Am I missing something or aren't 10 round mags for a centerfire rifle like the SKS prohibited???
Kim
Yes, you
are missing something.
10 round magazines for the SKS are indeed prohibited. (magazines for a centre-fire semi rifle may only hold 5 of the prescribed cartridge)
However, 10 round magazines for other firearms are not. For example, the XCR pistol in 7.62x39 has a ten round magazine. This magazine is perfectly legal, as it is a pistol magazine.
There is
no law saying you cannot insert a pistol magazine into a rifle. It is illegal to modify said magazine to fit the rifle as you are re-manufacturing it and in essence creating a prohibited device. There is
no law saying you cannot modify the
rifle to accept the magazine though. There are several threads about how to mod your SKS to accept the XCR pistol magazine. It requires removal of material on the bolt and receiver if I'm not mistaken.
Magazines are legal entities by themselves, they are either legal or illegal, and that determination is made based on their
intended use. A pistol magazine does not become a prohibited device once inserted into a rifle, as it remains and forever will be a pistol magazine unless you alter it. You are committing no crime if you cram 16 rounds of 5.56 into a magazine limited to 5 rounds of .50 beowulf. The magazine is permissible because it is designed to hold 5 rounds of .50 beowulf and does just that, regardless of how it is otherwise used.
Common exploitations of this loophole:
LAR-15 magazines will fit into any rifle with a STANAG pattern 5.56 magwell, so rifles such as the AR15, XCR, SU-16, MR-1 will accept this 10-round pistol magazine
.50 Beowulf rifle magazines will fit into any of the same rifles and hold approximately 14-16 rounds of 5.56
.40 S&W magazines limited to 10 will hold about 13 rounds of 9mm, so if you own a pistol chambered in 9mm that also comes in .40....you may have a few rounds of extra fun at the range.
AIA Enfield magazines will hold 10 rounds of .308 and will fit in an M14.
All perfectly legal. The RCMP issued a bulletin clarifying this.
