What causes barrel leading w cast bullets (and how do we minimize it)?

[skarke]

I know that the mere fact of shooting lead means that some leading will probably occur, but here's what I see.

I have a 1911 shooting 228 Gr rn .452 double lube ring wheel weights with almost no leading at all.

I have a P89 shooting 124 gr rn .356 single lube ring wheel weights that leads horribly.

I have these theories:

1.  Too tight of a crimp
2.  No, I haven't slugged or cerrosafed my barrel.  My next order to brownells in coming up.
3.  I'm using blue angel lube.  It's hard, very hard, and requires heating.

Any suggestions? 

[Castaway]

Lloyd will be here shortly with more details I'm sure, but leading is caused by:  wrong sized bullet, too hard, too soft, lack of lube, wrong lube and condition of barrel.  To complicate matters, more than one of the above can be working at the same time. 

[Graybeard]

I probably have read of leading in Ruger barrels more than all others combined. I'm not particularly fond of Ruger guns and thus have shot them far less than others so am relating what I've read more so than what I've experienced in this regard. Quite honestly I've experienced darn little leading in my own personal guns in perhaps 40 years of using cast bullets.

Wheel weights are fairly hard alloy and should be up to the expected velocity of a 9mm so I'd not expect that alloy or velocity to be the problem.

As has been noted already there are lots of possible causes for leading. In your case I suspect it to be lube related.

I hate hard lubes with a passion. They are a pain to apply without heat and while nice to handle they don't in my experience lube nearly so well as softer lubes and with the one lube groove and high velocity of the 9mm I don't think it is doing the job for you.

It is important to match bullet diameter to barrel and in revolvers to the cylinder throats as well. My best guess is that switching to a softer and better lube will cure most of your leading UNLESS that Ruger barrel is just too rough for lead or is not properly matched to the diameter of your bullets.

[skarke]

Thanks guys.  I "got the lead out", then went over the barrel with a good scrubbing with JB.  The barrel looks pretty shiny.  I'm also gonna get the blue lube stuff out and try a softer lube, see what that does.  I don't anticipate a bullet/barrel match problem, but I have purchased some cerrosafe (had some around, can't find it), just to make sure.

The 45 just doesn't lead at all, at least not more that a couple of wipes with lead cloth will remove lickity split (yes, it's that pt1911 tack driver that I got lucky with).

The truncated cone bullets shot a lot better than the rn in the 9mm.  I'm thinking that the longer bearing surface might stabilize the bullet faster, thus less leading, but that is just a guess.

[Redhawk1]

I got this from SAM on ICCF, pretty good stuff.
Barrel Leading in Handguns or More Old Wives Tales

Every day on the boards I see a post about excessive barrel leading with cast bullets.
Invariably the culprit is “revealed” to be “soft bullets”. Nothing could be farther from the truth.

There are many causes for leading, rough bores, gas cutting and very seldom “soft bullets”.
Rough bores account for maybe 5% of the leading cases in handguns. The mechanism is simple, the rough surface snags off lead particles and leaves them in the bore either hung on the rough spot or laying behind on the bottom of the bore. As successive bullets pass the area, more lead is dragged off, a gap is left between the torn spot on the bullet and the bore and the primary cause of leading, gas cutting, takes over.

Soft bullets are the cause in less than 5% of the leading I see in handguns. In this case a really soft bullet is deformed from the base forward by the hot gasses of powder combustion, until a gap is left between the bullet and bore, then gas cutting takes over. To make this happen the bullets resistance to deformation must be less than the pressure of the gas. I see this in handguns when the pressure of the round exceeds about 25K CUP and the alloy is less than 6 BHN. That relates to dead soft lead and a full power load in a 9mm/357/41 Mag/44 Mag class cartridge. For reference purposes, most wheel weight metal I come across is about 8 BHN and needs to be softened for good use in 17K 38 special loads.

Now we get to the primary cause of gas cutting which is failure to obdurate or seal the bore. It can happen thru either or a combination of 2 mechanisms. Number one is a bullet that is undersized for the bore. Generically speaking a cast bullet should be .001” larger than the groove diameter. If the bullet is below this in size, either through initial manufacture or by being resized down by a tight cylinder throat, gas escapes through the “gap between the bullet and bore. This gas, acting much like the flame of a cutting torch, vaporizes bullet metal and deposits it in the bore. Succeed in bullets pass over the deposit, are further deformed by the “lump” and more gas cuts past making the problem worse and worse.

Many blame leading on poor lubrication but in actuality the lube has very little to do with it. 90% of a lubricant’s effect is in gas sealing. The other 10% is real lubrication, which is why shooting unlubricated bullets makes a progressive leading effect. 1 unlubricated bullet of adequate alloy and properly sized shows almost zero leading.

Now I will go to where you get your leading. Your bullets are too hard!
If the bullet isn’t sized to obdurate the bore, it has to depend on gas pressure to upset its base to completely fill the bore. If you have a bullet of 20-22 BHN (like most of the so called, “hard cast” bullets) that is sized to groove diameter, you get gas cutting. It takes roughly 40KCUP to upset the ‘hard cast” bullet to where it will seal the bore. Want to take a guess on what the SAAMI spec for max pressure is in a 38 +P? It is 18.5K.
For the 9mm and 357.it is 35K. You can readily see that only the very heaviest loads in 9 and 357 will upset the bullet to fill the bore. Of course most folks only use cast bullets for “light loads” because the lead so much and make the problem progressively worse.

For best results:
#1 make sure that the bullets are sized for your groove diameter 9and aren’t resized smaller by a tight throat)
#2 make sure that you use an alloy suitable for the round you are shooting i.e. “softer” bullets for lower pressure loads.
#3 match your loads to the deformation pressure of the alloy used, i.e. “heavy” loads for hard bullets.

If you must use a hard bullet in a light load, make sure that you have a bullet that is .001-.002” larger than bore diameter, WHEN IT GETS TO THE BORE (I’ll get into tight throats another time).

[Hank08]

Sharke,  Most 1911 barrels are .451 so .452 is about perfect and the velocity is only 750 to 800 fps and the hardness of ww is good for that velocity with just about any lube.  9MM, however, come in various sizes and the pressure is higher and the velocity can be 1100 to 1200 fps  which means the bullet needs to fit the bore tightly and a softer lube like 50/50 alox beeswax (often called the NRA formula) will often stop any leading. Crimp won't make any difference, You might have a rough barrel but it's more likely a combination of lube and velocity and possibly bullet size.  If your bullet casts larger and your sizing it, try some unsized.  When your ordering from Brownells get some "double tough" brushes.  These will remove lead in just a few strokes.  Once you get these variables figured out you shouldn't
ever get leading or very very little.
H08

[Graybeard]

While it often is a problem if lack of obturation were his problem here it should be worse in the case of the .45acp at lower pressure levels than the 9mm. Still from long distance none of us can be sure without being there with him and looking things over first hand.

[skarke]

More info.

Barrel slugs at .3553
Bullets size at .357
Bearing surface .331, OAL .553, .598 bearing surface to OAL ratio (forgot what that is called)on TC that shoot pretty well
Bearing surface .270, OAL .569 .474 bearing surface to OAL ratio on RN that shoot terribly

Don't have hardness data, but alloy is pure WW.
Barrel is pretty smooth and shiny.
There certainly could be gas cutting, there is also a little carbon in the barrel that doesn't show in the 1911 with the same powder/alloy.

I shot the TC AFTER I shot the RN, and the barrel might have already been leaded by the RN bullets.

Might the RN be "wiggling" down the barrel with no more bearing surface than what rides in the grooves?

[lsmith103]

Many moons ago when I lived in FL and was shooting in competition I was BSing with my reloading component supplier.  He also was a commercial caster. I needed some SWC's for my S&W M24 and noticed a small wooden barrel of them off to the side.  When I asked about that barrel he said he had made a mistake and they were, as I recall, 2 short on BHN. Long story short I bought the whole barrel for the lead cost then talked him into lending me an old hand sizer/lubricator and lube. I've shot those for years with mostly 1 hole groups at 25 yards. One swipe with a piece of leadaway when cleaning was all I ever needed

[Land_Owner]

Would firing an intermittent copper jacketed or FMJ round help clear the bore of any fouling?

I have a Ruger Super Blackhawk in convertible 45 ACP and LC that leads up like a PU truck at a mud boggin' with hard cast 255 gr Bull-X SWC's over hot Ruger LC loads.  It stinks when I have to put that gun away for spitting at me after it has barked only 10 to 20 times. It is a joy to shoot and a better huntin' buddy than most dogs when it is clean.  Would reducing the powder charge help reduce the leading?

I suppose I now need to check throat dia. and bullet dia. for mismatch too.

[SharonAnne]

I shot about 140,000 hard cast 45s through my 1911/.45acp. I had very little leading problem. If it did build up I used an old 45 brass brush and wrapped some copper 'Chore Boy' scrubbing pad around it. That would scrub any lead out quickly and inexpensively.

In my 9x23 I have shot either of 2 Winchester factory loads - 125gr Silvertips or 125gr jacketed soft points, 3-4k rds, or Ranier/Berrys 124gr truncated cone PLATED bullets, about 75k rds. At the velocity needed to make USPSA major power factor I did not want to bother with potential leading problems.

If you must use cast lead in your 9mm then I suggest you slug your barrel and size your bullets 0.0005-0.001" larger than bore size. You may need to shoot some jacketed bullets to polish the bore. Back when I did shoot cast in a 9x19 (9mm Luger/Nato) I found 0.001" oversize was needed for accuracy.

[Glanceblamm]

I suppose I now need to check throat dia. and bullet dia. for mismatch too.

I have been very lucky with three rugers in two different calibers. Measuring slugs can be agonizing work because of the odd number of grooves. I think that you need a "V" shaped contraption or ruler (i disremember the name) and then you do a conversion based on those numbers. Measuring the Cylinder throats can be even worse as you are putting a square peg (dial caliper) in a round hole. Sometimes I think that a lot of members here are doing pre-mature or unecessary work unless the piece has been measured out by a competent smith.

All is not lost for us laymen though as I found something that you can try that the experienced knew already...I had slugged my cylinder throats (all six) along with the barrel and agonized over the measuring as said.
I then took that barrel slug and put it in the cylinder and found that it was an excellent fit!...it slid through the throat area with very little resistance but yet that slug could not be wobbled or rattled using a pick while in that throat area.

If you take your slugs (either cylinder or barrel) and would try to run them through again, they will go of course but you still need to apply a moderate to heavy amount of pressure on the rod. But to take that barrel slug and to run it through a cylinder and have it go through easily obviously says that (in my case) the cylinder throat is larger than the barrel by .001-.002 and is where I want to be.
When I choose or size my bullets for loading, I will drop a bullet into the cylinder and see if I can push it on through. You want the so called (slip fit) and if I can push them on through with a plastic pen with moderate pressure and absolutely no hammering, I figure that I am good to go.

Sometimes the opposite can happen. I currently have a small lot of (bargin cast) bullets for the .44 that may be just a little too loose in the cylinder throats. I need to recheck these and will save them for the melt if I think that this is true.

[S.B.]

Sharon, actually, you use a micrometer and don't use it like a "C" clamp, they take an aquired feel?
Steve

[SharonAnne]

Steve. You lost me. What was I measuring?

[Lloyd Smale]

ive had very little leading problems in 1911s with even soft bullets. I use harder ones because the shoot more accurately for the most part. 9mms are a differnt story. Biggest reason is probably that there are so many differnt companys making guns with different dimentions and a guy has to really pay attention to fitting a bullet to your particular gun. Alot of 9s tend to have rougher bores for some reason and most can benift for some lapping. Look at your leading problem. If its in the first third of your barrel its usually a fitting problem and if its in the last 1/3 its usually a alloy or lube problem. Most guys with 9s tend to size to small. try a 358 and run that if it will chamber if not go to a  357 but no smaller. Cast your bullets out of at least ww in hardness and lube with a good lube. (no tumble lube here) Another thing ive seen cause leading in a 9 is bullets seated crooked. Its real easy with the 9 to start your bullets in the case lopsided. Ive seen a few 9s guys couldnt get to shoot that was caused by this. If there crooked they enter the rilfing at an angle and wipe the bullet. Shoot a bunch out of your gun into water and recover them and look to see if the rifling looks right on them. Another thing with the 9 you have to keep in mind is you tend to load the 200-400 fps faster then normal for a 45. Bottom line is fit is the most improtant thing in any cast bullet shooting. Unlike some i too believe that lube is a big factor. Ive just proved to many times that switching from one lube to another can alter accuracy just as much as swithching bullets or powder can. I dont buy into the therory that lubes only seal and dont lube. If you doubt this shoot oversized bullets that have to seal without lube and see how long it takes to plug your gun up. I am also a firm beilver in soft lubes. If you dont want to fool around experimenting with lubes go buy yourself some javalina and be done with it. Its smokey and messy but it does work. So cast your bullets fairly hard lube them with a good lube, fit the bullet to your gun, get the dimentions of your gun right if possible and lap your barrel and ill about bet your problem goes away somewhere in that list.

[Darrell Davis]

Sorry if I missed it in my quick read of the posts, but one thing I do not see mentioned is, "barrel choke."

I first became aware of this issue in revolvers while reading some of Veral's info 10 - 15 years back.

And yep, it is there and in measurable amounts.

Veral's solution was fire lapping, which in my experience did solve the problem.

Veral's feeling was, if you shoot through a tight barrel choke, the bullet will not bump up after the choke to again properly fill the bore.

Sorry, and unusual, but I come down on a different side then GB on the RUGER situation.  I have used them for years and found little issue with leading which was not quickly solved.

In fact, have great fun razzing a friend about his "bean can guns" (B&C = S&W, you know, like canned fruits and veggies of the S&W brand),  no offense ment to any "B&C" lovers out there, but we do have fun over the subject.

I cast almost totally with WW, and have for years quenched them directly from the mold.

Then I use a home brew for a lube. Over the years, I have slowly increasing the lube hardness to the point where the lube stays put but needs no heat to fill the grooves.

Works for me.

Anyway, Ruger or B&C, get some push through slugs and check out the barrel choke in your wheel guns. You might be in for a surprise.

Get in touch with Veral Smith (LBT) for questions and answers here on GB. If you check his part of the forum, he may have already answered the question many times over.

Keep em coming!

CDOC

[SharonAnne]

DD. what is 'barrel choke' in a rifled barrel? I have only heard that term used referring to shotguns?

[Mikey]

SharonAnne:  Mornin'!  The 'barrel choke' that Veral Smith refers to in his literature is also referred to as 'obdurations' in the barrel by others like Marshall Stanton.  'Barrel choke' as defined by these two gentlemen is the 'choking down' of a barrel, similar to the effect of a shotgun choke, but caused by imperfections in the manufacturing process - it's a tight spot in the bore.  You can feel these obdurations, or obstructions literally, by forcing a very tight dry patch down the barrel of a revolver or rifle and when the going starts getting tougher you have run into one of those obdurations - a tight spot.  Both Smith and Stanton believe these destroy accuracy but can be removed by fire lapping or bore lapping the barrel with properly sized slugs.

These obdurations size the bullet down to a smaller size in the barrel and the bullets do not expand back to or regain their original size after they pass through, and lose their accuracy.  You find these more often in revolvers where the barrel has been screwed in hard to the frame, or where a sight notch was milled or where a barrrel was stamped.  You find it much more frequently in rifle barrels.

You are likely not going to find any in pistol barrels such as those for the 1911 as there is no stamping or milling or cutting on the barrel length.  For many revolver shooters, relieving the forcing cone to 11 degrees has much the same effect and resolves much of the inaccuracy caused by these bore imperfections, and often cures leading problems.

OK, that's about all the brain power I have this morning...............HTH.

[coyotejoe]

Indeed, I have a Charter Arms .44 Bulldog (old 3" version) which is very definitely "choked" where it threads into the frame. No doubt the bullet is sized down in passing through that choke and is then loose in the rest of the barrel length. It leads with hard or soft bullets. I have some Hornady swaged lead round nose that are very soft. They lead as much but no worse than very hard cast bullets.
 I also have a .357 in which I would like to shoot cast bullet .38 special loads but it leads so badly with any load, pop gun or full .357 magnum, hard cast or soft swaged, that I ordered a case of Winchester 158 grain JHP just to avoid leading.

[SHOOTALL]

isn't a Colt Python choked ? or taper bored .
I realize its from forcing cone to muzzle not a point .

[skarke]

coyotejoe,

Did you slug the barrel?  Bullet size, from what everybody on this site is telling me, is critical.  Also, I worked my ruger barrel over pretty well with JB (4 patches, 25-30 strokes each with new JB), and the leading has almost disappeared (accuracy improved as well, likely because there wasn't half a bullet's worth of lead in the barrel ).

[BAGTIC]

I load my bullets hard, HTWW. I load them as cast.  If it chambers it is not too big. There is no sizer made that will fit your bullet to your bore like your barrel.

Some revolvers have a problem in that the cylinder throats are smaller than the bore. Get them fixed. If a bullet must be bumped up to seal the bore it is too small to start with.

I firmly believe that too small a bullet is one of the most common causes of leading. If a bullet doesn't fill the bore lead will be shaved/smeared off the bullet. If the bullet is a tight fit there is no place for the lead to go. Natures abhors a vacuum/void and will fill it with whatever is at hand.