If you want them for reloading your own ammo for a single gun then gages aren't always needed.
The IMPORTANT thing is that your resized cases easily fit into the chamber of your gun. Make your reloads chamber as nicely as good quality commercial ammo and you'll be ok.
If your resized cases don't fit - then lower the die about 1/16 of a turn and resize ANOTHER case & test again.
Something to think about is
'how to those gages KNOW anything about my gun?'
The main purpose of HS gages is for mfg and gunsmiths to use to verify that their chamber are 'in spec'. And for people who reload for several different guns to verify that their cases will fit in all the guns.
Do you use a gage to determine if a new shoe fits?
And YES, many people DO recommend precise measuring of chamber HS and very detailed setting of the resize die. And many still have problems that are resolved by 'lower the die until the case fits in the chamber'.
note: a smallbase resize die is sometimes needed to reduce the body diameter of the case enough to easily fit the chamber - and that isn't a HS issue or measurement.
For both 30-06 and 308Win, I've always used a smallbase resize die, and the resized cases have worked fine.
You can try a non-SB die, and if it works, then great.
Avoid Forster. They are a few dollars cheaper so they're tempting, but the dimensions are not as precise as Clymer or better. If you ask PT&G they will send you a calibration certificate with each gage.
A forum community dedicated to M14 and M1A Rifle owners and enthusiasts. Come join the discussion about optics, ammunition, gunsmithing, styles, reviews, accessories, Modern, Devine, SOCOM, EBR, classifieds, and more!