What is this stuff in my forcing cone?

[barnfrog]

Did you ever get a bullet remover, either a hammer or collet, so you can check to make sure the coating isn’t getting damaged during seating or crimping?

Seated a couple and then whacked them back out with the inertial puller. Did not see any compromising of the coating. So based on an infinitesimal, statistically insignificant sample size, that's not the problem.

The DEWCs are BHN 12 and are loaded with 3.3 grains of Red Dot, which I don't think is too hot. It should be enough pressure to obturate sufficiently, although I haven't chronographed them. The SWCs are BHN 18 and loaded with 6.2 grains of Universal or 6.5 grains of Unique. The Unique load could be too high, as the load data I have says that's probably in the area of 30,000 psi. The data I have for Universal doesn't give pressure in psi. Also haven't chrono'd either of those loads.

 

[GeoDudeFlorida]

Seated a couple and then whacked them back out with the inertial puller. Did not see any compromising of the coating. So based on an infinitesimal, statistically insignificant sample size, that's not the problem.

The DEWCs are BHN 12 and are loaded with 3.3 grains of Red Dot, which I don't think is too hot. It should be enough pressure to obturate sufficiently, although I haven't chronographed them. The SWCs are BHN 18 and loaded with 6.2 grains of Universal or 6.5 grains of Unique. The Unique load could be too high, as the load data I have says that's probably in the area of 30,000 psi. The data I have for Universal doesn't give pressure in psi. Also haven't chrono'd either of those loads.

You’re not running too hot for lubed lead and those coatings are made to withstand rifle velocities. If the coatings aren’t being compromised then I’m not sure what the problem is, but there is a problem.

 

[barnfrog]

I'm loading up a dozen of each combination and will shoot them all this weekend, checking the cone after each cylinder. Maybe that will help narrow things down.

 

[GeoDudeFlorida]

I'm loading up a dozen of each combination and will shoot them all this weekend, checking the cone after each cylinder. Maybe that will help narrow things down.

Not having access to a decent gunsmith is a big deficit but it doesn’t mean you’re on your own. However, if it turns out to be a seriously misaligned cylinder, it might need to go to Ruger.

 

[243winxb]

A little lead doesnt seem to hurt accuracy. My S&W 44 mag 29-2 after factory barrel set back. After cleaning photo.

Slower burn rate powders are less likely to produce leading. Like Alliant 2400 in 357 mag. The pressure increase is not as fast.

 

[barnfrog]

So I got out to the range this weekend and shot my test rounds, checking the barrel after each group of six, taking pics from various angles. Also set up my Chrony F1 for the first time since picking it up last year, so I can add velocities to the data. I shot them in one order on Saturday, and then just for the sake of thoroughness I went back Sunday and shot them in reverse order. I was hoping that one load might stand out and produce obviously more leading than the others, but unfortunately that wasn't the case.

I'll spare you the complete spectrum of images I took and just give you one example. The pic below was taken after shooting six rounds of plated 148-grain wadcutters (just out of curiosity) and six rounds of coated 148-grain wadcutters. You can see obvious leading. From my observation it isn't only on one side of the cone, but is fairly evenly distributed around it. Average velocity was 812 fps.

As a reminder, these are BHN 12 bullets from MBC that are Hi-Tek coated. I did the smash test with a hammer and found no compromising of the coating, and tried seating and pulling a bullet with identical results. But even if my limited testing was wrong and the coating was somehow compromised, I think I'm in about the right pressure/velocity neighborhood for a bullet of this hardness that there shouldn't be this much leading after only half a dozen shots, even from an uncoated cast bullet. If anything, maybe my pressure is too low and there's not enough obturation to prevent gas cutting. Is that possible?

By the time I got to my last two test loads, my group sizes had grown significantly, so I think the fouling is causing accuracy issues. Sure would like to figure this out because I don't want to have to scrub my barrel after every 24 shots. If I have to resort to plated and jacketed bullets I guess I can live with it but I'd rather find and address the cause.

 

[GeoDudeFlorida]

So I got out to the range this weekend and shot my test rounds, checking the barrel after each group of six, taking pics from various angles. Also set up my Chrony F1 for the first time since picking it up last year, so I can add velocities to the data. I shot them in one order on Saturday, and then just for the sake of thoroughness I went back Sunday and shot them in reverse order. I was hoping that one load might stand out and produce obviously more leading than the others, but unfortunately that wasn't the case.

I'll spare you the complete spectrum of images I took and just give you one example. The pic below was taken after shooting six rounds of plated 148-grain wadcutters (just out of curiosity) and six rounds of coated 148-grain wadcutters. You can see obvious leading. From my observation it isn't only on one side of the cone, but is fairly evenly distributed around it. Average velocity was 812 fps.
View attachment 1146519
As a reminder, these are BHN 12 bullets from MBC that are Hi-Tek coated. I did the smash test with a hammer and found no compromising of the coating, and tried seating and pulling a bullet with identical results. But even if my limited testing was wrong and the coating was somehow compromised, I think I'm in about the right pressure/velocity neighborhood for a bullet of this hardness that there shouldn't be this much leading after only half a dozen shots, even from an uncoated cast bullet. If anything, maybe my pressure is too low and there's not enough obturation to prevent gas cutting. Is that possible?

By the time I got to my last two test loads, my group sizes had grown significantly, so I think the fouling is causing accuracy issues. Sure would like to figure this out because I don't want to have to scrub my barrel after every 24 shots. If I have to resort to plated and jacketed bullets I guess I can live with it but I'd rather find and address the cause.

Just my opinion but, I think it’s time for a trip home to the Mothership. Call Ruger and find out about the shipping and cost.

 

[drband]

What is the measured diameter of your bullets. I suspect they are undersized for your bore/chamber throats.

You noted earlier your barrel slugged at .3585 and your chamber throats are close to the same size. Getting several measurements of your chosen bullets might shed some light. Don’t rely on the size listed on the bullet box!

 

[.38 Special]

So I got out to the range this weekend and shot my test rounds, checking the barrel after each group of six, taking pics from various angles. Also set up my Chrony F1 for the first time since picking it up last year, so I can add velocities to the data. I shot them in one order on Saturday, and then just for the sake of thoroughness I went back Sunday and shot them in reverse order. I was hoping that one load might stand out and produce obviously more leading than the others, but unfortunately that wasn't the case.

I'll spare you the complete spectrum of images I took and just give you one example. The pic below was taken after shooting six rounds of plated 148-grain wadcutters (just out of curiosity) and six rounds of coated 148-grain wadcutters. You can see obvious leading. From my observation it isn't only on one side of the cone, but is fairly evenly distributed around it. Average velocity was 812 fps.
View attachment 1146519
As a reminder, these are BHN 12 bullets from MBC that are Hi-Tek coated. I did the smash test with a hammer and found no compromising of the coating, and tried seating and pulling a bullet with identical results. But even if my limited testing was wrong and the coating was somehow compromised, I think I'm in about the right pressure/velocity neighborhood for a bullet of this hardness that there shouldn't be this much leading after only half a dozen shots, even from an uncoated cast bullet. If anything, maybe my pressure is too low and there's not enough obturation to prevent gas cutting. Is that possible?

By the time I got to my last two test loads, my group sizes had grown significantly, so I think the fouling is causing accuracy issues. Sure would like to figure this out because I don't want to have to scrub my barrel after every 24 shots. If I have to resort to plated and jacketed bullets I guess I can live with it but I'd rather find and address the cause.

For what it is worth, shooting cast through a bore with even slight copper fouling can sometimes cause leading - and leading which is unusually difficult to remove. Whenever I plan to shoot both cast and jacketed/plated, I shoot the cast bullets first. (How coated bullets might interact with copper fouling, I have no idea.)

Also, I am unsure if any of your cast bullets are uncoated. If you have used uncoated, lubed cast bullets, do they lead the bore?

 

[barnfrog]

What is the measured diameter of your bullets. I suspect they are undersized for your bore/chamber throats.

You noted earlier your barrel slugged at .3585 and your chamber throats are close to the same size. Getting several measurements of your chosen bullets might shed some light. Don’t rely on the size listed on the bullet box!

I miked a number of the MBC bullets and they were all right around .359". On the advice of a gunsmith I tried sizing some to .358" but I was not able to detect any difference in leading or in accuracy. The ones that were shot just prior to taking the picture I posted above were not sized.

For what it is worth, shooting cast through a bore with even slight copper fouling can sometimes cause leading - and leading which is unusually difficult to remove. Whenever I plan to shoot both cast and jacketed/plated, I shoot the cast bullets first. (How coated bullets might interact with copper fouling, I have no idea.)

Also, I am unsure if any of your cast bullets are uncoated. If you have used uncoated, lubed cast bullets, do they lead the bore?

I did shoot some lubed cast bullets a while ago, but I got them in an estate sale and had no idea what alloy was used. I shot them over 5.0 grains of Bullseye and they grouped terribly. I didn't notice any leading, but I wasn't specifically looking for it.

 

[GeoDudeFlorida]

I miked a number of the MBC bullets and they were all right around .359". On the advice of a gunsmith I tried sizing some to .358" but I was not able to detect any difference in leading or in accuracy. The ones that were shot just prior to taking the picture I posted above were not sized.

I did shoot some lubed cast bullets a while ago, but I got them in an estate sale and had no idea what alloy was used. I shot them over 5.0 grains of Bullseye and they grouped terribly. I didn't notice any leading, but I wasn't specifically looking for it.

If I recall correctly, you did try factory lead and they were just as bad?

 

[barnfrog]

If I recall correctly, you did try factory lead and they were just as bad?

Factory lead ammo? Negative.

 

[GeoDudeFlorida]

Factory lead ammo? Negative.

If you talk to Ruger about it having tried factory ammo and the results will help. Otherwise the only conclusion they can come to is that it’s not the gun. I’m thinking it probably is - but I could be wrong.

 

[drband]

If you talk to Ruger about it having tried factory ammo and the results will help. Otherwise the only conclusion they can come to is that it’s not the gun. I’m thinking it probably is - but I could be wrong.

Agree. You need to be able to tell them it does this with factory ammo. Ruger is pretty helpful but I suspect they may say it’s within factory specs. But it sure won’t hurt to ask them— I have been pleased with Ruger service on my SBH.

 

[barnfrog]

If you talk to Ruger about it having tried factory ammo and the results will help. Otherwise the only conclusion they can come to is that it’s not the gun. I’m thinking it probably is - but I could be wrong.

It would also give me some assurance that it's not my reloads as well. I'll have to see what I can find that's not $1.50 a round.

 

[joneb]

Have you measured the cylinder throats of this gun?

 

[barnfrog]

Have measured the cylinder throats of this gun?

Yes. A .358+ gage is the largest that will fit in four of them, and a .359- is the largest that will fit into the other two. The barrel slugged to a groove diameter of .3585" using a micrometer.

 

[joneb]

Yes. A .358+ gage is the largest that will fit in four of them, and a .359- is the largest that will fit into the other two. The barrel slugged to a groove diameter of .3585" using a micrometer.

I have had issues with Ruger revolvers mostly in .44 cal they size their cylinder throats at .434" and larger which sucks for lead bullets.
I have a Ruger Security Six 357 Mag. with .3575" throats and it does pretty well with .358" lead bullets .

 

[barnfrog]

Finally got my hands on some American Eagle 158-grain LRN ammo. Pics shown below are clean bore, then the bore after 24 rounds of the AE factory ammo, and then the bore after 12 of the Acme reloads. Oddly enough, the grooves and rifling are cleaner after the reloads. Almost like the Acme bullets removed the lead fouling. At any rate, the pics after shooting factory ammo do show some lead fouling, so I think it's worth a call to Ruger to see if they'll take a look at the gun.

 

[Mk-211]

Did it get the lead out or just cover it with carbon fouling?

After looking at it close up, I agree that it should go to the factory.

 

[barnfrog]

Did it get the lead out or just cover it with carbon fouling?

A valid question. The clean bore shows what look to me like machine marks perpendicular to the lands and grooves. They aren't as visible after shooting the factory ammo and are completely obscured by the lead fouling, but reappear after shooting the reloads. Not sure if that is definitive or not.

 

[Mk-211]

Yeah, I can definitely see the chatter marks in the bore.

 

[GeoDudeFlorida]

Yeah, I can definitely see the chatter marks in the bore.

It looks like the rifling button was dull.

 

[FROGO207]

The older Ruger revolvers had an 18* forcing cone. I have re reamed several of mine to 11* as well as opening up the throats to .001 over groove diameter. This has pretty much stopped all my excess leading problems in about 11 Ruger revolvers. As far as I am concerned this is a good investment if you are going to shoot a pile of lead bullets and want max accuracy each and every shot along with easier cleaning. I have had to do this with S&W, Rossi, Taurus, and several other revolver brands as well. Most will have some cylinder throats that do not match the revolver barrel. Using jacketed bullets will not be a problem with them that way but lead or coated it shows up every time.

 

[Show Me]

Might been said. Never saw lead withstand bronze wool. Cuts better than copper scrubber pads. Wham bam