I need verification on whether I'm looking at the correct headspace gauges for 300 win mag action
http://www.midwayusa.com/find?userSe...e+.535%22+Base

Now I've been doing some reading on headspacing and could use a little clarification. If I will only use factory ammo I should be fine checking headspace with the gauges listed in the link, but if I were to hand load (which I was strongly considering at some point) would I have to use another method of checking for correct headspace? All the videos and reading material I've read so far only used the go and no go gauges for headspacing, so exactly what is the field gauge use for?