Barrel leading issue, need advice.

[scooter123]

Purchased a 6 1/2 inch 610 3 weeks ago. My main intent is to use it for 40 S&W, which is currently 6 dollars a box cheaper than 38 spl. Since I also have three 40 caliber semi's having wheelgun in that caliber has a lot of appeal.

First time I took it to the range shot 72 rounds with it and found a brass shaving in one chamber when cleaning it. Barrel was clean with only a small amount of leading.

Second trip to the range I shot 96 rounds. Got home and found two chambers with shaved jacketing and in one chamber it too a bit of effort with a pick to break it free. Also found that the barrel was farily heavily leaded just past the forcing cone in two grooves. I felt a near doubling in resistance on the first patch as soon as I got within an inch of the forcing cone. So far I have about 6 hours of patching the barrel with kleenbore lead away patches and now have the lands and groove completely clean but there is a line of leading adjacent to each land. Patches now run smooth from crown to forcing cone.

BTW, I am not really a fan of using a brush on the bore, to me that is an absolute last resort. Oxides of copper are harder than 436 stainless and most lead removing solvents will oxidize a bronze bore brush.

Ammunition used was Federal Champion 180 gr. FMJ from Walmart. I also used the same ammo in my Sig P229 and it only took 20 minutes of patching the barrel in that gun to have it looking unfired without any trace of leading.

Yeah, I know, I am probably being OCD about removing all trace of leading from the barrel but OCD runs in the family. I also have a hunch that any lead present will just attract more lead.

Enough of the history and my obesession. My concern is the leading itself and I would appreciate some guidance.

One, will this problem resolve itself as the forcing cone and barrel wear in?

Two, the sharp corner for headspacing the 10mm round is obviously shaving jacketing when I am shooting 40 caliber ammo. Could this be the cause of the leading that I am seeing?

I have been thinking about hand stoning a very small lead on this edge in each chamber. With a bit over 20 years of tool and die experience I am fairly confident that I can do this and get an even lead on every chamber. However, that will be about 6 hours of some very tedious hand work that I am not looking forward to.

I could also send it to S&W, however since the 40 S&W isn't a primary caliber for the 610 I suspect that there may not be a lot they can do except tell me to use it for 10mm.

Note, I did send S&W and email last night inquiring if it would be possible to purchase a cylinder assembly specific to the 40 S&W. I have not heard back from them on that yet, however I sort of expect that the answer will be no. If the answer is yes, I'll get the second cylinder for it and leave the 10mm cylinder alone.

I'll also note that at no time was the leading severe enough to effect accuracy, from start to finish the gun was a tack driver. However, because I was shooting at 40 feet there was no evidence of shed jacketing in my targets. Next time I hit the range I'll do some shooting at 10 feet and look for that.

 

[BruceM]

The problems you are experiencing is a prime reason why shooting .40 S&W ammo from the 10mm 610 revolver is a bad idea IMO. The idea is even worse in an autoloader for the same reasons. Can you make it work-yes. Does it work well-no!. I lot off text is devoted on these forums to gas cutting of revolver top straps and how to avoid it at all costs, yet nobody seems to care about what shootings .40's does to the chamber mouth of a 10mm gun. In grand scheme of things, which is worse-chamber erosion or a little gas cutting. Well, that's another rant for a different thread.

If you are shooting FMJ ammo, you do not have leading but rather copper fouling. You get leading from firing hard cast or swaged lead ammunition. For the copper fouling, use one of the solvents made especially for tough copper problems with patches or a nylon bristle brush. I've heard good things about KG-12. Even if you use a bronze brush, it will break down sooner but it won't melt from the solvent. If you're not satisfied with the results, there always is the Outer's Foul-out which will remove the fouling by the reverse electroplating method.

Removing the chamber step in the charge holes will relegate the gun to more or less junk status to most future buyers. That's another bad idea in my view on a number of levels.

You yourself admit to being more or less anal retentive about some things. Why don't you just come to grips with the fact that you're going to have issues trying to get the gun to perform correctly with the .40's and stick to 10mm ammo, even if it means taking up reloading. You'll probably get lots better results with a lot fewer problems.

2 cents worth.

Bruce

 

[Aussie44]

Chamber erosion is no different than shooting 38s in a 357 or 44special in a 44 mag.As for flame cutting,It goes so far then stops.Don't worry about it shoot and enjoy.As to your leading problem try different ammo.


Ken

 

[BruceM]

The difference is that there's a step in the charge hole of a 10mm or .45 ACP revolver which isn't there in a .357 or .44 magnum.

Thank you for re-enforcing my point about the flame cutting. On steel guns, it's a fact of life when shooting real, full power magnum ammunition.

Bruce

 

[scooter123]

I don't intend to remove the step in the chambers, just relieve the sharp edge by adding a 0.002 to 0.003 inch chamfer. However, your mention of gas cutting points me in a different direction. At work we have on rare occasions had parts "explosively" deburred. The thought comes to mind that simply firing the gun may relieve that edge and solve my problem.

As for reloading, I plan on doing that when the budget permits AND components are available. Since there are zero primers currently avaliable in my area, there really isn't any point in purchasing a reloading setup. I talked to one local gunshop who used to stock reloading components and the primer situation is pretty hopeless. Federal told him that they would sell him primers, however the minimum order quantity was ONE MILLION primers, cash up front, and they would give no assurance on a timely delivery. Needless to say, he didn't place the order and has had no luck finding any available in the normal distribution channels.

As for the issue being copper fouling, I know the difference between copper and lead fouling. This was lead fouling without doubt. The deposits just past the forcing cone were a very light gray to whiteish in color.

This why I suspect the root cause may be that that sharp corner in the chamber is shaving the jacketing occasionally. I've also seen jacket debris lodged in just two chambers, which makes me suspect that there may be a very small burr present that's causing the problem. Tommorow I think I may take it into work and check each chamber with a gage pin, if there is a burr in these chambers I should be able to feel it.

I am also still waiting to hear back from S&W on purchasing a 40 caliber specific cylinder assembly. For me that would be the ideal solution because it would work better and also allow me to leave the 10mm cylinder unaltered for occasional handgun hunting.

 

[BruceM]

Any "leading" would be due to melted lead from the exposed base of the FMJ bullet and, to be honest, I've never heard of anybody having leading issues when shooting jacketed bullets. Lewis lead remover should clean up whatever is there. Except for the Foul Out, it is not possible to remove 100% of any type of fouling from the bore so, in essence, what cleaning actual does is reduce fouling to the point where accuracy is not diminished.

What would be interesting to find out is if the chamber throat dimensions from the case mouth (step) to the face of the cylinder are with spec. or if one or more is tight. This could account for some jacket shaving. I suppose if it were especially tight, a loaded 10mm round would be difficult to fully insert into the chamber.

I'll be interesting to find out what's really up.

Bruce

 

[m657]

re: "shooting .40 S&W ammo from the 10mm 610 revolver is a bad idea"

and the assorted comments on fouling, etc....

This is certainly news to me. I have been shooting my 3 7/16" 610 in assorted matches and practice for nearly 2 years with minimal leading issues.

I have mostly used cast lead 40 cal, but some FMJ along with less than 200 rounds of 10mm.

I have excellent accuracy with either, and to date no leading OR copper fouling issues. Can't explain that, as I didn't know I should expect a problem. The barrel that this week end put well over 100 rounds of cast 40 downrange, has little fouling of any kind. I will give it another look tomorrow for final cleaning and post again.

On the other hand, for extreme lead fouling my 5" 625-8 was so severe I actually sent it to the factory for help, after extensive efforts of every liquid and brush known to man, including Lewis lead kit, failed to remove the residue of something around 400 rounds of moderate reloads.

Don't know what to do to remedy the OP problem. Personally I just have been fortunate to not experience it in the 610.

 

[scooter123]

Just got a reply from S&W.

Hello, we do not currently manufacture a cylinder for .40 cal, I will pass this along the the development team for consideration.

PG

As I expected, no joy. BTW, that was the complete reply, no suggestion that I leave it alone or send the gun in. I also suggest that they look into making a 9mm moon clip cylinder assembly available for the 620/686 models. With the cost difference between 9mm and 38 spl. being what it is, I suspect that making this option available would be pretty popular.

Took this cylinder into the shop today and check the bore size with -.0002 gage pins. Every cylinder was bored to 0.400 inch with the exception of one that was at 0.401 inch. I expect that is well within the specification.

Currently I am hand stoning the sharp edge in each chamber with a 1/4 inch diameter round Arkansas stone. It's slow going and giving me a good dose of writers cramp. I'm also taking a less is better approach. I expect that finding the correct balance of how much lead-in is needed will probably take a month or more and plan on stopping as soon as it stops shaving jacketing. The post from M657 is encouraging because it indicates that I don't have to remove very much from that edge.

 

[m657]

I looked down the bore today and saw a little leading in the first 1 1/2" , more on one side than the other. It was what I'd consider 'lightly leaded'. I ran a dry bristle thru it and some loose debris was knocked out. There remained "a little" lead on the 6-7 o'clock region....enough that my OWN OCD part of my brain fired up....fortunately the "Carpe man~`nana" genes kicked in too....

Will have time tomorrow to do a thorough cleaning. This gun saw about 150 rounds per speed steel match (all reloads) and whatever practice I manage to shoehorn in. I did shoot a couple pin competitions with it with jacketed 40 once and jacketed 10 once....months ago, and with no bore cleaning since required.

Note on pin results: 40 will knock 'em down & roll 'em off the back of the table if you hit 'em right. The 10 smacks 'em with authority and shoves them VERY rapidly backwards in an upright position if you hit the sweet spot.

However, I have to admit....45ACP works a LOT better for moving the pins.

And of course, 44 mag pretty much destroys them.

 

[scooter123]

Just an update on the jacket shaving issue. I used an Arkansas stone to relieve the edge that references the 10mm case with a 10 degree chamfer of about 0.030 X 0.005 inch by eyeball estimate. Basically it's a very small forcing cone.

Distinct progress has been made. Fired 90 rounds today and after cleaning the gun only found minute particles of shavings in two chambers in the cylinder. Leading in the barrel was also reduced by at least 75%, it only took about 15 minutes of patching with lead away patches to remove all traces of resistance in the area of the forcing cone. It took another 2 hours to get the barrel clean enough to satisfy my OCD and it's not perfect. Frankly I think the way these barrels are rifled is going to force me into accepting the slight lines of leading alongside each land.

I spent some more time stoning the 2 problem chambers lightly and used some diamond lapping compound on bamboo skewers chucked up in my Dremmel to polish these new micro forcing cones.

All told I have between 8 and 10 hours of work into detailing the cylinder. Good news is that 10mm rounds still seat properly with no tendancy to jam and I think the latest work will eliminate the shaving problems. However, I would NOT recomend anyone attempt this without a lot of experience with this kind of detail work. I have over 20 years of experience doing this in Tool and Die work. Note that all the stoning I did was by HAND. There is a reason for that. By doing it by hand and counting the cycles of stoning I was able to get a constant cone in each chamber. If I had used a Dremel with a diamond bit it would have been much faster and much more uneven. Quite simply, use a Dremel for anything except polishing and you'll just hack it up because it's too aggressive to maintain control. Hack it up and you'll probably have problem with the bullet tipping in the cylinder bore and create a cascade of problems. That will mean that you'll have to purchase a new cylinder. It's a case where the slowest method is safest.

For anyone with this same issue, I would suggest asking S&W to produce a 40 caliber specific cylinder for the 610. If enough of us ask, they will listen. Until that happens, just shoot the gun and keep a close eye on the leading. It's inconvenient but in time flame cutting will erode that edge and the problem will reduce itself.

PS, I plan on drawing up a sketch of this modification and will forward it to S&W. With a custom cutter for their CnC machining center, this micro cone could be added with very little increase in cost.

 

[500 Magnum Nut]

The only thing to do is clean it well after range visits. Use a bronze brush or better a lewis lead remover tool to clean the chambers. Use the lead remover tool on the forcing cone too, as this build up will cause spitting.

The lock up should be Ok, but to check it quickly, I'd just make sure as you cock the cylinder around, make sure the cylinder stop snaps into each cylinder notch.

I'd use Remington Bore cleaner with a bronze brush on the barrel. I found this to be the best at removing lead and copper fouling.

 

[scooter123]

I've been paying attention to the forcing cone on the barrel throughout this process. From the indications in the forcing cone after a reange session, this particular gun has the cylinder perfectly centered and the timing is spot on perfect.

Checking the cylinder has indicated that the leading issue lies further back. Yesterday the two chambers that had some particles of shaved jacketing also showed some leading in the cylinder bore that was consitent with the location of those particles. The good news is that he particles were very small, nothing like the .400 inch long and .050 wide splinter I found prior to making the decision to work on the cylinder.

I think the decision to design the cylinder in the 610 to headspace the 10mm round was a mistake. With the cost difference between the 10mm and the 40 caliber, most users will be shooting mainly the 40 caliber ammunition. It is, after all, a moon clip gun and moon clips are cheap enough that having a good stock of spares isn't likely. If they had cut the cylinders in the same manner as the 357 Magnums this would allow the 40 caliber ammunition to be used without any issues beyond the carbon fouling that occurs when using 38 spl. in the 357 Magnums. Granted, doing this would allow the 10mm to headspace properly, however having to always use moon clips is a price I would glady pay.

To be honest, I've found that using moon clips is so convenient that I cannot imagnine ever shooting this gun without them.

The degree of leading that I found after my second outing with the 610 was heavy enough that I feel it presents the potential for a safety issue. I would suggest that anyone shooting this gun with 40 caliber ammunition patch their barrels at least every 72 rounds in order to check for leading in the barrel and stop when it becomes heavy enough to make running a patch down the barrel difficult.

BTW, thanks for the suggestion on the Remington Bore Cleaner, I'll scout some up and give it a try.

 

[scooter123]

Just a followup report. Put 90 rounds of 40 caliber downrange today with not one single trace of shaved jacketing in any chamber in the cylinder. There was still a bit of drag in patching the barrel for the first 2 inches past the forcing cone but it cleaned up nicely in only 10 minutes.

At this point I'm saying it's good to go. The remaining leading is pretty minor and will most likely go away as the forcing cone wears in.