Gas Checks

  Gas checks are small "CUPS" that fit around the base or "shank" of bullets that have been designed and developed for gas checks.   The purpose of the gas check is to allow equal pressure across the entire circumference and area of the base of the bullet, which is composed of lead and other metals, to go down the barrel and not have the base of the bullet deformed or splayed by the pressure that is applied when the primer ignites the powder.   You can put enough powder behind a lead bullet without a gas check to completely deform the bullet before it exits the barrel, due to excessive pressure deforming not only the base of the bullet, but also the cutting gasses that will blow around the base of the bullet deforming the sides of the bullet.  A major misconception is that the gas check is to keep the lead from melting while it travels down the barrel. Once the firing pin strikes the primer, the primer fires and ignites the powder in the shell casing, and the bullet is in the barrel only a matter of milliseconds. There essentially is not enough time for the lead to melt in this time. One example is if you take a standard propane torch that you can purchase in most hardware stores and light it, the flame is very hot, but if you take your hand and pass it through the flame very quickly you do not get burned, right? You might feel some warmth, but you do not get burned. The same goes for the lead in the base of the bullet, it does not melt, MOST OF THE TIME. The exception to this MOST OF THE TIME is that if you have a long barreled rifle, the bullet is in the barrel longer and has more exposure to the burning powder, but again, it usually does not melt and MOST bullets for rifles are gas checked. The main purpose of the gas check is to keep the cutting gasses that result from the burning powder from blowing around the base of the bullet and attacking the ridges in the cast bullet. It really takes a long time to melt lead, just remember the propane torch above and see how long it takes to actually melt a bullet, you will be surprised.  

Gas Checks traditionally have been made of Copper, and still are being made and sold today, and there is nothing wrong with them and they work fine.   There are those that swear by only using copper gas checks, but in my experience I personally can find no advantage of using copper over other available materials.   The Gas Check Store manufactures aluminum gas checks, and with hundreds of thousands sold all over the world no one purchaseing them have had any problems or complaints with them, while they still maintain good accuracy and no reported leading of the barrel.

To figure which size of gas check you need, you should follow a rule of thumb formula that has been around for years.   The formula is as follows:

(SBD - SD)/2 = Material Thickness

SBD is the Sized Bullet Diameter
SD is the gas check shank diameter on the end of the bullet
Material Thickness is 0.008", 0.010", or 0.014" material thickness

For example, I cast Lyman 358156 Bullets, and after sizing the SBD = 0.359" and the SD = 0.341".
So by using the formula above (0.359" - 0.341")/2 = 0.009" which rounded up to 0.010".
I would select 0.010" gas checks because 0.008" material would be too small.
If the SBD was 0.358" and SD = 0.341" then (0.358" - 0.341")/2 = 0.008" so I would then use 0.008" stock.
Use a set of micrometers to measure your bullets, then do the above calculation.

  All of the gas checks that are offered by The Gas Check Store are to be used ONLY on bullets that are designed for gas checks. Gas Checked bullets have a small groove almost like another lube groove on the base of the bullet or the bullets shank. This groove is smaller than the diameter of the bullet and is described above as "SD", or shank diameter. The Gas Check Stores gas checks are not intended nor to be used on plain based bullets, and if the buyer does use The Gas Check Store gas checks on plain based bullets it is at the buyers descretion and responsibility for any and all consequences resulting for this use. There has been research, design, development, testing, and volumes of books detailing gas checked bullets, and to put a gas check on a bullet NOT designed for a gas check will degredate the ballistics and functionality of such bullets. The Gas Check Store does not advise nor advocate this practice and advises against its use.

  The Gas Check Store currently sell 7 different calibers of Gas Checks, and they are:

Gas Check
 Recommended Shank Size 
Recommended Calibers
22 Cal Bullets
270, 6.5mm/264, and 7mm/284 Bullets
30 Cal, 7.62/39, 303 British

 35 Rem., 38 Spl., 357 Mag., 357 Maxium 

44Mag, 44Spl, 454

44/454, 45/454, 458

500 S&W

  If you have the need for a gas check caliber that The Gas Store does not sell, please drop the Gas Check Store an e-mail and I will do the best I can to tool up for them and start making them for you.

 Any and all consequences and or actions resulting from the purchase and or use of these products rest solely with the purchaser. The seller assumes no responsibilities with the selling of these products or their use. The Gas Checks sold on this web site are NOT intended to be used on bullets NOT specifically designed for gas checks. Reloading should only be done or attempted by trained or qualified persons. Never smoke nor drink any alcoholic beverages during any aspect of the reloading process.

The Gas Check Store does it's best to assure the best quality control that is available, but at times it is not possible. The aluminum that The Gas Check Store uses is ordered bulk. The exact dimensions are not always perfect. Some of the aluminum will vary as much as 0.003" to 0.005 inches in thickness, and that I have no control over. When The Gas Check Store does notice these differences, the material is returned to the vender and new material is requested, but some times the thickness will vary within the material that is ordered. If your order does not meet advertised specifications, it most likely is due to the varying dimensions of the material that The Gas Check Store has ordered. It is very hard if not impossible to note these small dimensional variations when manufacturing the gas checks, and if you are not satisfied, please notify The Gas Check Store and your order amount will be refunded. To date The Gas Check Store has only had one order returned and that was due to the customer ordering the wrong caliber gas check bullet for their requirements.

 Caliber   100 Cost   200 Sample Cost   250 Cost   500 Cost   1000 Cost   3000 Cost   5000 Cost   10000 Cost 
 22 Caliber 0.005" and 0.008" material only n/a $10.00 n/a $19.00 $26.00 $75.00 email for pricing email for pricing
 7mm  0.014" material n/a $10.00 n/a $19.00 $26.00 $75.00 $125.00 $245.00
 30 Caliber 0.008", 0.010" and 0.014" material  n/a $10.00 n/a $19.00 $26.00 $75.00 $125.00 $245.00
 35 Caliber 0.005" and 0.008" material only n/a $10.00 n/a $20.00 $31.00 n/a n/a n/a
 44 Caliber 0.008" & 0.010" material only n/a $10.00 n/a $23.00 $33.00 $89.00 $160.00 $310.00
 45 Caliber  n/a $10.00 n/a $23.00 $33.00 $89.00 $160.00 $310.00
 50 Caliber 0.014" or 0.020" material only $10.00 n/a $22.00 $40.00 $72.00 $180.00 n/a n/a
Available in Mid March, 7mm Gas Checks. Prices will be the same as 30 Cal Gas Checks
13 March, 2013

   When you order gas checks from The Gas Check Store, you will ALWAYS get more than you ordered. If there is an irregular one, it is easily spotted before you mount it on the shank of the bullet so just throw it away because as said above, you will ALWAYS have extras in the event that an irregular one slips by.

This page was last updated on 26 September, 2015

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