I can only find one source of headspace gauge for the 338 Federal and that is from Midway which may take up to 60 days before delivery. I checked Sinclair and Brownells and cant find one specifically for the 338 Federal but other ones that are good for .243, 7mm 08, and .308 all with the same gauge. So my question is seeing that the 338 Fed is just a necked up .308 just like the .243 and 7mm 08 are just necked down .308, can the .308 gauge be used for the 338 Federal?