Whidden Shoulder Bump Gauge Number

[Pawnee Bill]

Just got my 223 Rem F/L Click Adjustable sizing die from Whidden and included was a shoulder bump gauge. It has the number .330 inscribed on it. I guess I'm really dumb, but what does that number mean? I would think it would say 23 degrees.

 

[L.Sherm]

Its the dia. of the shoulder on the datum line of a 223 case

 

[K22]

L.Sherm answered your question. I just want to add that these are excellent one-piece gauges. They are caliper group specific and do not have inserts / holder interfaces which can induce error.

I have a one for each caliper group I load and really like them. They are also relatively inexpensive.

 

[Pawnee Bill]

Thanks for the info guys. Why are they marked with the dimension rather than the shoulder angle?

 

[L.Sherm]

The datum line is the datum line no matter the angle

 

[SKWERLZ]

As stated it’s the datum for a 223/5.56 cartridge

The lil whidden gauges are pretty good.

 

[PatMiles]

Other cartridges use the same diameter to read the measurement at that datum line.