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

Nice write up.  Having said all of that, though, would you buy another Vulcan receiver?  The reason that I ask is that I will probably see them at a gun show this weekend & I might buy one, if your answer is "yes."

Quoted: Nice write up.  Having said all of that, though, would you buy another Vulcan receiver?  The reason that I ask is that I will probably see them at a gun show this weekend & I might buy one, if your answer is "yes."

If it suited the build, yes.  My experience with Vulcan has been only positive, and the gun runs great.

Thanks for taking the time to write up your impressions.
I could submit one missing item.

The CAV MKII has what NO other lower has, be it Nylon,Plastic or metal that is the ability to slap a .45 Grease gun mag into it. The magwell has been opened up to allow the GG mag.
A couple members have already have built working one off models.
A contractor already has a prototype mag block designed and is QA/QC it .

If it suited the build, yes.

Sorry, I don't understand.  

Thanks for your response, though.

Quoted: If it suited the build, yes. Sorry, I don't understand.

In other words, if light weight and low-cost were a large priority for a particular rifle that I want to build, then I would go for the Vulcan.  Or if I wanted a lightweight but didn't like the CavArms lower grip or looks, I'd get the Vulcan.

But it works both ways.  If I want a lightweight rifle, and it had to be able to take a beating, I'd go for CavArms.  Or if I couldn't live with the Vulcan non-warranty and didn't care what it looked like, I'd go for CavArms.

Thanks for your response, though.

You're welcome.  I've been helped so much by AR-15.com I just want to contribute something useful.

C_M

Pictures?





Cav arms lower isnt listed at $750? I thought it was $150.

Quoted: Cav arms lower isnt listed at $750? I thought it was $150.

Misprint, corrected.  Thanks!

Thanks for the info.  I have a Vulcan I used to build an "Ultralight" with and love it.  I wanted to try a Cav Arms too but was reluctant.  Guess I'll get my order in for a "Bright Yellow" one!

-------------------------------------------------------------------------------- Quoted: -------------------------------------------------------------------------------- If it suited the build, yes. -------------------------------------------------------------------------------- Sorry, I don't understand. -------------------------------------------------------------------------------- In other words, if light weight and low-cost were a large priority for a particular rifle that I want to build, then I would go for the Vulcan. Or if I wanted a lightweight but didn't like the CavArms lower grip or looks, I'd get the Vulcan. But it works both ways. If I want a lightweight rifle, and it had to be able to take a beating, I'd go for CavArms. Or if I couldn't live with the Vulcan non-warranty and didn't care what it looked like, I'd go for CavArms. -------------------------------------------------------------------------------- Thanks for your response, though. -------------------------------------------------------------------------------- You're welcome. I've been helped so much by AR-15.com I just want to contribute something useful. C_M

Thanks for the clarification.

I took the CavArms lower out to the range and tried it with two different uppers.  One is a J&T A2 receiver and 16" Model 1 lightweight barrel.  The other is the Vulcan carbon/Aramid flat top and Bushmaster 16" Superlight barrel.

Both combinations ran flawlessly.

I was especially intrigued with the CavArms lower and Vulcan upper.  It is a nice alternative to the Vulcan lower.  Very light and handy, looks rugged.

C_M

A pic of the Cav/Vulcan would be nice...and at this point is REQUIRED.  

As to the one off M3 mag setup how about this.  

Where can one purchase a copy of the plans for the mods to make the .45? Thanks

Quoted: Where can one purchase a copy of the plans for the mods to make the .45? Thanks

Very simple, buy an  Oly .45acp upper and a set of 2 piece 9mm mag blocks and a couple M3 mags.   You can cut the mag blocks down with an angle grinder and a little patience.  When you've cut enough to make the M3 mag fit you're done.   Push the blocks all the way up with the upper installed and when it wont go any further it's in place.  Put the M3 mag in to help hold the blocks in place and drill a couple of holes through the receiver and block and put in a roll pin to secure it.  You can partially unscrew the mag catch so you can seat an M3 mag in and use the slot in the receiver to scribe an outline into the mag, pull the mag and hit that spot with the angle grinder and the notch is all set.   Load the mag and go shooting!  If you're completely incompetent at machining as I am you'll be able to do it in an hour or so.  Only tools you need are a file or two, a couple drill bits and drill and an angle grinder ($10 at harbor freight) a vise and some patience.

Any updates onthe Cav Arms v. Vulcan?

Quoted: ...My experience with Vulcan has been only positive, and the gun runs great.

VulcanArms?  The formerly Hesse Arms?  Man I saw this .50 BMG rifle that had a bolt that looked like it was constructed out of a half-inch pipe nipple.  I couldn't imagine if anyone actually bought that damn thing, much less how many of its owners it must have eventually killed.  I just figured they couldn't be too competent, and their products were probably all garbage.  Was I wrong, or is this another Vulcan?

So what's the deal?  Is this the same Vulcan?

I've been seriously considering a Vulcan upper and lower for awhile now... I know people will complain about the material but I know theose HKs have been working fine. I'm not 100% sold yet though.

I've been thinking about a vulcan upper/lower set also for a lightweight 9mm build.

Carbineman, I got a quick question on the Vulcan upper.  I did a lightwieght upper build using one of those...but I don't think the barrel nut seated as far as I'd like.  I torqued the barrel nut down as much as I feld comfortable doing, but the gap between the reciever and the barrel nut is a little bigger than normal...not much, but it is visible...and when I stuck a bolt/carrier in it, it would not go all the way into battery w/o me pushing it.  That made me VERY nervous, and I haven't shot the rifle as a result.  

Did you experience anything similar in your build?  Thanks!