I compete regularly in CBA bench rest matches and normally have a more than adequate supply of reloading materials. An order with Midway for a couple of thousand gas checks was 2 months on backorder and my supply was running short. So I purchased a 30 cal. FREECHEX II on ebay and started experimenting to see if it would produce similar results as compared to the Hornaday units and act as a backup if the shortage continued.
Even though aluminum is suppose to be OK as a check material, I cringed at the thought of possibly scratching my new Lilja hand lapped barrel and opted to buy some 0.010” soft copper sheet and 0.012” brass shim stock for testing. I used a 1 ton Harbor Freight (inexpensive) arbor press (1/2 ton or mallet would also be OK) and the fit was snug on the 0.283” OD GC shank of the custom 170 Gr. LBT bullet running a BHN of 27. This is loaded in a 30 BR configuration with 33 Gr. of Varget speeding along at about 2,500 fps. I normally shoot sub-MOA with the occasional flyer. The test on these two materials produced the following 5 shot groups at 100 yards:
0.012” Brass: A.) 1.160” (0.792” 4/5)
B.) 0.674”
0.010” Copper
A.) 1.270”
B.) 0.645”
I cleaned between each metal. Seems like I need more foulers and less cleaning. What this does tell me is that lack of commercial GCs would not prevent me from competing.
On the economics of it all, the copper was expensive for the small quantity I bought, a 6” x 12” sheet at $9.00 plus shipping ”€œ an emotional buy to get things started. I then bought a 6” x 100” roll of half hard brass shim stock from McMaster-Carr (
I would use the brass in competition, but I would anneal them as I do with the Hornaday's but didn't do it in this test. Midway informed me that my 2 boxes of backordered GCs are on their way so I will use them in future matches as the additional time needed to make the GCs is something I'd rather not do at this time. Maybe after I retire. But it is nice to know that I now have a viable backup system if copper supply becomes a problem ”€œ I read somewhere that the Chinese are making a heavy investment in copper to replace the US Greenback, so who knows.
I just though I would share the results of today's test for anyone having trouble getting GCs. :)
Either way, the checks crimped firmly onto my 314299 bullets and I couldn't pry them off with my fingers.
) clustered very nicely into 1 1/2” or maybe a shade less.</p>
<p> More tests are forthcoming.</p>
<p> Also of interest is the fact that my lube is home made. Kinda makes a man proud to cast his own bullets, check them with his own checks, then lube them with his own lube!</p>
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<p> I'm no metallurgist, but I find the notion that aluminum will scratch or wear a bore almost laughable. </p>
<p> Anyone ever sharpen a knife on a beer can? (Me neither)</p>
<p> Can aluminum stock be machined with steel tooling without excessive wear of the tools? (Contact Veral Smith, Lee Precision, NEI Handtools, etc.)</p>
<p> Anyone ever heard of handgun chambers/cylinders being worn from firing Blazer aluminum cased ammo in 9mm, 357 Mag, 40 S&W, 10mm, or 44 Mag.? </p>
<p> Remember the old Colt Combat Commanders that had aluminum frame mated to steel slides? Did the steel slides wear excessively from sliding back and forth over and over against the aluminum. Doubt it.</p>
<p> 35W</p>
<p> P.S.- As a side note, I found that aluminum guttering also might make good gas checks. At about .018” it makes a much heavier/thicker check that is similar in dimension to my Hornady gas checks. And with a 10' piece of gutter a fella should be able to get 1000's of checks for under $10.</p>
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