Just thinking

[pipehand]

What is the minimum thickness required for an Aluminum gas check to perform? Before you answer, I'm not talking about whether it would crimp onto a shank set up for Hornady checks. If, for instance, using .005" beer can aluminum checks installed on a gas check shank that was just .010" smaller than the ideal bullet size, would it work? I've seen the posts about the PB versions of Pat Marlin's checkmaker dies and the concept seems to work. Would it require a larger forming punch to make it work? I'm thinking of opening up the gc area on a Lee mould first before I screw up more expensive, and proven moulds that I already have.
Next question: I'veseen mention of annealing aluminum for use as checks, but no mention of the process. Does it anneal like steel, or like brass?

[ReloaderFred]

I'll leave the first part of your question to those who have more experience with aluminum gas checks than I do, since mine is limited to using copper.

As to annealing aluminum, it's not like either steel or brass. Aluminum will melt before it glows, so it has to be done carefully. I've annealed aluminum strips by holding them over a low propane torch flame and just watching for it to start to turn color on the end. Then I move it rather slowly through the flame and watch the surface of the aluminum to see if it's changing at all. "Slowly" is a relative term, since if you go too slow, the aluminum melts, especially if you stop the movement. I was doing 1/2" wide strips of .009" aluminum, and I had to keep it moving through the flame or it drooped like wet noodles. For me, it was a trial and error thing, but I was able to make it work.

I'm sure there is a way to do it in an oven, or something similar, but this was the expedient way for me to do it at the time.

Hope this helps.

Fred

[beagle]

I've experimented with leaving aluminum strips on a kerosene heater for awhile and one batch worked. I seem to get interrupted before I can do a big batch.

Now, aircraft sheet aluminum comes in 0 temper and about any thickness but you may have to look for it.

I'll be watching this thread as I'd like to know how to do it as well./beagle

[1_Ogre]

pipehand:
First you have to know what caliber you are going to gas check. On 35 Cal (38/357) .008" gives a loose fit after putting the gas check on and sizing. I have found that .010" works real good. On 44 and 45's, use .014".

[pipehand]

Not really, Lead. Instead of fitting metal thickness to an existing shank , for example, the .284 shank of most 30 cals, I was thinking of making the shank fit the gas check thickness. Should only need a proper sized reamer to modify stock moulds, or a full custom when ordering a new one. Maybe I should rephrase my question. Is a .005" thick aluminum gas check going to do what a .016" thick copper gas check does, fit being equal for both? Still need to know the temp/duration for annealing beer can alloy.

[PatMarlin]

Pipehand- I believe the answer to your question is yes.

If you had a plain base boolit and used a PB gas check such as my design accuracy
is showing to improve with some pistol calibers to date.

It also depends on what your goals are. For hunting and plinking .004-.005
beer can checks are working on standard gas check shank boolits. Benchrest
paper punching groups no- then you want to experiment with material thickness.

I think your idea to get accuracy with thin metals by increasing your shank
diameter is a valid goal. For that matter make it a plane base and use a PB check.
Then you have the best of both worlds.

Here is an example of what Jim Sheldon did with beverage can checks:
http://castboolits.gunloads.com/showthread.php?t=91133

Below Patrick L:

I did get to the range today. I only took the .30-30.
I'm not as good a shot as Ben, but I think I did OK. Let me start with a few
excuses why I don't have "one ragged hole." First, I shot iron sights, on
a .30-30 carbine. Second, my eyes are bad. Third, it was humid as h*ll, and
my glasses fogged up incessantly. That should cover it.

Seriously, the gun was my dad's old Marlin 336. Its a pre Micro Groove, so
nice cut rifling. Its also pre drilled & tapped for scope, and there's no way
I'm gonna drill & tap it. I did mount a receiver peep on it though. It shoots
better than I can shoot it, that's for sure.



My load was 8.1 gr Green Dot, our Lee GB copy of the Lyman 31141 sized .311, lubed with LBT Blue Soft, and a CCI 200 primer. My gascheck was .004 soda can aluminum.

It really was disgustingly humid, so I only fired two groups, benched at 50 yards.





This is typical of what this gun will do. Its interesting that in both targets there's a nice little cluster forming at 6 o'clock in the X ring. the fliers, if you want to even call them that, are because I have such a hard time with iron sights. Sometimes I wish I could scope this gun, just for group testing. Oh, and the vertical stringing in the second target is not typical at all, and it is not a gun problem, it was a result of me not being able to focus the sights clearly and consistently enough today. Did I mention it was really humid ?

Just for laughs, I fired a third group with genuine Hornady gaschecked boolits, and it looked about like the first. Which is to say I think these perform just great. Next up will be the '03 Springfield 30-06, but it will probably be mid week before I get back to the range.

30/30 Guy and his Plain Base "PB" die results:
http://castboolits.gunloads.com/show...php?t=93833%0D

[pipehand]

Thanks for the reply guys. Pat, if I were to bore the shank out to, say, .301" would that basically be like having to order a completely different checkmaker? I've never used your product, but it would seem to me that"standard " fits the shank, and groove diameter is then matched with material thickness. I would imagine that the forming punch would have to be .017 larger than one designed to fit a .284 shank.
One of the alleged attributes of the gas check is that it scrapes leading and allows it to collect in the lubricated groove ahead of it, keepin a consistant bore condition. The PB check setup doesn't allow for a groove ahead of the check.
What got me to thinking about this is the chart of shank size and check thicknesses that was posted for the different calibers. Is the .016" that Hornady uses for the 30 cals really necessary, or is it traditional to match the first gas check bullet designs? Other calibers have thinner checks. We know that gas checks work. It would really help if we could pin down how they work.

[PatMarlin]

You're going to have to experiment on your own Pipehand. That's what I have to do.

Guys on this very forum are shooting minute of angle- one hole groups at 100 yards with .014 aluminum so take the theory of what a gascheck measurement should be, including a groove above the check and throw it out the window. We have broken all the rules. The rules are helpful, but just guidelines.

I've shot 1 hole groups at 50 yards with 30 caliber and .010 1/2 hard copper. The reason only 50 as for the past 2 years, that's the only range I've had time to work with- out my back doorstep.

[PatMarlin]

I kinda smile when I see guys come up with a gascheck dimension formula of what it has to be. If that were the hard rule to be adhered too, my .010 copper check would not work. Patrick and Jim above wouldn't have got the groups they have.

Think about a copper bullet in 30 cal... .308 diameter correct? What does it do- obturate in the bore to the bore's dimension when fired. Higher powered most of the time yes, but a gaschecked cast boolit is going to do the same.

Just one of the things that make cast shooting so interesting.

[PatMarlin]

Thanks for the reply guys. Pat, if I were to bore the shank out to, say, .301" would that basically be like having to order a completely different checkmaker? .

Not sure I follow. Boring, and shank are opposite things. Do you mean turning a shank to .301- and in my case it would be turning the male forming die?

[Jim Sheldon]

Here is an example of what Jim Sheldon did with beverage can checks:
http://castboolits.gunloads.com/showthread.php?t=91133

Almost correct Pat,
Actually I used .005" brass shim stock for the thin stuff. I didn't have any aluminum beverage cans on hand as neither my wife or I drink soda or beer

I have a friend locally who's going to save me some of his Pepsi cans so I can play with that thickness of aluminum. Considering the results I'm getting with .014 Amerimax and the brass shim stock, if you get the load right behind it, the accuracy is there, if the rifle & shooter are accurate in the first place.

That convoluted statement comes from an old Pennsylvania Dutch proverb I heard years ago. "If we had some ham, we'd have some ham and eggs, if we had some eggs."

Jim

[pipehand]

Not sure I follow. Boring, and shank are opposite things. Do you mean turning a shank to .301- and in my case it would be turning the male forming die?

I meant boring or reaming out the shank portion of the mould to drop a boolet with a larger gc shank. And, yes, I do believe that the male forming die would have to be bigger.
I realize I'm going to have to experiment on my own, but I was hoping I wasn't heading of into completely unchartered territory. The reason I frequent this board is for the wealth of knowledge held by many of the posters here. The recent "shortages"
and rediculously high prices of components have drawn a lot more people into casting and reloading, and has created a market for products like the Checkmaker.
Maybe this idea will be taken up by someone besides myself, but I do want to discuss its viability. When the first gaschecked boolets were designed, copper was cheap and beer came in wooden kegs and glass bottles. We have all sorts of new materials to play with and a great forum to brainstorm on.

[PatMarlin]

I think it's a good idea Pipeine. Can't think of a downside as long as you can ream it out accurately. LEE mold would be a good place to start.

Just off the top of my head, I think I would clamp the mold in my Mill vise and use a plug gage pin the same size of the existing shank hole to chucked up- and align the mill chuck dead nuts, then use a chucking reamer the size you desire.

I'm sure some of our machinists here at CB have done it, and know of a good way.

[PatMarlin]

This would also be a good idea for 50 caliber mold owners who have check shanks that use .020 and thicker diameter gas checks. Why the extra expense for heavy copper?

If they reamed it out to use .010- .014 there would be a huge savings. Maybe there's a reason here that I'm not aware of with the 50 caliber?

[pipehand]

Thanks Pat. Already figured out the experiment. Lee 312-155 mould with only one of the cavities to have a .301 shank, the other left stock for Hornady checks. Fired in a Ruger 77 in 7.62x39 with a proven accuracy level with the original NEI version of the Harris mould. That would minimize variables so that I wouldn't be comparing apples and oranges. Should only cost my time and $100 plus mould modification machining costs. That assumes you would make me a custom checkmaker at the stock price. Whatcha think?

[PatMarlin]

I'm not doing any custom dies, but I am offering a custom male forming die for existing calibers at an extra $9.95. So if the male die change will work for your purpose then no problem.

[pipehand]

Pat,sorry for the confusion. The male forming portion of the die was what I though would be custom. Will have to order the Standard 30 cal die and the custom .301 male forming die. Tough sourcing selfish funds during the impending season of giving, but its gonna happen!
BTW All, I did a search on annealing Aluminum. Get it to 800 degrees F and you're good. Some tips included smokeing it with a pure acetylene flame, and then hitting it with a "neutral" oxy-acetlyene flame until the carbon burns off. Another tip was to rub soap on the Al and heat it with a brazing torch until the soap turns black. Aluminum melts at around 1200 degrees.
I wonder how hot the oven at home gets on the self clean cycle. Immersion in a hot pot of lead might work if nothing sticks to the aluminum.
By getting the standard die, which by all reports works well with thicker aluminum, I'm not out anything on the experiment if it totally flops, except, possibly the mod on a $20 Lee mould and the extra male forming punch. This sound like an experiment I can afford! If it works, it pays for itself in the first 2.5k rounds, with the added warm fuzzy feeling of DIY'ing.