Aluminum Oxide a Problem?

[Jeff H]

Aluminum oxidization is obviously very hard - it's used in abrasive papers for the specific task of wearing down another surface. After all, they make sandpaper out of it, right?

I have always been under the impression that aluminum oxidizes very quickly and forms a thin "protective" coating on itself so assume that about everything aluminum is oxidized by the time I get my hands on it. The point being that the oxidation is there whether it looks crusty or not.

Anodizing, if I understand that correctly, is a form of induced oxididation of aluminum and is known for being extremely hard too. I am not using anodized stock, but just wanted to reinforce the point of my concern that aluminum oxide is very hard.

So, has anyone of metalurgial merit officially poo-poo'd the notion that we are slowly fire-lapping our barrels into smooth-bores using aluminum checks?

Now, I'm not trying to bust anyone's bubble or rain on their parade here, as I have a GC maker myself and have been very pleased with the resulting components and the control I have over size in terms of compatibility with several different moulds. Since I have been messing with them in a .357 Max. rifle, I have the bug to mess with them in a particular .223 Remington that has an affinity for cast bullets as well. .22 GCs are (were?) cheap, but not to be found and I do like having control over the qulity of my components even just that I could have them when I want, even if under siege as it feels we are currently. I just like making my own stuff as much as I can too.

I am hoping to hear that the oxidation on purchased or scrounged stock is not a concern.

[tjones]

My old man a very wise man used to say to me, a little knowledge is dangerous !

[fishhawk]

well lets look at this. Yes alum oxide is hard and used in sand paper but it is fractured alum oxide so there will be sharp corners that will remove material, is a smooth alum oxide on flashing that's used for gas checks abrasive? I haven't seen evidence of it in my usage yet.

[Jeff H]

My old man a very wise man used to say to me, a little knowledge is dangerous !

Ignorance is bliss?


well lets look at this. Yes alum oxide is hard and used in sand paper but it is fractured alum oxide so there will be sharp corners that will remove material, is a smooth alum oxide on flashing that's used for gas checks abrasive? I haven't seen evidence of it in my usage yet.

Good point and yes, it's smooth but still hard, which is what I wonder about. I know it doesn't feel abrasive but neither does a ceramic sharpener. It may well be absolutely no concern whatever but I wanted to get others' perspective. How much shooting have you done with the alunimum checks? I just started recently and have only aout a hundred of them through a bore that might actually benefit from some controlled abrasion - so I have not seen any signs and wouldn't expect to at this point.

Thanks for the replies.

[Heavy lead]

It may be hard, but with the very thin layer of hard aluminum oxide covering a very soft metal, both in the form of aluminum and lead I cannot see the harm.
That is a completely unscientific observation FWIW.

[tjones]

I'd bet your couldn't file your fingernails faster than they'd grow with the microscopic film of oxide.

[Jeff H]

It may be hard, but with the very thin layer of hard aluminum oxide covering a very soft metal, both in the form of aluminum and lead I cannot see the harm.
That is a completely unscientific observation FWIW.

Well, that's where I'm at on this myself. Seems ok based on my unscientific observations, but are we rationalizing? I'm on board with everyone else's thoughts but just don't know if I am correct in my thinking.


I'd bet your couldn't file your fingernails faster than they'd grow with the microscopic film of oxide.

Agreed. The smoothness of the oxide and the resilience of our nails - might take a while. Still, I couldn't possibly file my nails at 2000 fps. Again, what I am hearing is making sense but based on my own limited knowledge.

[Mooseman]

I have tried to point this out many times in discussions about Aluminum. As a Machinist /Gunsmith and someone who has worked with metals for 40 years I will never put an Aluminum gas check down one of my barrels. As has been stated, Aluminum Oxide forms almost immediately on any aluminum surface and it is what stops aluminum from corroding. It is abrasive , and aluminum oxide will cut hard steel and cut it fast. I use plain aluminum rods to sharpen the hardest Ka-Bar knives by using them like a sharpening steel. It will put a razor edge on a knife. Try it for yourself on an old Aluminum cleaning rod or piece of aluminum tubing.If you cut Aluminum foil with scissors it will sharpen them (google it if ya dont believe me). In our machine shop, we used aluminum bars to hone sharpen hard tooling cutters.
Anodized aluminum has the oxide crystals grown larger and hardened like corundum giving it an even more abrasive surface. Aluminum foil which is about as pure as you can get,has been used for removing rust from chrome bumpers for years , and I have used it to lap barrels with many times, as well as other applications needing a fine abrasive surface.
Getting back to Gas checks, you have several things to consider, not only the Abrasive oxide, but the residue in the barrel combining with the soft aluminum surface under pressure will wear rifling. Another consideration is the contact of Aluminum with brass (which is copper and zinc)
in loaded ammo as it forms an electrolysis between the 2 dissimilar metals, and add to that the acidic environment of gunpowder and over time you are asking for trouble with corrosion , metal Ion transfer, and possible bonding of the Aluminum to the brass case wall. It is one reason why Aluminum is never used against copper in any application.
Extensive Lab tests were done rubbing a steel rod on Aluminum roofing panels and it was determined that the 2 metals would transfer back and forth between themselves and cause wear to both surfaces and they were then photographed with electron microscopes to determine wear patterns and how oxides formed and reformed.
All this Information is out there including tests of hard cutters NASA did for machining parts for The Aerospace program and how some HSS cutters were useless with certain coatings as the Aluminum bonded to them during use, similar to what can happen shooting aluminum down a barrel at high speed.
Ask yourselves this...Why doesnt Hornady or Lyman etc. make AL checks since its cheaper than Copper ? Why are there no Aluminum jacketed bullets ?
Its Has nothing to do with the softness of the material and everything to do with the Abrasive nature of The Oxide as well as how it may react loaded in Brass cased ammo.
Rich

[Jim]

..... Why are there no Aluminum jacketed bullets ?.....


There ARE aluminum jacketed bullets. I dug quite a few of them out of a berm last year when I was cleaning a pistol range.

http://www.ncbi.nlm.nih.gov/pubmed/7114018

[tjones]

Now I know why airplanes can cut though the air so nicely

[Sasquatch-1]

in loaded ammo as it forms an electrolysis between the 2 dissimilar metals, and add to that the acidic environment of gunpowder and over time you are asking for trouble with corrosion , metal Ion transfer, and possible bonding of the Aluminum to the brass case wall. It is one reason why Aluminum is never used against copper in any application. Rich

I am not a machinist nor am I a metallurgist (sp) But I do have one observation to bring up about the above statement. Wth the Blazer aluminum case ammo, why is there not a problem with storing this? You have either a lead bullet or copper jacket touching the aluminum case. I have NO scientific background to fall back on and I am just putting the question out there.

I do not shoot aluminum through my guns but have heard that with the gas check you have a film of lube being laid down prior to the aluminum going down the barrel.

[fishhawk]

The only way this will be decided is with 2 brand new rifles same make same model figure out some way to measure the barrel bore of each and then fire 5000 rounds of each alum and copper gas checks down the barrel then take the measurements again.

[dancingbear41]

There ARE aluminum jacketed bullets. I dug quite a few of them out of a berm last year when I was cleaning a pistol range.

http://www.ncbi.nlm.nih.gov/pubmed/7114018

I still have a number of boxes of Winchester Silvertip. I am going to have to access this article as well! Thanks.

[tjones]

I've cleaned many machine gun barrels, seen cutaways too. Some even had riflings left but generally the first six inches were history.
Anyway it wasn't oxides of anything that blew them away. Just plain old hot gases.

[Hogdaddy]

The only way this will be decided is with 2 brand new rifles same make same model figure out some way to measure the barrel bore of each and then fire 5000 rounds of each alum and copper gas checks down the barrel then take the measurements again.

I'm up for the research, Just Need equipment ; ) :kidding:

H/D

[Case Stuffer]

Every material in the world is abrasive ,period! There is however a great deal of difference in the levels of abrasion and ofcourse the force(s_ applied have a rather large effect also.


Years ago I manufactured a product and during one of the operitions I used a mechanical counter and triped it with my trigger finger. This counter had an aluminum arm on it and within a matter of a few weeks the wear on it was very obvious.

Post # 12 and 14 are both correct,IMO.

I fully realize that movies are not real but I still cringe when someone empties a clip of 20-30 full auto ,reloads and repeats. In the first place what a waste of ammo and second place now barrel is damaged and is only good for Spray & Pray. As I said I know movies are not real and firearms shooting blanks with placed controlled explosives used to show bullet impact but guess what U-tubers do the same thing with their personal firearms.

[ubetcha]

I am not a machinist nor am I a metallurgist (sp) But I do have one observation to bring up about the above statement. Wth the Blazer aluminum case ammo, why is there not a problem with storing this? You have either a lead bullet or copper jacket touching the aluminum case. I have NO scientific background to fall back on and I am just putting the question out there.

I do not shoot aluminum through my guns but have heard that with the gas check you have a film of lube being laid down prior to the aluminum going down the barrel.

I was going to ask the same question.During the lubing and/sizing procedure,there should be a thin layer of lube on the bullet and gas check,providing the check is not wiped clean of course.Should'nt this provide some protection between the brass case and the bullet and with the lube layer on the bore provide some protection for excessive wear? Even if a sharpening steel or sandpaper become clogged up with oil or grease or sanding debris,doesn't that greatly reduce it cutting ability?I'm asking these questions because I don't have an answer

[Jeff H]

OK, definitely some serious thought going into this and all of it seems well founded. How do we test what we (presumably rational beings) are not mistaking conjecture for what we believe to be common sense? I am not trying to discredit anyone's ideas, rather I tend to question my own thinking until I can satisfy myself that I am on the right track - and I AM thinking along the lines of both perspectives presented here.

Mooseman, I particularly appreicate your effort here. That took some time and I am certain you knew you would be compelled to explain some of it, but we'd never get anywhere on anything if everyone had the exact same ideas. Several things I hadn't thought of myself too, like why don't manufacturers make aluminum checks? Dissimilar metals - I have seen instances where there were supposed to be issues but weren't and then where the issues were real but unexpected. I suppose some of that may have to do with conditions.

Aluminum bullets? Yes, this was one of my first rationalizations - Winchester Silvertips. But, I have learned that just because someone makes something doen't mean it's all good, but then again, they have been making these for a long time. I have never heard even a question raised about these and I while live down a dirt lane, I don't live in a cave. That's a single example. Maybe something to hang our hat on, maybe not. Dissimilar metals between aluminum and steel is real. Carpenters hanging gutters and installing aluminum trim see the results. Brass and aluminum? That's one I had never considered but then there's the Blazer ammo thing. On the other hand, how many times have we done something for decades only to find out it was not necessarily ideal? Never mind the Chicken Little Syndrome, there are real examples.

HD, your a every generous to volunteer your time so readily. I might be able to save you some time though. I am shooting the .357 Max. in a H&R Handi Rifle with aluminum checks. The greatest danger I face with that is that I may end up with a smoother, shinier bore, and I will be watching it. So far, I have shot only a handful of RDO 190s at moderate (for the Max.) velocities and the only observation I can share is that after firing twenty rounds I ran a brush through it. I got a significant puff of "dust" out the end when the brush cleared the muzzle. No lead, no chunks, in fact, the bore looked quite good, just a little dull until I brushed it. Ten strokes, ten puffs. Not something I have observed before. Swabbed it with some Break Free and set it muzzle down to await the next opportunity to shoot.

I certainly appreciate the patience on this one. Maybe, as at least one has implied, the energy put into the thought is not necessarily terribly well spent. I'm open to that too but still want to know. Anyone or everyone could be absolutely correct in this matter.

[Jeff H]

I was going to ask the same question.During the lubing and/sizing procedure,there should be a thin layer of lube on the bullet and gas check,providing the check is not wiped clean of course.Should'nt this provide some protection between the brass case and the bullet and with the lube layer on the bore provide some protection for excessive wear? Even if a sharpening steel or sandpaper become clogged up with oil or grease or sanding debris,doesn't that greatly reduce it cutting ability?I'm asking these questions because I don't have an answer

I wondered about that too. The bullets I am shooting now are tumble-lubed. The ones I have just prep'd are conventionally lubed, but I wiped the bases free of lube. I am sure I didn't get it all off, so maybe.....

There have been mild steel jackets in the past too. I have never looked into that too much but wondered if there was any accelerated wear because of them. Probably, but enough to make a significant difference - I don't know. I believe they would have been softer than the barrel steel - but barrels arent particularly hard either.

As far as using two fresh rifles, I agree, but time and funding probably rules many of us out as participants. Disinterest will likely knock many out of the running as well. After all, if it's working, why worry? It's strictly a point of curiosity for me, for one thing, but I also want to make sure I am not screwing something up. Again, the worst I could do is make a less than perfect-looking bore look a little better and should be able to see that. Even if that happens, the process may be self-limiting and actually beneficial.

I will be shooting another H&R with aluminum checks as soon as I can swing another check-maker. I will keep an eye on both. I certainly don't want to make anyone uncomfortable about using them and don't want to ruin the fun and gratification of making our own stuff, after all, I'm invested in the concept myself. The .008" GCs I made yesterday look fantastic and fit two moulds pefectly, so I am excited about using them. I have never liked using GCs in the past and have nly "needed" them on a few revolvers which are history now anyway. Once I started shooting cast in rifles, things changed a bit and GCs made more sense, so I can't just avoid them anymore.

Again, I certainly appreciate the patience on this question. It would be easy to get defensive about it or consider it a waste of time when there don't seem to be bore exhibiting scary symptoms. This is one of the few

[Jim]

Here is a METALS GALVANIC COMPATIBILITY CHART (http://www.leadertechinc.com/PDFs/enclosure-shielding-solutions-11/galvanic-potential-diff.pdf) that shows the values of dielectric reactions between various dissimilar metals.

[fishhawk]

what may be possible for the 2 gun test may be a handi-rifle with 2 of the same barrels (308?) but either way it would be a long drawn out test. another thing that may be a influence could be velocity pushing a 31141 out of a .308 with 10-11 gr of reddot may do nothing but a charge of 40 gr of BLC2 may be a whole different problem if you got the velocity up to the 2000 fps range. so there's another thing to consider

[tjones]

WOW! What the chart shows is that in galvanic reactions with iron and aluminum is about ten time less than that of copper or brass.

WHAT A FIND, GREAT RESEARCH. tj

[Jeff H]

Here is a METALS GALVANIC COMPATIBILITY CHART (http://www.leadertechinc.com/PDFs/enclosure-shielding-solutions-11/galvanic-potential-diff.pdf) that shows the values of dielectric reactions between various dissimilar metals.

Thanks, Jim.
As an engineer and project manager for an OEM, I have had customers claim that galvanic reaction was causing percieved problems where it might have been a problem had it not been for the conditions under which two dissimilar metals were in contact. As a carpenter, I have removed mix-n-match aluminim gutters with steel fittings and fasteners where the crust tha formed looked as if it could grow legs and crawl away. Depending on the conditions and evironments, I have seen either no affect or extreme affects but have never been smart enough to figure out which conditions contributed positively or negatively either way.



what may be possible for the 2 gun test may be a handi-rifle with 2 of the same barrels (308?) but either way it would be a long drawn out test. another thing that may be a influence could be velocity pushing a 31141 out of a .308 with 10-11 gr of reddot may do nothing but a charge of 40 gr of BLC2 may be a whole different problem if you got the velocity up to the 2000 fps range. so there's another thing to consider


Exactly! And exactly what I had hoped to not have to do. Someone out there must already know what the results will be - whether that someone is among us is still in question. We percieve as we make our own observations and it seems none of us has actually percieved any startling evidence. We hypothesize based on our prior knowledge and act according to good judgement. Neither is anything approaching superstition but neither is as definitive as the test you suggest - which would be the only way to nail it down for sure, unless someone else has done it - within the context of firearms or another set of similar conditions.

I am not up for the test myself. I don't see yet anything that scares me enough to make me feel it is necessary for the level of curiosity or concern among us collectively. I am certain I have not used enough of them to date to notice anything significant and may never, but I am sure there are many here who shoot much more than I. My shooting/reloading/casting habits have evolved from being measured in thousands of rounds to tens of rounds and when I see something new, I enjoy the collective wisdom of those here who are contributing more to the cause by expending more of their time and ammunition. Certainly, the varying perspectives and experiences are a wonderful resource.

In the meantime, it seems many experienced people see no issue but some have expressed seemingly valid reservations. I'll watch the two I am using and see how things go. Not the most perfect test, but if it affects what I am actually using then it concerns me most, so that's probably the "best" test for what I am seeking to achieve even if it's not the "best" test all-'round. Not to seem selfish, but there are those who would benefit from knowing what higher pressures or velocities would yield and I am not running terribly high pressures on anything so my experience may not be very useful to others in the long run. Actually, the whole point in having the .357 Max. is not to run it "at max.," but to better .357 Mag. ballistics somewhat (the barrel length does a lot of that work for me) and extend my range somewhat. The point behind the .223 is to not startle my rural neighbors (and I dislike noise myself) when I have a pest to deal with which is just out of reach of the effective range of my .22 LR.

[Jeff H]

WOW! What the chart shows is that in galvanic reactions with iron and aluminum is about ten time less than that of copper or brass.

WHAT A FIND, GREAT RESEARCH. tj


Hmmm, so, if there are aluminum deposits left in our bores after firing, maybe it's not as bad as aluminum gutter/trim with steel nails?

Oh, man, this is infectious.

Aluminum GCs sitting in brass cases for a long time,.....

Blazer ammo with aluminum cases/copper jackets,.....

The two seem to contradict, but the ammo-makers may know things we don't.



OK, I may be making a mountain out of a mole hill on the aluminum oxide thing, so I will leave this one alone. I will defer to post #2 before I drag everyone into another adventure. It's intriguing but I have burdened everyone enough with my original inquiry. Everyone's contributions are greatly appreciated. Hopefully, the ultimate result will be WHY it's OK to do what we're doing.


tjones, easy there, buddy. Remember what you said......;-)


The only thing that would make such discussion better would be the setting; at the tailgates of a couple trucks at the back edge of a long lane while comparing targets and deciding which load to try next.

[Mooseman]

There ARE aluminum jacketed bullets. I dug quite a few of them out of a berm last year when I was cleaning a pistol range.

http://www.ncbi.nlm.nih.gov/pubmed/7114018

If you look at Winchester silvertip bullets you will notice the silvertip cover on the lead is at the front of the ogive and does not ride the bore when fired. Some bullets that resemble aluminum such as Aguila ICQ are actually a zinc alloy , which is neutral as far as abrasive oxidation or Galvanic action.

Another thing to consider.. ask any longtime gunsmith about 22 rifles that were cleaned with the cheap aluminum rods and how the end of the barrel and crowns are badly worn because nobody used a bore guide. It was combined Al-Oxide , and powder residue that caused the wear using those rods.

Like I said previously...test it yourself by sharpening your toughest steel knife on an aluminum rod used like a crockstick and then get back to me.

[Jeff H]

If you look at Winchester silvertip bullets you will notice the silvertip cover on the lead is at the front of the ogive and does not ride the bore when fired. Some bullets that resemble aluminum such as Aguila ICQ are actually a zinc alloy , which is neutral as far as abrasive oxidation or Galvanic action.


Yes, the rifle Silvertips are as you describe but the pistol bullets don't look like they adhere to that model.

I have a box of .257 Roberts Silvertips I have been holding onto for some time and the TIP is aluminum-colored but the rest of the jacket is like a "normal" jacket. Been meaning to chronograph those for something like 20, maybe 25 years now.

The Silvertipped pistol bullets do not look like that and I always assumed they were aluminum all the way to the base. I have never shot, let alone recovered one, so I don't know for sure.

You also mentioned something about a 2kfps threshold too. I have seen references to keeping things under that velocity with aluminum checks. I have no idea what the difference would be personally because I haven't run mine that fast. I suppose that Winchester might have been onto that if they really made the pistol bullets with a completely aluminum jacket and the rifle rounds only partially so.

Speculation on my part which neither supports or denies any other ideas stated so far.

[Mooseman]

The Silvertip® uses unique jacket materials custom tailored for specific calibers in the line to assure maximum performance. There are actually two different jacket materials used, one for the high velocity calibers, like 357 Magnum and one for the low velocity calibers like 38 Special. This enables Winchester to custom tailor performance for each caliber and ensure rapid energy deposit.
I believe they are Nickel / nickel alloy...Not Aluminum.
Rich

[Jeff H]

..........I believe they are Nickel / nickel alloy...Not Aluminum.
Rich


Hmmmm, no acquital through that avenue then.


I should have thought to look that up.

[fishhawk]

Well like I said before this will not be settled until some one some how can do a definitive test with measurements that can be duplicated that's the way I see it.

[Jeff H]

Well like I said before this will not be settled until some one some how can do a definitive test with measurements that can be duplicated that's the way I see it.


No argument there.

I was hoping someone knew of something that had already been done or that there was some other scientific evidence (either way)someone knew of.

In the meantime, I see nothing to disuade me from their use - just curious.


Thanks for entertaining my query, all.

[fcvan]

The plain based checks I make from soda can are made with the inside of the can facing out. There is a coating on the can to keep soda and beer from reacting with the fluid. Also, I have purposely made some checks and left them out to see if they oxidize. Under magnification I cannot discern any such oxidization. I also have seated and lubed some checks and let them sit for over 6 months. Under magnification, I still cannot detect any oxidization.

The checks I make from aluminum flashing also have not shown any oxidization. True, aluminum oxide makes great sandpaper abrasive. Untreated/coated aluminum will oxidize. The material I use is treated, is not oxidized, gets covered with boolit lube when seating, and has not shown any oxidization. Untreated aluminum will oxidize. Flashing material and soda can material is treated to prevent oxidization. Slapping some lube on them also treats the aluminum. I'm going to keep using aluminum checks because I make them and are pleased with their performance.

[Mooseman]

It takes a scanning Electron Microscope to see the Oxide...http://iris.lib.neu.edu/cgi/viewcontent.cgi?article=1656&context=physics_fac_pubs

Your aluminum can material is coated with a micro layer of plastic/epoxy resin , but the oxide is still under that on the surface of the raw aluminum, and pressing out checks with a punch scrapes that surface coating...
http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1080&context=grcsp

[fcvan]

Mooseman, thanks for the links. I found them to be interesting reading. I'm not seeing the coating coming off of the soda can material, nor am I seeing appreciable wear in the check forming dies or in my sizing dies. I will certainly keep a look out for increased wear on these and on my barrels. Time will tell and I will keep the micrometer handy.

[Jeff H]

..........I still cannot detect any oxidization............have not shown any oxidization......., is not oxidized,...........and has not shown any oxidization. Untreated aluminum will oxidize...........treated to prevent oxidization............I'm going to keep using aluminum checks because I make them and are pleased with their performance.

Not the crusty stuff we can see and feel but the microscopic oxidation that forms almost immediately on freshly exposed (machined) aluminum and prevents or slows down the kind of oxidation/corrosion we can see and feel (the crusty stuff). Unless the material you are referencing is processed in a special atmosphere (possible), it would have the oxidation I am talking about even under the coatings you are talking about (also possible). This oxidation is not considered a nuisance typically, rather a benefit in most cases.

This is on our pots and pans utensils, etc. and forms a protective barrier - what Mooseman is referencing using a microscope to see. It's not terribly apparent that it is hard (or even there) because the substrate that supports it (the aluminum) is soft and gives way under the thin, thin layer in the form of dents.

I don't plan on not using mine either and do not intend to deter anyone else. My original curiosity was whether anyone knew of proof that it does no harm much more than it was about whether or not we should be using them.

I'm using them. I'm on board with others' opinions that it seems to be ok, but I also can appreciate Mooseman's points and will definitely keep them in the back of my mind.

[tjones]

The green growing crusty "brass oxide" is better ?

[Jeff H]

The green growing crusty "brass oxide" is better ?

No, of course not. I'm differentiating between the oxide we can't see and which is on most things aluminum as opposed to oxidation/corrosion that is very obvious to our senses - like "green growing crusty" stuff on brass, which we can see and feel. In other words, the oxidation I am talking about versus the "crusty stuff" would be like the bluing on a steel rifle versus plain ol' rust. Not a perfect example but similar in terms of one looking "ok" and the other very obviously not.

[Mooseman]

Oxides have different properties...and Brass / copper oxide is not considered to be an abrasive like aluminum oxide is.

[tjones]

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

[Ajax]

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

[Sasquatch-1]

Here is an alternate way of checking this. If anyone here shoots a steady diet of Blazer aluminum case ammo through a semi auto it should cause the same effect shouldn't it? Measure the chamber and after about 6 months of a steady diet of these if there is an effect there should be some chamber wear.

As stated before this is from a very unscientific and unknowledgeable person.

[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. :shock:

[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

[Jeff H]

........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.........HollowPoint

It's not so much a concern as a point of curiosty for me.

It just may be a moot point - its debatability is obviously proven by the discussion that has occurred so far and while each of the contibutors may have started with certain opinions and perspectives, sharing them and considering others' in the process has probably led some to alternate assumptions and some of us full circle.

I personally was not aware that so many rounds of GCs were being used myself but contributions of such accounts in this thread have led me to be open to assumptions other than those with which I started. It may seem simple after reviewing all the comments, but I think all the comments contribute to somewhat greater clarity on others' positions. Before this discussion, I had my own assumptions to work from. I have gained a lot of insight from the discussion myself.

[tjones]

Well said. Assume, well taken apart is *** out of you and me. Assume! Tests are the answer! -tj

[mold maker]

So now we need to worry, about the passivated layer in our bore, cutting the AO2 off our Alu checks????
Until there is PROOF of Alu checks damaging bores, as in destroyed or at least measured wear, of a number of tested barrels, it's all conjecture. Even a 1-1 test proves absolutely nothing, as a fluke in the results on either, ascues the results.

[Jeff H]

So now we need to worry, about the passivated layer in our bore, cutting the AO2 off our Alu checks????
Until there is PROOF of Alu checks damaging bores, as in destroyed or at least measured wear, of a number of tested barrels, it's all conjecture. Even a 1-1 test proves absolutely nothing, as a fluke in the results on either, ascues the results.

I believe that everyone who has contributed to the discusson so far recognizes that this has pretty much all been conjecture. That seems to have been established but the reminder is appreciated.

I believe that in my original post I merely asked if proof existed. I am not demanding proof of anything, no one is obligated to provide it and I am not disappointed that no one has. However, I do value and appreciate the opinions and facts that have been offered throughout the discussion and particularly value the respectful way in which they have been issued and recieved.

There was no original assertion which anyone should have felt obliged to prove or disprove. A question was asked and opinions were provided. No one who offered an assertion or opinion has attempted to convince anyone else that it is proof. Some provided interesting facts.

No one need worry or not worry if they didn't already before this thread started.

[Bwana]

There ARE aluminum jacketed bullets. I dug quite a few of them out of a berm last year when I was cleaning a pistol range.

http://www.ncbi.nlm.nih.gov/pubmed/7114018

Yes there are, it's just that they haven't been produced in numerous years. If you would look at the date on referenced article you would notice the date 1982. Back then Winchester made "silvertip" handgun ammo for 32acp, 380acp, 9mm, 38/357, 44spl, and 45acp, and 45colt. They had aluminum jackets with a groove that had lube it in. A search for prior discussion would have turned all this info up.

[Treeman]

Interesting discussion. I used to worry about this sort of thing.....but as I studied things I got a lot less concerned. Most barrel erosion is caused by hot GASES at high pressures. The second most damaging wear is traceable to poor cleaning practices. Abrasive effect from jacket materials of gas checks? Every shot deposits carbon from powder combustion-an abrasive. One of the ingredients in primers is GROUND GLASS. Shattered silicon crystals are an abrasive for sure.....but how fast do barrels wear out? Depends on the caliber and usage but worst offenders are ultra high velocity cartridges that burn handfuls of powder and the wear is clearly NOT caused by the passage of bullets with oxidation layers or carbon particles and glass particles getting ironed into them from the previous shots. The ruinous wear is gas erosion just in front of the chambers. Even the high wear arms last for many times their initial cost in ammunition costs. Shooting cast bullets at the typically lower pressures we spend many, many times the cost of the firearm in ammo before wearing out a barrel let alone the entire gun..... I don't want to wear out my precious guns yet I wish that I could be so fortunate as to wear one out shooting it. Most of mine will survive me and the new owners are going to marvel at how "new" they all seem.

[mold maker]

No intention to offend, but this subject has used a ton of ink, to no avail. No extensive tests have been reported that would clearly ID a problem. Conjecture does little to further anything but more conjecture.
Yes I have polished many gemstones with AlO2. It does cut to a tiny extent, but it is a tiny flat surface, held solidly against a soft lap with either a slurry of AlO2 compound, or the AlO2 impregnated into it's surface. It doesn't happen in a nano second, nor without pressure applied.
If the Alu gas checks do anything, they will improve (conjecture) the bore surface after many thousands are used. The benefit of a gas check on a lead boolit, isn't conjecture.
The Alu check does the same thing a copper or brass one does, only much cheaper, and in some cases better.

[Jeff H]

No intention to offend, but this subject has used a ton of ink, to no avail........


Well, a ton of pixels, maybe.;-)


Cheaper is one thing - HAVING is quite another. I punched out a couple hundred today in short order. Didn't have to wait until I had enough of an order to make shipping costs worthwhile, didn't have to wait for them to be delivered, didn't have to grumble about no one having them in stock..... That's really pretty cool.

[seppos]

I will have to test the aluminium as gascheck instead of copper.. Not that it mather in weight of the bullet.

S