do bullets metal from firing?

[chboats]

If the exposed lead at the base of a FMJ were melting and fouling the comp, why does it not foul the gas systems of M1s, M14/M1As or any of the current ARs being used in 223 when shooting FMJs?

Carl

[Jack Stanley]

Maybe this train of thought is way off and I don't think I can support it anyway but here ya are . Perhaps the hot powder gasses are condensing on the somewhat cooler compensator . The gas cylinder and front of the operating rod of my Garand get a buildup when firing military ball but I rather doubt it's lead from the base of the bullet .

Jack

[Mal Paso]

This why ask. I want to know the truth not some theory. I haven't shoot that gun in a long, long time, so maybe I should. Heck it could be memory. I'll clean the comp, and take pictures, load up some FMJ's, and bring back more pictures.

BTW, it's NOT leading the barrel, only the comp. I get the wad argument, but a shotgun is very low pressure, and a 38 super loaded to Major is quite high.

Thanks for all the input

Sent from my MB886 using Tapatalk 2

It's not your fault. You had no way of knowing this is a Religious Issue.

Seriously, I think the hot gas needs to be moving at a high rate of speed past the metal before gas cutting can take place.

[Skip62]

It's not your fault. You had no way of knowing this is a Religious Issue.

Blahahaha, good one

Sent from my MB886 using Tapatalk 2

[44man]

^ I would suspect the poly remaining in the case melted because of the prolonged contact with the hot case, rather than the microsecond of powder burning. No? Ejected brass from my ar can melt the nylon mesh in my brass catcher.

<edit>BTW, did you try boiling your 35 rem cases? Perhaps soaking in acetone would have worked?</edit>

Sounds reasonable but the .35 has no shoulder to speak of to catch fibers so it is strange. I never had anything burn, even a newspaper wad over the flash hole. Some are black but you can read the paper on most.
Now I have seen .38's shot with wad cutters of pure lead coat the outside of cylinders and frames with lead. They did not melt but could not take the gas cutting at the gap. They cut steel with water today with no heat. There is a lot of force changing direction at the gap, remember the guy that cut his thumb off with a .460? It was not burned off.
With the comp, it could be the same as it is at the gap, mechanical cutting of a soft lead bullet core from gas escape. Use a hard core and it might stop.
I have shot PB boolits to over 55,000 psi with no lead at the gap or on the cylinder.

[Larry Gibson]

I've cleaned a lot of "debri" from several comp M1911s. I think the OP is confusing Carbon build up with lead. The carbon fouling from the powder can look like leading (shiney and silvery) when it is scraped or brushed out. The exposed base of lead bullets do not melt when fired.

Larry Gibson

[Smoke4320]

I argee its mostly carbon buildup .. same thing happens in suppressors over time

[grampa243]

I argee its mostly carbon buildup. i have not yet fired a lead boolit in my AR(will fix that soon ) only v-max and HP types with full copper bases. but the the carbon buildup in the gas system does kinda look like leading. i think you will find that what powder you use will change this some as well.

[btroj]

I've cleaned a lot of "debri" from several comp M1911s. I think the OP is confusing Carbon build up with lead. The carbon fouling from the powder can look like leading (shiney and silvery) when it is scraped or brushed out. The exposed base of lead bullets do not melt when fired.

Larry Gibson

Exactly

[Skip62]

I've cleaned a lot of "debri" from several comp M1911s. I think the OP is confusing Carbon build up with lead. The carbon fouling from the powder can look like leading (shiney and silvery) when it is scraped or brushed out. The exposed base of lead bullets do not melt when fired.

Larry Gibson

That could be absolutely correct. I didn't realize carbon was silver in color, so I "assumed" it was lead. I don't have any FMJ's like I thought, so until I get some I won't be able to see what happens.

Thanks

[pdawg_shooter]

I paper patch and the bullet base is covered with paper. It dont even scorch, much less burn. I have recovered many patches that hace a bit of carbon on them from the powder, but none burnt. Paper burns a 458 IIRC, way below the melting temp of lead.

[NSP64]

Skip62
Get some TMJ (Total Metal Jacket- plated all around) and shoot those in your comp gun and see if you get buildup.

[Skip62]

Skip62
Get some TMJ (Total Metal Jacket- plated all around) and shoot those in your comp gun and see if you get buildup.

Well, I get none from hollow points

Like I said, it could just be my memory, I've been wrong before, many, many times

Sent from my MB886 using Tapatalk 2

[pcarpenter]

You don't have to melt lead to end up with it in a comp, etc. If you doubt that some can rub off without melting, look at your fingers when you are done handling lead bullets. Almost certainly, some gets "rubbed" off when the bullet goes streaking up the bore and exits with the muzzle blast.

I had this discussion with a guy at the range who insisted that he had to use gas checks to prevent the bullet base from melting. He pointed out the rough bullet bases as evidence. I mentioned that powder granules under tens of thousands of pounds of force (per square inch) can easily mark up the base of the bullet, even when the lead is not in a molten state. Certainly the flame temp is high enough to melt lead, but it's not in contact long enough-especially in a short pistol barrel--to transfer enough heat to the lead to get it done.

Someone on this forum did some macro photography of pistol bullet bases after firing and you could tell what sort of powder had been used by the imprints in the bullet base. Yet another reason why this is a great forum....lots of experimenters!

Paul

[fcvan]

I have a Glock 22C and I get carbon and debris around the ports when I shoot my cast boolits. It doesn't appear to be any more than the same gunk I get in the action around the feed ramp. I'm looking forward to shooting some powder coated boolits to see how they do. I shot some in my G23 and they worked great. The bore shined like a new dime with one pass of a dry patch. I think a lot of the gunk I normally get with cast is boolit lube and carbon.

[gunseller]

One time I played around shooting a cast bullet in a 44 mag into a block of wood. I put an X on the base of the bullet so I could tell it from others I was shooting into the block. After four firings the X was still on the bullet. I lost the bullet after the next firing. Under sized bullets lead barrels not melted bases. The lead in a comp or the front of a cylinder may coming off the side of the bullet as it passes the opening and gas gets the micro second to come around the base to the side walls of the bullet. As stated this acts loke a cuttong torch. As for plastic melting why is there no melted plastic from Remington accelators? I have shot plastic sabos for a 45 cal ML in 45-70s loaded with .357 bullets at a high speed without melting them. I same rifle I have gotten plain base cast bullets over 2000 with no leading.
Steve

[dverna]

I tend to the side that the temperature/time relationship makes it difficult to accept lead is melted from the base of the bullet.

If that is so, why does lead melt from gas cutting when shooting an undersized bullet?

Thanks for any insight.

Don Verna

[303Guy]

... why does lead melt from gas cutting when shooting an undersized bullet?

It's to do with what constitutes pressure and temperature - high velocity atoms and molecules. You can get an idea of the gas cutting effect by directing a water jet from a garden hose at something soft. Those molecules are not high enough to damage the lead base of a boolit but powder kernels sure are and those can peen the boolit base.

These are rifle boolits using rifle powders.


Base Peening. Click on that first one. The second is showing the kernels in the impressions.


Gas cutting


Intact base and base edges. (Apart from the ding on one side).

[pcarpenter]

Thank you, 303Guy. I knew I remembered seeing the thread and pictures. I appreciate you re-posting them. I think I may save those off for future reference. It's one thing to tell a guy about the theory behind something. It's another to have first-hand, tangible illustrations.

Folks, if there's a guy who's done a lot of "what if" testing, it's our friend from NZ. I've read plenty of his posts on paper patching and other more esoteric aspects of our hobby and if there's some question about how or if something will work, he tries it.

Just for clarification and to address the original poster....I spent a while shooting heavy cast bullets in my 300 Blackout AR-15 where there's a port and a flash hider to "foul". Both ended up with a slight silver coating that is definitely different in color than the typical gray-black carbon fouling that I get when shooting jacketed ammo. I am in total agreement that there's no reason one can't shoot cast bullets in ported guns or gas operated semi-autos. What you get in the way of fouling is not big chunks of lead but sort of a "vapor trail" that deposits with the carbon....and you can tell it from the carbon because it's silvery in color. It cleans off with the carbon and I still believe that this is not because the lead is being melted, but because it's being "tracked" in the bore and blasted out. Think of a "lead" (graphite) pencil. Because of the grain structure of graphite, you don't have to melt it to remove bits of it. It's certainly not melting as you drag it on a piece of paper. You can then take your finger and further smear what has rubbed off. Take one of your lead bullets and bear down on it and drag *it* on a piece of paper and see what you get. I tend to believe that the slight vapor trail of lead that shows up on compensators and gas ports is not because the lead melted, but rather because it leaves "tracks" in the bore (not to be confused with leading) and tiny amounts are blasted around the bullet when the combustion gasses exit. Those gasses have tremendous energy and could easily remove some of this "tracked" lead. We already know that the combustion gasses are moving at a higher velicity than the bullet. High speed photography shows the gasses escaping forward around the base of the bullet as bullets exit the muzzle. That's the reason why square bullet bases and square crowns are so essential to accuracy.

Paul

[cbrick]

Good post Paul, very well explained. Thanks.

Rick