Ruger 10mm woes, PICS added 10 13 2020

[ezekiel38]

I've had Rugers since 1962 when I received a Ruger Bearcat as a gift, when I was a teenager. In revolvers my preference has always been S&W for DA guns. Partly because of work and then there is the mechanial finesse of an old Smith over a Ruger DA.

Long about August of this year I purchased a Lipsey's limited edition 5" half lug blued GP 100 in 10mm. I've owned several GPs and a Target Gray 4" I owned shot the tightest group of any 357 I ever owned, by any brand in 50 years of shooting 357.

I currently own a Match Champion 357 that is a nice shooter but not stellar.

But this 5" 10mm is a royal pain in the tush. Best groups I can get with it are two to three inches at 25 yards from a supported standing position.

Leads like crazy with in 20 rounds the forcing cone looks like the Comtock mother lode. Scrubbed the cylinder mouths several times with a bore brush and chore boy. Have bullets that mike .400, .401 and .403. To cut to the chase, the cylinder chamber mouths run from .400 to .403+ and are rougher than a cob.

I'm afraid to send it to Ruger as the last revolver I sent to them they did not fix. It had undersized chamber mouths causing high pressure with moderate factory 357 rounds.

What to do?

Pondering the sending of my 10mm Gp to a well respected gunsmith and have it rechambered to .41 Special. Rebore the cylinder and the barrel and check for cylinder alignment and timing, headspace and endshake and then send it back. This is a forum where guys are building "hotrods" all the time. Would like your opinions.




The curious one is how the cylinder ratchet upper digs into the recoil shield. Another pic shows the chamber mouths of the cylinder and the third shows the forcing cone on the eight oclock side where the lead builds up. Would love to have Mr. Bradshaw look at these pics. About 120 rounds through the gun half and half jacketed and lead, and factory and handloads. What is the forum's impressions. Appreciate you sharing your wisdom.

Zeke

[wheelguns]

I would send off the cylinder to have the throats uniformed. Once they are all the same size, you will be able to get a bullet with a good fit. This should help out a lot.

[bula]

Thinking an opinion from 2 Dogs needed before following any path too far. 

[ezekiel38]

Yup to wheelguns and to bula. had to talk like a dutch uncle to get the 403s. I'm no longer a caster and wanted a DA gun for low country field work. Nothing too big with teeth and claws. Should contact 2 Dogs.

[wheelguns]

It has been my experience that when you get that lead in the forcing cone, your bullet is too small.

[Encore64]

I find this odd. I'd be tempted to contact Ruger first.

I bought the first of these guns I could get and it's tied for my most accurate double action revolver.

Throats in mine are a uniform .402"+, but not quite .403". I shoot .402" GT HP Bullets seated long in mine and it's very accurate.

I did replace the Ruger Moon Clips with TK .050" Clips.

The barrel gap in mine is fairly tight at .003-.004". Seating the 200 grn GT Bullets long over Longshot Powder allows an easy 1300 fps.

I hope you get this gun corrected. They are nearly the perfect packing double action revolver.

[bradshaw]

ezekiel38.... double action chambers should be finely polished or ROLLER BURNISHED. Simultaneous extraction requires straight chambers smoother than for the single-extract single action. CHAMBER LEADE----ramp breteween CHAMBER WALL and EXIT HOLE must be smooth to prevent bullet abrasion. Perhaps I’ve been fortunate, but I’ve experienced little or nothing in the way of chamber exit diameters in Ruger revolvers. The natural tendency for a gun owner is to measure what he or she can, and ignore hard-to-measure yet vital RUNOUT (CHAMBER-to-BORE ALIGNMENT). The FORCING CONE is about impossible to measure, yet submits to knowing visual inspection.

Once again we face a revolver’s ORCHESTRA of DIMENSIONS. What can you get away with? Which dimension or combination of dimensions dooms accuracy?

I would try to speak with the service manager and back it up with a letter describing the disease. “Severe leading” does not sound like an invention of yours. By your description the cylinder should be replaced.

Old timers talked about slugging the bore of any revolver before hand loading lead bullets for it. The practice is not obsolete, its necessity revived around 1980 when, in response to timing and erosion issues from widespread, high-volume consumption of magnum ammo, S&W and Ruger swept the challenge under the rug by hogging out the forcing cone. I watched it happen, tried in vain to head it off. Forty years later the practice continues, albeit not as bad as in the past.

When other dimensions nibble perfection, a revolver with .006-inch RUNOUT may group inside 4-inches @ 100 yards. Anyone who disputes this is free to state their case ON THE FIRING LINE. Queer the forcing cone, or the bore (either one), and .000-inch runout won’t shoot 4” @ 100 yards.

Persons who don’t understand REVOLVER ACCURACY can’t be expected to make it tick.
David Bradshaw

[ezekiel38]

I originally had high hopes for this revolver as I've always been a GP 100 fan. I guess I will contact Ruger CS tomorrow and see what they say. I want this gun to shoot and pack as a nice mid weight 5" with aN accurate, solid punch. I had a 5' 27 Smith years ago and it has become too large and heavy to pack in these later years. I will keep you posted.

To respond to Encores' post. Three of the cylinders are almost uncanny in their ability to put three touching at 50ft from a Weavers stance from a wobbly old man. I am using GT 175 TCs, sized .402 and seated at 1.250 as any thing longer won't fully seat in the chamber and allow the cylinder to turn.

Thanks to all of you for such excellent input.

[bradshaw]

Oct 11, 2020 21:11:11 GMT -5 ezekiel38 said:

I've had Rugers since 1962 when I received a Ruger Bearcat as a gift, when I was a teenager. In revolvers my preference has always been S&W for DA guns. Partly because of work and then there is the mechanial finesse of an old Smith over a Ruger DA.

Long about August of this year I purchased a Lipsey's limited edition 5" half lug blued GP 100 in 10mm. I've owned several GPs and a Target Gray 4" I owned shot the tightest group of any 357 I ever owned, by any brand in 50 years of shooting 357.

I currently own a Match Champion 357 that is a nice shooter but not stellar.

But this 5" 10mm is a royal pain in the tush. Best groups I can get with it are two to three inches at 25 yards from a supported standing position.

Leads like crazy with in 20 rounds the forcing cone looks like the Comtock mother lode. Scrubbed the cylinder mouths several times with a bore brush and chore boy. Have bullets that mike .400, .401 and .403. To cut to the chase, the cylinder chamber mouths run from .400 to .403+ and are rougher than a cob.

I'm afraid to send it to Ruger as the last revolver I sent to them they did not fix. It had undersized chamber mouths causing high pressure with moderate factory 357 rounds.

What to do?

Pondering the sending of my 10mm Gp to a well respected gunsmith and have it rechambered to .41 Special. Rebore the cylinder and the barrel and check for cylinder alignment and timing, headspace and endshake and then send it back. This is a forum where guys are building "hotrods" all the time. Would like your opinions.

Uneven contact of cylinder ratchet and STANDING BREECH. Firing pin bushing looks solid with horizontal high spot reflecting cartridge drag. Areas which appear sandblasted are unmachined casting, not an offense, although bearing surface for ratchet should be smooth. Good place to dab ANTI-SEIZE COMPOUND or chassis grease.

Chambers appear reamed but without final pass with ROLLER BURNISH. Cannot see LEADE----ramp between CHAMBER and EXIT HOLE (aka THROAT). Chamber exits appear chamfered at CYLINDER FACE, in my view a horror; to the manufacturer an abuse of process to remove burrs. This feature alone may contribute leading. If the lead is rough, leading starts as bullet enters exit holes.

FORCING CONE appears smooth, albeit very light ring possible 2/3-in; probably inconsequential. Leading commence @ 8 o’clock suggests chamber-to-bore misalignment, although it could also be an off-axis forcing cone (doubt it here). Another egregious misuse of chamfer, this time on BARREL FACE. Suspect manufacturing expedient----at the expense of proper assembly technique.
David Bradshaw

The curious one is how the cylinder ratchet upper digs into the recoil shield. Another pic shows the chamber mouths of the cylinder and the third shows the forcing cone on the eight oclock side where the lead builds up. Would love to have Mr. Bradshaw look at these pics. About 120 rounds through the gun half and half jacketed and lead, and factory and handloads. What is the forum's impressions. Appreciate you sharing your wisdom.

Zeke

[ezekiel38]

Thank you David, I so appreciate uou expertise and your kind heart to give this evaluation. Thanks again, ever so much.

Tom

[bradshaw]

Tom.... while light CHAMPHER id fine on the mouth of a cartridge case, it is borderline horrible on the BARREL FACE or EXIT HOLES on the CYLINDER FACE. Invites SIDEBLAST and contributes nothing to accuracy. Such chamfers are either done out of ignorance or as an expedient.

Suspect you have slugged the bore and found it smooth & even. If you haven’t, slug it. In the old days, handloaders slugged the bore to measure GROOVE DIAMETER. Today we encounter too many cases of rifling with loose or tight spots, or a compression ring where BARREL SHOULDER meets FRAME. Providing groove diameter is on the bullet, tight exit holes don’t necessarily degrade accuracy with jacketed, but nearly always with cast. Loose chamber exits promote BLOWBY, and don’t help accuracy. A loose groove diameter may increase velocity, while degrading accuracy.

To know what a bullet feels like in FORCING CONE which is too deep, try running between pullman cars on a train traveling croocked rails. Likewise an off-axis or rough forcing cone. The bullet enters rifling smashed on one shoulder, with its heel smashed. Called deformIty or OBTURATION. Such a bullet has lost its DYNAMIC BALANCE at the start of the rifling. It’s great to read bullets fired into snow. Any bullet fired through water jugs without deformity also describes its launch.

A few notes on why revolver accuracy is an orchestra of dimensions.
David Bradshaw

[taffin]

Back in the 1980s my Ruger Redhawk stainless steel would not make it through shooting 10 chickens without letting up terribly using the Keith bullet. I switch to the Thompson/Lyman #431244 Gas Check and all problems were solved. Have you shot any jacketed bullets in it?

[Encore64]

Tom, I replied to your PM.

Agree with David on this. Looks like a mass of smaller issues combined to make one mess.

I've never fully understood any manufacturer's ability to vary in quality so much from gun to gun.

Talking to my favorite gunsmith a few days back. He was telling me about building two custom Bearcats for a customer. The guns had consecutive serial numbers. He found one gun nearly perfect and the other he simply described as a nightmare to get right. This is so typical these days.

You may find a few jacketed bullets to shoot ok in that gun, but shouldn't have to.

If you hone all that mess out of the chamber throats, no telling how much oversized they would be.

I think contacting Ruger CS would be a good start.

Send them a link to this thread...

[ezekiel38]

The gun has gone away, to a new owner who knows it's limitations. Other issues in my life right now demanding real attention and the 10mm was a hopeful experiment for someone else to finish.

Appreciate all the input from Mr. Bradshaw and Encore and all the others that chimed in. Back to 44s, for field work.

[Thunderjet]

I played the same dance with Ruger to many times. Buy a revolver that made it past Quality Control, send it back, maybe send it back again. Then end up with a revolver I might like but had little confidence in it.
Never again. I'll buy a BFR, FA, or a S&W instead.