How much leading is too much?

[zxcvbob]

I just got back from the shooting range. Shot 100 rounds of .357 Magnum using Lee 148 grain wadcutters with the "tumble lube" micro driving bands. They were cast from scrap lead with very little tin; kind of halfway between hard and soft. When I got home, I could still see the rifling but it was pretty crudded up. (actually, it didn't look much worse than when I checked the bore at the range after 30 rounds.) I got some little chips of lead out when I cleaned it, but not as bad as i expected. ETA: These were magnum loads, not target loads in 357 brass.

I very seldom shoot that many magnums at a time; usually I shoot 38 Specials, and those don't lead much at all.

So I can tweak the lube, or the lead, or the powder; maybe switch to a different powder, or be happy with what I've got. Tough decision

If I shoot these in my Marlin carbine, can I expect the leading to be worse, or better? The velocity will be a lot higher, but it won't have that forcing cone and cylinder gap thing to deal with.

[GP100man]

Basically 2 types of leading goes on .

1 is an undersized bullet lets gas blow by & smears lead from 1 end to the other , variations are lead in cyl & forcing cone then it stops some where afterwards , the bullet istoo small then pressure bumps it up & makes a seal.

Also in this category is the fact that lube helps seal & condition the bore , running out of lube will generally show leading in the muzzle end.

2 as the bullet starts moving in the throat it`s not spining ,then it hits the rifling & starts !!
If the alloy is`nt strong enuff to grip the rifling ya get a gap cut into the side of the bullet ,wide open for gas cutting , this is disquised alot by type 1for the simple reason people do not stop & look or swab the bore!

Also people mistake type 2 leading in revolvers as "spitting" or "out-of-time" because the pressure is blowing the forcing cone clean as much as possible !


Alot of variables in between, but if the revolver is set up for lead & loaded correctly for the alloy used you can enjoy lead free shooting .

As far as your question as to how much is too much???

I have to ask 3 questions .

1 did you have any malfunction due to a "dirty" cyl or other part ???

2 did you notice accuracy falling off due to "dirty" bore ???

3 do you accept the fact that it`ll take more time/labor to clean your firearm???

Last but not least the question on the WC in the carbine with TL design.

I have no exp , but suspect they`ll perform as well as in the handgun until pushed harder.

[WIL TERRY]

WHY would you be shooting 38 wadcutter bullets with " 357 MAGNUM LOADS NOT TARGET LOADS IN 357 BRASS ??
THOSE bullets are SPECIFICALLY designed to perform at midrange verlocities but you want them to now be 357MAG bullets performing where none were supposed to go, and you're worried about too much leading. SO....just how fast do you REALLY want them to fly ??
AND there is one other thing you should give DEEP thought about; WC seating depth and " 357 MAGNUM LOADS NOT TARGET LOADS IN 357 BRASS.
And so it goes...

[TXGunNut]

Only thing I can add to GP100man's excellent post is that leading with certain loads and firearms is normal and if your accuracy and functioning is good then it's all good. In my experience (when leading occurs) lead builds up to a point and then stops, many revolvers are most accurate @ that point, BTW.

[zxcvbob]

This was probably more the "type 2" leading. I'm not convinced the Lee tumble lube bullets can hit the rifling with as much force without stripping as a bullet with wide bands.

No malfunctions or binding at all, although the gun was pretty hot when I finished. As far as accuracy goes, I shot the whole box in about 10 or 15 minutes, shooting at metal plates, including some weak-hand shooting which I don't practice nearly enough. So the accuracy was good from the beginning to the end of the session, but if it wasn't I'm not sure I could tell. Maybe I can repeat this exercise next week shooting a little slower at paper targets.

I'm fine with having to clean the revolver when I'm finished shooting. I'm not so sure about cleaning a leaded-up carbine. Also would shooting 200 rounds in the revolver start causing problems? How about 300? Hopefully the leading is self-limiting.

These are mainly rhetorical questions; I have to answer them myself. But it was fun, cheap, and good practice, all at the same time.

[Unclenick]

The tumble lube bullets give you the opportunity to use any of the small "micro band" grooves as a crimp groove, so you could seat them out and have what amounts to just a flat meplat, low BC bullet. I don't know if that's what the OP did, but it's doable. The one difference I'd choose is the alloy, I'd want an alloy as hard as the more common commercial cast bullets. Scrap is often part wheel weights an part more pure lead, so just not hard enough for magnum velocities. I'd want something about BHN 16 or higher.

[zxcvbob]

SO....just how fast do you REALLY want them to fly ??

1400 fps from the 4" revolver and 1800 from the carbine would be nice (I don't expect that with this particular load, these were probably closer to 1150 today)

[TXGunNut]

Also would shooting 200 rounds in the revolver start causing problems? How about 300? Hopefully the leading is self-limiting.-zxcvbob
The last few years I shot PPC I didn't clean my barrels at all during the season. Average season was 10K+ rounds. I shot mild 38 target loads and soft swaged bullets, FWIW. Some guys did it that way for years, I just cleaned the cylinder and forcing cone after each match.
Conventional wisdom would seem to favor a bit harder than normal bullet for your application, wouldn't hurt to try. It would be nice to know the hardness of your alloy but it's just a number, the actual performance of the bullet in the barrel and on target is more important.

[wncchester]

"How much leading is too much? "

I don't see how that can be qualified; it's not possible to measure it with micrometer and the results are all that matter anyway. I figger if it affects my accuracy any visible amount it's too much but that very rarely occurs with my 9mm/.357mag/.38S./.44 mag/.45ACP loads.

[shootniron]

n my experience (when leading occurs) lead builds up to a point and then stops, many revolvers are most accurate @ that point

I have cast bullets for myself and loaded\shot thousands upon thousands of rounds and found the above statement to be the absolute truth.YMMV

[GP100man]

With my limited exp (2yrs) with the chrony most WW alloys run in the 11-13 bhn tend to start strippin at around 1200 fps, after that it needs a little help.

A GC helps & a little lino helps , then ya get into the bullet designs .
One proven design is one with a wide front driving band !

Then ya get into lubes !& it goes on & on !!!!

Kinda like a race car spending $$$$ to go a tenth of a second faster!!!!

WC loads in a 357 case are hard to find documented in later info sources , ya gotta dig in archives then compare powder speeds .

[Unclenick]

The problem is not knowing the gun. I have a 1911 I've had over 2000 rounds of lead through without cleaning and, like TXGunNut said, the lead simply reached an equilibrium level where it shot out as fast as it accumulated. It was just modest streaking near the lands. At the other extreme, you get stories about guns that had almost no visible rifling left until the owner caught wise and cleaned the accumulated fouling out. Then the rifling was magically resurrected. In those situations you can shoot until accuracy goes away, then you'd better clean because pressures are going up at that point, too.

With revolvers, I find you get the least leading and best accuracy if the chamber throats are half a thousandth to two thousandths bigger than the bore groove diameter and the bullets are kissing the sides of the throat when you chamber the rounds. Additionally, it is pretty common to find a constriction in revolver throats where the barrel threads were compressed by tightening in the frame, and that tight spot needs to be lapped out to minimize leading and maximize lead bullet accuracy. That constriction and extreme bore roughness often don't seem to matter to jacketed bullets, but they can be death to accuracy with lead, so lapping is attractive at that point.

I suggested commercial cast bullet hardness earlier (BHN 14-18, usually), and I think that's not a bad place to start when you don't know the gun. On the other hand, Elmer Keith developed the .44 Rem Mag using mostly 20:1 lead:tin (BHN 10), then finally switching to 16:1 (BHN 11) to reduce leading. Those are a little harder than air cooled wheelweight metal, which is BHN 9, according to Lyman, though a lot of wheelweights have less antimony and tin than they did when that was written, so lower numbers are possible. In a nice smooth gun with no bore constrictions, high single digit BHN numbers work fine with many loads. Keep in mind that Keith was driving the bullets with higher pressure than H110/296 does, and still didn't need the BHN 16 alloy that most commercial casters use.

Zxcvbob said he had scrap lead. I don't know what's in it, but I know the stuff from digging up the club range backstop has a lot of .22 rim fire bullets and swaged jacketed bullet core lead in it, so I'm never clear what to expect by way of alloy content from it. BHN 6 or so seems to be pretty typical for it. My approach is to assume I need to add at least 2% tin. Modern lead-free solder is about 95% tin, and I just buy it on sale and pretend it's 100% tin and add 2% of it by weight. I do check the label to be sure it doesn't contain zinc, which some lead-free electronics solders have had in the past, but it usually makes for poor wetting and flow, so it's not normally present. I've never seen it in plumbing solder yet, but double-check the MSDS for whatever you buy if you go this route. If the scrap came from a scrap yard, it may contain about anything from wheel weights to lead cable sheathing (near pure).

[wncchester]

I once had a younger friend who had purchased a very pretty used stainless S&W .357 and a half box of yet unused WW factory lead bullet ammo. He came to me in near tears because accuacy was terribe and his bore was "so worn out it didn't even have any rifling", at least none he could see! I sat him down with a new bore brush and showed him how to keep the rod off the bore/muzzle as he worked. Took him about half hour of boring work and a couple more brushes but he had clean lands and grooves again!

We pulled his cheep soft swaged bullets, seated some of my hard cast alox lubed bullets and the accuracy was great, he loved it! Turned out the original owner thought the barrel was toast to so he sold it to my friend for cheap. I had thought of offering him a percenttage of what he had paid for it before putting him to removing the lead but I didn't have the heart to do that. Original owner was badly chagrined tho!

Moral: Leading is what it is, no way to predict it but it can be cleaned out and compensated for or corrected by an ammo change.