Hornady Cartridge Gauge vs Dillon Head space/Case Length Gauge. 308

[brccd]

Hi All,
Happy New Year!

So I posted some threads on 308 case checking, and using Hornady Cartridge Gauge...

Some cartridges that after small base sizing did fit, then loaded the cartridge with primer powder and bullet, then some didnt fit...

Well got the Dillon case length/ head space gauge, tried those cartridges and cases in the Dillon gauge and they were good!

What is going on?

The cartridges that quite didnt fit in the Hornady cartridge gauge, were used in two rifles and worked fine.

So what is the difference then between the two gauges? shouldnt they be measuring the same thing?

Has anyone used both of these gauges to check things? What was your experience? Which should be trusted?

Thanks!

 

[drop_point]

Machining tolerances are a thing. The ultimate test is your barrel.

 

[dellet]

In general, a case length/headspace gauge, will only check those two measurements. No diameters or bullet seated length. Some headspace gauges will accept fired brass so that you can compare fired and sized brass for you die settin.

A cartridge gauge is cut using a minimum chamber sized reamer. It is designed to mimic a finished barrel. It should check a loaded cartridge. Lengths and diameter. Not only length of base to shoulder datum and overall case length, but overall cartridge length and base to bullet ogive, or jam length.

When your case passes the gauge, then fails as a cartridge, there are only a few possibilities. The bullet is seated too long and will possibly be in the lands of your rifle. The bullet is not seated straight, and contacting the chamber wall of the gauge. The neck wall of the case is too thick and when the bullet is seated, the diameter is then too large diameter for the chamber.

A good cartridge gauge will fail a lot of loaded rounds that will fit most rifles. Most real live chambers are not “minimum”. Basically a go/no go or limit gauge is designed to tell you it’s time take actual measurement.

One of the better loaded ammo gauges out there is the Sheridan slotted. The slot in the gauge allows you see where the contact points are and narrow down the failure point.

Your chamber is the ultimate guide. Sizing brass to fit a minimum chamber, where yours is closer maximum will lead to over working the brass, poor cartridge to chamber fit. Short brass life, not the ultimate accuracy.

Always pros and cons to any tool Or method.

 

[brccd]

thx for descriptions! i did check those out and see what you mean. i did also order the Sheridan slotted cartridge gauge. Thats coming friday, and think that one will be the most useful. as you say, it looks like the hornady cartridge gauge is at min measurements. definately a number of things to keep in order to get it all right...getting there though!