Cause of cylinder face lead buildup?

[elano]

When I shoot MBC 158g round nose cowboy boolits over any charge of bullseye, my revolvers tend to foul the front face of the cylinder in what looks like lead rings around each hole the same thickness as the forcing cone. The barrel cone also has this lead buildup. It is to the point that 100 rounds can cause binding issues in some guns. This does not happen when I use the swc 357 action boolit by mbc or any jacketed load. This happens in every revolver I try it in. What's going on here?

[Multigunner]

Sounds like the lead is too soft and the bullet base may be of a shape that enables vaporization of lead from the base.
Since it happens the same way with several different revolvers its a bullet related issue.

Some other propellent might not cause this level of leading with this bullet.

An over the charge wad of some sort might reduce or eliminate leading, but aside from a light paper single layer cigarette paper wad I haven't tried any wadding over a charge of bulleye, so I can't tell that its safe or not to use anything more substantial.

I used the light wad only to hold powder against the flashole to insure complete ignition of small charges.

[elano]

Interesting. I think I will buy some semi wadcutters with my next purchase then. The lead vaporizing makes sense! Thanks!

[44man]

Interesting. I think I will buy some semi wadcutters with my next purchase then. The lead vaporizing makes sense! Thanks!
Soft lead, plain and simple. Soft semi wad cutters will not cure it.
Much of your boolit is blown from the gap. The rest slumps into a blob. GG's are also gone.

[elano]

I believe the hardness is bhn12 according to the website. Ive been using 3.5g of bullseye however even 3.2g caused the lead buildup.

Do you think lowering it to around 2.8 grains of bullseye will fix the problem?

I have about 200 rounds left to experiment with.

[44man]

I believe the hardness is bhn12 according to the website. Ive been using 3.5g of bullseye however even 3.2g caused the lead buildup.

Do you think lowering it to around 2.8 grains of bullseye will fix the problem?

I have about 200 rounds left to experiment with.
It could but Bullseye has a very fast thump on a boolit. You might make them better by going to a slower powder to stretch out the pressure curve without increasing velocity.
I don't shoot light stuff but many here can give better info.

[w5pv]

When I shoot MBC 158g round nose cowboy boolits over any charge of bullseye, my revolvers tend to foul the front face of the cylinder in what looks like lead rings around each hole the same thickness as the forcing cone. The barrel cone also has this lead buildup. It is to the point that 100 rounds can cause binding issues in some guns. This does not happen when I use the swc 357 action boolit by mbc or any jacketed load. This happens in every revolver I try it in. What's going on here?I had the same problem and used a drop of Sticky's 40/40/10 lub on the base of each boolit.I let this dry before reloading and it seems to stopped the leading.I used a smaller loading block and turned the boolits upside down to put a drop on each boolit.Hope this helps. These were plain based boolites 2.4 grains of 700x behind 93 grain 32 round nose.

[bigboredad]

if you are looking for a soft recoiling load try trail boss it's a fast powder but is designed for cast bullets. I have had really good luck with it in my wife's .357 vaquero and my .45 acp loads.

[elano]

Okay so my options are a reduced load or a slower powder? I have some unique handy, how about that?

[44man]

Okay so my options are a reduced load or a slower powder? I have some unique handy, how about that?
Yes, try it. All is trial and error after all.
I have not tried Trail Boss but I hear good things.

[subsonic]

Depending on who you beleive, TB is supposed to be close to titegroup for speed. I have even seen in a magazine that data is interchangeable, but i don't beleive it.

I would try your Unique at a starting load from a manual.

[Groo]

Groo here
Trailboss is a fairly fast powder but seems to act like a slow one..
I have best luck with a near full case [to the bullet base] a strong crimp and ,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,, get this mag or win primers ...
The powder is so bulky that you need to get to get the fire going..

[elano]

Okay I have an update. On a whim I took a micrometer to the bullets that are leading up the cyl face and found that the round nose bullets are measuring .3570 while the semi wadcutters that do not lead up the cylinder are .3575. Is this my problem? Or is .0005 not enough to make a significant difference?

I just loaded up 100 rounds to test with different powders and charges but now I'm wondering if I should even bother. Scrubbing the gun for 45 minutes is getting old.

Any thoughts?

[Wayne Smith]

Measuring your boolit without measuring your chamber openings doesn't tell us much. Try taking each boolit and dropping them into your chambers. Do they fall through or do you have to drive them?

[elano]

The round nose pushes through with a finger. The swc does not. It is like that on all my revolvers.

[elano]

Cute cat btw Wayne.

[Wayne Smith]

Cute cat btw Wayne.

Unfortunately he died a few years ago at age 18. He was murder on squirrels. Would love to find another who will also kill squirrels.

[chboats]

An experience I had with lead build up on the face of the cylinder. I was working with a friend who shot a lot of ICORE matches. He wanted to try lubing with a dry lube. We tried moly, graphite and a couple of others. Powder lube was applied in a tumbler. The boolits were Lee 358 150 1r cast of WW and range lead, sized to .358. We tried air cooled and water dropped. The air cooled measured 11-13 bhn with an LBT tester, the water dropped measured 27-30. The lead would build up to the point that the cylinder would not rotate. There was minor leading of the barrel in and just ahead of the forcing cone.

As soon as he gave up on the dry lube and let me lube the boolits with other forms of lube such as BAC or any other reasonable lube, all the leading went away. It even cleaned all the traces of lead from the face of the cylinder.

All loads were with Bullseye, Clays, or RexII and were loaded to 38 +P levels

Carl

[elano]

Okay well today I tried a harder bullet (357 action measuring .3575) with 3.5g bullseye and it actually leaded up the cyl face even more, not to mention smoked like crazy!! I attribute this to the bullet being TOO HARD since the same bullet over 6+g of bullseye leaves no lead residue on the face. 14-15 grains of 2400 works the best with this particular bullet.

Then I experimented with the softer round nose cowboy bullet that is giving me the problems, this one measures .03570.. I loaded it over 4.0g of unique and it began to lead up the face so I stopped. I'll prob shoot them up anyways since I have 50 loaded up.. I know bad idea.

I now have 2 plans of action.. I'm going to do a little more trial and error. If I can't get a 38 special bullet from Missouri Bullet to quit leading up my guns I will have to switch to a different brand. I just ordered some match 38 bullets which are identical to the 357 action semi wadcutters, but with the softer alloy. We will see! I love the service and quality of MBC but man I can't stand scrubbing lead off the cyl face! Barrel is okay, but the cyl face is just a pain!

[Silver Jack Hammer]

Read Shooting Times Jan 11 Alan Jones Going Ballistic The Lowdown On Lead Fouling.

I bought a brand new Security Six Stainless 4" when I was a rookie cop and it bound up after 100 rounds at a qualification course. Too soft lead.

Other than that I have never had your situation since, I just about always use Bullseye in the .38 for cowboy.

Wayne Smith has the right question, tell us what the caliper read is on the cylinder throats. Measure all six.

I cast and shoot a lot of junk wheelweights and shoot many rounds per sesson with cowboy with my Colts and haven't experienced this. Alox is what I use and don't have any problems.

[elano]

Thank you very much for the reply. I am almost positive I now know what is wrong. The bullets I've received have been sized too small. I bought another box of bullets from missouri bullet and took the micrometer to it. Shure enough the soft 38s measured .001 smaller than advertized on the box. .0357 instead of .358. So did the .30-30 bullets I ordered. They averaged .308 instead of .309. However the 9mm bullets were right on if not slightly larger, .3565 average which is great.

I'm sure this was a mistake by the company. I e-mailed Brad at missouri bullet and update with what's going on.

The experience has got me interested in casting my own.