Most of my go to, long guns are carbines, ( is that an oxymoron? ) because it is light, and short, easy to handle, so I will carry it. I love my M1a's, but I have humped one, for a full day, and well, I ain't 20 any more. They will stay in my stable, but a word of advice, if you pack a full size rifle, like the M1, M1a, HK 91, FN FAL, sling it right off the bat, if you keep it in one hand cruising, it will get very old, very fast. If your like KSAIL, fresh from the sand box, your used to carrying much more and god bless ya.
My personal carbine that is the grab an go, an A3 DPMS, 16" with a comp M2 aimpoint, stock front sight base and a Troy folding rear sight. So far always reliable, and it has 2 30rd mags in a magcinch attached, so if I'm out in 5 seconds, I got 60 rds at the ready. It does have a flashlight attached. Quad rail, and I'm thinking a new attachment, not a coffee grinder, but a simple tube or container of some type to carry spare batteries, otis cleaner, spare parts etc.. My aimpoint is a 10,000 hr, May send it in for the 50,000 hr upgrade. 10,000 hrs gives you 1 yr, if you leave it on, in a low setting for the whole yr. Watch the classifieds and you can find one for under 400, steep, but worth it.
AK's, I'm cool,with that, it does have better penetration, and 200 yrds and under, great, short rifle, + I have lots of it stored away, 7.62x39 of course. This cartridge will, penetrate a telephone pole and have enough energy left over to knock over a 25lb steel plate. Course sights, not ideally placed, but usable, better than average trigger pull, if long.
If you own an AR with a 1in8 twist or faster, and you can afford it, check out the mk77 ammo, 77 grn bullet is getting great reviews from the sand box, for penetration and accuracy. If not the 62-63 grn armor piercing, is a good alternative. Leave out hollow point and soft points in .223. They will blow up on foliage.
Magazines, the AK mags and M1a/M14 mags are robust, but I have Vietnam era m16 mags that still function flawlessly, I try not to stomp on them, as they will bend, Pmags are stouter.