It is plastic feed lips, but as mentioned by sillymike, you can replace the tower assembly. They are listed at $24 on the Black Dog Site. It took a while to sort out mine. Found it worked fine with most 40gr round nose lead ammo, but a lot of FTF's with most types of hollow point ammo. It's nice to have, but I find I spend most of my range time shooting my BC 25 round mags as the drum takes about 5 min's to hand load, and the BC mags can be loaded in 20 sec's using the the loader. Also, when the drum is fully loaded, it gets a little heavy so when firing off a full drum in my SR-22 it get's a little tiring and those last rounds tend to wander a bit. It is fun to rapid fire off 50 rounds though.