Doug Guy Does a Great Cylinder Throat Job

[Silver Jack Hammer]

Doug Guy did a cylinder throat job on my Ruger SBH 3 screw. The factory cylinder was so tight it wouldn't chamber an RCBS 44-250-K unless it was crimped over the driving band. Accuracy was OK but nothing exciting.

After Doug Guy recut the cylinder throats I had a range session with my brother to allow him to experience shooting my Sharps. There was a 2" steel plate at 200 yards we were clanging with the Sharps and the freshly machined magic SBH was pulled out. Once the elevation was solved that SBH didn't miss a beat.

If you have any inclinations to have a revolver's cylinder throated, I'd recommend you send it to Doug Guy.

[Piedmont]

OK. So what were the original cylinder throats in thousandths? How large in diameter were the bullets in your loaded rounds that wouldn't chamber, and to what dimension did Doug open your throats to? It seems you might have gotten by fine by just sizing your bullets a little smaller, but I don't know what the throats measured before recutting and maybe you had a reason for not wanting to do that. This isn't disparaging anything you or Doug did but it seems like you left out a lot of information.

[Outpost75]

In my case the .45 ACP cylinder of my Ruger Blackhawk convertible had .450" throats which were so tight that most factory jacketed rounds would not chamber. The .45 Colt cylinder had similar .4505" throats which were smaller than barrel groove diameter. Doug reamed both cylinders to .4525 and they now shoot well. Excellent workmanship, fair price and fast turnaround.

[Silver Jack Hammer]

Piedmont, I don't have those dimensions for you. The boolits that failed to chamber were sized from .431" to .429" and they would not seat all the way into the chamber. This SBH has countersunk cylinders and the rims of the cartridge loaded with RCBS boolits would stick out of the cylinder and not allow the cylinder to turn. I do not have the measurements as to how far the rims stuck out of the cylinder but it was apparent to the eye and noticeable to the touch. The 429421 would chamber when crimped at the crimping groove however the RCBS 44-250-K has a driving band which is larger than my Lyman mold in 429421. The RCBS is my preferred mold.

We talk about cylinder throat size in the thousands but I measure the throats with a dial caliper, which only gives accurate measurements in the hundredths. I do not have pin gauges. And then such a measurement would only be at the chamber mouth. Measuring in the thousands at my bench would require slugging and using a micrometer, six times. I never fooled with that.

This 3 screw cylinder was too tight for the RCBS boolit not at the mouth but within the chambers. I'd had to devised a method to measure within the chamber about .1" from the case mouth. This would have required casting the chamber and mic'ing that mold. I've never done that before and wasn't inclined. What was apparent was there was a problem, it didn't work. I wrote to Dave Scovill about this and also acknowledged that Ruger chambers are tight and suggested I try sizing the boolits smaller. Like I said, that didn't work. What did work was my gun after Doug Guy re-cut the cylinder throats, for a very reasonable price and a very quick turn around.

[bedbugbilly]

From the numerous posts I've read on here . . Doug has an excellent reputation for doing excellent quality work. If I ever need assistance with throats - he's the first I'm going to contact. Glad to hear of your satisfaction and that you wheel gun is now working much better with your components! Enjoy!

[Markbo]

Cost? I have several .45s I need evened up. A new set of pin gauges revealed the inconsistencies. I am hoping it will improve accuracy. BTW would he need barrel/throat diameter first??

[DougGuy]

Thanks fellas for the compliments, and GLAD the results are paying off!

Barrel measurements really aren't critical or even necessary, as long as the boolit is at least the same size or bigger. Ruger barrels are really consistent, the .45 barrels are all generally right on .451" in the grooves and the .44 barrels are .429" with some .430" so as long as you are sizing above these dimensions, should be good to go.

The most important thing with cylinder throats is getting them all the same size and as close as possible to each other, once they are all the same you can easily size to match the throats. This reduces the differences in recoil and pressure that a large throat compared to a smaller throat produces. The greater the difference, the greater the chances that boolits will fly to different points of impact. The closer you can get the cylinder throats to a constant diameter, the less difference between them and the greater chances that boolits will strike a point of impact closer to each other from shot to shot. This is the real payoff in having throats reamed.

When Ruger reamed cylinders they did so on a Hitachi machine with 3 cutters, which reamed 3 of the 6 throats, then they would index over one hole and ream the other 3. As these reamers wore, they were replaced one by one, instead of all 3 at once. The worn reamers cut a smaller hole, naturally, and the newer ones cut larger holes. It is very common to see cylinders with 3 pairs of throats, each pair a different diameter than the pairs on either side of it.

Some cylinders can be evened out with a .4315" reamer if none of the throats are already larger than the reamer. Most of the time the .44 cylinders will need to be reamed .4325" to get all the throats even.

It seems to really help if the forcing cone is addressed with an 11° cutter as well as working over the cylinder throats. Once the throats and forcing cone are corrected, the only other thing needed to do the "quick and easy" accurizing for a Ruger single action revolver, is swapping in a Wolff 30oz. trigger return spring. This spring makes it easier to hold the sights motionless while firing, which really shrinks groups.

If you want cylinder throat work done, simply send a PM here on the forum.

[T-Bird]

very happy with my 686 no dash Doug did for me in the spring. Shoots better than me now. Shoot Straight, T-Bird

[06ackley]

I agree he does great work.He did two of my Redhawks for me.

[Markbo]

Doug do you foresee any problems on the carpenter steel used on the new Lipsyes .480s?

[DougGuy]

Doug do you foresee any problems on the carpenter steel used on the new Lipsyes .480s?

I don't foresee reaming those cylinder throats unless the one they sent Jeff Quinn was hand picked and the rest of them aren't going to be like the one he got. His would let a .475" boolit slide right into the throats.

FWIW, I am awaiting shipment of an 8 flute TiNi Carbide throating reamer of my own design that will let me do the Tenifer, Melonite, Isonite salt bath hardened barrels. The more exotic gun makers get with the materials used in barrels and cylinders, the more cleverly devised tooling will be needed to 'smith these animals.

[Spector]

Does that mean you will soon be able to throat Springfield XDs 45 ACP barrels? If so that is great news?...Mike

[Tar Heel]

I don't foresee reaming those cylinder throats unless the one they sent Jeff Quinn was hand picked and the rest of them aren't going to be like the one he got. His would let a .475" boolit slide right into the throats.

FWIW, I am awaiting shipment of an 8 flute TiNi Carbide throating reamer of my own design that will let me do the Tenifer, Melonite, Isonite salt bath hardened barrels. The more exotic gun makers get with the materials used in barrels and cylinders, the more cleverly devised tooling will be needed to 'smith these animals.

You are going to need a bigger shop soon!

[Silver Jack Hammer]

In re-reading my post there is a mistake. The 200 yard target was 2' not 2".

It was a round steel plate spray painted black in the Boise August sun.

[mozeppa]

doug just did 11 cylinders for me.

yes eleven!

good work and good turn around.

[rintinglen]

He did my M-69 S&W 44 and the job could not have been done better. The .4285 throats are now an even .4315

[rintinglen]

He did my M-69 S&W 44 and the job could not have been done better. The .4285 throats are now .4315-ish and the leading problem is greatly reduced.

[Markbo]

Interesting....what size bullets did you shoot and what size bullets do you plqn on shooting now?