Hi all:
As some of you know, I built a nice ultralight with a Vulcan carbon/Aramid lower and upper receiver. It turned out great. I have about 2,000 rounds through it and it runs like a champ.
I just got a Cavalry Arms Mk II lower which I will be using for my next build. For posterity I thought a comparison between the two plastic lowers might be helpful. There is no "recommendation" in this topic. It's just a comparison FYI.
Vulcan lower receiver:
- Material: carbon/Aramid, strong and "slippery" feel, very light.
- Appearance: proportions and appearance are exactly like any lower receiver. Finish is black and somewhat shiney.
- Weight: seems to weigh almost nothing.
- Warranty: precisely none. This is a large and legitimate gripe about Vulcan. You buy your part, you take your chances.
- Building: uses exactly the same parts that you would use in any lower receiver. Pins and parts go in very easily. Holes can be cleaned/sized with a twist drill by hand very easily. "Dings" don't mar the finish.
- Ergonomics: uses same grip and buttstocks as any AR-15. Endless combinations to suit the builder.
- Price and Availability: few or no stocking dealers that I know of. I got mine from Vulcan for $53 + FFL transfer + shipping. "List Price" is $80, very competitive with generic forged AL stripped lowers.
CavArms Mk II lower:
- Material: glass-filled Nylon 6, feels strong and rugged.
- Appearance: Beefy. Thicker around the mag well and along the upper edge. The finish on the gripping surfaces have a gritty texture, not slippery at all. Overall it looks rugged. However it does have prominent seams all around where the two halves are vibration-welded together.
- Weight: very light. My Vulcan lower with ACE ultralight rifle stock seemed to be slightly heavier than the finished CavArms.
- Warranty: lifetime warranty. Cavalry Arms has a great reputation for standing behind their products and being easy to work with.
- Building: very different from a standard lower. Grip, trigger guard and buttstock are part of the unit. Pivot and takedown pins are "Speed Pins," and no detents keep them in place. Uses a carbine buffer and spring, but no buffer tube. The buffer pin is special to CavArms and is held in place with a long pin that goes through the stock. All the holes on mine were perfect, and I didn't need to drill or clean them. Safety detent and spring drop-in from the top, install very easily, clipping the spring was unnecesary. Overall it was a very easy build, faster than the Vulcan, because my dealer installed the buffer pin as a courtesy and there are fewer parts to install.
- Ergonomics: Nice grip, thicker than a standard A2, with a curved backstrap. You'd better like it because it's the only shape you can get. Buttstock is A1 length. Again, no options for anything else.
- Price and Availability: many stocking dealers locally and on the Internet, and EE. I got mine from a local NC dealer. "List Price" is $175, but dealers will put together packages and have sales. Can also be purchased assembled. Even at list priice for an assembled lower it's a good deal for a quality product.
I left out
durability for a reason. I have no way of being sure about durabiity, since I am not going to do destructive testing running over my rifles with a truck. My subjective view is this: the Vulcan is thinner, and being plastic it
looks less robust than the CavArms. As I said above, I've put ~2,000 rounds through it and there are absolutely no signs of wear on the Vulcan parts. I don't think I'd use it for a hammer or wack someone over the head with it and expect it to keep running. On the other hand the CavArms lower feels very solid and beefy. Again, this is all subjective, and it's all I can offer.
C_M