5.56 Timeline

Got enough LOP adjustment?

The AR went from a 2 position colapsible stock, to a 3 position, and finally a 4 position for the military. In the civilian world 6 position stocks became standard. Other stocks, like the 8 position UBR Gen 2, offer even more adjustment options.

I remember when I build my first AR15 that I wanted to have as much adjustment as possible in the stock. Now I find it silly that I own a SR25 with a 10 position receiver extension and I only ever use 2 positions of those ten.

Now it certainly not bad to have more stock length options, but I wouldn’t pay a premium for it now.

Range Report mounting the M203

Decided to throw the LMT M203 on the AR as it was intended. The M203 slides over the barrel and index on the barrel nut. It then clamps to the barrel. The KAC QD M203 mount has an insert that allows you to adjust the length of mounting area. Depending on wear and tolerance stacking you use this insert to make sure that there is no forward/backwards play in the launcher.

This spacer solution that KAC came out with is rather nifity. In their QD mount this insert is X shaped with 4 U notches in it. Each notch is cut to a different depth, allowing you to pick between 5 different thickness to take up any potential slack in the mounting.

Yes 5 options. The 4 notches are each different thicknesses, and if they are not enough, you can flip this spacer around, to use the backside, for a 5th option.

I should have taken a picture of it for this description.

Anyways, the rambling was to explain that the M203 launcher puts the barrel in tension, applying forward pressure on bottom of that M203 step cut into the barrel.

On this gun, that pressure moved the point of impact about 5 MOA up. I adjusted the zeros on the iron sights and the ACOG. I started at 25m, then adjusted the ACOG zero again at 100 yards.

Since the M203 was moved to this gun, I put on a leaf sight for it on the top rail. Fortunately it was right on, and no adjustment was needed. (Well, it impacted about 8 inches high at 100 yards. 1 elevation increment on the leaf sight would move the impact about 5 meters, so I choose to call that close enough)

Best part for me is that my stand alone mount has its’ own sights. I’ll be able to just pull the M203 right off this upper and slap it on the stand alone mount when I want to run it by it self, and I can throw it on this upper when I want to run it on an AR. I’ll just have to remember the 5 MOA point of impact shift should I take the launcher off this rifle.

I recall back when I was in the Corps, some of the M203 gunners liked having the M203 on their rifle during rifle qualification as the extra 3 pounds helped keep the rifle steady and made for less movement during firing. Personally, unless I knew I was going to be lobbing a bunch of 40mm, I’d rather have it off my gun. But here I am throwing it on a gun anyways.

Optic of the week: Nightforce ATACR 1-8X24 F1

Nightforce introduced two 1-8X scopes at the same time. A NXS 1-8X and the ATACR 1-8X. I recall looking over the specs on each and wondering why someone would pick the larger and heavier ATACR over the NXS. I really wanted one of the NXS 1-8X scopes, and I still do. I’m a big fan of the NXS 2.5-10X24 scopes and the NXS 1-8 is slightly smaller, and includes newer nicer reticles, first focal plane, and daylight bright illumination.

That said, not that long ago I was trying to sell a gun wasn’t using and I was offered an ATACR 1-8X24 in trade. I took the guy up on the deal. I figured if I didn’t like the scope, it is still easier to sell a scope than a gun.

Note that the scope comes with excellent Tenebraex flip covers. I am only using the cover on the objective lense.

After throwing the scope in a Larue mount I had laying around, I felt it was a little big and heavy for a 5.56 rifle. Not excessively so. The scope by it self is actually lighter than a Elcan Specter DR. Often when I dislike a scopes weight, I go and compare it to the Elcan and tend to find the scope I am complaining about is lighter. Now once you include a mount, this scope and mount would be about a quarter pound heavier than an Elcan Specter DR, but this scope is a 1-8X unlike the 1-4X Elcan. At 21 oz, I feel this a little big for a light and handy gun.

Playing around a bit, I tried throwing this scope on top of a .308 AR. That just felt right to me. It balanced well and felt like it fit me and the gun perfectly.

At 1X the ATACR has a reticle with thick side and bottom bars. Looks almost like a German #4 reticle. This lets you use the scope for fast work up close when the illumination is off.

Once you turn on the illumination, at 1X it starts to feel like an Aimpoint.

I have yet to use a 1X-whatever power scope that truly feels Aimpoint fast at 1X. But these newer scopes are getting closer to it. The 1X on the ACTAR still feels a little bit like looking though a bubble at 1X. The flattest feeling scope I have used at 1X is still the Leupold MK6. But the illumination on the MK6 1-6X was rather unforgiving of head position. The ACTAR is far superior there.

As you increase the magnification, you get to use the “FC-DM” reticle which is a mil based Horus like Christmas tree of dots.

There is a 4 segmented larger circle that is 2 mils in diameter. This gives about a 6.75 MOA illuminated center dot when you are running the scope like an reflex sight. There is a center .35 mil dot which is about 1.2 MOA.

If you crank up the brightness while magnified, you will see other parts of the reticle exhibit some stray illumination. The brightness knob has an off setting between each brightness setting you can can easily turn it off or back on to your preferred brightness. This knob is easy enough to turn that I have a little concern it would turn on in my range bag and drain the batteries.

Nightforce doesn’t list battery life on their website, which usually means very poor battery life. The manual says 29 hours at maximum brightness. That is rather pathetic.

Adjustments are made with the excellent capped .1 mil turrets. Nightforce includes thread protectors should you want to run the turrets exposed. I fired 2 rounds at 25 yards and found I was impacting 2 mils right and 1.5 low from my desired point of impact. Nice, easy, numbers I quickly measured using the reticle. I dialed in the adjustments and moved out to 100 yards. I found I was impacting right where I wanted to be.

When shooting at 100 yards, I found that center 1.2 MOA-ish dot felt huge. If I were doing any sort of pure precision work at 100 yards, I’d make an elevation adjustment and use a different part of the reticle for aiming. That large dot was covering up the 3/4 MOA dot I was aiming at and also covered up my impacts.

I think I see so many of these 1-X power scopes for sale barely used because people by them thinking that they will be getting a scope that will be Aimpoint fast at 1X, and work as a sniper scope at 8X only to find out that the scope will end up sucking at one or the other function. More likely terrible at both.

With the ATACR it feels pretty nice at 1X, but it makes the center of the reticle far from ideal for any sort of precision work at 8X.

The reticle markings on this scope have a grid of dots reaching down to 10 mils. I estimate that amount of hold over would get my 308 rifle out to about 825 yards. The ammo I am using would be going sub-sonic at about 875 yards. I figure this scope could handle the practical range of the rifle with just hold overs at max magnification.

I like this scope but I’m not sure if I would recommend it. It is rather pricy, and there are other lighter and cheaper options. 1-10X scopes are on the market, and and improving all the time.

Still I like this one more than I expected. I think I’ll keep it around until I find something better.

Upgrading the military shotgun – Part 4 – Stock and Sling mount

Part 1 HERE.
Part 2 HERE.
Part 3 HERE.

We started with the old M500M, pretty much a 6 shot Mossberg 590 shotgun.

Your generic riot gun. We made a few changes, but it is time to make the most often made change in military shotguns. A pistol grip.

Pistol grip only shotguns sell fairly well in the civilian world. All manner or cheap M500s, Maverick 88 Persuaders, and the like are sold to ignorant novices looking for a home defense gun. Experts and experienced gun owners tend to scoff at this as people tend to shoot pistol grip only shotguns very poorly.

USMC Breacher with pistol grip shotgun

In the above picture of a “SEAL Armory” you see two military M500 shotguns that have been retrofitted with pistol grips. They don’t even have the same model pistol grip on them. It makes me think these were retrofitted at different times.

So why would the miltiary be retrofitting these shotguns to pistol grip only if pistol grip only is considered so terrible in the civilian world?

Simple answer, these are now a breaching tool, not an offensive weapon system.

The full sized shotgun was intended by the military to be a proper weapon system. But our modern combat now often requires breaching locks. Shotguns excel at that, so the military pump shotgun has primarly become a breaching tool.

There was another picture I wanted to share but for the life of me I can’t find it. It clearly showed an individual with a carbine, shotgun, and pistol. The shotgun was clearly just an additional piece of equipment for breaching, not intended as a combat weapon as he already had a rifle and pistol.

Breaching with a full size standard shotgun sucks. So going to the pistol grip makes it a great deal handier.

With the M500A2 MEK, the military went with the Mossberg FLEX system. I am told that the Flex system was developed at the request of the miltiary. Previous systems required tools to change stocks and/or had issues breaking.

Direct from Mossberg you can buy a Flex stock adapter, or a kit that includes the pistol grip. I opted to get the kit with the grip as it is cheaper than buying it seperately.

Inside you would find the adapter that attaches to the receiver, and a grip that slides on to it.

The miltiary also adds a sling mount plate. In this case an Ergo sling mount. This took me a long time to get as everywhere was out of stock. I ordered from Optics Planet that said they would ship it in a week and after a month I cancelled my order with them. I found one for sale by an individual online, bought it, and USPS decided to give it a tour of the US. But I finally got it.

The Ergo sling mount is machined from aluminum and has loops on each side allowing for ambidextrous use.

I had expected this sling mount to be thin stamped steel. I was rather surprised that it was a 1/4 inch thick aluminum.

When I went to assemble everything. I found that the bolt included with the Flex adaptor had greatly reduced thread engagement due to the 1/4 inch thick sling plate. While it likely would have been fine, I was worried about it pulling out under recoil and damaging my receiver. So I bought a longer bolt from the hardware store. (With my luck, it will probably be this replacement bolt that snaps in half and screws me over).

A quarter inch longer socket head screw from the local hardware store.

The Flex adapter bolts on to the receiver, and uses a belleville washer. You torque it to about 12.5 lbs/ft. Which isn’t really that much.

Then the locking mechanism is slid in from the top and a split pin holds that in place. It is fast and easy to install.

A tapered splined interface connects the Flex adapter on the receiver and the stocks or grips. I found this was very tight and secure. So tight I had to use a mallet or screwdriver to install or pry-apart the stock from the receiver. I would not call this quick change. I don’t know if it will loosen up with use, I just hope it doesn’t become sloppy and loose.

The end result

One thing I don’t like is how thick that Ergo sling plate is. It moves the grip 1/4 inch farther back from the trigger. I found I had to stretch my trigger finger to reach that trigger. But shooting was just fine. I also don’t like how much harder it is to hit the slide release on the left side of the gun while a pistol grip is installed.

I had to use a mallet to switch between a stock and the pistol grip.

By pulling up on the latch on the Flex adapter, turning it 90 degrees, then spending 5 minutes hitting things with a rubber mallet, I could switch between a collapsible stock and the grip.

The Flex stock is purchased by it self, not including the adapter that needs to be mounted on the receiver.

Now Mossberg offered a similar unit that attaches directly to the receiver. I just happened to have one around(not that I wanted it, I sold it after taking these pictures).

Flex left, direct attach right
Direct attach left, flex right.

The older style direct attach unit that screws to the receiver does not let you removed the trigger group on the Mossberg when it is installed. To completely disassemble the gun, you would have to unscrew a set screw, remove the AR15 style stock, unbolt the adapter, then you could fieldstrip the shotgun. That is terrible in my opinion. It has a longer length of pull. It appears to use a commercial spec receiver extension but I did not double check that. Neither stock could interchange on these two.

The direct attach model also was blockier in profile up near the top of the grip. I wonder if that would make it less pleasant against the webbing of your hand while shooting. But I didn’t try using it. I’ve also read that with these units if you removed the stock and attempt to use them pistol grip only they would sometimes break the attachment bolt. I don’t know if they mean the bolt attaching it to the receiver, or the bolt attaching the grip to the adapter.

I only fired a handful of shots with the pistol grip only, then with the collapsing stock. I had expected the pistol grip to be uncomfortable as it is hard plastic. Surprisingly (to me) it wasn’t unpleasent, but it wasn’t something I would want to shoot a great deal.

The collapsing stock with pistol grip also makes the slide release harder to hit. I was expecting to notice a great deal of difference while shooting it at different lengths, but I didn’t really notice much.

Personally, I’ll likely end up picking up the Flex quick detach standard stock for this someday and mainly use that.

The work and modifications are complete. I’ll talk a little about the history and though process of the “Military Enhancement Kit” in the upcoming last part.