MATCH or BENCH REST PRIMERS
The difference between match primers and standard primers is the degree of testing and quality control used in their making. Hornady reports that in their research that match-grade primers performed very, very consistently from load to load as measured in their pressure tests. CCI states that Benchrest cups and anvils are selected for exceptional uniformity. During the assembly operation, the operator who meters the primer mix into the cups (or "charger") is chosen from the most experienced workers with an outstanding record of consistency. The BR line runs at a little slower pace to provide time for extra inspection.
STORING YOUR PRIMERS
Primers can be damaged by extreme heat, cold, and humidity. Therefore proper storage is necessary. We have seen primer shortages and therefore runs on primers by people stocking up for the future. What would be the use of having 20k primers if you don't store them properly and they deteriorate?
Heat dries out the priming compound making it brittle and subject to disintegration during the seating process, causing a misfire. Further, the primer can still detonate if you try to disassemble misfired rounds and punch out the "bad" primer. That is one reason that de-priming "live" primers is discouraged. High humidity can cause the priming compound to be too wet to detonate properly as well. Therefore you should take pains to store primers in a cool, dry place. No garages, attics, sheds, or damp basements. Desiccant in the larger container that holds your primer boxes is probably a good idea if it is humid where you live.
Metal ammo cans are popular for storing various items like ammo and brass among reloaders. However they should not be used to store your primers in (or your powder as well). If anything sets off those primers (or lights off the powder), the metal can just adds shrapnel. Of course you shouldn't store primers and powder together for obvious reason.
There are watertight plastic ammo cans like MTM's Sportsman's Dry Box [#SDB-0] or their military-sized (AC30C & AC50C caliber) O-ring sealed plastic ammo cans available, or you could use some type of wooden box etc. that would be a better choice than the usual G.I. steel ammo can for your primer storage.
PRIMER CHART & REFERENCE GUIDE
Small Handgun Standard .017" cup thickness
Federal 100 - Has a soft cup - good to use if hammer strike is light.
Federal 100M - Match version of above
Magtech PR-SPC - Lead-free "Clean Range" primer for indoor ranges etc.
Remington 1 ½
Wolf Small Pistol SP - brass cup
Small Handgun Magnum .017" cup thickness
CCI 550 See Note 1 at the bottom of page
Federal 200M - Match version of above
Remington 5 ½
Wolf Small Pistol Magnum SPM - brass cup
Large Handgun Standard .020" cup thickness
Federal 150 - Has a thinner cup
Remington 2 ½
Wolf Large Pistol LP - brass cup
Large Handgun Magnum .020" cup thickness
Wolf Large Pistol Magnum LPM - brass cup
Small Rifle Standard
CCI 400 -thin .020" cup, not recommended for AR15 use by CCI/Speer. Good for .22 Hornet, .30 Carbine. See Note 1 at the bottom of the page
CCI BR4 - match primer with a thicker .025" cup.
Federal 205 - Mil-Spec cup thickness according to Federal - okay for 5.56mm. .0225" cup thickness.
Federal 205M - same as the 205 but the match version.
Magtech PR-SR - .025" cup thickness (not much feedback yet on this new primer as to AR15 suitability but with the same cup thickness as the Rem 7 1/2 it looks good so far)
Remington 6 ½ - thin .020" cup, intended for older, lower pressure rounds Remington says do not use for the .223 Rem or other similar pressure rounds. Good for .22 Hornet, .30 Carbine.
Remington 7 ½ BR - A match or "bench rest" primer. Lyman & Nosler classify this primer as a Standard. Remington says the compound is the same as the 6 1/2 but with a thicker .025" cup.
Winchester WSR - some piercing issues noted when changed from silver to brass cup. Cup thickness is a bit thinner at .021". Most say they are good to go for the AR15 despite that, probably because of the hardness of the cup. Some feel they are less resistant to higher pressures.
Wolf Small Rifle SR - soft, sensitive copper cup, not recommended for AR15/military rifle use or high pressure rounds.
Small Rifle Magnum
CCI 450 - same thicker .025" cup as the BR4 and #41.
CCI #41 - commercial version of the fully-qualified DOD primer for use in U.S. military ammo. With this primer there is more 'distance' between the tip of the anvil and the bottom of the cup than with other CCI SR primers. .025" thick cup. Same primer mix as CCI 450.
Remington 7 ½ BR - A match or "bench rest" primer. Hornady, Handloads.com, and Chuck Hawks classify this primer as a Magnum, differing from other sources that classify it as a Standard. .025" cup thickness.
Wolf Small Rifle Magnum SRM - hard, less sensitive brass cup intended for AR15/military rifle and high pressure rounds.
Wolf Small Rifle 223 SR223 - "This is the newest primer available in the Wolf line. It is ever so slightly hotter than the small rifle magnum primer and it comes with a brass colored thick cup. This primer can be used in place of the SRM primer or used when a different powder is used that is hard to ignite."
Large Rifle Standard
CCI 200 - mild in brisance. Hard enough for use in semi-automatics.
CCI BR2 - same as the 200 but the match version. Hard enough for use in semi-automatics.
Federal 210 - medium brisance between CCI/Remington & Winchester. Do not use in semi-automatics.
Federal 210M - match version of the above primer. Do not use in semi-automatics.
Remington 9 ½ - mild in brisance.
Winchester WLR - the hottest standard primer. Hard enough for use in semi-automatics.
Wolf Large Rifle LR - all brass - Used by noted match shooter David Tubbs who says: "Be sure they are seated into the case - if not they can be hard to ignite. Russian primers use a different sinoxide compound (closer to the European type), which, in my testing, consistently delivers better extreme spreads over Federal..." Hard enough for use in semi-automatics.
Large Rifle Magnum
CCI #34 - commercial version of the fully-qualified DOD primer for use in U.S. military ammo.
Federal 215 - original magnum primer
Remington 9 ½ M - mildest magnum primer.
Wolf Large Rifle Magnum LRM - all brass
CCI #35 - commercial version of the fully-qualified DOD primer for use in U.S. military ammo.
Primers recommended for use in .223 Rem/5.56 semiautomatic rifle loads:
CCI #41, 450, BR4 (#41 & 450 good with ball powder)
Federal 205, 205M
Remington 7 1/2 BR (good with ball powder)
Winchester WSR (good with ball powder)
Wolf SRM (good with ball powder)
Wolf SR223 (hotter than SRM - great with ball powder)
Primers recommended for use in .308 Win/7.62x51/7.62x39 semiautomatic rifle loads:
CCI #34, 200, BR2, CCI 250
Winchester WLR, WLRM (good with ball powder)
NOTE 1: According to Speer/CCI Technical Services - Both the CCI 550 Small Pistol Magnum and CCI 400 Small Rifle primers are identical in size. Both primers use the same cup metal and share the same cup thickness. Both primers use the same primer compound formula and same amount of primer compound. They can be used interchangeably.