First, thanks to all for the replies. I'm a curious sort and this had me puzzled as it didn't seem to have any rhyme or reason. So I asked.
The LR and SM that I have, in BLUE boxes, are GM210M GM205M. Box says FEDERAL LARGE RIFLE MATCH PRIMERS then GM210M. Small Rifle same order of wording. I'm presuming the GM is for Gold Metal M for Match.
What started this quandary is... I purchased the first batch from a well know on-line distributor and the second from Cabala's locally. Cabala's was $5.00 more than the base price of the on line distributor but I didn't have to pay shipping or HASMAT so they were actually less expensive. All were/are in Blue boxes.
Last night I was looking for Varget powder. Looks like almost everyone is out of 8 lb. cans. Found some and it was a couple of dollars cheaper than where I normally buy so I decided to look at their primer prices. Almost $10.00 a 1,000 cheaper. But! They were in RED boxes that say Gold Metal Match hence the WTH.
It appears the primers ARE the same just packaged differently. I hate it when they do that!!!!!
Dave, for my 308 I weigh every bullet, trim every case to length and weigh every powder charge to ##.00 grain. If it's 0.1 over or under it goes back in the dispenser. Best 100 yd. 5 shot group so far measures 0.198 center to center. All calibers are checked for length, necks and primer pockets cleaned every time they are loaded. I'm not that particular with the 45/70. At 60 + gr. I'll let it go 0.1 over or under but not 0.2
Sounds like a lot of work but it's fun. It's not a job it's an adventure.