gas check thickness

[MT2DAY]

I just started shooting cast rifle slugs w/gas checks. I had picked up two round tins of horandy gas checks about 1600. I worked with two bullet designs and started on second full tin and thought I would get another thousand checks.
The old hornady checks I have been using measured .021 thickness, the thickest I have been able to find is .017
now for the questions
does anyone make .021 copper checks?
has anyone had experience changing check thickness?

I got this note from hornady
"the thickness of the gas check is .017 and has been this thickness for all the time of production. Thanks"
From: Hornady Manufacturing, Inc

[JeffinNZ]

Why do you believe you need 0.021?

Gas check material thickness is a function of half the difference between GC shank and final sizing diameter.

EG: X = (.310 - .284) / 2 [where .310 is the sizing dimeter and .284 is the gas check shank diameter]
X = 0.026 / 2
X = 0.013

Comprende?

[tjones]

Yep I bet that's what they start with. Who knows what the stamping and milling process does to the finished product.- tj

[MT2DAY]

don't need them but that is what I have been using. have you ever seen a .021 30cal hornady gc?
has someone custom made the ones that I have and I will never find them again? if so maybe I will sell them and get the standard thickness checks or rathole them in case I get a mould with a small base.

[JeffinNZ]

Hornady specs are 0.017 thou. I suspect you are measuring the flared 'crimp on' top edge.

[MT2DAY]

wow after reading many posts here for awhile I guess I have been lucky.... jeffinNZ your replies to my posts are very snobbish and do no address any of my questions. please do not waste my time or take up space on my thread.

[WashingMike]

MT2DAY- You probably will not be able to readily find exactly that thickness of gas check again, especially if they are indeed old. My experience has been that the gas check thickness is more an issue in applying it to the bullet's base. I suggest you shoot all the checks you have and enjoy them. The new checks you will purchase will work just fine for you and you probably won't even notice any difference. I don't. I use whatever I find cheap.
I am sure Jeffy above means no ill will, you will find the lads around here often send abrupt messages so as not to waste words. Let me welcome you to the addiction of casting Boolits.

WashingMike

[JeffinNZ]

wow after reading many posts here for awhile I guess I have been lucky.... jeffinNZ your replies to my posts are very snobbish and do no address any of my questions. please do not waste my time or take up space on my thread.

I'm sorry you've elected to interpret my responses as such.

[fcvan]

Wow, I thought gave a no-nonsense matter of fact response to the question regarding check thickness. I didn't see snobby ness anywhere. Anyway, too thick of a check can sure make sizing a chore.

I have a CheckMaker die for 30 cal and several 30 cal molds that have different shank sizes. One boolit likes checks made from .014 aluminum, and the other likes then .010 thick. I can use the .014 checks on them both, but the one with the oversized check shank takes a lot of effort to seat/size. I'm definitely liking the fact that I will never have to buy another box of checks again!

[tjones]

I just started shooting cast rifle slugs w/gas checks. I had picked up two round tins of horandy gas checks about 1600. I worked with two bullet designs and started on second full tin and thought I would get another thousand checks.
The old hornady checks I have been using measured .021 thickness, the thickest I have been able to find is .017
now for the questions
does anyone make .021 copper checks?
has anyone had experience changing check thickness?

I got this note from hornady
"the thickness of the gas check is .017 and has been this thickness for all the time of production. Thanks"
From: Hornady Manufacturing, Inc

After the check is finished you need a point micrometer to measure the thickness. No doubt they start with .017. Cheap point mikes start at $65, Chinese. Good ones from China to our USA specs, or Japan start at $150 and run to $440. for 30 degree points. I don't have one, can afford either, seems only calibration shops do.

[MT2DAY]

For reference I measured each gas check three times using an old craftsman 1" mic and a small steel ballbearing first with just mic then w/bearing on both sides and got the same results on on the four checks I tested, .021. ball bearing on both sides told me the base is flat.. just for fun I will use rcbs case master and retest and try to measure the lip thickness. I'm curious to know how much the forming process distorts the lip...
because the moulds that I have have proper base diameter I believe I will set the remaining thick gas checks aside and get some gators,,,curious about the bite lip.
some time this spring I will set up bench and chronograph and do a series of shots.. I'm thinking 10 shot groups in 30-06 using my best grouping primer/powder for each bullet with only change being check thickness 178gr and 200gr.... .021 and .017 GC....
rifle cleaned after each group with one fouling shot that does not count[9 in paper] evenly spaced to keep barrel temperature consistent
any other thoughts about how to make test better?

[MT2DAY]

Sorry Jeff after being stuck inside for the winter and creaking more when I get up I guess I'm getting raspy..... after rereading everything slowly I believe I will do as mike says and not overthink this. the few groups I fired last fall were not great but conditions were not good and I have had all winter to twist...
ending note: using the case master with bent point rod the average is...close to the bend of the gas check the thickness is .010, up to .021 at lip edge and every gas check varies as I measure around the perimeter like its cocked, might change the center of gravity.

[338RemUltraMag]

A .021 thick 30 caliber check would not be able to seat on a .284 shank, the OD of your checks are most likely in the .317 range and .021x2= .042 so .317-.042= .275 subtract that from .284 and you get an ID .009 too small for a standard diameter shank.

I make my checks from .014 metal and they crimp securely onto a .316 boolit.

[doctorggg]

I use 0.14 copper for all my 30 caliber checks with zero problems.

[Faret]

I use 0.14 copper for all my 30 caliber checks with zero problems.

Could you tell us where you found the copper?

[elwood4884]

The reason you might be having an issue finding the thicker style checks is because Hornady changed their gas check design quite some time ago. They now use a crimp on style gas check. The early ones they use to have werent designed this way. The old style ones did not contain the flared mouth that crimps into the bullet. Might be a reason for the difference in size.

[MT2DAY]

I talked to an old boy that told me hornady would do custom runs decades ago...so I will save them in case I get small base mould.