Aluminum Oxide a Problem?

[Jeff H]

But zinc oxide, and tin oxide is and iron oxide is. Sage (sagebrush7) claims he has run millions of aluminum checks through his tools. Maybe someone should ask him if he's worn them out dimensionally. tj

Now, that's something to consider. Millions? Maybe not at 1500 or 2000 fps but it's a lot of aluminum through steel tooling.

Does any one have proof that using aluminum gas checks are damaging barrels?
I see a lot of speculation on both sides but nothing that proves they are causing damage or that they are not. I agree with fishawk, until a test is done we will not know.

Andy

No, and that's the point. Everything conjectural indicates that it's just fine. Other things conjectural indicate that it might not be, in spite of what we are seeing.

I was asking specifically whether someone has ever offered a scientific explanation for why it's ok, or not. My own assumption is that it is - it seems to be fine. No one seems to be experiencing any issues. Again - asking if someone has done a test or has information which would provide data showing one way or the other. I don't disagree that a test would be necessary - curious as to whether it's been done - within the text of a firarem or otherwise.

None of us so far have the answer and I'm not sure it's worth pursuing it further. I enjoy kicking things around but I enjoy shooting more. I won't stop using them myself just because we know of no definitive test having been done.

[tjones]

Yes, millions, just looked on ebay he's at 1625 sales and that's just reported. Its seems somewhere here he reported nearly 300,000 on one of his tools alone. 300 reported in last 30 days, so millions seem quite okay. No way to know about the sagesoutdoors.com website activity. -tj

[waksupi]

I remember as a kid, taking a piece of aluminum foil and rubbing it with my finger, until it was shiny as a mercury dime. I recall the stuff I rubbed off, felt fairly slick. That would be easy to try at home. I would think that as fine as that oxide is, the barrel would likely have the throat burned out from powder long before any AlO2 caused any decipherable wear. The fineness of the abrasive, added to the lube on the boolit, would make this a non-issue to me.
One of our most corrosive elements is oxygen.

[MUSTANG]

In earlier posts, it was stated that the use of an Aluminum Cleaning rod was the cause of barrel damage at the muzzle due to aluminum oxide abrasion. Back in my military career, over in Okinawa during the early 1980's, we had a Contact Team come to the Armory and the issue of unapproved Aluminum Cleaning rods arose (military approved cleaning rods are all steel). The contact team did not address aluminum oxide as a problem, rather their stated position was the softness of aluminum coupled with the oils and greases around the cleaning and lubing processes resulted in random dirt/salt/metal particles becoming embedded into the cleaning rod, with these embedded particles acting as a cutting agent against the barrel.

The contact team's admonitions seemed not just plausible, but eminently sound. I have adhered to this sound wisdom ever since.


Mustang

P.S. I shoot Aluminum Gas Checks in several pistol &b rifle calibers. I believe that my great grand children may have to worry about the wear in the barrels of these particular firearms when they get to my age.

[gunguychuck]

I am sure if aluminum would wear out a barrel faster than copper it would also wear out your check makers faster also. I am sure some of you have made many thousands of checks with your check makers. I am sure sagebrush has run millions through some of his.

[historicfirearms]

I had pretty well decided to buy a 35 cal Freechex III, but now I have some doubt. Has anyone here fired at least a few thousand aluminum checks and can provide some insight? Also, how do aluminum checks work in chrome lined bores?

[Jeff Michel]

I was always under the impression that aluminium oxide was to aluminium as rust is to ferrous metal. Aluminium oxide, the abrasive is man made, produced in a furnace under intense heat. FWIW, I've shot Al checks for quite a while, in calibers from 500 S&W to .22's, thousands of rounds I have not seen any evidence of Al accumulation in any of my bores or any appreciable wear. Maybe I'm lucky, or maybe it's not as big a problem as some would believe.

[338RemUltraMag]

My 30 cal check maker is as hard or harder than barrel steel, so far I have 300,000 checks through it with no problems, I am shooting them exclusively in all my rifles with no problems. It seems the issue is slightly exagerated, with the cost of aluminum checks by the time you burnt out a barrel you could buy a new one with the savings vs copper checks.

YMMV

[historicfirearms]

My 30 cal check maker is as hard or harder than barrel steel, so far I have 300,000 checks through it with no problems, I am shooting them exclusively in all my rifles with no problems. It seems the issue is slightly exagerated, with the cost of aluminum checks by the time you burnt out a barrel you could buy a new one with the savings vs copper checks.

YMMV

Thanks, this is what I wanted to hear. I'm going to go order a the check maker.

[geargnasher]

Wow, good thread. I especially appreciate Moosman's first post, I learned my daily limit right there!

I believe Blazer cases are coated with epoxy or some such, so there may be a sort of galvanic barrier there. Anyone know for sure?

When copper and aluminum are joined as in house wiring, the mechanical connection points must be manufactured and rated for such and treated with a heavy coat of NoAlox, which prevents ion transfer between metals.

Some shooters report aluminum streaks on top of the lands at extremely high velocity when using aluminum gas checks, so the galling/transfer back and forth is probably occuring. I suspect that aluminum gas checks haven't been "known" as a problem because the majority of those shooting them aren't pushing the limits, and a number of those that are are probably using chrome-lined barrels.

I also suspect that boolit lube, like cutting fluids, aids greatly in preventing the galling action, but maybe not. I know that oiled aluminum oxide sandpaper still does it's job.

Gear

[Rick459]

the only problem that i have with Aluminum Oxide is that i don't have enough in my Bead Blast Cabnet.

[oldgeezershooter]

Isn't this sort of like when the Food and Drug administration feeds lab rats 1000 times more of a substance than they would normaly ingest and it causes cancer or kills them?
I think you would have to run a whole bunch of Al. GC's through your firearms to notice any real damage.

[Clinebo]

Aluminum Oxide in its native form is known as Sapphire! On the hardness scale Sapphire is a 9 and Diamond is 10.
http://en.wikipedia.org/wiki/Sapphire

[Mooseman]

Amen Clinebo ! There is all kinds of info if you look for it.

You know the funny part of this whole discussion boils down to one thing I keep hearing...COST !!! Aluminum is cheaper...BlaH Blah Blah.
Some bubba decides he doesnt want to buy good Copper checks , and says "hey, I can make checks out of my Beer can !"...and here we are.
Call me old school for 40 years of gunsmithing/metalworking/ loading and competition shooting and hunting, and never using anything but lead and copper, but I
think my fine quality guns deserve the VERY BEST ammo, powder ,Primers, and bullets I can feed them because of the Job they do for me. They protect me, they feed me, even some clothes from skins they have gotten me, and they dont ask for much in return except a little care, and oil , and I refuse to be a cheap bastid where their diet is involved. They wear fast enough without me accelerating the process and with original barrels and parts becoming increasingly hard to get I try and keep them in the best shape I can and still get the use out of them they were designed for.
I don't care what you do with your guns ,I wont be working on them! I just stated my position and why I use copper down my barrels all the while hoping the accuracy doesnt decline due to wear before I'm the one worn out and gone...so, I will keep spending 30-50 bucks for 1000 copper checks for the Boolits that need them... to me its just safer and cheaper being old fashioned.
Rich

[tjones]

Acording to this thread the faster the bullet goes the more wear there is. So I suppose the barrels are longer to slow the bullet down. I certainly don't see barrels looking like funnels wearing from the muzzle back to the chamber.
Just how thick do out think the so-call infamous oxide is anyway? 1000 grit, 10000 grit 1,000,000 grit. Someone said you need a scanning electron microscope to see it. Really now, the only thing here is the thread has become total ca ca.

Now we're shooting rubies and saphires. How 'bout diamonds from carbon?

[Whiterabbit]

Just a word on the metallurgy. Saw someone link to a galvanic corrosion chart, and Rich mentioned Al oxide forming quickly. Couple corrections:

galvanic corrosion is meaningless here. we aren't talking about macroscopic rust eating away or pitting a surface, we are talking about a passivation layer of oxide on the metal surface. ALL metals have it. All of them. All. All metal forms an oxide in the presence of oxygen, and it's the cohesiveness of this passivation layer that defines "stainless" characteristics. Thus, metals like stainless steel and titanium that have very tight passivation layers are considered corrosion free. Those passivation layers effectively protect the surface FROM galvanic corrosion. low carbon steel does not have a nice tight passivation layer, and we've all seen the result of that.

As for this pasivation layer forming on Al (or any metal) quickly, that's deceptive too. It forms INSTANTLY. The only way to actually expose a bare metal surface is in a vacuum chamber. The moment you vent, your metal is oxidized. Sure, the passivation layer can thicken given time, but you can not remove it without instantaneous reformation. So it is more accurate to suggest that it thickens quickly, but it forms IMMEDIATELY.

I make no judgments on the effects of this passivation layer in firearms barrels, I leave that for you guys to discuss. I'm just commenting on the metallurgy.

[Sagebrush7]

Yes, millions, just looked on ebay he's at 1625 sales and that's just reported. Its seems somewhere here he reported nearly 300,000 on one of his tools alone. 300 reported in last 30 days, so millions seem quite okay. No way to know about the sagesoutdoors.com website activity. -tj

TJ My original 30 cal FCIII was 2 1/2 years old. This unit was used in a pneumatic press and showed very little wear. Charlie said it was in pretty good shape except it had split down the middle. Probably caused by trying to push out stuck checks with a punch and the stress of the pneumatic press. It is best to drill them out with a small drill bit. Not complaining about the cutter. Charlie even offered me a new one!

[Jeff H]

.......I make no judgments on the effects of this passivation layer in firearms barrels, I leave that for you guys to discuss. I'm just commenting on the metallurgy.

Nor do I but I definitely appreciate your input.

What you describe is what I was trying to say about aluminum - the oxidation referenced in your post, not crusty stuff you can see and feel. It's there. It may be thin and it may be smooth, but it's there and it is hard. It deforms with the soft substrate and may pose no real threat or at least not wear barrel steel any quicker than other things we put through our barrels.

I had not even thought about galvanic reaction until it was mentioned later so that's not what I was talking about either but it did make me wonder about aluminum checks seated in brass cases and left for a long time. I try not to load a lot that will sit around anyway, so it probably wouldn't be an issue for my loads anyway.

I'm not just straddling the fence and trying to stir things up either. My question is not meant to cause panic or to pacify - I simply do not know and am curious. I've seen a lot of good rationale in this thread and have learned a few things. Haven't answered the original question either but figured that out on the first page. In the meantime, this has been a good discussion. There would have been a fight by now on many other forums. Makes me feel good about the virtual company I keep.


Mooseman, I agree with what you are saying and my heritage and my instincts are at home in your logic. As far as "cost," well, as much as I am aware of how we gun and knife folk can be susceptible to trying to justify our choices sometimes, I may be guilty of it from time to time myself. I could have bought 4k Hornady gas checks (back in November) for what I have in my check-maker. If I mentioned "cost," I would have to admit that I was probably rationalizing. I do like to be able to make them myself. Maybe not practical but if I am going to fiddle with an extra component, I should get the pleasure of being able to make it.

[Whiterabbit]

I had not even thought about galvanic reaction until it was mentioned later so that's not what I was talking about either but it did make me wonder about aluminum checks seated in brass cases and left for a long time. I try not to load a lot that will sit around anyway, so it probably wouldn't be an issue for my loads anyway.

galvanic is a red herring. You need a circuit for ANY galvanic corrosion. open circuit, stop corrosion. metal contact is part of the circuit, usually contact with moisture completes it. Whether in water, dirt, or just humid air. That's why coatings prevent rust. The dissimilar metals are still touching but there's no circuit path to finish the corrosion cycle.

In this case, you'd need a dielectric (water) inside the case, where the AL and brass are in contact and exposed to air. Humid air will work too. I'm pretty sure the powder in the case will act as a moisture getter and preserve the anode just fine. Same reason steel or copper or even lead in contact with the brass doesn't have issue either. They are ALL galvanic cells, of differing efficiency. And if an exposed bullet/brass case is not a sufficient galvanic cell to corrode efficiently within 50 years, you'll be fine with aluminum inside the case.

[HollowPoint]

I think that generally speaking, even a life time of shooting aluminum-gas-checked cast bullets out of just about any firearm will equate to the firearm more than likely far out living the shooter; unless the shooter uses that firearm to commit suicide with. In that case, who know what might happen to that gun.

I can see the point on both ends of this topic but the logic of it eludes me. I must be to much of a simpleton.

To me it seems pretty simple. If aluminum gas-checks trigger a concern for you. Don't use them. If thousands of shots have to be fired using them before you start getting signs of wear then, the point is as close to being a mute-point as you can possibly get without it actually being a mute-point.

I use both copper and aluminum home made checks. Unless a guy has the laboratory equipment for definitive testing, the assumptions made on this thread are really only extrapolations based on this, that or the other.

Given enough shots fired, even copper or brass checks will eventually do to your barrel what aluminum is feared to be doing.

HollowPoint