Great article on Ruger cylinder throats

[rvpilot76]

http://www.singleactions.com/RugerCylinderThroats.pdf
Funny, I have the exact same pistol, and I'm having my throats opened up by the Cylindersmith to the exact same dimensions. I even have the oversize Belt Mountain base pin installed. Mine, however, is a #5 Keith style. I also added a Power Custom free spin pawl

Enjoy!

Kevin

[44man]

None of the groups were very impressive even after opening the throats. All of them look like typical 100 yd groups to me.
Of course loads were not worked and the right boolits selected. Then there is the one thing that opens groups in the .44 and that is the use of magnum primers even with 296.
6/10" improvement is not good enough. My .45 Vaquero went from 4" at 25 yd's to 1" at 50 yd's and I shot several 75 yd groups with it at 1".
He might have fixed the gun but he has ammo problems.

[nicholst55]

None of the groups were very impressive even after opening the throats.6/10" improvement is not good enough. My .45 Vaquero went from 4" at 25 yd's to 1" at 50 yd's and I shot several 75 yd groups with it at 1". He might have fixed the gun but he has ammo problems.

+1. He's still got work to do in load development and boolit selection.

On the same forum there's a thread titled "Ruger Tuneup,' or something similar, where a guy did a before and after comparison with a used Ruger Vaquero .44. He recut the forcing cone and reamed the throats, recrowned the muzzle and smoothed things up and put in a spring kit. He cut group size dramatically doing all that.

Reading that thread prompted me to buy the forcing cone reamer from Brownells. I haven't made it to the range yet to test the results.

[whisler]

I'm certainly not a gunsmith and can't say that it is wrong but I really don't understand how either of these statements below are true. How do you cause a bullet to re-expand after it has been swaged down by the cylinder throat. Also how does an oversized throat cause a bullet to over-expand. If these are possible, some one help me understand how it works.

"The round shoots a 0.400” bullet that when fired is squeezed down to 0.395”. After jumping the cylinder gap and engaging the forcing cone, the bullet is then re-expanded by a few thousandths in order to seal against the barrel’s lands and grooves. Thus, the slug changes diameter three times before it exits the barrel. How much, if any, does accuracy suffer when a bullet goes from 0.400” to 0.395” and then back to 0.400” prior to leaving the gun?"

"Throats that are too large can be just as unfavorable as those that are undersized in that they cause the bullet to over-expand."

[Char-Gar]

I have opened up the cylinder throats on several Ruger 45 and think it is a very helpful thing. I looked at the man's results in the article and they were not very impressive. I attribute that to the fact he used store bought cast bullets. These store bought cast bullets are often of the wrong hardness and often use worthless lube.

If he were a savy caster, he could drop those group sizes a bunch.

[44man]

Charger hit the nail on the head! [smilie=1: I even see the same things in Handloader and other rags. Groups posted that would keep me from buying that gun.
An undersize throat will shoot jacketed bullets better the cast but still not what the gun should REALLY do. But a throat that is a little oversize does not hurt a great deal and can shoot as good if the right boolit, alloy and load is found. Not real hard to do. I never worried about throats .001 or .0015 larger then the boolit. Just use a larger boolit! My SBH has .4324 throats and .430 groove size. It will average 1" or less at 50 yd's with .431 boolits. .430 jacketed shot good enough to hit 79 ot of 80 at IHMSA.
I have posted this before but it might be usefull here again. Vaquero .45 at 50 yd's with a Lyman 452651 weighing 347 gr's. Reamed throats but no forcing cone work. 1.5# trigger. 5 shots in 3/4".

[C A Plater]

My .45 Bisley had under size throats that measured .447 on the largest. Didn't put enough rounds through to say how it effected accuracy but it sure did lead up the first couple inches of the barrel. I had them opened up with a .451 reamer and the leading went away. Since then I have been happy with the accuracy and while it may not have helped it most certainly did no harm.

[Bass Ackward]

I'm certainly not a gunsmith and can't say that it is wrong but I really don't understand how either of these statements below are true. How do you cause a bullet to re-expand after it has been swaged down by the cylinder throat. Also how does an oversized throat cause a bullet to over-expand. If these are possible, some one help me understand how it works.

"The round shoots a 0.400” bullet that when fired is squeezed down to 0.395”. After jumping the cylinder gap and engaging the forcing cone, the bullet is then re-expanded by a few thousandths in order to seal against the barrel’s lands and grooves. Thus, the slug changes diameter three times before it exits the barrel. How much, if any, does accuracy suffer when a bullet goes from 0.400” to 0.395” and then back to 0.400” prior to leaving the gun?"

"Throats that are too large can be just as unfavorable as those that are undersized in that they cause the bullet to over-expand."


Whisler,

There is never a sure things with guns or cast. These statements can both be true and false.

Lead under the correct amount of pressure will expand out until stopped by steel. Same is true with copper. Solid copper will obturate at 40,000 psi. Problem is that you need the right powder speed and bullet hardness to make either true or false. Say if you shoot Bullseye, pressure peaks with the base of the cartridge still in the case and drops from there on out as the volume increases. So if it sizes down either in the throat or at a tight spot under the threads and the remaining pressure isn't high enough to re-obturate the bullet, then the statement is false. Slower powder would still be burning and expanding the gas, so there is a more likely chance the bullet would expand again just as written.

[9.3X62AL]

I'll pile on here with Chargar and 44Man.

I have a BisHawk in 45 Colt, and it had the Famous Undersized Cylinder Klutziness (no acronym to follow) common to Ruger 45 Colts of its vintage (~10 years old). Throats ran .449"........all the same diameter, even if wrong--so they were at least consistent. Groove diameter is .452". The revolver was a "one boolit wonder", and would do half-decent work with Lyman #454490 @ .452" (255 SWC/GC), but scatter 200 grain target SWC's comprehensively and other designs were worse--some tipping at 25 yards, too.

Not good. I opened the throats to .453", and used .454" boolits to assess whatever changes resulted.

Night and day. The 200 grain target SWC's shot GREAT, as have #454190 and #454424. Even #454490 @ .454" tightened up noticeably. (Note--I never attempted .454" boolits in the stock throats). So, my results have satisfied me that an overall improvement was made by finishing the revolver's construction with the throating reamer.

[whisler]

BA: Thanks for the explanation. I have much to learn here.

[rvpilot76]

[QUOTE=nicholst55;243622
Reading that thread prompted me to buy the forcing cone reamer from Brownells. I haven't made it to the range yet to test the results.[/QUOTE]


I'd be interested in those results. Heck, I might even be persuaded to send my barrel out to have it modified, if you felt so inclined.

Kevin

[45r]

All I had to do with my 41 bisley hunter was put a scope on it, firelap 72 rounds and trigger job and it shoots 2 inch groups at 75 yards with 220 saeco,lyman,210rcbs and 255 OGF Mtn Mold boolits.It hangs right in there with my model 83 F/A.

[Blackhawk Convertable]

Lee's articles are always good. And the times I've had the opportunity to correspond with him, were very informative. He's one of the good guys. (Most Ruger nuts are, you know)

[Blackhawk Convertable]

Besides, it's his birthday today...