Aluminum gas checks

[dddddmorgan]

Can you use the aluminum gas checks the same as the copper?

I want to order some from Sage and they're out of copper but have aluminum.

[bimus]

I have had no problems with sage aluminum gas checks mostly used on 30carbine.

[pworley1]

I have not noticed any difference except the price.

[MUSTANG]

Have not used a copper gas check for about 20 years now. Only problem I ever had is when seating a cast boolit base below the neck and trying to break down a loaded round with Impact Boolit Puller; a couple of times the Gas Check pulled loose and remained in the neck (pulled by drilling a hole, inserting screw ad pulling gas check with liters).

[FrontSite]

Have not used a copper gas check for about 20 years now. Only problem I ever had is when seating a cast boolit base below the neck and trying to break down a loaded round with Impact Boolit Puller; a couple of times the Gas Check pulled loose and remained in the neck (pulled by drilling a hole, inserting screw ad pulling gas check with liters).

I notice the same thing (gas check staying in the cartridge). I use a shortened bicycle spoke to punch the check sideways, grasp it with a 6" forceps and tug it free of the case. i didn't like the drilling part as i had metal bits in the salvaged powder.
Try it see if it works for you.

[FelixTheCat]

I would be wary of using aluminium in a projectile. Aluminium may be soft, but the oxide layer that inevitably forms over the metal is very hard indeed. Aluminium oxide is a main ingredient in many abrasives.
I know the wear rate in the chambers of aircraft cannons from using aluminium cartridge cases is significant. The weight saving is however great enough to justify the expense of having to change barrels regularly. (... and the airforce has Deeep pockets!)

[MUSTANG]

I would be wary of using aluminium in a projectile. Aluminium may be soft, but the oxide layer that inevitably forms over the metal is very hard indeed. Aluminium oxide is a main ingredient in many abrasives.
I know the wear rate in the chambers of aircraft cannons from using aluminium cartridge cases is significant. The weight saving is however great enough to justify the expense of having to change barrels regularly. (... and the airforce has Deeep pockets!)

FelixTheCat:

I encourage you to review the many posts and pages on the use of Gas Checks made from aluminum. The concerns you postulate HAVE NOT proven to be issues for myself and many, many others. I have fired many thousands of rounds through my Remington 700 in 308 Winchester with velocities of 1700 to 2200 FPS using Aluminum Gas checks and there is no visual affects to the barrel - nor, has there been any detriment to the accuracy potential of the Rifle.

It would be interesting to hear more information on your reference to wear rate on the aircraft cannon (Chambers you mentioned). If it is the Chambers as you cited; this would indicate an Aluminum cased cartridge (20mm or 30mm?); & the case being the wearing point in the chambers you cite - not the barrel/s of the Gun.

[longbow]

While it is true that aluminum oxide is abrasive, the layer forming on a gas check is very, very thin and fine, not like aluminum abrasives. Also, in most cases the gas check is put onto the base of the boolit then is run through a sizer/luber so the surface is being scraped in the sizer and lube is being put over it. I wouldn't claim that removes all the aluminum oxide and I also can't say I have shot enough aluminum gas checks to show any wear difference between aluminum and copper.

I have read warnings about the abrasiveness of aluminum gas checks for many years but I have as yet to experience, or read of anyone who has experienced, noticable barrel wear from them.

but I am with Mustang, I do not believe it is a problem but to each their own.

YMMV

Longbow

[405grain]

I make 30 caliber aluminum gas checks from Ace Hardware flashing using a Pat marlin's check maker. Since I'm powder coating the bullets anyway, I just PC over the gas checks, and if there were a problem with an oxide coat (which there really isn't) that would negate it.

[gloob]

Well, if you want to worry over nothing, you could also be think about what color PC to use. Finely ground metal oxides are used to add many of the colors, and some of them are harder than barrel steel.

[TurnipEaterDown]

I suspect that any abrasion concern by the aluminum oxide particles is negated by their size -- nano meter range (one source states atmospherically oxidized particles are ~ 4nm). So small that the effect on a firearm bore would have to accumulate over a long time to discern, and very easily "lost" in the lubricant film thickness of either the bullet lube or the paint (powder coat) barrier commonly used with a cast bullet.
eg. Yes, abrasive as a particle, unlikely to effectively abrade the bore due to characteristics of the system. Nano-meter --> 1/1000 th of a millimeter. Millimeter is ~ 0.004 inch, so these particles are on the order 0.000016 inch.

[JonB_in_Glencoe]

Most aluminum used to make GC's has a coating...like lithograph plate.

[elmacgyver0]

I will most likely be dead before aluminum gas checks wear out my barrels, then I won't care anymore.
Nuff said???

[2TM101]

I will most likely be dead before aluminum gas checks wear out my barrels, then I won't care anymore. Nuff said???

Anyone make these out of regular soda cans? I make percussion caps that way. I don't see how the thinner aluminum would degrade the performance any.

[Ben]

Might be a real good idea to read about using aluminum to make your own gas checks. I think you'll quickly see that pop can thickness aluminum is useless for making gas checks. It has some limited use for making plain base bullet gas checks.

[MUSTANG]

Anyone make these out of regular soda cans? I make percussion caps that way. I don't see how the thinner aluminum would degrade the performance any.

I have been using the Amerimax Aluminum Flashing that is 0.014" Thick. (4 inch x 50 foot roll). Have used it for at least 10 years on dozens of different .30, .224, and 7mm cast boolit designs successfully. The 0.014 seems to be the ideal thickness for making checks in these calibers (my experience). Keep in mind one will want 0.014 inch thick material (Amerimax Mfr #68104).

Ace Hardware carries it: https://www.acehardware.com/departme...lashings/58012

Amazon also carries: https://www.amazon.com/FLASHING-ALUM...s%2C382&sr=8-3

[TurnipEaterDown]

Most aluminum used to make GC's has a coating...like lithograph plate.

The oxidation will be there before the coating is ever applied. Aluminum oxidizes to a protective film in milliseconds when exposed to air. As a friend who has worked w/ aluminum in forgings and castings for for mass produced parts over decades told me: you have never seen aluminum that wasn't oxidized.

Under the coating, and nowhere as large as the coating thickness. Probably never touches the bore.

[gloob]

I have been using the Amerimax Aluminum Flashing that is 0.014" Thick. (4 inch x 50 foot roll). Have used it for at least 10 years on dozens of different .30, .224, and 7mm cast boolit designs successfully. The 0.014 seems to be the ideal thickness for making checks in these calibers (my experience). Keep in mind one will want 0.014 inch thick material (Amerimax Mfr #68104).

Ace Hardware carries it: https://www.acehardware.com/departme...lashings/58012

Amazon also carries: https://www.amazon.com/FLASHING-ALUM...s%2C382&sr=8-3

14 should be perfect for 30 cal. 224 gas checks are supposed to be 8-9 thousandths. That's what my Hornady checks measure. But 13-14 thousandths will fit on there pretty good, too.

There's a sticky at the top of this subforum. It shows shank size for common calibers. If you subtract the shank size from sized bullet OD, divide that by two, then add 2-3 thous, you'll get nominal gas check material thickness. But of course, your own mold, gas check die, and sizer die might work as good or better with a non-standard thickness.

Roof flashing can be had in 0.008-9, as well. This is what I use for 223 checks. The 14 thous stuff probably works better, but they don't go on as easily, requiring some time and fiddling to force them on all the way, with my mold. With the 8 thous material, I can crank out boolits.

Going by the shank sizes, 7mm bullet checks should be 20 thous thick! 14 thous doesn't even make up the difference between OD and shank size, leaving 3 thousandths of gap all the way around. 14 thous checks surely work much better than nothing, but not as good as they should.

30 cal, (308-284)/2 = 12, plus 2 = 14 thous
7mm, (284-250)/2 = 17, plus 3 = 20 thous
277, (277-253)/2 = 12, plus 2 = 14 thous
6.5, 8 thous
223, 8 thous

It's a bit curious that 7mm uses such a thicker check than the larger 30 cal. I wonder if cast bullet velocities are generally a bit higher with 7mm vs 30 cal or 277 (277 seems to also use the same check thickness as 30 cal).

Just measured one of my Hornady 7mm checks, and it's 20 thous on the nose. They fit my boolits like a glove.

I believe 17 thousandths is another common gas check thickness. Not sure if there are any others. 8, 14, 17, 20.

[2TM101]

At the moment I have no bullet molds for gas check bullets so I can't use regular ones.

I had never heard of a plain base gas check until you mentioned it, but now I am very interested in making and using those

[gwpercle]

At the moment I have no bullet molds for gas check bullets so I can't use regular ones.

I had never heard of a plain base gas check until you mentioned it, but now I am very interested in making and using those

Sage's Outdoors sells the Plain Base Gas Checks made to go onto plain base boolits , on their website are instructions and tips for getting them attached proberly to the base of a bullet ... there are some tricks to getting it done correctly .
www.sagesoutdoors.com
Check them out !
Gary