameter .

Personally I would rather see a mechanical test (Ransom/whatever) before deciding on firelapping, the before and after results, but done in a professional way with all things considered.

AS for the Cylinder throat ream, it seems to be a proven fact that some relationship between the throats and barrel groove diameter have a beneficial advantage, but I have searched for and never found what that relationship should actually be in actual controlled testing.

I believe it is generally assumed that cast bullets should be 1 thousandth over barrel groove diameter and a firm push to go through the cylinder throats witch would equate to roughly 1/2 thousandth give or take, I say give or take because you have to take into effect the accuracy of your sizing die, did the crimping die resize, etc. Now this is coming from someone with no real practical revolver experience, just reading.
Witch leads me to the following hypothesis, if the basics have been observed like the cylinder throat barrel groove situation (and in between) , just start shooting and have fun, because it is never going to be perfect because of the lead mixtures, altitude, temperature, wifes attitude and so on. Take full advantage of the years of experience on this web site, double check everything, and go for it.

[2shot]

Theoretically fire lapping is supose to get the constriction out and at the same time taper the diameter of the barrel from larger at the forcing cone area to smaller at the muzzle end. I don't know if that's true or not because I have never fire lapped any barrel whether handgun or rifle. You are correct in assuming that the throats should be 1 thousandth of an inch over the barrel groove diameter and with the constriction in my barrel I'm at .451 and I'm sure that the middle of the barrel is .452 or close to it. Because you mentioned it, my sizing die is one that I bought back in 1970 used from a guy that was getting out of shooting. Over the years of use it has opened up from .452 as marked to .4527 but then it was made in the 1950's and the number of bullets it has sized is coming close to matching the government bailout dollar numbers, probably time for a new one but that isn't the problem here with this Bisley.


I have built several 1911's for bullseye shooting for my own use over the years. One is a Colt Gold Cup frame with a Caspian slide and Kart hard fit barrel and trigger work. I did all the work myself and for the last 2 years this Frankinstien 1911 has kept in the area of 1 1/2 - 2" groups @ 50 yards from a Ransom Rest. The others I have built have stayed in the area of 2" @ 50 yards.

The reason I tell you about the BE shooting and the building of 1911's is because I want this Bisley to shoot and I'm not afraid to try something machining wise to get it to shoot. The fire lapping though is something that I figured (as have others here) is something that is more hit or miss than I care for. I don't know at this time if I will try it, and I probably will not. You are right though and I'm going to shoot this gun a bunch and see if the throat reaming has helped it at all.

Bottom line with this gun is, if I can't start calling my shots then I'm dumping it. In my eyes there is nothing worse that knowing the sight picture was perfect and the bullet landing 4"' randomly over the target from where I was holding. In target shooting that will lose the match for me (not that I would use this gun for that) , in game shooting ( the reason I bought this Bisley) it's the difference in a clean kill or a wounded animal. For me that's unexceptable.

2shot

[NHlever]

If you are a machinist, I would suggest to you that the "constriction" that we hear so much about is more likely a slight "kink" in the barrel because the frame wasn't ground perfectly square with the threads. That is also what makes many Blackhawks require a different front sight height..... Hard to fix, but possible. The constriction under the front sight was caused by more heat than necessary to solder on the sight quite possibly.

[2shot]

You are right NHlever. The constriction at the forcing cone area is from the crush fit of the threads where the barrel is joined to the frame. This crush fit is the easier of the two fixes for the barrel. The constriction at the barrel muzzle end just may be from what you stated, the barrel getting to hot when Ruger soldered on the front sight. That's what worries me. If the factory has created a hard spot by over heating this area then there's a problem. No amount of fire lapping is going to remove this hard spot evenly with the rest of the barrel and I fear the groups shot would be worse that what they are now. The solution to that of course is to cut the barrel and resolder the front sight but I really like the longer barrel. I may have to do some thinking on re-barreling this Bisley if I want to get it shooting the way I want. This would make an interesting project for me and really don't have anything to loose by trying.

2shot

[NHlever]

The barrel steel in your Blackhawk is 4140, and that steel is a bit different about heat. If it were pre heat treated 4140 you could harden it more by just heating, but straight 4140 doesn't get much harder if just exposed to heat, and let air cool which is what happens with the soldering operation. The solder they used to use flows at about 1100° f so it is below the critical temperature anyway, but I have seen barrels being soldered that were much "warmer" than that. We did lap barrels on occassion by casting a slug of Cerrosafe, or lead, and doing it by hand. We made the casting fairly long, and never pushed it out of the barrel completely. We would push it out about half way, coat it with the lapping compound, and then work the lap until it wore enough to cast another one, etc. Cerrosafe does wear faster, but it works without warming the barrel very much.

[Bucks Owin]

More on the constriction business, my Blackhawk .44 and .45 both have about .0005" of "choke" near the muzzle. This is supposedly a GOOD thing and shouldn't need removal as I hear. Could well be, both sixguns are plenty accurate!....FWIW, Dennis :Fire: BTW, fire lapping can polish out an already too fat throat if that description fits your gun. I prefer to "lap" with plenty of shooting! And J-word bullets can help burnish too..:shock: