Barrel Leading

[Bill Steele]

I have been loading some .44 target loads for my Model 29 and have noticed some leading in the barrel. The leading seems to be worst in the first few inches of the grooves.

I am loading Missouri Bullet Company 240gr LSWC (Elmer Keith style) bullets (BH18).

I have tried a number of light loads using Trailboss, W231, AA #7.

All the loads I am running are below 1000 FPS.

Any ideas?

[bumpo628]

I have been loading some .44 target loads for my Model 29 and have noticed some leading in the barrel. The leading seems to be worst in the first few inches of the grooves.

I am loading Missouri Bullet Company 240gr LSWC (Elmer Keith style) bullets (BH18).

I have tried a number of light loads using Trailboss, W231, AA #7.

All the loads I am running are below 1000 FPS.

Any ideas?

I did some reading over on castboolits.gunloads.com about leading. They said that if the leading is towards the exit of the barrel, it might be an insufficient lubricant issue. If the leading is towards the entrance, then it might be a hardness issue. Since you said they were BHN 18, I bet it's not the second case. You might try tumble-lubing with LLA even though they already have the little blue band of wax.

[Bill Steele]

How hard is hard enough...

I did some reading over on castboolits.gunloads.com about leading. They said that if the leading is towards the exit of the barrel, it might be an insufficient lubricant issue. If the leading is towards the entrance, then it might be a hardness issue. Since you said they were BHN 18, I bet it's not the second case. You might try tumble-lubing with LLA even though they already have the little blue band of wax.

I was wondered about the lube issue as well. These bullets do have the blue wax band, but otherwise no apparent lube.

In all the reading up I have done on the subject there seems to be a wide range of opinions about hardness. Some guys say, "you need a softer bullet to seal things up with lighter loads", other guys say, "you are using too soft a lead in your bullets.." Which leads me to the conclusion, there may not be an absolute answer to this question.

I may try some lube if I cannot find something easier to try first.

Those Moly lube bullets are sounding better and better all the time.

I am also going to try a little more powder in the loads I have already tested and see if that affects the problem.

Some fun.

[BigBronco]

I found a note in one of the bullet boxes stating that a slower burning powder may help. This was with moly coated bullets. It seems the faster powders may leak hot burning gasses to the edge of the bullet and contribute to melting the moly coating. I know this can happen with under sized lead bullets also. Possibly you are getting the hot gasses melting the side of the bullet. I am not sure but may be worth a try. I allready use a slow burning powder 2400 #54 on burn rate chart . Trail boss is # 19 231 is #29, AA #7 is #50. The lower the number the faster the powder.

[xrMike]

A lot of people use chore-boy to deal with leading problems. In my experience, it works pretty good. The lead just comes right out of your barrel in little slivers. 5 - 10 passes with a hunk of chore-boy and my lead was all gone.

Although I will say, I used to get a lot more lead when I was loading very light loads for my 1911. Once I bumped up my charge to 5.2 grains (W231 + 200 grain bullet) my leading problems mostly went away.

I also use Missouri bullets.

[EmmaGoldman]

Bullet diameter? Barrel groove diameter? Throat diameter?

a slightly stouter load might cause better sealing, which will probably fix this, but proper fit is a better solution that works at all velocities.

That little blue wax strip should be plenty of lube at these low velocities. Lube failure appears as leading at the muzzle end of the barrel.

[Bill Steele]

I found a note in one of the bullet boxes stating that a slower burning powder may help. This was with moly coated bullets. It seems the faster powders may leak hot burning gasses to the edge of the bullet and contribute to melting the moly coating. I know this can happen with under sized lead bullets also. Possibly you are getting the hot gasses melting the side of the bullet. I am not sure but may be worth a try. I allready use a slow burning powder 2400 #54 on burn rate chart . Trail boss is # 19 231 is #29, AA #7 is #50. The lower the number the faster the powder.

Thanks, now that I have all the lead out of the barrel (long cleaning session that), maybe what I will do is try some #9 that I have (seems to be pretty close to 2400 on the chart).

Unfortunately, so far I have always brought a number of loads, so I have no feedback on what is causing the problem and what doesn't. I will start running one load at a time and get a little more scientific. I will probably run out of the MBC bullets before I get conclusive results. Next batch of bullets I will try the moly coated bullets.

[bjl333]

You can look into gas-checks for the bullets. Also check the timing of your 29. Timing issues can cause leading as well.

[EmmaGoldman]

Soft bullets for light loads. Hardness is only helpful for high velocity, usually rifle velocities.

[Bill Steele]

Bullet diameter? Barrel groove diameter? Throat diameter?

a slightly stouter load might cause better sealing, which will probably fix this, but proper fit is a better solution that works at all velocities.

That little blue wax strip should be plenty of lube at these low velocities. Lube failure appears as leading at the muzzle end of the barrel.

I haven't mic'd the barrel grooves yet. I had thought I might do the bullet swagged through the barrel thing, but have not yet.

The throats are .4295 (all pretty consistent). The bullets I have mic'ed come in pretty consistently at .430 raw.

[Bill Steele]

You can look into gas-checks for the bullets. Also check the timing of your 29. Timing issues can cause leading as well.

Timing, lockup, alignment all are really good.

[EmmaGoldman]

I haven't mic'd the barrel grooves yet. I had thought I might do the bullet swagged through the barrel thing, but have not yet.

The throats are .4295 (all pretty consistent). The bullets I have mic'ed come in pretty consistently at .430 raw.

if you're going to slug the barrel, I suggest softer lead than those you are shooting (way easier!)

Throats might be a hair tight, but S&W can run small on throats and barrels. The big problem would be smaller throat than barrel.

[Asherdan]

Lead in the first couple of inches of barrel indicates the bullet is undersized initially and your getting leading from gas cutting before the pressure 'bumps up' (or obturatation) to seal the bore. Have you slugged your bore and cylinder chambers? You need to find out the true diameters of your cylinder mouths and your bore. If the cylinder mouths are under your bore size they are sizing down the bullet which is then being bumped back up by pressure as it travels the barrel.

MBC's standard cast size is .430, I believe, but Brad confirmed they have a .431 sizer and can supply bullets at that size on request. See what your chambers and barrel are at and then you'll know if cast will work out for you in that revolver without having to do something like having the cylinder chamber and mouths touched up and uniformed.

[Bill Steele]

Thanks guys.

I measured the throats (with the bullets I have) and they all came out consistently at .4295"

I will get some softer lead bullets and check the barrel dimensions. It sounds like my barrel might be slightly larger than the throats.

The accuarcy doesn't seem to be affected by this phenomenon. I have not benched it at anything longer than 18 yards, but at that range she drives tacks.

[Asherdan]

Nevermind. Carry on.