ProMag SKS 7.62x39mm 20-Round Polymer Magazine

The ProMag SKS 20-round magazine is the most common way to convert an SKS from its fixed 10-round magazine to a detachable box. It drops the reload from a stripper-clip-fed internal magazine to a swappable 20-round magazine, and the 20-round body is the capacity that runs most reliably out of ProMag's SKS lineup. The 30 and 40-round versions add capacity but compound the feeding problems that plague SKS detachable conversions; the 20-round is the one to start with.

The body is DuPont Zytel polymer. SKS detachable-magazine reliability is genuinely inconsistent, and the cause is the rifle, not just the magazine. SKS magazine wells vary widely between manufacturers and production runs, so ProMag itself notes the magazine may require hand-fitting or may not be suitable for a given rifle. Expect to test-fit, tune the rock-and-lock engagement, and verify feeding with your specific carbine before trusting it. This is a range and plinking upgrade, not a guaranteed drop-in.

One legal note: swapping in a foreign-made detachable magazine changes the 922(r) parts count on an imported SKS. Confirm your rifle stays compliant on imported parts before running a foreign-made detachable magazine.