Aluminum gas check material

[Freightman]

I have access to 200' x12" of pure aluminum sheeting and it is .025 is that to thick for gas ck material?

[Von Gruff]

I am sure those more qualified than I will answer, but I believe it depends on the shank size and the finished boolit size.

There was a thread a while back where the differences in these sizes were theorised on with experiences obtained in some testing but I was unable to get a definitive answer to the question of how much is too much.

For instance my 7mm 284641 boolit, the shank measures .2545 and my finished sizing is .2855 so the difference is .031. In this instance, an absolute minimum of GC material would be .0155 and I had been using a two ply GC of a .012 and a .006 for a forming down of 5 thou or 2 1/2 thou either side. These GC were often able to be pulled off with either the fingers or came off when the sized boolit came out of the lubrisizer and concerned me as to the effects on accuracy which was not where I wanted it to be.

I decided to try 2 x the .12 for a .024 which gives me a forming down of .017 or 8 1/5 thou either side. It took a while to lap out the tool for the thicker material so it would not thin the sides of the check. I cut a pin punch down to the taper so it was the correct dia to give a flair to the sides of the check for a noce slide on fit to the shank of the boolit for sizing, which is easily done through my lubrisizer. These do not deform the shank that I can see and can not be removed. This was on 70/30 ww/lino boolit that I run at 1900fps, but my plinking alloy of 50/50 ww/pb also took the check without nose deformation.

Have only had a short run at the range so have been unable to come to any definite conclusions as to thier effect on accuracy other than to comfirm it would stay inside 2 1/2 in for 10 shots at 100yds at 1900fps

Have a test sample loaded with my 2415fps load to see if they will hold up to that velocity as it has been the experience of some, myself included that the al GC dosent seem to hold up too well at the higher velocities. It was the consensus that the al was too soft but I wonder if the problem may not have been that the thinner al Gc that most use is too soft but that the thiness and generally minor forming down may contribute to the velocity - accuracy difficulty and that a thicker al check with more forming down may adress the issue.

Have also got .021 copper to try and am only waiting on a heavier duty checkmaker to give it a whirl as well although I did cut enough for 10 checks so I can give them a testing at the same time as the .024 al gc on the same straight lino boolits at 2415fps.

Von Gruff.

[JIMinPHX]

Try it & let us know.

I've been using aluminum beer bottles (bud lite) with good results in every gun that I tried them in except the ones that had chrome bores. Those fouled terribly.

[ReloaderFred]

I believe .025" will be too thick, but I may be wrong. I've been using .009" aluminum flashing that I've had to anneal to get good checks. Mostly I've been using .010" soft copper foil, and it works the best in my experience.

Hope this helps.

Fred

[D Crockett]

the best thing I have found so far in making gas checks is printing plates from a print shop they make real good gas checks for my 30/30 bullets D Crockett

[Von Gruff]

I believe .025" will be too thick, but I may be wrong. I've been using .009" aluminum flashing that I've had to anneal to get good checks. Mostly I've been using .010" soft copper foil, and it works the best in my experience.

Hope this helps.

Fred

Fred, I have to ask what you base your belief that the .025 will be too thick as there has been no indication from the OP as to what shank dia or sizing dia are. Without this information saying it will be too thick as you only use .009 is not necessarily adressing the same data as the question was asked about. We need Freightman to bring his details to the forum so we are conversant with his particular circumstances.

Von Gruff.

[Freightman]

Well I do not have a GC maker yet but I do have this material and was wondering if I keep it for future use or use it for a grass barrier for my flower beds. All the moulds I have that use GC's are standard as Hornady fits fine.

[edsmith]

.025 is too thick except mabey for .50 cal. it will jam up your check maker.they are not made to accept that thickness of material. go to http://castboolits.gunloads.com/showthread.php?t=11997 scroll down to the hornady chart. colum E. proper material thickness or close to it.

[ReloaderFred]

Von Gruff,

I'm basing my opinion on the fact that I've tried to punch out aluminum that was .019" thickness, and it wouldn't punch. Neither would .020" brass plate. I couldn't get the punch through the material on a Rockchucker press. Perhaps it could be done on a punch press, but I couldn't do it on a reloading press and I wasn't willing to jump up and down on the press handle to prove it could be done........

Hope this helps.

Fred

[Von Gruff]

Von Gruff,

I'm basing my opinion on the fact that I've tried to punch out aluminum that was .019" thickness, and it wouldn't punch. Neither would .020" brass plate. I couldn't get the punch through the material on a Rockchucker press. Perhaps it could be done on a punch press, but I couldn't do it on a reloading press and I wasn't willing to jump up and down on the press handle to prove it could be done........

Hope this helps.

Fred

Fred caan I ask what type of GC maker you are using as I have cut the .021 copper with one of Charlies frechex 11 tools that he suplied with the comment that it would cut the the thickness that fitted in the cutting slot and tried .0175 hardened brass.. I only cut and formed a few as a trial as Pat is making me one of his checkmakers to handle the .021 copper that I sent him a sample of.
Generally for the .024checks, as in 2 x .012 with the frechex tool, I cut one disc then another before forming the check.

I did have to lap out the base of the tool to except the thicker material and modify the stem to suit.

Von Gruff.

[Freightman]

Thanks for your input I think I will use it as I intended to as a water stop for my rose beds.

[ReloaderFred]

Von Gruff,

I'm using Pat's Checkmaker die. I'm not able to get it into the press to take advantage of the maximum leverage at the top of the stroke. When it proved too difficult to cut the material, I backed off and discarded it. I'm not one to ruin equipment trying to make a point, and there are better materials that are more suited to the task, so I went no farther in the experiment.

Hope this helps.

Fred

[JeffinNZ]

I like just a little extrusion. The reason for this is when the material is extruding it produces perfect checks in every respect. That said too much extrusion is going to cause you problems with tearing and jamming. If you have a shank of .284 and a forming die of .308 your have .024 of difference, perfect for .012 material. I would not use material of a gauge greater than .013-.014 in this situation.

[longbow]

I made my simple check maker to standard GC shank and OD's for .30 cal. and use 0.019" old gutter aluminum.

I punch disks with a hand punch then drop them into the sizing die for forming. They do extrude a little and are almost too long for the short shank on my NOE 0.314" x 129 gr. ~ they do fit but just. They fit well on the longer shank of my NOE 316299.

So, assuming the punches and dies are to "normal" diameters for a given caliber and you have the horsepower to punch and swage the check, the limiting factors are the final depth of the cup and whether you get tearing and jamming as Jeff mentions.

Having said that, 0.025" material would result in too deep a cup for the short gas check shank on some boolits.

FWIW

Longbow

[Von Gruff]

As said earlier I lapped out the base of the maker so there wouldn't be excessive exstrusion of the doubled .012 litho plate. You can just see the polished ring where the al has rubbed past the base die. The edge of the GC look rough in the extreme close-up but should have no effect in use.
http://i667.photobucket.com/albums/vv39/VonGruff/002-7.jpg

Seated on a boolit it shows that the cup is not too deep for at least this boolit which is what matters in this case.

http://i667.photobucket.com/albums/vv39/VonGruff/020.jpg

Von Gruff.

[Ben]

Keep us posted with some pics of targets and load data please. I'd be interested in knowing how they shoot ?

[Von Gruff]

Will do Ben but we are having another week of spring weather with high winds and squally rain and even had a bit of snow as well so it will be at least next week before it settles again.

Von Gruff.