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Bullet hardness questions. MBC, please weigh in.

Discussion in 'Handloading and Reloading' started by 0to60, Jun 11, 2011.

  1. 0to60

    0to60 Well-Known Member

    First, read MBC's essay on BHN and how CUP is used to determine a BHN that won't result in leading:

    Ok, now my questions.

    1) In their example, they cite a .45acp round consisting of a 200gr LSWC over 5 grains of Bullseye, 900 fps at 20k CUP. I'm looking at several sources of reloading data, and 5 grains of Bullseye will push a 200gr LWSC somewhere south of 900 fps, at CUPs of around 15k.

    I'm not trying to be a stickler here, but they use their numbers to arrive at a BHN that they claim will cause no leading. But, it looks to me like their data is significantly off, and if I plug what I believe to be more accurate numbers into MBC's formula, I'm getting BHNs of 12 or so. This is a big difference, as their website implies you use their BHN 18 LSWC for 5gr Bullseye. By MBC's own reasoning, this load should be producing a fair amount of leading.

    2) MBC offers a ".357 Action!" round that's a BHN 18 158gr SWC, for "magnum velocities". A "magnum velocity" for a 158gr bullet out of a .357 magnum should be around 1300 fps. So I'm looking at reloading data and I'm seeing that, on average, that load should produce around 40k CUP. If I plug THAT number into MBC's formula, I get a requisite BHN of a whopping 32. How is it possible that MBC's BHN 18 bullet can be pushed to those velocities without causing significant leading, as according to their own explanation? Indeed, in a different thread, MBC has said that that bullet has been pushed as far as 1450fps without leading.

    Now, I've read a lotta threads around here where folks are talking about their pet loads and whether they cause leading, and there seem to be a lotta cases where one guy says a load causes no leading, and another guy stopped using that load because it caused too much leading. So is this all a "your mileage may vary" thing? If so, that's fine, but where does that leave MBC's handy formula? Indeed, why pay attention to BHN at all if everyone is getting different results?
  2. glockky

    glockky Well-Known Member

    Man i see where you are coming from I had a lot of problems because of this. I was new to lead and bought the 18 BHN 185gr swc's for my 45 and they ended up being a bust. They were just too hard I had them at midrange jacketed data and the lead wasnt as bad but i was just afraid to push them any farther which is what they needed.
  3. Galil5.56

    Galil5.56 Well-Known Member

    I've read a lot about formulas for what makes for the ideal hardness vs pressure used (BTW, C.U.P.S is measured in C.U.P.S, not P.S.I.), yet I have had success like many others "breaking the rules"... In my experience, proper bullet fit to the barrel/throat, plus good/proper lube matched to the job pays the largest dividend, but of course hardness/alloy used must be taken into account. Even if say commercial "hardcast" leads your particular barrel despite proper sizing, an application of Lee Liquid ALOX will many times cure it.

    Also have to factor in the barrel used... Some barrels simply lead more than others even when "optimal" variables are used, same goes for copper fouling. If only it were so easy to say use X, Y, and Z, and get A, B, and C.
  4. bluetopper

    bluetopper Well-Known Member

    Really.........your barrel will probably not lead at all at either hardness. Pressure and velocity data is merely a guide. Pick a hardness and try it. You'll see, it's not worth fretting over.

    The problem of leading, from my experience, is waaay overblown.........especially on internet forums.
    Last edited: Jun 11, 2011
  5. USSR

    USSR Well-Known Member

    You're over-thinking the BHN thing. Much more barrel leading is caused by improperly sized and/or lubed bullets than by too hard or soft bullets. Just use a reasonable hardness and make sure they are sized properly for your particular gun.

  6. 0to60

    0to60 Well-Known Member

    Define "reasonable hardness".
  7. murf

    murf Well-Known Member

    with the weapons you are using, reasonable should be 12, 15, maybe 18bhn.

  8. bluetopper

    bluetopper Well-Known Member

    For instamce, I use the same 38 cal. 148gr DEWC bullet in my 38 for powder puff target loads as I do loaded in 357 cases stuffed full of as much 2400 powder as I can get in to it with no leading in either loading.
  9. USSR

    USSR Well-Known Member

    Tell me the cartridge and load.

  10. 0to60

    0to60 Well-Known Member

    Umm... the ones I mentoned in my original post.
  11. 243winxb

    243winxb Well-Known Member


    45acp test. To me, leading is when accuracy is lost. Some barrels will look bad, but still produce the same accurate groups. Photos of test i run using 200gr swc hard, heat treated cast bullets with 5.0gr 700X. Accuracy was the same from first group to last. Click photo for larger view. [​IMG][/URL][/IMG] [​IMG][/URL][/IMG] [​IMG][/URL][/IMG]
  12. Overkilll0084

    Overkilll0084 Well-Known Member

    MBC has a formula? Never noticed. At the end of the day they are inexpensive cast bullets. Just shoot them & enjoy.
    I run the .45 Softball w/ 4.6 of bullseye. I get a hint of lead in the 1911 and slightly more in the Witness. Neither could be considered bad. A little solvent and a little brushing and it comes out.
    I run the .357 Action from mild to wild. I find that leading is minimal up to 14.0 gr of 2400. Above that it gets worse quickly. 14.0 is plenty warm. It's accurate as well. If I want more, I'll find some jacketed.

    For entertainment, get a sample pack of the 180 Strikers (.357). Very accurate and they put a serious thump on bowling pins.
  13. 336A

    336A Well-Known Member

    I learned about bullet leading the hard way several years back with my .38 SPL and .41 mag. I didn't do my research and got caught up in the harder the bullet the better it must be:rolleyes: Uncle Elmers' bullets were a BHN of 15 (Lymans standard #2 alloy) and he got by fine when useing them for his stout .44 loads.

    Today when I'm looking to purchase cast bullets I want a bullet that is no harder than 16 BHN. These will work fine in both the .38SPL and .41 mag. The very first bullets I used were 18 BHN and they leaded horribly at the forcing cones of my revolvers. The reason they leaded in the .41 was I useing them to replicate the old police loading with 8gr of Unique.
  14. 243winxb

    243winxb Well-Known Member

    Bullet Fit & Lube

    44mag test. Using mag. shot as an alloy, containing 6% antimony. Oven heat treated/water cooled. These very hard bullets left the barrel looking much like the 45acp bbl. Accuracy was very good. Bullet fit, with good lube are most important. Very soft alloys, close to pure lead will let a bullet skid, resulting in poor accuracy. I find bullets in the back stop with blue & red lubes still in the grease grooves, not so with NRA type 50/50 lube. I have to wonder if commercial lubes are getting the job done. :confused: After 40 years of casting, testing is the only way to know what works. Air cooled alloys with some antimony & tin, using NRA type lube, still gets the job done. :) [​IMG][/URL][/IMG]
  15. Walkalong

    Walkalong Moderator

    As Don posted, there is more to leading than velocity or pressure and BHN. The alloy mixture makes a difference as well. Many different alloys can have the same BHN.

    Also as Don posted, bullet size in relationship to our guns throats and barrel are much more important. With a good fit, we can get away with an alloy/BHN that may not be optimal, but with a poor fit, the perfect alloy/BHN will lead.

    Buy some 12 BHN bullets for your 200 Gr .45 ACP loads, buy some 18 BHN bullets for your full strength .357 loads, and quit worrying about it.

    Check the throats in your revolver to make sure they are not undersized. If they are, you must have them reamed to .001 over the bore (groove actually) size. I would rather have throats I need to ream than big sloppy way oversized throats.
  16. 0to60

    0to60 Well-Known Member

    The reason I asked this question in the first place is because MBC makes kind of a big deal about choosing the right BHN and how to do so mathematically. If I am to "eyeball it", as most of you are doing, then I can save myself some $$$ and order from mastercastbullets. The thing that was holding me back was that MBC seemed to imply that 18 was the correct BHN for the 200 gr SWC round that I like. But if I can get away with BHN 14, then my next order will be from mastercastbullets.
  17. Galil5.56

    Galil5.56 Well-Known Member

    If the fit and lube is good for the application, I'd go for the BHN 14 option from your caster of choice using loads, loaded to normal .45 ACP working pressures. I have cast and shot a ton of 200 grain LSWC's, using nothing but air cooled wheel weights that are a lot softer than BHN 14, using a lot of different propellants and pressures, and the results when properly sized and lubed are fantastic. As I said in my first post, fit to the barrel and proper lube used in my experience maximizes accuracy, and minimizes lead fouling.

    Why I would choose mastercastbullets.com is because I'm sure Mike would gladly send you some no cost samples to make sure they are what you want, and then if you do order them and find them not to your liking, here is a quote from his site:

    "RETURN POLICY: Money back for all unused bullets. MASTERCAST pays return shipping and will refund the shipping charges you paid to have the bullets sent to you."... How can you beat that?

    Second reason I would choose Mastercastbullets.com is the savings is as you know huge compared to other suppliers I have seen for a shipped to your door price for the same bullet/alloy, especially if you only order 500 bullets which gets shipped for $5.25 plus insurance.
  18. 918v

    918v Well-Known Member

    Leading is caused by alot more than BHN. Bullets, contrary to popular belief, do not slide on top of the rifling. They do not need to obturate the bore to not lead.

    When a bullet is sitting in the chamber, the nose part of the bullet sits in what's called the freebore. That is the part of the barrel without rifling. This freebor is often .001" to .002" larger than the groove diameter. Upon ignition, and before the bullet enters the rifling, the case unglues itself from the bullet shank and hot gas begins to spread throughout every bit of airspace inside the chamber. Since gas travels instantaneously at 7000 FPS and the bullet has to accelerate to 1000 or so FPS, you can imagine the gas will overtake the bullet in the freebore and force itself down the barrel, cutting off lead in the process. This is one of the ways leading occurrs.

    This is where BHN comes in: As ignition begins, the base of the bullet gets hammered with a wall of gas. A soft alloy will immediately deform (obturate) when hit with that force. So a soft bullet sitting in the freebore .001" larger will deform and fill that .001" gap, thereby sealing the system.

    A hard alloy, on the other hand, will not deform as much and may not seal the freebore. The gas, then, has the opportunity to escape around the bullet and cut lead off the shank in the process, and deposit it in the barrel. Typically, this will lead the first inch of the barrel.

    Now, you can use a bullet that is at freebore diameter and it will not need to obturate. But such a bullet is difficult to chamber. You can't push a .453" plug into a .453" hole very easily.

    Or you can use a softer bullet.

    Or you can change the load for one that will generate higher startup pressures, but you have to be careful here. It is not the peak pressure that is important, but the initial starting pressure. In some loads peak pressue does not occurr until the bullet is well down the bore. We need the pressure right before the bullet starts to move. Fast burning powders like Bullseye are our friend.

    I have found revolvers to be more sensitive to this variable than autos. Maybe this is due to their longer jump to rifling and the forcing cone. My 1911's shoot 22BHN Lasercast bullets just as well as 12 BHN Missouri bullets with the same mild 4gr Bullseye powder charge. My S&W 625 leads like crazy with the Lasercast bullet, though, and the accuracy sucks.

    Here is a thread from rec.guns that people should memorize:

  19. bds

    bds Well-Known Member

    I had a similar discussion at the range yesterday afternoon with two new reloaders who bought 1911s to start loading for.

    It is my opinion that leading depends primarily on 5 factors:

    - Bullet to barrel fit - Bullet diameter .001" over barrel (.452" diameter bullet vs .451" barrel)
    - Bullet base's ability to deform to seal against the barrel - obturation
    - Sufficient powder charge/chamber pressure to cause bullet base deformation - obturation
    - Bullet lube type/performance - ability to liquefy and seal forward of the bullet lube ring yet form a solid gasket around the bullet
    - OAL/leade/free bore/throat distance - how far the bullet has to "jump" from case neck to the start of rifling

    Not all factory barrels have .451" groove diameter and some are larger. My M&P45 is .451" but the PT145 is .453". Missouri Bullet 200 gr SWC (18 BHN IDP #1) with 5.0 gr of W231/HP-38 don't lead the rifling in the M&P45 (just a light smearing at the chamber end and absolutely no leading whatsoever in stainless Kimbers) but leaded down the rifling in the PT145 and accuracy suffered significantly.

    If you have over sized barrels, typical .452" diameter bullet may not provide tight enough seal and cause leading by (in sequential order):
    - During the initial powder burn, hot high pressure gas travels faster than the bullet while the bullet jumps through the leade/free bore/throat (distance from case neck to the start of rifling) and turns some of the hard lube into liquid at the surface, but because of the over sized barrel, instead of sealing the bullet to the barrel, liquefied lube gets blown off forward of the bullet causing the bullet to be "naked".
    - As powder continues to burn, hot high pressure gas causes "gas cutting" and bullet base erosion of now naked bullet softening the surface of the bullet.
    - As bullet travels down the barrel, rifling do not "dig/grip" the softened surface of the bullet and strip off lead (this explains the long strips of lead along the rifling) instead of bullet's bearing surface gripping the rifling to rotate.

    Leading caused by improper bullet to barrel fit will be aggravated by harder bullet (BHN 21-24) as bullet base will deform less and more hot high pressure powder ignition gas will leak around the bullet. For the PT145 oversized barrel leading issue, I thought about ordering oversized bullet (.453") but I wanted to keep the same diameter bullets in stock. My leading issue with PT145 was addressed by using softer 12 BHN 200 gr SWC (Bullseye #1). The softer bullet deformed well with the 5.0 gr of W231/HP-38 charge and now leaves a light smear at the chamber end. Even the lighter recoiling 4.0 gr of Promo/Red Dot charge works well now in the PT145 and accuracy also improved (of course, the 12 BHN bullet shoots fine in M&P45 and Kimbers with no leading).

    Very true. With proper bullet-to-barrel fit, deformation of bullet base and proper lube type, bullet slides on liquefied film of lube much like car's engine parts moving on a thin film of oil that prevents metal-to-metal contact.

    I also looked at the BHN "formula" but moved away from using it as a sole determinate to reduce leading as there are many production variables that exist like leade length (can you say Glock?), rifling type and height (rounded hill/valley of Glock), barrel groove diameter, OAL and lube type.

    All in all, based on my experience with MBC bullets in 18/12 BHN, I now use more simpler guidelines:

    18 BHN bullets:
    With proper bullet-to-barrel fit (.001" over), I can use mid-to-high range lead load data (or reduced jacketed load data) with no leading or minimal smearing at the chamber end.

    12 BHN bullets:
    With proper bullet-to-barrel fit (.001" over), I can use start-to-high range lead load data (or reduced jacketed load data) with no leading or minimal smearing at the chamber end.

    With oversized barrel situation where groove diameter is same or larger than bullet, I can use mid-to-high range lead load data (or reduced jacketed load data) with no leading or minimal smearing at the chamber end.

    For me, even the higher pressure 9mm/40S&W loads work, even down to start charges. Yesterday afternoon, 300 rounds of 9mm 125 gr RN (18 BHN SmallBall) were shot with lighter 4.0 gr charge of W231/HP-38 at 1.120" OAL loaded for my daughter (I usually prefer 4.2-4.3 gr). This is essentially the start charge according to Hodgdon (125 gr LCN 3.9-4.4 gr at 1.125" OAL) yet the load reliably cycled the slides on G22/G27 using Lone Wolf 40-9 conversion barrels and ejected spent cases behind me and to my right. Few strokes with copper bore brush dipped in Hoppes #9 solvent showed very light smearing at the chamber end that was removed with 3-4 strokes with old copper bore brush wrapped with copper scrubber strands (Chore Boy).

    I get the same results with 40S&W 180 gr TCFP (18 BHN IDP #5) loaded with 3.8 gr charge of W231/HP-38 at 1.125" OAL that my wife likes to shoot out of G22/G27 (factory or Lone Wolf barrel). I prefer to shoot this bullet with 4.0+ gr of W231/HP-38 out of M&P40/G22/G27 as the sharper recoil matches the recoil of my 155/165 gr jacketed match loads and brings the front sight faster back on target.
    Last edited: Jun 13, 2011
  20. Walkalong

    Walkalong Moderator

    If the bullets fit the groove diameter, but are smaller than the throat/freebore in an auto, they can lead if the bullet does not get hit with enough pressure to obdurate and seal the throat. It will lead much worse if it is undersized for the groove diameter as well.

    Just like a bullet needing to fit the throats on a revolver, but not nearly as critical.

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