Cylinder reaming

[King Medallion]

I just sent 2  Blackhawk cylinders out for reaming. One is a NM .45 Colt and the other is an OM .41. The throats measured by mu calipers @ .447 and .407 respectively, not worth a damn for accuracy, especially cast bullets. After measuring my NM 30 Carbine and OM 357, I see they will need reaming as well. Hear I thought it was just me being a bad shot all these years. Anyone else have their cylinders reamed?

[Trailrider]

When I bought my first Old Model Vaquero in .44-40, the chambers were so tight and not uniform that I could not easily chamber factory loads! In addition, the throats were .425" in diameter! I finally persuaded Ruger (along with some help on similar problems by Duke Venturino, et al, in print) to do something about it. I sent the gun back and they did, indeed do something, either reaming or replacing the cylinder. HOWEVER...they left the .425" throats! The groove diameter of the barrel is .429".  I was going to have the throats reamed out, but decided to try shooting hard-cast bullets of .430", just to see what would happen. Naturally, I assumed that accuracy would be horrible. But, when I did some testing, by shooting from a sandbag rest at 25 yds, I found the gun would group 1-5/8" 5-shots consistantly! How was/is this possible?  I used hard (BHN 17-22) cast bullets. Although I have not removed the barrel to prove my theory, I believe that the hard cast bullets squeeze down going through the throats. But the internal compressive stresses in the bullet matrix do not have time to dissapate (in the form of heat) in the time the bullets pass through the throats, so, when the bullet hits the forcing cone of the barrel, it re-expands! Excited by these tests, I procured another .44-40 cylinder with the looser chambers and the .425" throats, which was fitted to another OM Vaquero originally in .44 Magnum. (I had a .44 Magnum cylinder fitted to the first gun, giving me a pair of convertables.)  Accuracy in the second gun is also very good, considering it has a 5-1/2" barrel instead of the 7-1/2" on the first gun.
Hence, I have no intention of reaming the throats of the .44-40 cylinders. The secret is to use hard-cast bullets.
(Note: in spite of the accuracy of these guns, that does nothing for the speed of my shooting! That is pretty slow, and may be getting slower with my age!) 

[rickk]

In the older ones, be amazed not that they are undersized but that they are all close to the same size.

Ruger has since changed the way they do reaming so that they are much more consistent and most likely a lot closer to whatever target value they strive for.

[Trailrider]

In the older ones, be amazed not that they are undersized but that they are all close to the same size.

Ruger has since changed the way they do reaming so that they are much more consistent and most likely a lot closer to whatever target value they strive for.

That was a problem with the first .44-40's in the OM Vaqueros. No two of the throats were the same size. They apparently "gang" reamed the throats using six different reamers. The results were variations in the diameters.  I can't swear to it, but I think they switched to reaming with a single reamer for all six. Still, they left the throats .425".  Why? Because the SAAMI dimensions for the .44-40 bullets is .427 +0 - .003"!  SAAMI has never, to the best of my knowledge upgraded the bullet dimensions to match modern guns with .429" rifling grooves. It was only after many complaints that Ruger finally opened the .44-40 and .45 LC throat dimensions. Then, shortly thereafter, they discontinued the .44-40 guns. 

[rickk]

correct, they ream them one at a time now with a single reamer, so they should all be the same. It is a bit easier to keep an eye on a single reamer as it wears, so the whole process should be better.

[Chev. William]

I have Two original Winchester 1873's that Slug .434" Groove Diameter/.430" to .431" bore diameter.
They do NOT "pattern Well" with modern 44-40 Factory cartridges with .429" or Smaller Jacketed Bullets.
However; with 'oversize' Cast Lead sized to .434' to .435" they do well at my 100 yard shooting.

SAAMI came into Existence well after My rifles were already in customer's hands as one is a 5 digit serial number and the other is a low 6 digit serial number.

Too bad they don't do Historical Variations on their Recommended Practices.

Sighing,
Chev. William

[Coffinmaker]

In my past life as a practicing CAS Gunsmith ........... I could count the number of Rugers with correct cylinder throats on one hand.  To
be honest, I only worked on ONE Ruger is correct throats and that gun was actually 3 of 6. 
Occasionally, a gun will still shoot with undersized throats.  I strongly disagree that hard case bullets will "bump up" or "re-expand" once
they have been swaged, either by a luber/sizer or incorrect throats.  Once small, small.  They will tend run the bore a little kattywumpus,
engage the rifling and actually group.  It is unusual though.  Normally undersize bullets will tend to shoot "patterns" rather than groups.

When there are accuracy problems, excessive felt recoil,  high pressure indicators or leading with normal range loads, the first stop is to
check the throats vs bore.  Cylinder Throats that match bore diameter and good forcing cones are quite important.

Coffinmaker

[Drydock]

Yeah, crystalline structures don't behave that way.  BUT every gun is a physical law unto itself it seems.

[Chev. William]

All My New Model Ruger Single Eight cylinders are Freshly reamed from 8-shot .22 Mag Cylinders up to .25" Caliber. suitable for .25ACP and my Lengthened derivatives.
So All My chambers and throats are cut with a single Finish chamber reamer in that Designation.
e.g: .25ACP, .25 Magnum auto (In works now), .25ALS/.25 Stevens (Long) (future when the Reamer is Done), and .250ALRM.
I ordered my reamers from PT&G and my gunsmith reams the Cylinders to specifications.

in shooting my .25ACP Cylinder, I found it worked great with Jacketed bullets but 'shaved lead in the cylinder with Lead bullets.
we found the Throats were sized for the Standard .25ACP FMJ Bullet.  I have had my gunsmith 'open' the throats out to work with My Sized Lead bullets but have not been to the range to try the new throats yet.

I also had him redo the .250ALRM throats to work with my Lead bullets.

We are Experimenting with a .22LR 6-shot cylinder for reaming to .32 Colt Long of .318" Case Body diameter it is intended to go into my new Ruger Single Six in .32H&R Magnum, but I also have purchased a Stainless Steel New Model .22 Mag 6-shot cylinder to also ream and fit.  I hope i twill make Black Powder clean up easier in the future.

Found out BP cleaning again when I shot Buffalo Bore .38 Colt through my Original Nickel Plated Colt Lighting DA revolver.
The smile on my face paid for the three days of Cleaning afterward.

Last time I had shot BP was in 1980s in 44-40 Hand loads through an Iver Johnson Cattleman and I had forgotten the Cleaning ritual.

Best Regards.
Chev. William

[Chev. William]

I now have in my hands the First Re-machined Stainless Steel ".22MAG" Ruger 6 shot cylinder Chambered For ".32 Colt (Long) Cartridges of .318 Body diameter using a PT&G Finish Reamer.

The Throats Measure About .313" diameter, using a Dial caliper, and the Chamber Mouths Measure Between .322" and .325".
The rim Rebates measure .387" diameter and .345"-.355" Deep.  The Narrowest Chamber to Chamber web Measures .145" and the Narrowest Chamber to outside surface measures .072".  Some Chambers have circumferential tool Marks in them so it seems the Reamer may have been Allowed to load up with chips at some points in the work.  Sad but it does Happen.

I have yet to Fire Any Cartridges through This Re-machined Cylinder as the Revolver is still with the Gunsmith so he can "fit the Remaining used Cylinders to it for future Reaming.

Being Retired and on a Low Retirement Income that is NOT Increasing As Fast As California Taxes is Very Frustrating to me at this time of my Life.  Too Old to Work in the Movie Industry Ful Time any more and Too Young to Quietly Go Softly into that Good Night is a Problem.  I finally Placed one o fMy Gun collection on Consignment Sale to see How The "Market' is currently.

Good News is my Niece And her boyfriend came over Last Week and Began Preping and painting my Front Porch railing and the Front Porch roof Post And Beam.  Very Kind and Generous of them.

Best Regards,
Chev. William