Cylinder/forcing cone gap issue

[castmiester]

Had a similar discussion about checking end shake on another thread, and while checking with feeler gauges l noticed that it was going in fine at first but not making it out the other side. On the bottom of the cylinder it was fine but not at the top. After some discussion about the firing pin driving the cylinder forward was the time to check the gap, that’s when l noticed the gap difference top and bottom. My take is shims and possibly the retention bushing at the rear, where the extractor comes out. The bushing has four tabs that the yoke snaps into. Over the years l disassembled it to inspect and lubricate. Now l realized maybe l did it to much and weakened the bushing tabs and it no longer supports the yoke like it should?

Wondering if it would affect accuracy.. bullet alignment to effect barrel harmonics? Guess there’s no real way to check wear on this bushing. The bluing on the yoke is slightly worn off. No wear marks beyond that, gouges or anything like that. Bushing isn’t loose. Yoke seems to snap in securely. Retaining screw on cover plate is always tight. No yoke movement in frame.

[Forrest r]

It the later stages of wear it will not only affect accuracy. The velocities will fall off. Extreme cases will have lead spitting.

A picture of a s&w 586 bbl. It had already been sent back to s&w twice before having it setback and a new forcing cone cut.

[IMG][/IMG]

That bbl didn't even come close to gaging evenly. Accuracy was starting to fall off and the loss of velocities was impressive.

What bullet style you use/shoot has a lot to do with alignment issues and accuracy. Bullets without shoulders are less affected.

[castmiester]

I only have about maybe 1000 38 spl low pressure and a few hundred 357 rounds through the gun. First Revolver I bought... Taurus 66. Didn't have the money back then to buy something good. But I just bought a Redhawk for 575, recently. Think I'll stick with a better quality gun from now on. How many rounds you have through your Smith ? And you did have the extractor rod groove machined too when you had the barrel shoulder setback ?

What bullet style you use/shoot has a lot to do with alignment issues and accuracy. Bullets without shoulders are less affected.

SWC
What is that ?

having it setback

set the shoulder back on the barrel for more forcing cone protrusion. So gas eroded the face of the cone. Now I doubt I need a bushing. I could close the gap with shims but the face of the cone needs squaring.

[243winxb]

Some cylinder faces have high spots. A gunsmith can chuck cylinder in a lathe and turn off the high spots. If thats the problem?

[rintinglen]

Having a barrel set back involves removing the barrel from the frame, facing off the shoulder where the barrel abuts against the frame in a lathe, then putting the barrel back, cutting a new forcing cone after squaring the face of the cone. Brownells sells a forcing cone tool for this.

"Now I doubt I need a bushing. I could close the gap with shims but the face of the cone needs squaring."

No, that doesn't work, shimming the extractor to force the cylinder forward is a bad idea. Raising the extractor to maintain proper firing protrusion and closing excessive barrel cylinder gap seems plausible, but weakens the junction between the extractor arms and the cylinder. If the barrel is square, the possibility that the frame top strap is stretched. I have seen this in older S&W 29's subjected to large amounts of heavy loads, especially those that were used in silhouette competition. There is no cheap fix for that, it requires a new frame. However, given the low mileage on your gun, I would be surprised if that were the problem. it may have been a condition present from the factory.

[Forrest r]

A swc is what's known as a semi-wad-cutter. A couple different hp swc's I cast for the 38spl's/357 mag's. All of them have a shoulder/sharp front edge on the front of the top drive band.
[IMG][/IMG]

These are a fn (flat nose) style bullet. They have rounded sides with no shoulder that is easier on the forcing cones when timing/mis-alignment could be an issue affecting accuracy.
[IMG][/IMG]

every +/- 100,000 rounds that 586 went back to s&w to be rebuilt.

[castmiester]

Forrest r

I know what a SWC is I meant that's what I have casted. They are 10 BHN, so I don't believe that would be that harmful on the cone. Could be wrong though. The cone is tapered and the SWC doesn't make contact with the cone, even with the shoulder or a slight misalignment. The bullet is half way past the cone by the time it makes contact with the rifling. The bluing is barely wore off the face of the cone and if you were correct on......

What bullet style you use/shoot has a lot to do with alignment issues

There is not lead spitting going on so It doesn't lead me to believe of misalignment. A worn yoke bushing does.

243winxb

Some cylinder faces have high spots

doesn't appear this one does, considering the bluing is barely worn off, and is an indication of low mileage as another poster said.

[HWooldridge]

Back in the late 70's, a good friend of mine bought a new model 19 Smith and put about 20,000 mid-velocity .357 rounds through it with no ill effects. Forcing cone gap was still tight, no spitting, accuracy still fabulous, etc. I bought a new Colt Mk III Trooper about the same time and reached about 10,000 rounds in the same time frame, but my loads were split about 50/50 between .38 Special and factory level .357 (handloads of WW296 and 125gr JHP). The Colt was starting to erode around the back of the forcing cone but it still shot well.

My buddy's gun was stolen or lost, we still aren't quite sure which - I sold my Colt to a co-worker and he was still banging away with factory loads when I left that company.

It really surprises me the Taurus is wearing away that fast; it may be due to a lack of good heat treatment but that's speculation on my part.

[castmiester]

HW

I agree.... the internals are hardened, but others are not. Where I bought the gun they stopped selling them... too many had to go back for repair too soon. Just because they're now made in the USA since 19', doesn't mean nothing to me.

[M-Tecs]

HW

Just because they're made in the USA doesn't mean nothing to me.

If you are referring to the Taurus Model 66 it's made in Brazil.

[castmiester]

If you are referring to the Taurus Model 66 it's made in Brazil.

Don't know how accurate this info is...

In 2012, Heritage Manufacturing was also purchased and its production later moved to Taurus' Miami, Florida plant.

I know that... but as of 19' they moved from FL to GA. I bought my 66 in 09. Sad part is the shop owner told me the Revolvers are ok, just the 1911 style had the problems. Safety issues....

Taurus settled a lawsuit for $39 million and recalled nearly one million handguns produced between 1997 and 2013 due to "safety defects"

[M-Tecs]

I know that man... but as of 12' they moved from FL to GA and make them here. I bought my 66 in 09

The first US made ones didn't happen until 2019
https://www.guns.com/news/2023/03/03...thwest-georgia
By August 2019, the company announced that the first “Bainbridge” marked gun had rolled off its assembly line.

[castmiester]

they would lack warranting my pistol that's for sure !!

If Ruger is iffy, then your know Taurus is ! I'm glad I got my recent Ruger from 85' ! And to be honest I wouldn't relish buying a new gun by any manufacture... tell me I'm wrong and set me straight otherwise. And I'm not interested in sending them back because they don't sell parts, due to restrictions.

[Outpost75]

Careful inspection of a new revolver reveals ALOT!

BEWARE of file marks cut across barrel where it protrudes through frame window. Therein lies a clue!

Hand filing to correct a tight gap requires care and skill which is rare in the modern era.

[castmiester]

Careful inspection of a new revolver reveals ALOT!

BEWARE of file marks cut across barrel where it protrudes through frame window. Therein lies a clue!

Hand filing to correct a tight gap requires care and skill which is rare in the modern era.

And seeing obvious things that shows there’s no need for unnecessary repairs.

[FergusonTO35]

My S&W 10-5 has a really tight gap, like .002. I like it that way, never causes any problems.

[castmiester]

My S&W 10-5 has a really tight gap, like .002. I like it that way, never causes any problems.

that doesn't change the fact that my cylinder is canted slightly and Taurus won't sell a measly little bushing to fix it, and.. I can't find it anywhere.

[FergusonTO35]

No, I wasn't commenting on that specifically. Just saying I like the tight gap on mine since we were talking about that.

[castmiester]

No, I wasn't commenting on that specifically. Just saying I like the tight gap on mine since we were talking about that.

Yeah I hear yeah..... this is frustrating and that's what this current Gov't administration goal is.

[Jtarm]

Careful inspection of a new revolver reveals ALOT!

BEWARE of file marks cut across barrel where it protrudes through frame window. Therein lies a clue!

Hand filing to correct a tight gap requires care and skill which is rare in the modern era.

Nowadays, I go through the used revolver check on new guns.