For years, Californians have lusted for the Mech Tech carbine conversions for 1911 pistols. The problem is that, although it's legal to have a pistol grip on 1911 pistol, it is not legal to have a pistol-gripped semi-automatic rifle with a detachable magazine. Moreover, it is not legal to have a semi-automatic centerfire rifle with an overall length under 30". The easy solution for this is to use the fixed-stock version, which measures 32.38" in overall length.
There are two solutions to this: render the magazine non-detachable, or nullify the pistol grip. Nullifying the pistol grip is possible but silly, however fixing the magazine is doable. When the kit is installed, the magazine is fixed and only removable via the use of a tool, thus satisfying California law.
Glock conversion units would be legal the same way, however someone would have to come up with a bullet button or fixed magazine kit for one before they could enjoy the same legal status.
-- SeanNewton - 15 Aug 2008