Call it 'Human Error'.
The error is to believe the sales hype on any given packaged product.
Someone is TRYING THEIR BEST to sell you something...
When you are dealing with YOUR specific firearm, or YOUR specific brass coming out of your press,
They would have to show up and PRECISELY MEASURE your specific set up to produce anything that precisely fits YOUR firearm.
The problem is, they don't.
I remember a thread not to long ago about a guy having issues with cartridge over all length.
I said to simply make a round that fits into his magazine so he knows it mag/feed,
The get an 'L' bracket & hose clamp from the hardware store, put the 'L' along side his case Go/NoGo body gauge, drop that functioning round in the gauge, and the lower leg of the 'L' should touch the bullet point, tighten down the hose clamp...
Now his gauge show him over length rounds at a glance.
Long rounds wouldn't seat in the Go/NoGo gauge.
People blew up! Some said you NEVER modify a gauge in any way, some said to measure each round with a caliper/micrometer, one even implied the gauge would some how make the round unsafe to shoot...
I guess the idea was too simple to grasp.
Once you know the precise ogive diameter of YOUR throat, that diameter hole can be drilled in exactly the same kind of gauge 'L' lower leg.
This will give you a quick reference gauge to tell if ogive is going to hit the throat or not.
It's NOT an exact, absloute measurement, it's a 'Quick Gauge', just like the case body gauge is a quick gauge you started with.
It's now a Datum line on the shoulder to ogive quick gauge, since case quick gauges index (Zero, Datum) off the shoulder.
Simply tells if you got the ogive too far forward... Like all quick gauges, it's a Go/NoGo indication.
*IF* you can make a consistent case, (human error)
*IF* that case fits the chamber, (human error)
*IF* you don't screw the case up during loading, (human error)
*IF* you can seat a bullet consistantly, (you guessed it, human error)
THEN you need a way to measure the ogive to case base.
Case gauge checks the case (for human error) and since the bullet sticks out the end of the case gauge, a simple bracket (L or U shaped) hose clamps on the gauge body,
Drilled with your chambers specific diameter ogive hole, gives you a Quick Gauge to check your work.
Like I said before, the ONLY way to know EXACTLY what the ogive diameter is in the first place is to use the specific bullet you intend to fire,
Put an extension on it so you can get it in and out of the front of the chamber,
I use cheap copper tubing with a bullet sacrifice soldered onto their bullet,
And put the bullet against the throat in the chamber, turn the tubing about 1/6 turn and extract.
This will show you EXACTLY where the rifling lands scratched the bullet.
This is the EXACT spot the rifling will hit that particular bullet, expressed in a circle around the bullet (diameter hole) you will need to make a direct read adapter or a quick gauge.
Go to ANY hobby machinist or machine shop, anyone with a lathe.
Have a piece of bar stock first pilot drilled for center, then drilled/reamed out until the hole is big enough to reach the line on your test bullet.
Then simply face the bar stock off square, and cut it off square.
This is your direct read adapter for precision measuring equipment.
The adapter goes in the measuring tool & gets measured. This is the number you subtract from total.
Then you put a completed round in the adapter and measure again, subtract adapter from total, exact ogive to base measurement.
The adapter will be fairly short, it only has to cover the distance from bullet ogive scratch to a little past the point of the bullet. Small enough to misplace...
If you want to attach to to a caliper, then add about 5/8" for the attachment slot and screw.
See case Datum length adapters for slot/screw attachment.
The same size hole drilled into an L or U bracket attached to a case gauge will give you a quick reference gauge, Go/NoGo, based on the shoulder of the case, this means you MUST make CONSISTANT Datum length cases...
If your bullet is seated too long, the case won't seat in the gauge.
If it's seated too short, there will be a gap between bullet and adapter you attached.
This isn't difficult or expensive, it's just necessary for precise measurements.
The cost will be about the same in total as for 'The Nut' which is 'One Size Fits Nothing' since there is no way to order one that fits YOUR chamber. It's a general comparison tool for general use...