S&W Model 10-5 Lead buildup just ahead of forcing cone?

[VariableRecall]

I had tried out my Model 10-5 in an outdoor range session using some of the only .38 special that I was able to find at retail from around last November: HSM Cowboy. They were using Starline brass and had some pretty nice RNFP boolits in them. I'd assume they comply to some sort of historical accuracy in terms of shape, powder, and lubricant. They had felt like lighter loads and had a very pleasant smelling smoke to them. Considering their price, I wouldn't get them again, but it was what I had in my inventory in terms of factory .38 Special.

I had used around 36 of them at my range session. When I cleaned my 10-5, I had noticed leading in my barrel for the first time I'd had it, right ahead of the forcing cone, at the start of the rifling in the barrel. It's very mild, but it certainly was something to note. The rest of the bore was sparkling clean, which I'd have to admit, made the leading look very obvious. I doubt the amount of leading would be detrimental to accuracy or safety, but it's clearly something to make note of and clean up.

I've had a good experience with using Boolits sized to .357 and .358 so far, but I'd assume the area where the rifling starts is going to be the most likely spot for the leading to occur.

[Larry Gibson]

"I'd assume the area where the rifling starts is going to be the most likely spot for the leading to occur."

It is when the lube used is too hard.

[Walks]

Yep a problem with commercial cast.
They use a Hard lube that won't be "dislodged" during shipment or sale.

[VariableRecall]

"I'd assume the area where the rifling starts is going to be the most likely spot for the leading to occur."

It is when the lube used is too hard.

I'm planning on using slightly thinned Lee Liquid Alox (about chocolate syrup consistency) if I'm going to get the opportunity to cast for it. I've had good results with using that, and Hi-Tek on the Commercial cast bullets in my inventory. Like I had said earlier, never had leading remain after a cleaning session when I was using them.

I've yet to try pulling one of the HSM Cowboy loads to see what's inside, but I'd assume there's going to be some sort of traditional lube down there. The ammunition has stayed since it got into my hands in completely temperature controlled environments, so I doubt it was the weather that may have contributed to the small amount of leading.

[Mk42gunner]

Probably a combination of too hard alloy, too hard lube, and maybe too small in diameter. Any one of those things can cause leading, two or more in combination is just asking for it.

FWIW, I have never had leading with appropriate sized boolits cast from plain old ACWW (mine are about 12.5 BHN) lubed with FWFL (recipe in the lube section). I have started to use BLL (also a thinned Lee Liquid Alox) with .38 Special wadcutters, it seems to be working fine with my limited testing so far.

Good luck,

Robert

[ddixie884]

Probably good info from all the old hands here...........

[Petrol & Powder]

Yep, all been said - commercial cast bullets with a hard lube. And the alloy may be hard.

I can't speak for powder coating and it's been a long time since I used tumble lube.

With 38 Special and conventional lube using a lubersizer - the old stand-by of NRA 50/50 is hard to beat.
I used BAC [White Label] for a while in the hopes of finding one lube suitable for all handgun loads. That didn't work out. Unless you are pushing magnum loads, NRA 50/50 will work for just about any handgun cast bullet.

As a side note, before I started casting, I used a lot of commercially cast bullets. They came from various suppliers and ranged from adequate to horrible. Hard alloy, hard lube and undersized were the common features. When I found what worked, I would try to buy more but that was sometimes difficult. Commercial casting operations were sort of a regional affair (lead is heavy !) and before the internet was "a thing", it was common to roam about a bit in search of supplies.

[Tar Heel]

Whites 50/50 is the ticket. Shoot up the commercial hard cast stuff or better yet, melt it down and soften the alloy for your own mold. Then lube up with 50/50.

[Petrol & Powder]

VariableRecall, Just to provide some information:
White Label is a trade name for a family run company that produces and sells excellent cast bullet lube.
Here's a shameless link to their website: https://www.lsstuff.com/
And they are GOOD people, which is more than enough reason to support them.

NRA 50/50 formula: 50% Alox 2138F, (or the current substitute) and 50% pure yellow beeswax. NRA 50/50 has been a well known cast bullet lube for over 50 years. When it comes to standard velocity, cast lead handgun bullets, NRA 50/50 may be the cast bullet lube that all other lubes are compared to. Some people don't care for the smoke it produces (which I don't find to be a problem outdoors) and some people feel it is a little too soft in extremely hot weather (which can be addressed by other lubes such as BAC). Other than those minor complainants, 50/50 will fill most standard handgun cast bullet needs.

NOW, none of the above is carved in stone or royal decree, there are alternatives. But NRA 50/50 deserves to be in your memory bank. It's a good tool to have in the mental toolbox.

[TimD]

VariableRecall, Just to provide some information:
White Label is a trade name for a family run company that produces and sells excellent cast bullet lube.
Here's a shameless link to their website: https://www.lsstuff.com/
And they are GOOD people, which is more than enough reason to support them.

NRA 50/50 formula: 50% Alox 2138F, (or the current substitute) and 50% pure yellow beeswax. NRA 50/50 has been a well known cast bullet lube for over 50 years. When it comes to standard velocity, cast lead handgun bullets, NRA 50/50 may be the cast bullet lube that all other lubes are compared to. Some people don't care for the smoke it produces (which I don't find to be a problem outdoors) and some people feel it is a little too soft in extremely hot weather (which can be addressed by other lubes such as BAC). Other than those minor complainants, 50/50 will fill most standard handgun cast bullet needs.

NOW, none of the above is carved in stone or royal decree, there are alternatives. But NRA 50/50 deserves to be in your memory bank. It's a good tool to have in the mental toolbox.

+1 for White Label. Good products and great people.

[Char-Gar]

I agree, hard wax lube, granite hard bullets and probably a rough forcing cone to boot. Softer bullets, softer lube and a lapped forcing cone brings delight to a revolver shooter's heart.

[PBSmith]

I''ve read this post with great interest, as I have been shooting a new-to-me S&W10-5 and have experienced a leading problem just in front of the forcing cone. Ten rounds and I'm reaching for the bronze wool and brushes.

I was puzzling over the responses given here to this problem - puzzled because all of my home-cast bullets are relatively soft (mix of pure Pb + COWW) and lube is the NRA 50/50 mix. I size to 0.357, and finished bullets push with light effort through the cylinder ball ends. Most of what I have been loading are solid wadcutters, pushed faster than target loads but not above "full charge" speeds.

When Char-Gar mentioned a lapped forcing cone, I said, "Ha! That's got to be the problem: a rough cone."

Without starting a new thread on this topic, I wounder if some of you experts can explain what's involved in lapping a revolver's forcing cone. Is it something the home gunsmith can tackle with care and time, or is it best left to a professional? What, if any, special tools are required?

Since the leading in my case always occurs at the same circumference places at the start of the rifling, I'm wondering if there might be a rough burr at the leading edge of the cone. Does lapping take care of this? Or might a few rounds of hard lead or jacketed rounds knock burrs off? I purchased the 10-5 "used", but I doubt it had been fired much before it arrived in my hands.

Look forward to your responses.

Edit: Unlike the OP's experience, the leading in my case does indeed affect accuracy.

[Petrol & Powder]

With the proper tools and some commonsense, the forcing cone can be lapped to remove tooling marks. However, If your leading is forward of the forcing cone, it's unlikely that the forcing cone is the source of your leading.

Here's a link and all due credit to Fryxell:

http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm

[dogdoc]

I have had leading like described with commercial hard cast hard lubed bullets for years. Simple solution is tumble lube them with Lee liquid Alox or 50/50. Works great with no leading. Done that with many thousands. Smokey however.

[Old Caster]

If you have to use a heater to lube the bullets, it is too hard for standard velocity bullets. My choice is Lars 2500 but i like 50/50 too.

[VariableRecall]

VariableRecall, Just to provide some information:
White Label is a trade name for a family run company that produces and sells excellent cast bullet lube.
Here's a shameless link to their website: https://www.lsstuff.com/
And they are GOOD people, which is more than enough reason to support them.

NRA 50/50 formula: 50% Alox 2138F, (or the current substitute) and 50% pure yellow beeswax. NRA 50/50 has been a well known cast bullet lube for over 50 years. When it comes to standard velocity, cast lead handgun bullets, NRA 50/50 may be the cast bullet lube that all other lubes are compared to. Some people don't care for the smoke it produces (which I don't find to be a problem outdoors) and some people feel it is a little too soft in extremely hot weather (which can be addressed by other lubes such as BAC). Other than those minor complainants, 50/50 will fill most standard handgun cast bullet needs.

NOW, none of the above is carved in stone or royal decree, there are alternatives. But NRA 50/50 deserves to be in your memory bank. It's a good tool to have in the mental toolbox.

Looks like some excellent products and wholesome people on there. However, I don't have a Lubrisizer or a sacrificial toaster oven if I had wanted to torture myself with pan lubing or more practically Powder Coat.

I do have a Lyman Lubrisizing die for .357 on the other hand, thanks to a generous reloader on this forum.

My plan is to use Alox when I start casting. Alox worked great so far and the mess is contained to the can it was shook around inside.

[VariableRecall]

Probably a combination of too hard alloy, too hard lube, and maybe too small in diameter. Any one of those things can cause leading, two or more in combination is just asking for it.

FWIW, I have never had leading with appropriate sized boolits cast from plain old ACWW (mine are about 12.5 BHN) lubed with FWFL (recipe in the lube section). I have started to use BLL (also a thinned Lee Liquid Alox) with .38 Special wadcutters, it seems to be working fine with my limited testing so far.

Good luck,

Robert

I couldn't really change anything up with these Factory bullets, but I'd certainly take your advice into consideration in the future.

By the way, here's the best photo I got of the leading. the bore is otherwise sparkling. I apologize for the bad lighting.

Attachment 282048

Would that amount of leading be OK? I'd certainly want to get rid of it but it appears to be a very thin layer.

[Petrol & Powder]

The attachment will not open, at least not for me.
I think that 36 rounds of some particular cartridge is probably not the best yardstick to form an opinion about leading.
While it's entirely possible those particular cartridges are loaded with a less than ideal bullet (alloy too hard, sized incorrectly, hard lube, some combination of all three?) a box or two of those rounds isn't worth worrying about. Clean the gun and carry on.

From reading your first post, I did see that the cartridges were loaded in Starline brass, so there's a plus. You got some good brass out of the deal.

[DougGuy]

If a .357" boolit won't slip through the cylinder throats, all the lube and alloy advice in the world, as good as it is, will not prevent you from firing your loads through a multi port sizing die each pull of the trigger.

The use of soft alloy and soft lube will ease the situation somewhat *IF* your loads are assembled with enough energy to obturate the boolit to effect a decent seal in the bore after it exits the cylinder and encounters the forcing cone.

Most would want to size to .358" and have cylinder throats sized to accommodate the .358" so it reaches the barrel at intended diameter. This, and softer alloy and lube will cure nearly any and all leading issues.

[JoeJames]

What size were the boolits? In part attracted by the Starline brass, I bought a box of HSM 44 Special cowboy loads once. Tried them in a Henry Big Boy I used to have (Yes I know the Henry was bored pretty loose) and got about a 6” group at 15 yards with one boolit making a perfect silhouette of the side of the boolit on the target. Just saying ...