I recently picked up 24 old Colt 20-round mags. I need to function check them but can’t find anything with the search function. If there is a thread on this, can someone point me at it?
I figure load 20, insert mag with bolt closed, charge, shoot two, unload to one and fire it. Does that seem reasonable?
Thanks,
hals1
Mark the magazines with colored tape / sharpie marker so you can keep them straight.
I would fully load each magazines 3 times and shoot the whole thing 3 times before I deem it acceptable for real use. Make sure it locks the bolt back when empty. Doing a combination of charging from bolt closed, charging from bolt open, etc to make sure it doesn’t jam up in ever possible sencario.
I would also make sure it drops free from several lowers.
Look it over for cracks in the feedlips and floorplate tabs.
If it doesn’t pass any of these steps, then I would get rid of it.
You also don’t have to have a special session for this and burn up a bunch of money in ammo. You can do this when sighting a new gun or in a normal practice session, just incorporate these magazines into the session.
And make sure you use a quality gun that works.
Yea I guess that sounds like a fair way to go about it !! When I get new (old) mags,I always take them and insert them into the rifle first (empty) and see how they go in,hit the Mag release & make sure they drop free,re-insert,pull bolt back & make sure the bolt stays back,hit bolt release,& then start over with the next mag !! 
I don’t know if loading and shooting 2 rounds is a true test but it will get ya started. I would break them up into groups after doing the initial drop free & bolt hold back test and get to the range & run them like they should be,full mag,maybe download 1 round and empty each mag fully,& just make a day at the range checking out your new mags !! If ya want just go blaze away and check them,but make a good secession out of it,checking mags,doing mag changes shooting & movin,etc,run em and have fun doing it !! If ya have any problems,look them over,maybe they just need some new Springs etc !!