Gas Check confusion

[semtav]

maybe trying to reinvent the wheel,

first, I'm shooting the carcano bullets as cast at .271, but putting on a gas check that winds up about .267. If the gas check is suppose to seal the gasses , is that too much gap?

Second, I thought I 'd get smart and put a 270 gas check on. (They are hard to find.) So I got an old tin (round tin of 1000 Hornady GC's in sealed can) only to measure them and find out they are .284 dia. Mislabeld tin ??

Now I look on the Gas check Sticky chart and find that the 270 GC's are supposed to be .266, the 6.5 .271 and the 7mm .290.



http://www.tmtpages.com/LinkSkyImages/forum_images/Gas_Check_Dimensions.gif





If the 270's are smaller than the 6.5's, is Gas check size really that critical.








Just a follow up, I looked at the chart again, and it shows dimension A on the 270 GC as .277 and dimension C as .266, so there must be a misprint on the chart.


thanks

[StarMetal]

maybe trying to reinvent the wheel,

first, I'm shooting the carcano bullets as cast at .271, but putting on a gas check that winds up about .267. If the gas check is suppose to seal the gasses , is that too much gap?

Second, I thought I 'd get smart and put a 270 gas check on. (They are hard to find.) So I got an old tin (round tin of 1000 Hornady GC's in sealed can) only to measure them and find out they are .284 dia. Mislabeld tin ??

Now I look on the Gas check Sticky chart and find that the 270 GC's are supposed to be .266, the 6.5 .271 and the 7mm .290.



http://www.tmtpages.com/LinkSkyImages/forum_images/Gas_Check_Dimensions.gif





If the 270's are smaller than the 6.5's, is Gas check size really that critical.








Just a follow up, I looked at the chart again, and it shows dimension A on the 270 GC as .277 and dimension C as .266, so there must be a misprint on the chart.


thanks

Why on Earth would a 270 gascheck smaller then a 6.5 one? You better believe that chart is wrong. No, NO 6.5 in the world has a groove diameter that even comes close to the 270.

Joe

[semtav]

Why on Earth would a 270 gascheck smaller then a 6.5 one? You better believe that chart is wrong. No, NO 6.5 in the world has a groove diameter that even comes close to the 270.

Joe

If dimension B is .255 and the gas check is .017 thick , dimension C would have to be at least .289. So mine are probably 270 cal checks.


Again tho. will checks sized to .266 work good in a barrel that has .271 grooves?
(bullet is also .271)

[swheeler]

Measured Hornady 270 gas checks-.286OD and hornady 6.5 gas checks .266 OD

[Eutectic]

The chart is a nice one but pretty useless without a GOOD proof read...

Dimension "C" for Hornady's .375 gas check is also incorrect.

Eutectic