Leading

[Cadillo]

Ever since I started casting bullets I've always had nagging issues with leading in my Sig P-220's in .45 ACP. During that time, I tried various alloys, bullet profiles, lubes, and sizing at both .451 and .452. I even put a very nice Barsto barrel in one of them, but the problem continued to varying degrees until this week, when I tried something that I read somewhere on this forum, but which I was slow to try due to it's just not seeming to make sense.

As I shoot a lot of ammo during each range session, I've always loaded light to moderate loads in the various calibers I load for in order to avoid developing a flinch, which always ends the day's centerfire shooting for me. In which case I always shoot a hundred rounds or so of .22lr to regain my trigger control before retiring.

To this end I had always loaded my 200 grain SWC's with anywhere from 4.0 to 4.6 grains of WW 231, and always had some level of leading just forward of the chamber. This week I took my latest recipe and I bumped the charge up to 5.0 grains from 4.6, which is a little more recoil than I like for my usual regimen of 200-300 rds of .45 ACP, but the load is accurate and NO LEADING. Bear in mind that the charge adjustment was the only change, other than the various 200 grain bullets, none of which lead at this charge weight. Same cases, alloy, lube, primer, sizing diameter, OAL(bullet specific), etc.

Just to make sure this was not a fluke, I have loaded and shot this new charge weight three times in the last six days, and the result is always the same, no leading. Alloy is 15 lbs. lead, 15 lbs. WW, 1 lb. tin. Lube is BAC, which I really like for ease of use, low smoke etc. Bullets are Saeco #68, Lyman 452630, and Lyman 452460. Sizing is .452.

I had always thought that more velocity meant more leading, but somehow, that is not always the case. In this instance, more velocity meant no more leading.

I still don't get it, but I won't argue with success. :D

[putteral]

My favorite load with 231 (HP38) is 5.2grs with 200gr cast. Never had any leading in my P220.

[gray wolf]

I can't add to much, but I will say I am glad it worked out for you.

[runfiverun]

i believe you just proved to yourself that lead obdurates.

[cabezaverde]

My favorite load with 231 (HP38) is 5.2grs with 200gr cast. Never had any leading in my P220.
My exact load for my Smith 457 and 4516.

[felix]

"lead obdurates" is false logic. ... felix

[303Guy]

"lead obdurates" is false logic. ... felix True, but no more so than calling a boolit a hollow point!:kidding::mrgreen:

[Echo]

i believe you just proved to yourself that lead obdurates.

I often see obduration on this forum - not a lot, but some...:kidding:

[felix]

obDurate is NOT obTurate. Two completely different meanings. Same with THEIR and THERE. ... felix

[Cadillo]

I was hoping that someone might chime in offering some sort of possible reason why an increase in powder charge would either reduce or eliminate leading in some scenarios. One possibility, a guess on my part actually, is whether or not the lube needs a certain minimum threshold of pressure, temperature etc. in order to aid in sealing the gasses behind the bullet given certain conditions of bore versus bullet diameter, alloy hardness, lube type etc.

My guess is that someone else has probably previously made a similar observation regarding reduced or eliminated leading with increases in velocity, pressure, and might be able to offer up their ideas. It would be interesting to know what someone else thinks about how and why this occurrs.

[Piedmont]

runfiverun gave you an answer, he just can't spell. You upped the pressure. If obturation took place now you got a gas seal, so no blowby and no leading.

[44man]

Increasing the load can extend the peak pressure point until after the boolit has left the case and entered the rifling, reducing the skid. A lot of air space in a case can let the powder ignite quicker.
Some say MORE PRESSURE, OBTURATE! NO, not correct. Pressure extension makes a lot more sense. How can you make a boolit obturate if it is already over bore size? Is there some magic wand you wave around?
Felix is right, a boolit does not obturate, it expands TO obturate in the bore. Obturate merely means to SEAL. So you do not obturate a boolit, you expand it so it does.
Not good for accuracy in any event. Fit the boolit so it does not need to expand.
It is just language, say expand the boolit, not obturate the boolit. Two different words with different meanings. not like mold and mould that mean the same thing.
Moot point anyway, I ignore it most of the time even if it is wrong.
If I hit a boolit with a large hammer I only expand it, I did not obturate it in any way.

[runfiverun]

obturate= to seal.
obdurate=flex or twist, or change shape.
as in you can obdurate a boolit to obturate a bore.
to me anyways.
i bet more arguements have been had over the meaning or understanding of these two words than any other issues ever, with cast.
either knowingly or mistakenly.

[Cadillo]

Increasing the load can extend the peak pressure point until after the boolit has left the case and entered the rifling, reducing the skid. A lot of air space in a case can let the powder ignite quicker.
Some say MORE PRESSURE, OBTURATE! NO, not correct. Pressure extension makes a lot more sense. How can you make a boolit obturate if it is already over bore size? Is there some magic wand you wave around?
Felix is right, a boolit does not obturate, it expands TO obturate in the bore. Obturate merely means to SEAL. So you do not obturate a boolit, you expand it so it does.
Not good for accuracy in any event. Fit the boolit so it does not need to expand.
It is just language, say expand the boolit, not obturate the boolit. Two different words with different meanings. not like mold and mould that mean the same thing.
Moot point anyway, I ignore it most of the time even if it is wrong.
If I hit a boolit with a large hammer I only expand it, I did not obturate it in any way.

Best answer so far. Makes sense! Thanks! :-)

[felix]

You need to throw out your dictionary, 5R5. It does not agree with those I have used. ... felix

[runfiverun]

dictionary??
i'm still working on phonics.

[BSkerj]

obturate= to seal.
obdurate=flex or twist, or change shape.
as in you can obdurate a boolit to obturate a bore.
to me anyways.
i bet more arguements have been had over the meaning or understanding of these two words than any other issues ever, with cast.
either knowingly or mistakenly.

Man...you Soda guys sure can use some big words...I have a hard time spelling Pocatella...or is tello ?:bigsmyl2:

[Piedmont]

Words mean things. I'm seeing definitions here that are just wrong. Google is your friend if you don't know what something means.

"How can you make a bullet obturate if it already over bore size?" 44man

Well first off, you mean groove size, but that isn't where the obturation takes place. It is in the chamber or at most the throat which is larger than the barrel groove dimension.

[44man]

Words mean things. I'm seeing definitions here that are just wrong. Google is your friend if you don't know what something means.

"How can you make a bullet obturate if it already over bore size?" 44man

Well first off, you mean groove size, but that isn't where the obturation takes place. It is in the chamber or at most the throat which is larger than the barrel groove dimension.
That is also correct but since it is used as commonly as obturate and is easier to type then groove to groove, I am guilty too. :bigsmyl2:
Our saving grace is that we understand what is meant, being casters.
I have never responded to "spruce plate" either although I have never found one growing on my trees. :redneck:
If all of you knew how many times I use the dictionary for a simple word, you would laugh. Then I find a problem, how do you find the word in the dictionary without knowing how to spell it? [smilie=p:
Why does spell check always put a line under certain words?
But we do have fun over such simple stuff, don't we?

[Piedmont]

44man, LOL. I suspect that whole spruce plate thing might actually be due to spell check. Microsoft probably doesn't have a clue what a sprue is!!!

What I worry about is the newbies. If you or someone else types bore diameter when they mean something else, I wonder about the new guy trying to figure this stuff out and concluding something wrong because the wrong word was used.

[runfiverun]

we keep it plain ole pokey.
it's waaay too long.
i just say i'm goin to walmart.

[44man]

44man, LOL. I suspect that whole spruce plate thing might actually be due to spell check. Microsoft probably doesn't have a clue what a sprue is!!!

What I worry about is the newbies. If you or someone else types bore diameter when they mean something else, I wonder about the new guy trying to figure this stuff out and concluding something wrong because the wrong word was used.
Thank you, you are right and I will use groove from now on. I have tried to be careful but it still gets away from me.