Leading accumulating in a Muzzle Brake

[gixer454]

So my research of previous posts hasn't really answered the question: What causes lead to accumulate in a muzzle break? The culprit is a 300 Blackout shooting the Lee 312-155-2R with 16 grains of H110 out of a 16" 1-8 twist barrel with a 1.35" three shot group at 50 yards and a VG6 Gamma 300 BLK brake. Feeds like a dream come true, locks the bolt open.

I have a hunch on what is causing it, but I want to know what everyone else has to say.

[45-70 Chevroner]

If you are going to shoot cast in a gun with a muzzle break you will have to put up with leading in the break. I have never seen one that did not lead up when shooting cast. IMHO No amount of load changing will fix the problem.

[waksupi]

I had a rifle with a brake. I took off the break, and tumbled it in moly until well coated. It still fouled, but it took a lot longer.

[gixer454]

What are your theories as to why you get lead in the brake? I have absolutely no lead in the barrel and the load shots fairly decent.

[waksupi]

I was actually getting more of a heavy powder fouling, rather than leading. I considered it more cosmetic, than a function problem.

[45-70 Chevroner]

I know this was not directed at me but my theorie is that the boolit heats up as it travels down the barrel and then throws off a little lead just as it leaves the bore. This is more of a guess than anything but I do know that comps lead up when shooting cast and the hotter the load the more the leading.

[mongoose33]

Are you sure it's lead and not lube?

[bhn22]

It's probably gas cutting around the bullet base as it leaves the barrel and enters the comp. Try to recover a few bullets and examine them to see where the lead is coming off the bullet. Are you using gas checks?

[454PB]

I get a build up of "crud" in the muzzle brake of my Taurus RB .454 Casull. It's not lead, it's lube.

[Jupiter7]

In what rifle? If it's an AR and there is leading on the brake then there is most certainly lead in the gas system, I would pull and disassemble the bolt and check the rings and boat tail area of te bolt. If it's silver in color and doesn't come off with standard cleaners, it's lead. Powder fouling can sometimes have a silver color to it but will remove very easily.

[gixer454]

I am using a gas check, and the bullets are HiTek coated and pass the smash and wipe test. My theory is that I either have some gas cutting or my alloy is still too soft, even with the coating. I chatted with Glen Fryxell briefly and he believe that the bullet is allowing some gas cutting. I have my eye on another bullet mold that I would like to try and I am in the process of using a harder alloy to see if that makes any difference.

[Le Loup Solitaire]

One of my S&W M41's wears a muzzle brake to help with muzzle jump. It does after any number of rounds start to show accumulation of lube from the 22 cals and fouling, but no lead. It doesn't effect accuracy, but presents a grungy cleaning job when the day is done. So I take it off and clean it. LLS

[runfiverun]

check my response on the other thread it'll give you an idea of what is happening.
it's similar to some of the others answers.

[Echo]

My comments are aimed at your use, or non-use, of a GC. If no GC, then, as Harry Pope pointed out 100 years ago, lead bullets leave tails behind them from the rifling action. Those tails could affect the accuracy of the cast bullet, so he supported muzzle-loading of the bullet to cause the tails to disappear. When the bullet clears the muzzle, muzzle blast will dislodge the tails, and if there is a brake attached, they will accumulate there. That's what happened with the HS .22 Match gun I shot as a new shooter - I had to take the brake off every so often to gouge out the lead. GC's on your boolits should cut down on the leading considerably.
Or. Maybe you boolits are sized too small, and are letting gas leak through and gasify some alloy from the bollits. Are you also getting bbl leading?
Or. . . .

[303Guy]

I get a build up on my suppressor baffle and that's with jacketed's. It's not lead but it does look like lead. One clue as to what it is is the difficulty in removing it. Lead is soft stuff and doesn't stick to steel very well. Powder fouling is hard and does stick to steel.

[gixer454]

check my response on the other thread it'll give you an idea of what is happening.
it's similar to some of the others answers.

Will you post a link to the other thread please?

I am sizing at .3095", which matches my throat exactly. I size after coating. Maybe I need to try to go up to .310" or even .3105"? I should be running the bullets at about 1800fps although I don't have that verified yet. The actual weight of the bullet is 151 grains with my alloy.

136363
I am positive it is lead and not powder fouling.

[gixer454]

I am using Hi-Tek coating, not powder coat.

[MtGun44]

My compensator on a Wilson LE Comp .38 Super built up a lot of lead,
had to chisel it out periodically.

[truckjohn]

Your brake looks like it's cut large enough that it should not touch the bullet... Actual "Lead" in this type is most likely from the bullet hitting the inside of the brake... I am kinda thinking that the 1.5" at 50 yards indicates that something is amiss... If you go out further - do you see "Egg" shape holes or evidence of tumbling?

Do your groups change when you remove the brake?

A couple ideas...

1 - the Brake ID is not alined concentrically on-center with the rifling, but is aligned to the OUTSIDE of the barrel... This is a very common thing... "Well, the hole is big enough that it doesn't matter... I will just thread the outside of the barrel and it will be fine" ... And then the bullets hit... Happens with cans too... Accuracy in this case gets much better without the brake...

2 - The bullet is wobbling in the brake and hitting... Muzzle crown is the typical #1.. Bullet base squareness and the throat/leade being cut off center to the rifling comes close behind... Last is bullet defects that cause them to be imbalanced... Accuracy in this case is still poor without the brake although not hitting the inside of the brake may improve the accuracy a little...

3. Design of the brake allows the gas venting to "Push" the gun in one direction while the bullet is still inside the brake - and the bullet hits the inside of the brake.. Accuracy in this case also gets much better without the brake.

Thanks

[cs86]

I was having this issue with my 300BO, but I was initially getting leading in the barrel too. I'm not sure what the main problem is with my leading problem and I'm still testing. A theory I'm working on is that with my 1:7 twist is pushing the 150gr boolit to fast and the softer bullet and powder coating can't handle the fast spin at higher speeds. So it would lead the barrel then the next round would push lead out and accumulate on the break. Sometime I plan on trying to slow it down and try some different powders to see if I get rid of the leading. Eventually I plan on testing heavier boolits to accommodate the fast twist. I'll be curious as to what you figure out.

[gixer454]

I am getting this bullet to try next, the profile screams "I'll feed" to me and I think the heavier bullet and increased contact area on the bore may help with the gas cutting issue.

http://noebulletmolds.com/smf/index.php?topic=614.0


I have ZERO lead in the barrel or on the bolt. I wonder if the bullet is swelling after it exits the barrel and scrapping the ID of my brake but I know I will play hell proving that theory.

[bbqncigars]

I only two guns with brakes on, and the brake will accumulate some dark fouling. The fun part is that the fouling on the big one will turn blue/green if left alone. The gun is a .50BMG shooting virgin AP projectiles with good accuracy. There's a lot of powder burning to vaporize some metal. Brake erosion is not uncommon in this caliber. The brake on the FAL just collects powder fouling (wet patch w/Hoppes #9 just stays black). Just because your brake is dirty, it doesn't mean bad things are happening.