Home Forums Hunting & Shooting Handguns Is Revolver Barrel "Slugging" and "Cylinder Reaming" Necessary?

After decades of handloading for rifles, I am just beginning my quest to reload for my 38/357, 44 Mag, 45 LC and 454 Casull. I am starting with my 454 Casull and then will move to the others. I plan to load hard cast bullets as the main purpose is for bear defense in the mountains and for plinking and familiarity with my rounds. We don't have a pistol/revolver reloading section; so, I figured the topic would best be addressed here.

Having said that, my research has lead me to a couple of issues I've never faced with my decades of loading for rifles. In researching reloading for my 454 Casull (Ruger Super Redhawk Toklat) I repeatedly come up with assertions that I need to "slug your barrel for size and you may need to ream you cylinder throats". I'm all about safety. I've also read that using a caliper is not accurate enough to do this. So, onto the questions. First, do I need to "slug my barrel"? If so, how is that done? How do I determine if it is needed? I see on some bullet manufacturers sites that my 454 Casull cast bullets actually do come in different sizes based upon my actual firearm's measurements. Can someone shed some light on this/these subjects for me? Thanks in advance.

I will note that after using multiple different factory loads of a large variety of bullet types and sizes, I've experienced no malfunctions at all.

My experience is limited but I had one revolver that the cylinder mouths were smaller than the barrel so the bullet was undersized travelling down the bore, not conducive to good accuracy. After the cylinders were opened up to .002 (as I recall) over the barrel, accuracy improved noticeably. I also fire lapped a Blackhawk out of curiosity and noticed only a slight improvement in accuracy but it seemed much easier to clean. YMMV but I would shoot it first and see if your satisfied and then start trying things to improve accuracy.

In addition to the questions in my original post, Redleg172's post elicited another question from me. Is this a safety issue or a potential accuracy issue or both?

It's an accuracy issue. Most of those suggestions for slugging and reaming relate to cast bullets which are far more sensitive to fit although jacketed bullets will also definitely benefit from proper fit.

The ideal situation we try to get is an ever decreasing diameter tube for the bullets to travel. Bullet diameter should match the cylinder throat diameter which is optimally about .001" greater than bore diameter.

Ruger single actions, especially in .44 and .45 caliber, tend to have a tight spot where the barrel screws into the frame. The bore is constricted .001-.002" so the bullet is squeezed down and then released into a larger diameter throat. Same thing happens with undersized throats, the bullet is reduced in diameter going through the throat and then released into the larger diameter barrel. Jacketed bullets have some resilience and will spring back somewhat but this is anathema to cast bullets.

Like rifles, the first test is to shoot it. If all is well and you are satisfied with the accuracy then nothing more need be done. If you think you and the revolver can do better then you can drive an oversize diameter pure lead slug down the bore (I use commercial muzzle loader balls or you can use a pure lead fishing weight as well) to give you the barrel's internal diameter and this in particular will tell you if there is a tight spot under the frame. If there is then don't trust the final diameter of the slug since it represent the diameter of the tight spot. I don't know the configuration of a Toklat but some Rugers have five lands and grooves, that will mess you up trying to take a reading of groove to groove.

A quick way to check throats is to get a jacketed bullet of known diameter (like it says on the box ) and insert it into the front of each chamber. It should be just a slip fit with no wiggle. If it won't go in at all then the throats are undersize and would most likely benefit from opening to bullet diameter.


This is only a summary of the Reader's Digest version and if you want you can delve deeply into the esoterica of revolver accuracy, but lots and lots of folks do just fine with jacketed bullets and revolvers right out of the box.


One hint I can give is that much like rifle reloading there are all kinds of things both practical and mystic you can try to get better accuracy, but the single most important factor in the construction of the loaded round itself is to get it straight. If the bullet doesn't get a straight start out of the case then you've already handicapped it from getting whatever level of accuracy it might otherwise have achieved. Obviously the powder and charge weight, primers et cetera have their own bearing on the matter but start with straight and IME you're halfway there already.

I am far from an expert on this subject, but I have a 45 colt Ruger Blackhawk that I was getting very poor accuracy and lots of leading with various cast bullet loads. After reaming the cylinder, leading is all but gone and accuracy is fantastic.

Thanks so far for the input guys. If it is more of an accuracy issue than anything else, I am less concerned than if it were a safety issue. I guess if the bullet doesn't tumble and I am accurate from 30 yards on in, I will be satisfied. I won't be loading hunting rounds. I will do as suggested and see if I get the accuracy I desire. After all, I may not be loading for hunting; but, I don't want shotgun-like patterns either.

IMO, it's the opposite of a safety issue. I've convinced myself that Ruger uses tight cylinder throats to protect the forcing cone. Oversized cylinder throats is what can cause problems.

Be aware that selecting a cast bullet that is .001 or .002 larger than the "stated" or "measured" barrel diameter MAY be sized down (by design) using a CARBIDE crimping die. I use a carbide ring crimper for cartridges loaded for a S&W .44s, but removed the ring on a separate crimp die for cartridges loaded for .44 SBH cylinders.

There is also a barrel leading component, making choosing
alloys/design more critical.

Get this wrong, and you end up with a lead lined smooth bore.
Cleaning w produce lead wire chunks.

If the dimensions are right, then the revolver will be more happy
With more bullets.


Two ways to approach this.

1. Shoot it. If you are happy, assume all is well. (It might be. Until you change alloy, design, or speed)

2. Measure. Make everything "right." It might just be. Will it guarantee
nirvana? Nope! But chances are, you will have a more consistently
happy revolver.

Funny this shooting thing.

High dollar customs that don't shoot/function well.
Cheap POS rifles that do.

Ugly, pitted barrels that shoot well, half fast ammo, scopes, mounting...
that always does well vs doing as much right as possible, and getting
disappointing results.

Every case is stand-alone.
The rules mostly apply to the average, they don't determine the individual.

I've seen Ruger throatchoke and it's no joke. Honing fixes that 99% of the time.

Rugers in 454 seem to be right about .452.

45 Colts are generally .449, or the ones in the past have been.

Thread choke also seems to be prevalent in the 44s and 45s, again excepting 454s.

The bottom line is that the throat needs to be the fattest diameter, preferably .002-.001 over groove with groove tapering so the muzzle is the smallest diameter.

Hornady is about the only jacketed bullets in 45 that mike .452. If they drop a bit snug, your probably good for about anything commercially available and the targets should reflect this.

I'd love to have a Ruger Super Redhawk 454 with .4525 throats.

I have had 3 Super Redhawks in 454 and measured 2 others with pin gauges.
Throats measured .455 to .456 in the 5 guns.

I sent a new Toklat back to Ruger (twice) for a couple of issues and asked for a new cylinder with .4525 throats.

I offered to pay. I begged them to look for a cylinder with smaller throats. Didn't happen.......

I have read on the web some folks have 454 Rugers with .452 throats.

I'd like to buy one of those.

Bigsky,
Not sure your location in Montana but if you are anywhere near Bonners Ferry, ID. I have pin gauges to check your throats.

Thanks for the offer molly. Unfortunately, I am in south central Montana in Billings. I'm hoping a local gunsmith has some.

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[/quote]
Thanks for the offer molly. Unfortunately, I am in south central Montana in Billings. I'm hoping a local gunsmith has some.[/quote]

Try the local machine shop, that's what I've found.

I slugged my Smith 25 45 Colt, I wasn't getting the accuracy I wanted with cast. ~ 4" at 45 Yards. I fire lapped it. -- .452" diameter -- The barrel does not lead at all with the loads I'm using. I've tried 5744 and Unique. 5744 left a lot of powder granules in the barrel. I probably didn't load hot enough, but I couldn't find verified load data with 5744, so I didn't push it.
I have been using 9.5 to 10 grains of Unique behind a 250 grain semi-wadcutter with a very wide flat point. It sort of looks like a Keith design. I may decrease the powder charge down to 8.5 grains, .1 grain at a time.The mold is by NOE.

I may want to find a gunsmith to open up the cylinder or at least verify my suspicion that the chambers need to be sized better.

As far as Ruger's go, when I had an FFL in the 60's and 70's I bought 10 Super Blackhawks in 44 mag. I sold 9. The one I kept must have everything right. I shot 2" groups at 100 yards with it when I was using it for silhouette - (240 grain GC). Without the gas check the groups were 2 1/2".

I doubt I'll ever have another revolver that shoots as well as that one. Besides at my age, I can no longer see that well, I now have a scope on that Ruger.

The SRH and newish Bisley 454 were both just fine @ .452-.453.
The larger throated Anacondas and 25-5's just get .455 bullets.