Slower Powder=Less Leading???

[timdco]

I have been shooting 240gr cast SWCs in my Smith 629 ahead of 10 grains of HP-38 powder and have been getting some bad barrel leading. I was told that a slower powder i.e. 2400 or IMR 4227 would yield less barrel leading. Is there any truth to this? Thanks.

[Crosshair]

Richard Lee in his reloading manual explained that is was pressure and not velocity that was the limit when using lead bullets. The harder(stronger) the bullet, the higher the peak pressure could be. One could find the max pressure a bullet could withstand by finding the Brinell hardness of the bullet.

So in your case, the slower powder will help you reach the velocity you want with lower pressure. If you load the slow powder to the same pressure as the HP-38 you will very likely still have barrel leading.

Perhaps you could try using GC bullets.

Hope this helps.

[dubber123]

I have been shooting 240gr cast SWCs in my Smith 629 ahead of 10 grains of HP-38 powder and have been getting some bad barrel leading. I was told that a slower powder i.e. 2400 or IMR 4227 would yield less barrel leading. Is there any truth to this? Thanks.

I don't think it's a powder problem, but more likely a boolit size or lube problem, most likely the boolit is too small. The boolit can be too small to begin with, or if for some reason the cylinder throats are smaller than the barrel, your booits are getting "sized down" before getting to the barrel. Not being sealed well to the bore will cause big time leading. A seriously crappy lube can do the same thing. A week or so ago, I shot some plain base boolits cast from wheelweights at right around 1,400 fps. with very little leading in a Smith 629. That should be quite a bit hotter than your HP-38 load. Something is causing your leading, but I doubt it's the powder. Hope this helps.

[GSPKurt]

My guess is use softer lead or bigger bullets.

[shooting on a shoestring]

Its true that all else being equal, slower powders TEND to lead less, provided you're not running velocities that are just too fast for cast boolits.

I would highly recommend you first look at the relationship between your chamber throats and your barrel groove diameter. In a perfect world, you want your throats to all be close to the same diameter of each other, say +/- 0.0002" would be nice, +/-0.0004" could be workable. BUT, they must all be larger than the groove diameter.

In addition, your boolits need to be 0.001" or so larger than your throats.

After you get those relationships in order, make sure you're using decent lube, Felix lube is great, then you will probably be able to use any powder you want.

One other variable is boolit hardness. Sometimes a fast powder under a soft boolit can bump up the boolit diameter on firing and help seal hence keep flame cutting around the boolit from happening. Sometimes a slower powder under a harder boolit will help due to less pressure and the harder boolit can take more abrasion before it leads. You can get harder easy be dropping hot boolits from the mould into a bucket of water, assuming you're casting wheel weights.

Oh, and be sure to start with a clean barrel. A copper fouled barrel can lead quickly.

Another trick is to work up some loads with cream of wheat filling the air space between the powder and boolit base. The cream of wheat will act like a gas check protecting the boolit base, and act like a brush and scrape off leading as it goes down the barrel. If you do go for cream of wheat (COW), keep enough velocity to blow the COW plug out of the barrel each time, but the COW will raise pressures quickly so don't work up in large steps. Often loads with COW in them will clean up a leaded barrel.

Good luck and welcome to the fun and madness of revolver boolits.

[Three44s]

Think of this as an interrelational thing.

No one "silver bullet" to solving leading.

Often when you change one parameter ....... and the leading stops ..........

....... well, you changed A parameter ............. but leading can still be near at hand!

I suggest a book from Beartooth bullets.

Three 44s

[Crosshair]

Ah, good points all. I forgot about possible lube/sizing problems when I wrote my first post.

[crabo]

One simple no brainer way to check if the bullets are being swaged down before it enters the barrel, is take your sized bullet, and try to push it through one of your cylinder holes with a pencil. If it won't go, you are swaging your bullet down before it enters the barrel.

Most revolvers have a tight spot where the barrel is screwed into the frame. In some cases, that can cause a bullet which starts out large enought to become undersized as it rattles down the barrel because it no longer fills the barrel. Firelapping would be in order here.

LBT and Beartooth both sell firelapping supplies. LBT's push through slugs really let you know whether or not you have any tight spots in your barrel.

[Bass Ackward]

Two types of leading.

First and worst is from gas cutting because pressure didn't come up fast enough that the gas blew the lube off your bullet. This can also be true for too hard of a bullet for the pressure.

Second type of leading is galling because your lube failed to prevent metal to metal friction at the velocity you were launching it at. Or your bullet was too soft for the pressure.


So a slow powder would prevent leading in case #2. But cause it in type #1.

[timdco]

I went to the sporting goods store and picked up a pound of Alliant 2400 today, loaded it up with 19 grains and shot about 25 times and I was amazed with the results. There was not one speck of lead in the barrel. This is quite interesting because this load develops several hundred fps more than the hp-38 load did. Just thought that I would share my findings.

[dubber123]

Did you chronograph the loads? I looked yesterday at your HP-38 load, and it should have been getting around 1,200 fps. I would not expect the 2400 loads to be much faster. The lack of leading is a step in the right direction for you. I hope the accuracy is up to par, it would be nice if a simple powder change fixed your problems. I have had great luck with 2400 in the 44 magnum.

[Lloyd Smale]

yes it can in a gun thats prone to leading. Ive found that once you get a gun squared away in all the aspects of dimentions that can cause leading that it doesnt make much differnce what powder you run. Bottom line is that as long as your using an alloy that is hard enough for the velocity your shooting and a lube thats good enough your gun shouldnt lead. At least not excessively.

[Crosshair]

Great to hear the good news. Did you only change the powder that you used or did you change the bullet sizing or other aspects of the load?

[timdco]

Nope, the only thing that I changed was the powder. I shot another 50 rounds and still absolutely no leading. I'm still amazed.

[9.3X62AL]

Well, COOL. If it ain't broke--don't fix it.

I use A LOT of Alliant 2400 for cast boolit revolver and rifle rounds. Good stuff.

[MakeMineA10mm]

I use W231 (which is the same powder as HP38) in my 44 loads, and I tend to not go over 7.0 grs. I've loaded up to 9.5grs, but didn't like the results.

My advice is to stick with 2400 for your warm loads, and, if you wanted to shoot some lighter loads in your 44, load the light rounds with 5.5 to 8.0 grains of HP38 / W231. I personally shoot mostly 5.6grs and 7.0grs in my 44 Mag S&W629s with 210gr to 250gr boolits. Never any leading.