Never seen a longer barrel for that gun.
However, I have owned a couple of these over the years. This is the one case where I prefer aftermarket mags over factory mags. MecGar mags have a thicker body and less flax than the factory mags. Also easier to load than the factory mags, IMHO.
Mecgar makes factory mags for many other gun companies, and are generally considered the best aftermarket mags. So, they are good stuff.