The importance of a case Gauge

[Shooting while seated]

When I started reloading, nobody mentioned a case Gauge, I am very luck I did not blow myself and my brothers very expensive Bushmaster AR-10

Luckily I ran into a range master who reloaded and was very sharp, I now nave at least two for every caliber that I reload.

I check, with the case gauge, every sing round that I reload and find 1-2 rejects per 100 every session.

When reloading 44MAG 4 in 100 will not chamber in my taurus 5 shot, I have not taken the time to figure this out.

I just wanted to make the Point of how important it is for the beginning reloader to have these tools.

Just a PSA from the man in the chair.

 

[jepp2]

I just wanted to make the Point of how important it is for the beginning reloader to have these tools.

I agree

https://forum.accurateshooter.com/threads/whidden-case-gauge-a-nice-tool-for-the-purpose.4012766/

 

[Richard Jones]

I am very lucky I did not blow myself and my brothers very expensive Bushmaster AR-10

Can you elaborate on this?

 

[rwj]

I agree

https://forum.accurateshooter.com/threads/whidden-case-gauge-a-nice-tool-for-the-purpose.4012766/

Every hand loader has one for each caliber - it’s called a chamber...

 

[rkittine]

I just got one called a "Slotted Case Gauge" from Sheridan Engineering. the bottom has a min/max cut out and the side has a cut out so you can see the cartridge in the gauge. I will be getting more of these to compliment that Whidden and Wilson ones that I currently have.

Bob

 

[Shooting while seated]

Can you elaborate on this?

When running my loads through his gun they would not eject and the next round would ram into it pushing the bullet down the case, i cant think of the term for that but it could have caused a detonation.

 

[Shooting while seated]

Every hand loader has one for each caliber - it’s called a chamber...

so you disassemble your gun and check each shell?

I am feeding 8 308s, 7 9x19, 5 223s and 7 40 sw that would not work very well

 

[Uncle Ed]

so you disassemble your gun and check each shell?

I am feeding 8 308s, 7 9x19, 5 223s and 7 40 sw that would not work very well

Chambers and reloading dies vary in size and the general thumb rule is "Your best gauge is your chamber". That being said I do not know any reloaders who disassemble their semi-auto rifles to check the fit of their ammo.

I also have many case gauges but my main concern is checking the case body diameter. I buy bulk once fired Lake City brass that has been fired in a multitude of chambers. I use the JP Enterprise gauges because it is smaller in diameter and closer to minimum SAAMI diameter. I check the resized case and the loaded cartridge in my JP Enterprise gauges. And if the cartridge fits the JP Enterprise gauge it will chamber in any rifle.

The problem with most bottle neck case gauges are they are made to check shoulder location. Meaning the case body diameter is closer to the maximum case diameter.

I use a Hornady cartridge case headspace gauge to check the shoulder of fired and resized cases.

For a semi-auto the resized case body diameter should be .003 to .005 smaller in diameter than its fired diameter. This allows the case to spring back from the chamber walls and extract reliably. And Lake City brass is very hard and springs back more than commercial brass when resized.

The photos below are to show the difference in case gauge diameter. A "FIRED" Lake City 7.62 case is in a Dillon .308 case gauge. And a resized case will drop correctly into the gauge but may not chamber in your rifle.

And below is the same fired case in a JP Enterprise case gauge showing its smaller body diameter.

So again, the majority of rifle case gauges are used to check the amount of shoulder bump. And these gauges do not check case body diameter. If the cases are fired in your rifle then checking the case body diameter should not be a problem. "BUT" if you are resizing once fired or range pickup brass then checking case body diameter is important.

Competitive pistol shooters use case gauges because they pickup their brass and end up with other shooters cases. And the problem with mixed brass is brass spring back after sizing. Meaning a normal die might not reduce the case diameter enough to fit your chamber.

If you use range pickup or buy once fired brass you need a case gauge that makes sure the resized case body diameter is small enough to chamber. This also applies if you have several rifles in the same caliber and do not keep the brass separate.

I'm a cheap bastard and buy once fired Lake City brass for a fraction of the cost of new brass. And I do not cry if I lose a few cases from rifles that throw perfectly good brass away and makes you go look for it.

They even tell you how to be a cheap bastard at this website.

Save $$ By Using Lake City 5.56x45mm Once-Fired GI Brass​

http://bulletin.accurateshooter.com/2019/10/save-by-using-lake-city-5-56x45mm-once-fired-gi-brass/

​

 

[rwj]

so you disassemble your gun and check each shell?

I am feeding 8 308s, 7 9x19, 5 223s and 7 40 sw that would not work very well

At least once to verify proper function. Better to discover issues on the bench at home than on the firing line.

 

[K22]

Good that you recognize the importance of establishing proper case headspace for reloads.

However the Case Gauge only establishes an approximation and while better than nothing a more precise way is to use a bump gauge and caliper to measure the fired unsized case head space (primer removed) then adjusting the full length resizing die to produce the desired shoulder set back so the sized case will properly fit the rifle chamber. Generally for bolt rifles this is .001 to .002 and .003 for semi-auto's. This die setting should always be check / verified against how well the sized case will fit in chamber of your rifle and adjustment made accordingly.