aluminum or copper ?

[sandman228]

I'm casting with a lee .358 200 gr flat nosed mold for my 35 marlin . I tried powder coating this bullet but it added to much to the diameter of the nose of the bullet and I'm having trouble getting it to chamber (even with shorter oal) . so I decided to cast a few hundred more and just tumble lube them . I made a dummy round and ran it through the action without issue. I did have to seat under min oal though to seat it in crimp groove and to get to chamber . so I plan on shooting this bullet tumble lubed and gas checked . these will be just plinking loads i found sage's outdoors online and looked at different checks i found what i need in copper and aluminum at same price so which should i use ?

[elwood4884]

The major advantage of aluminum over copper is typically cost. If you can get both at the same price I would go with copper. Try to get samples before you load a bunch to make sure you like fit and function.

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[elwood4884]

Aluminum typically has spring back that copper does not. Copper should give you best fit.

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[Sagebrush7]

I'm casting with a lee .358 200 gr flat nosed mold for my 35 marlin . I tried powder coating this bullet but it added to much to the diameter of the nose of the bullet and I'm having trouble getting it to chamber (even with shorter oal) . so I decided to cast a few hundred more and just tumble lube them . I made a dummy round and ran it through the action without issue. I did have to seat under min oal though to seat it in crimp groove and to get to chamber . so I plan on shooting this bullet tumble lubed and gas checked . these will be just plinking loads i found sage's outdoors online and looked at different checks i found what i need in copper and aluminum at same price so which should i use ?

Some types of aluminum flashing have a tendency to spring back. We compared the properties of C210 copper with available blends of aluminum and ordered some with the same tensile strength. Many on this Forum have tested the half hard aluminum shooting great groups. Our special order .010 aluminum has worked well on the .22,.35 .41 and .338 . This particular alloy has not had the spring back like common flashing that has a larger percentage of nickle in the blend. 35 Shooter and Ben have tested and praised its characteristics. James

[35 shooter]

I like Sage's .010" half hard checks in my 35 whelen so much, i've quit making my own.
They size on super tight and shoot very tight groups. They stay on for the ride even at 2500 fps. in the whelen. No springback to these at all...they form to the base perfectly and stay that way when sized.

That reminds me...i need to place an order too.

[JeffinNZ]

It's not quite that simple. There are different grades, alloys and hardness of aluminium and similarly copper. The best Al. I have found to date is lithography plate material. Generally available 6 or 12 thou or near enough to said. It is 3xxx alloy and harder than flashing. Dirt cheap at the scrap dealer too.

Don't forget that commercial checks are not necessarily pure Cu. They will be gilding metal like jackets. Zn content so harder.

[odfairfaxsub]

Had same prob w my 35 and loading coal. My only backwards input to this discussion is fouling. We have chemicals readily available to remove copper fouling but not aluminum unless I'm misinformed. Remember that I don't believe in my heart that you'll foul a barrel to a point of notice w copper gas checks just saying that if you want to clean down to steel better use copper.

[skeet1]

So far the best Aluminum I have found is from "Coil & Foil", it was more malleable than the flashing I had been using. They also sell copper. http://www.coilandfoil.com/

Ken

[RogerDat]

Copper is painful on price as compared to aluminum until one orders in rather large quantity, copper is still more expensive just not as much differential in bulk amounts. People use both, and they both work well. If you are just starting with this bullet why not order 1k or 500 of both. Both will work so nothing to lose, maybe in your own application one will work better.

Do a double blind test, have someone load from a box of copper and a box of aluminum They label boxes A & B without knowing which is copper or which is aluminum. They load for you from boxes switching back and forth. Shoot for score or group distance. Have them record the target results as being from box A or box B. At the end you will know if "A" or "B" bullets shot better. Check bottom of box where you wrote what type of GC it used to load each box. My guess is both will work equally well but what the heck be fun to shoot though a bunch with a friend. And at the end if there is any significant difference in your rifle with that bullet you will know it.

[Soundguy]

I'm doing a 200gr fn, .358, pan lube, with hornady copper checks, works great in a 35 rem/marlin 336

[hpbear101]

I have bought both aluminum and copper check's from Sage. They both work fine for me.

[dkf]

I have and use both copper and aluminum checks from various makers. Needless to say I am willing to pay more for the copper.

[dragon813gt]

All costs being equal I will buy copper. I make my own out of aluminium which is almost all that I use. I buy 375 checks because I shoot them in an extremely low volume.

[Tom W.]

I bought a check maker in .45 cal and found that a doubled over strip of Pepsi can made excellent checks. Just for S&G I took some of the .45 checks and tried them on my .44 boolits. They worked perfectly .

[HollowPoint]

I've used both home made and store bought aluminum and copper gas-checks and I can't really tell any difference. I make my 30-cal checks using a set of dies I got from Pat Marlins back when I first joined this site. I've also bought the name brand copper checks but I found them to sometimes not stay on as well or have to be forced on if I don't take steps to open them up a little in order for them to slip on as they should before sizing.

Just recently I started casting 6.5mm bullets and the pre-made copper gas-checks I bought for them; although they do work, tend not to stay on because the skirts just seem to short to grasp the gas-check-shank of my bullets strongly enough. To that end I made up a set of rudimentary gas-check dies that allow me to make both copper and aluminum gas-checks with skirts that extend far enough up the shank to nearly butt against the underside of the last driving band of my cast bullets. This forms a strong grip that allows me to use my suppressor without fear of baffle strikes by uncooperative gas-checks.

There is a draw back to having the skirts ride up farther than normal. I've made these higher-skirt checks with both copper sheeting and aluminum flashing and the thinest stuff I've used thus far is .01" in thickness which tends to result in extrusion of the material that requires either that I go to a thickness of under .01" material or I have to perform a secondary operation where it requires manually having to even out the mouths of the checks in order to get them to sit flush and symmetrically on the gas-check-shank of my bullets.

Locally, the thinest aluminum sheeting I can get measures .01". It's the flashing I get from the hardware store and it works great on my 30 caliber checks but not the 6.5 checks.

I can make these same aluminum gas-checks using the aluminum from salvaged soft drink cans and they work too but, that aluminum is a little to thin. So much so that although the gas-checks made from that material form to the perfect skirt height and length, they look to much like pop-bottle tops because of the corrugated edges that form when they come out of the die.

This is most likely a non-issue in terms of performance and more of an asthetics thing but, in the back of my mind these corrugated skirts just seem more prone to gas cutting than the smooth edges of a cleanly formed gas-check.

If I'm not mistaken, the fellow who runs the website for the link supplied above once graciously sent me out some samples back when I was developing my Boat-Tailed-Gas-Checks. I had forgotten all about him until now. I think I'll contact him about selling me some .008" thick aluminum samples before going whole-hog on buying a full roll of the stuff. I noticed he has more than a couple of thicknesses of aluminum under the .01" that's giving me fits right now.

HollowPoint

[HollowPoint]

I was able to get in touch with the guys over at the coilandfoil.com website earlier this week. They're sending me out a small sample of their .008 and a couple of other thicknesses for testing on my 6.5mm home made gas check dies. I'm fairly confident that one of these thinner samples will be just what I'm looking for.

If one of these thinner aluminum sheet product will eliminate the extrusion problems I've been dealing with, I'll be a happy camper with a seemingly unlimited supply of inexpensive gas check material.

Things are looking up.

HollowPoint