variations in cylinder throats

[Black Jaque Janaviac]

I slugged the chamber throats on my blackhawk's cylinder. Smallest was .3613", largest was .3626". Of the six chambers 4 were .361X", and two were .362x".

I am not too worried about the large throat diameter, but I am wondering about the two that are a good thousandth larger than the others.

What to do?

[fatelvis]

Contact Dougguy from this site. He will hone them out all to the same size, and does beautiful work! He's done two revolvers for me already.

[Der Gebirgsjager]

Well, you can easily bore out undersized chambers, but you can't conveniently add metal where there is none, so for practical purposes "it is what it is." The difficulty is usually in properly sized bullets being swaged down by undersized chamber mouths and then entering a properly sized bore where they are loose and poor accuracy results. I don't think you have anything to worry about, assuming we're talking about a .357 Mag. and that I correctly understand your post.

[Black Jaque Janaviac]

Der,

Yes you understood everything. I know ideally I would bring the two throats that are big down to the other four. But is it possible to bring the other four up to the .362" range?

[DougGuy]

Those readings seem quite large to me. In my experience it may be that pin gages may be a more accurate measurement than how you are arriving at the figures you have. It may also be that someone has worked over the cylinder before, did you buy the gun new or used?

The most important part about cylinder throats is that they are all even. Uneven throats cause variations in pressure, pressure variations cause the gun to recoil inconsistently in the shooter's hands, which causes it to shoot to different points of impact from throat to throat even though point of aim remains the same.

Most 357 Blackhawk cylinders will not chamber a boolit over .360" in diameter because it makes the shoulder of the case just below the case mouth too large to seat in the chamber, even if the throats are sufficient diameter to seat the .360" boolit.

I would be glad to take a look at your cylinder and pin it out, nothing like a second opinion. If in fact the cylinder throats are as large as you state they are, it may be the best move to get an RMA and send the gun back to Ruger and let them fit a new cylinder since those dimensions are WAY larger than any I have ever seen on a stock as-issued Ruger revolver.

If there is error in the measurements and they are not of the diameter you state they are, and they can be evened out and made consistent, I can certainly take care of that as well. Feel free to send a PM for further inquiry.

[Black Jaque Janaviac]

Yes the gun is used.

what is an RMA?

[DougGuy]

Return Merchandise Authorization. If you are certain your measurements are accurate, then it's a certainty someone got hold of those throats before you got the gun and it should go back to Ruger and let them fit a new cylinder to it. I have worked over hundreds of Ruger cylinders, and NEVER have seen one in 357 that even comes remotely close to those dimensions. It is exceedingly rare for me to come across one that even measures .360" in the throats, and these have no doubt been worked on before too.

I think you would be much better off starting with a factory fresh cylinder, these are normally undersized but the joy of this is that we can size them to fit our needs and I can get them a LOT more uniform than what they send out of the factory. Call it fine tuning for cast boolits, it works out much better to have throats in the .3585" ~ .3588" range for use with .358" boolits.

Also, if these throats are this big, and inconsistent, there may be more "work" done to the gun that doesn't meet the eye and the factory would replace these parts as well if they have been modified. You got this gun used, no telling what (if anything) has been done to the forcing cone or the barrel or any other parts.

[runfiverun]

362? wow.
I thought we were talking about a 38 smith & Wesson.

[Black Jaque Janaviac]

I looked on Ruger's website and they list $50 for fitting a new cylinder. Is that just the labor?

[DougGuy]

I looked on Ruger's website and they list $50 for fitting a new cylinder. Is that just the labor?

Yeah but you can't go by that. I have NEVER had them charge me a cent for any repairs they did for me over the years.

The gun can't be fixed like it is, the cylinder is already WAY larger than you could ever fit a boolit to, so it needs to go back to Ruger. If you call them and get an RMA and talk their customer service up, as in like tell them they are THE BEST in the industry, other companies could learn a lot from Ruger, your next purchase will be another Ruger, yada yada, they might even email you a shipping label, and send the brown truck by your house to pick it up.. All on their dime! It certainly won't be the first time they ever did this for me!

Bottom line, get the gun into their service department, then let them give you a quote on the work needed. If they are going to fix it for free, they will just go ahead and fix it, and they will call you when it is ready to be shipped to make sure someone will be there to sign for it. << The chances of this happening are very good! I would not be surprised if they just fixed it and sent it back.