Misc Chatter, Muzzle breaks on SBRs, AR Mags, Height over bore, MGI Hydra


Last weekend I was shooting M855 out of a 8 inch barrel with a muzzle break.  Each shot I saw a muzzle flash that extended past my peripheral vision.


Recently I saw a video where someone was doing rifle pushups with an AR15.  I was going to reference that video in this comment, but I don’t recall where I saw it.

Rifle pushups involve holding the rifle and balancing your self and it on the inserted magazine while doing pushups.  So the rifle and magazine have to support your weight and you have to balance your self on that single point of contact between the rifle magazine and the ground.

Here is a video of someone performing them with an AK:

First time I saw these, I recall the person explaining them telling us how you could never do this with the flimsy AR15.  I never thought to try it.  So I got a chuckle out of seeing someone to rifle pushups with an AR.

That got me thinking about the olden days.  For so long it was known that the weak point of the AR platform was the magazines.  That is why it was known that the AUG, G36, XM8, Galil, etc were superior weapons because they had superior magazines.

I think part of this came from the mentality caused by the Assault Weapons Ban (AWB).  During the AWB we were buying beat up old mags at very high premiums.  It didn’t help that the military just loves to never throw out old mags.  I’m fairly sure that while I was in Marine Corps, my self and my peers were issued mags older than we were.  Go to the Armory and try and swap out a mag that had bent feed lips where the rounds would just spill out like a water fountain and you would be told to fix the mag your self or they would charge you for a new one.

So for so many years I remember people talking about how the AR mag was the weak spot of the gun.  I think it was around the time Magpul started making the P-Mag that people starting throwing away their old beat up mags and buying new mags and we stopped hearing that saying.

Now it seems that people want any new 5.56 rifle design to use AR mags.

Now, to add the ultimate insult to injury, groups like Definitive Arms, Texas AK designs, and Zastava setup AKs that use M16 mags:

Oh what a world we live in.

~25 rounds fired at about 10 yards, point of aim was the red dot.

I also remember critics of the AR damning it for the height of the sights over the bore.  Because of that you couldn’t get a good zero, it was unsuitable for close quarters combat, etc.



While I was writing this, I remember the MGI Hydra.

The Hydra (which I think was also sold under other brand names) had a modular lower and a quick change barrel upper.  You could buy them separately.

The upper allows for true tool less quick change of a standard AR15 barrel just by flipping two levers.

The lower is modular allowing you to replace the front section with different magwells allowing for AK mags, 9mm mags, etc.  A M14 mag well rifle was shown, but I don’t think it was ever sold to the public.

In the past, I really wanted one of these lowers.  I thought it would be an excellent host for a SBR.  Out of curiosity I looked up the price of them while I was writing this.  The extra modular magwells are $275 each.

At that price, you could buy separate lowers and a tax stamp for each one.

No wonder I’ve never seen anyone own any of these.  It would be cheaper just to have whole new guns.

But, maybe if I win the lotto, I’ll buy one anyways.


  1. I think that Hydra is a nice solution to someone wanting a modular firearm. I think it falls into the same problem of the other “quick barrel swap” uppers and rifles; XCR, ACR, MRP come to mind. That problem is zero shift. You’ll be close, but not so much. I’ve owned or own the above examples and it’s convenient to just have a case of barrels for whatever you want to do. If you have time to BZO it’s great. Anymore just having a spare upper is far easier and usually cheaper or comparative in price depending on what you do to it.

    • When the Masada was announced, I really wanted one. By the time the ACR had come out I had lost interest.
      But just a few months ago Bushmaster announced they are going to sell some caliber conversion for. You will be able to buy a .450 Bushmaster barrel. Isn’t that awesome…
      Yea. . .
      I still like the idea of being able to easily pull a barrel once a year or so to aid in completely cleaning the copper out of it. But it is certainly unnecessary.

      • Ah, yes, the Masada. The buzz of SHOT 2007. RUMINT was S&W wanted to buy it then. Sometimes I wonder if it would have been better if they had. The original design was better in that an unmodified AR barrel could be used. The gas port restrictions were in the gas block but Bushmaster wanted to tie everyone to their parts that were all but nonexistent for years. In fairness to Bushy, in 2010 when they finally crapped out ACRs for sale it was a different political climate. Everyone was sure bans were on the horizon and every time some nut job shot up a school or gay bar the money was on ARs and mags. You could get at least 3-4 decent, functional ARs for the price of an ACR.
        Then they fractured markets with the next gen individual carbine effort. Remington took up the hopeful .mil development and put out vapor ware the small ACR community wanted but refused to market. In a way, it was a micro view into capitalism though. People started to tap into small manufacturers and machine shops to offer their own goods. Gunsmiths were offering barrel conversions based on your parts. Bushy finally took heed and started selling an unlisted package number for people wanting to do their own.
        The ACR is a fine rifle that could’ve been more. It’s actually a bulky rifle to handle and has a mysteriously heavy barrel profile that throws balance way off. Given the parent company I’m not surprised at the 6.8 and .458 news. They can’t be seen abandoning their namesakes.

        The XCR was around all that time but the company could be a little, I don’t know the best way to describe it really, interesting to communicate with. For a spell they had young lady there that was feat to work with. Whatever she made she was underpaid for the hassle. There was a small forum community dedicated to the platform with very loyal customers. Good people. Some days you’d get great interaction and feedback with the company and even owner and others you’d get told you were dumb for wanting something a certain way. Example was 300BLK when it was initially making waves. “We have x39 conversions, why do want this other thing? That doesn’t make sense.” Yeah, it’s the next big thing but for most shooters it made more sense. Better, reliable mags they already own for 5.56 and they get to claim cool kid status. 5.45 conversions during the heyday of the spam cans was another miss. They have them both now, several years later.
        The company had history with Remmy and MagPul over trademarks and patents and such but they were more worried about being righteous than playing it to their advantage. Being able to offer a full suite of MagPul accessories in exchange for settlement in a dubious bolt catch design infringement seemed more marketable to me, but that’s only my humble opinion.
        The rifle itself is still good. Not very refined in execution but in a way that’s better. Some parts are easier to fix and diagnose that way.

        The MRP made the most sense in that it was AR based, much like the Hydra. The leap to non-conformity isn’t as huge. Converting any barrel to MRP pattern wasn’t a chore for any shop with a lathe and a mill and more than one shop was doing it as of so many years ago. The barrel socket and securing method held zero reasonably well at least for the number of removals I’ve done. And yes, it makes cleaning way easier, especially after a long, suppressed day.


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