These are our heavy .30 caliber aluminum gas checks made for .303 rifles or other .30 caliber barrels over .314. These have been tested to .318, they should max out at .320. The .303 version is a tall gas check, about .010 more gripping area. Made with a thick aluminum, these are meant to be used when a normal .30 won't size up large enough. Works on the average .284 shanks.
We also have our Aluminum .30 caliber gas checks that will size to .314 max here: .30 /.308 / 7.62mm Caliber Aluminum Gas Checks
If you prefer copper we have a .30 gas check that will size to .314 max here: .30 / 7.62 Caliber Copper Gas Checks
The gas checks are sold in resealable clear plastic bags. Shipping is based on each item's weight. USPS postage rates are calculated in the shopping cart. USPS flat rate boxes and First Class mail are used to reduce shipping cost. Most orders ship in one business day Monday through Friday.
Sold in 4 quantities: 100 for $4.99, 250 for $8.49, 500 for $12.99 and 1000 for $22.00.
Posted by Ward on Apr 7th 2017
I have seated thousands of copper gas checks. I was looking for checks to fit 7.62 and bought these aluminum .303 gas checks. Using a Lyman Lubersizer, White Label Co. Carnuba Red high velocity wax and Lyman 311291 mould 30 cal 170gr bullets sized to .312" SKS these aluminum gas checks were an excellent tight fit. I place the gas check into the sizing die and then place the bullet into the gas check. These seem to take a little more effort / handle pressure to start the gas check into the sizing die, as compared to copper, but WOW what a nice tight fit on a 7.62 bullet. I thought the aluminum would start easier but since it is somewhat thicker than copper ............... I will definitely buy again! [ and it Sage sure does beat the MidwayUSA highly priced gas checks :-) ]
Posted by Patrick on Sep 11th 2016
I use it on the lee 303 British 185 gr mold, it's fit nice and easy, i crimp and resize at 0.311" for my win 94 over bored and this gas check gives me the best accuracy and no fouling.
Posted by Anthony on Aug 4th 2016
I put these on 200gr, .313 diameter LRN bullets I cast from a Lyman mold, and shoot them in Enfield and Mosin-Nagant rifles. The rifles have worn, over-size bores. I use a .314 Lee sizer die. I can push the bullets hard and get good accuracy and no lead left behind. I'm able to shoot these now at 1800fps instead of keeping them throttled back to 1250.
All prices are in USD.