Thursday, March 27, 2014

A2 Front Sight Modification to a Low Profile Gas Block

As previously posted, I recently purchased and received a PSA 14.7" CHF CL mid-length upper with a pinned flash hider. The next step on this project was to install a Fortis 12" REV rail and that meant removing the handguard, the handguard cap, the A2 front sight, the delta ring, weld spring, and snap ring. However, I wanted to retain the gas block on the A2 Front sight, therefore, it would have to be cut down and heavily modified to create a low profile gas block. Furthermore, because the flash hider is pinned, I decided to do the project with the front sight still attached to the barrel.

Before you get started, remove your upper from the lower (if attached), drop the guts (BCG & charging handle) out, and place them outside your workspace. 

Compile all the tools you will need for this project. I used whatever I had available, which probably made the process twice as long, however, I also did this project over the course of 3-4 days, in between my fulltime job and taking care of our one year old. With the right tools you could probably git 'er done without issue in a full day's work or less, all depends on your motivation & schedule.

My tool list:

         - Dremel 1 1/2" cutting wheel
         - Dremel bits from a sanding/grinding kit 
         - 1/16" pin punch 
         - Gas tube roll pin (to replaced the removed roll pin)
         - Hacksaw
         - Mill file
         - Pliers
         - Needle nose pliers
         - Birchwood Casey Super Blue
         - Aervoe Matte Black spray paint
         - Krud Kutter / Brake Cleaner
         - Painter's tape 
         - Eye protection
         - Dust mask
         - Vacuum cleaner with an extension wand or a portable handheld vacuum 

Wish I had:

         - An angle grinder (per this excellent video)
         - Tin snips

Let's get started.

[1] Remove the handguard

Before I attempted to remove the handguard I placed a block of wood under the upper receiver (pictured below) so that I would not place any pressure on the forward assist and to give me a relatively solid platform to work from.

I did not use any specialized tools to accomplish this action, I simply grasped the delta ring firmly (gloves might help), pulled down on it with my right hand, then used my left hand to hold onto the handguard while pushing the lower handguard off with my thumb and fingertips. Once the bottom of the lower handguard popped out, it was easily rotated out of the handguard cap (located behind the A2 front sight) and removed. Repeat the process to remove the upper handguard.

[2] Remove the gas tube

With the handguard removed, I marked my gas tube on both ends with a Sharpie marker to indicate where I should mask it off with painter's tape for the paint job to be applied later on.  I then used a 1/16" pin punch to knock out the gas tube roll pin. The gas tube was then removed and set aside.

With the gas tube now removed, I masked off the gas block on the front sight and the flash hider to eliminate unnecessary dust & debris entering the barrel. In a lot of the following images you'll see painter's tape moving to different locations, basically anywhere I'm working to mitigate nicks and scratches to the barrel, etc.....

Though not ideal, I have reused gas tube roll pins in the past without issue, however, for this upper I already had some unused roll pins on hand and tossed the roll pin I had just removed into the trash. Plan ahead for your modification and purchase some roll pins or reuse your roll pin. Your decision.

[3] Remove the handguard cap

This was an absolute PITA to do and tin snips, which I did not have, would have helped a lot. I resorted to cutting diagonally into the cap with my Dremel (as indicated above), getting as close to the barrel as possible without marring it, then using wire cutters (ineffective) and pliers to pry that mother off.

I also removed the sling swivel at this stage with the Dremel by grinding off the rivet end.

[4] Modify A2 front sight

To begin the modification I took off the major components of the A2 front sight (sling swivel, sling swivel tabs, bayonet lug, and the front post) by using my Demel tool and a hacksaw. An angle grinder would be have been the tool of choice in this stage, so if you have one, use it!

Throughout this stage there was a lot of residue and debris, this is where a handy portable vacuum comes into play. Additionally, you should have a dust mask and eye pro on. Be smart, not blind or suffering from some respiratory disease.

Throughout the deconstruction of the front post I also employed the use of a mill file to refine and grind down edges.

To get the hacksaw started on the correct path, I used the Dremel to cut in some guides.

With the major components now removed and the A2 front sight stripped down, I utilized the mill file to roughly grind down the edges and assessed the amount of additional material that needed to be removed in order to correctly fit the Fortis rail over the barrel.

The bottom of the gas block looks good, the top is going to need a lot of work.

Again, used the Dremel to cut guides and took off large chunks with the hacksaw. In between that, I used the mill file.

I finally reached a point where it looked decent and the fit was within tolerance, not a work of art, but functional. Edges were refined with the Dremel tool sanding bits.

With the major work completed on the gas block, I applied the Birchwood Casey Super Blue with a Q-Tip and then wiped away the excess with a damp towel. For those of you who do not plan to paint the completed gas block after the Birchwood Casey application, it does not have a black finish, more like a parkerized gray (as pictured below).

[5] Remove the Delta Ring +

Again, I employed the use of both the Dremel and hacksaw for the removal of the delta ring. I also wrapped the upper receiver with an old towel and taped it down to protect it before I got started on this section.

For the first cut I located the hole for the gas tube and rotated the delta ring from the top of the receiver to the side for a clear work space. Additionally, I also lined up the cut with a drop/indent on the barrel nut. The first cut was made with the Dremel for a guide and then straight to the hacksaw. The delta ring is a lot easier to cut than the front sight and it doesn't take much to power through it.

The delta ring requires two cuts on opposite sides and then it falls off.

To remove the weld spring and snap ring I used needle nose pliers. With a solid hold on the pliers, firmly grabbed an end point with the needle nose pliers, and rotated them off with force. Once you start, don't stop.

Slight marring on the barrel nut, but nothing significant.

At this point you may want to double check that the barrel nut is torqued correctly. If you have an AR combo armorer's wrench, Tapco makes a good one, make sure you create a 90ยบ angle with the AR combo wrench and the torque wrench to get an accurate reading. If you loosen the barrel nut, do not use your torque wrench, only use a torque wrench to tighten the barrel nut into place. The barrel nut should be torqued into place no less than 30 ft-lbs to no more than 80 ft-lbs (30-80 ft-lbs).

[6] Paint & Reassemble

The next step before reassembly on my project was to paint everything with Aervoe Matte Black spray paint. This is purely for aesthetics. I degreased the areas I wanted to hit with Krud Kutter (available at big box home improvement stores or you could use Brake Cleaner ), then boiling water, dried everything off, and then masked with painter's tape. When the weather was decent, I took everything outside and applied two coats of Aervoe Matte Black to the parts.

I painted the gas tube separate from the upper, however, you can also reinstall the gas tube prior to painting and do it all at the same time. Either way works.

The gas tube was then reinstalled with a new roll pin.

After everything was fully dried, I gave it ~48 hrs, I then wrapped the barrel in a plastic bag to avoid any unnecessary marring, especially after a nice paint job, and sent it up through the rail.

The Fortis rail is relatively easy to install. I plan on doing a small post on how to do it correctly in the next couple of days, because I did have some initial issues with it and will cover that in the post. However, I'll just state that I tightened it into place (after removing the plastic bag) with a torque wrench for now.

Looking good.

Below is the set up after two range trips and prior to adding Magpul MBUS Pro sights. This is the same lower from my staking post, but I switched out the ACS stock for a slim MOE carbine stock. I also really like the slim profile of the Fortis rail, however, as stated previously, I did have some problems when I initially installed it. No malfunctions and no issues so far.

Final notes. Of course having the right tools makes a world of difference, but I still got 'er done and it turned out well IMO. There are gunsmiths out there that do an excellent job converting A2 front sights in to low profile gas blocks at a very reasonable price. If you don't have the resources or time to do it yourself, google them up, check their references, and send it out. 

Time for a beer, this post took forever.

CarniK Con AK-47s (Part A) Video

Love these guys; pure comedy, excellent firearms, and this video is just epic.

Words of wisdom, "Become right handed."

Featured rifles:

Poly Technologies Legend 7.62x39mm
Type 56 7.62x39mm
Type 56-1 7.62x39mm
Type 56-2 7.62x39mm
Type 84S 5.56x45mm
Type 86S 7.62x39mm - Nice to see this firearm covered
SGL 31 5.45x39mm
Wz. 88 Tantal 5.45x39mm
AK-74U (AKS-74U) 5.45x39mm - I think I can safely say we would all love to own one... with a fun button

Sunday, March 23, 2014

Did someone say bacon?

On a completely different note, time for a bacon post! One of my vices is chocolate, another is bacon, thus, a match made in heaven that lays on my work bench as I piddle away on another project this evening.

It tastes exactly how you would expect it to and it's damned good with your favourite hot beverage or maybe even a Guinness.

Chuao Chocolatier Maple Bacon Bar retails for around $5, probably one of the most expensive chocolate bars I have ever purchased, besides a Ritter Bar. They are based out of California and I admire their adventurous spirit... a lot. Definitely something different to break up the monotony of Kit Kats and Baby Ruths. The Popcorn Bar was not at all what I expected, it's actually pop rocks in chocolate. An excellent item to play a prank on someone with, just pretend you are not having the same sensation they are.

Thursday, March 6, 2014

PSA 14.7" CHF CL Mid-Length Upper

[Click on image to enlarge]

Received my Palmetto State Armory 14.7" CHF mid-length light weight upper with a pinned flashed hider this past weekend and it looks good. It took about a month after ordering to receive it. It was well packaged and there were no blemishes (it was a non blem) or visible abnormalities upon opening and inspecting. The interior of the upper and the BCG were bone dry (explained later). 

PSA's description:

Kit includes a PSA 14.7" Hammer-Forged, Chrome-Lined, Mid-Length Light Weight Barrel, BCG, charging handle and our Classic Lower Build Kit (not pictured).

Barrel: A proprietary blend of Hammer forged chrome molly vanadium made by FN that is referred to as "Machine Gun Steel" by virtue of its use in FN's M249 and M240 weapons. The hammer forging process work hardens the steel, making it more durable. In addition, the chrome process for the bore allows for a lining almost twice as thick as a standard M16 for enhanced durability. Chambered in 5.56 NATO, with a 1/7 twist, M4 barrel extension, and a mid-length gas system. The special A2 light profile barrel allows for better balance and portability over the standard A2 profile and is Mil-spec phosphate coated. Barrel is High Pressure tested, and Magnetic Particle inspected, to ensure quality and dependability, and is finished off with an F-marked front sight post with sling swivel, standard hand guards and a pinned and welded A2 flash hider. The pinning and welding is makes the flash hider a permanent part of the barrel which brings it to the legal length.

Upper: Forged 7075-T6 A3 AR upper is made to MIL-SPECS and hard coat anodized black for durability. Featuring machined T marks, and a mil-spec finish. These uppers are made for us right here in the USA by a mil-spec manufacturer.Bolt: Bolt is made of Mil-spec shot-peened Carpenter 158 steel. Gas key is secured with grade 8 fasteners and staked per mil-spec. Bolt carrier is parkerized outside, chrome lined inside.Each upper is assembled to order with care and test fired.

Now for some pics. 

Profile pic of the PSA/FN mid-length light weight barrel. The upper, with the BCG and CH installed, weighs close to 4 lbs. 

The roll mark on the barrel. 

The pin and weld job on the FH to comply with Federal laws.

Disassembled Upper.  Anchor Harvey raw forge split 'A' marked (behind the shell deflector) with a small PSA laser etch, white fill logo on the opposite side of the upper receiver.

Bolt face. Residue from test fire still visible.

MPI test mark. I stripped the bolt down and everything looked GTG.

Feedramps look clean, no issues there.

And for the topic of debate, the "gray matter" (Breaking Bad, anyone?) on the interior of the receiver. There was some speculation that this section was somehow missed during the anodizing process, which cannot be possible, as the entire part is submerged. Some have stated it is a dry lube application, yet on some forum somewhere, I read that a PSA rep stated that nothing is applied to the interior of their receivers. However, this upper was test fired and arrived bone dry, therefore, I would like to believe that the gray residue is dry lube.

I applied some Hoppes 9 to the "gray matter" and it started to slowly rub off. However, I did not attempt to remove it, because if it is in fact dry lube, it's something I would rather leave on the interior surface of my receiver. As with all new uppers, I always apply a coat of CLP and wipe everything down as part of the initial inspection. The reason some parts look "wet" in some of the pics is from the CLP application, otherwise, as previously noted, the upper was dry. I'm sure once I get some rounds downrange it'll become apparent whether or not the entire upper was completely anodized. Will update once that happens and I can stop speculating. 

EDIT: I have taken this upper out twice now, with about 100 rnds down the pipe, and it is definitely anodized on the interior. The black anodized layer is slowly being revealed as the gray dry lube (which I still assume it is) rubs off due to the travel of the BCG. No problems here.

Final notes. PSA, love em or hate em, they deliver, though it may take months and many headaches for some, but post Sandy Hook, absolute mayhem, $100 pmags etc... and they took it in stride. I have had issues with them myself, but they have always made good, at least, once you get a hold of a representative. And those reps have never thrown down BS attitudes like many other vendors that shall remain nameless (as we all know who they are) have. All that said, this is a great upper at an unbeatable price.

Lastly, I am currently butchering this upper to get a Fortis 12" rail mounted. Was actually working on that earlier tonite after I got home from work and I hope to post that soon too!

Saturday, March 1, 2014

The Poor Man's Stake

Just finished putting together a new lower, which I may do a post on as well, but in this post I just want to do a quick overview on staking the end plate to retain the castle nut on the buffer tube/receiver extension. This lower uses an aircraft aluminum receiver end plate, therefore, I can easily stake it with a nail.

[1] Support the receiver extension

First & foremost, safety is your number one priority, so if your upper is attached to the lower like mine is in the picture above, be sure to clear your firearm before proceeding. Of course, you can also stake the endplate/castle nut without the upper attached to the lower.

Once cleared, remove your stock. 

If you have your AR combo wrench available it would be a good idea to double check that the castle nut is tightly in place at this point in time.

Place the castle nut and the receiver end plate directly onto a block of wood. This is necessary so that when you stake the end plate/castle nut the downward force applied will directly impact this area and not place undue stress on any other parts of your firearm/lower.

[2] Nail & hammer

I used a 2-3/8" VC Sinker that I had in my tool box and a claw hammer. Besides a nail, you can also buy and use a tapered center punch to stake the end plate/castle nut. Avoid the spring loaded center punches if possible, but you can use one if it's the only thing available. Using a roll pin punch is not suitable.

Locate the spot you would like to stake the end plate (that lines up with an indent notch on the castle nut), position the nail accordingly, and give the nail a few solid bashes with your hammer. It shouldn't take more than 10 hits to displace the material and stake your castle nut. 

If you are having trouble, you may have a CNC machined harden steel end plate as opposed to an aluminum end plate and using a nail is not advisable or will simply have no effect. A CNC machined steel end plate will have a very smooth side surface, whereas, most aluminum end plates will have an unfinished appearance on the sides, as pictured above. QD swivel end plates, for example, are usually CNC machined. You will have to use a tapered center punch for CNC machined harden steel end plates. A trick I use is to put down a piece of duct or electrical tape on the spot I want to stake, pressing down with my finger nail to reveal the edges & details, to give the center punch some traction on the smooth surface for the initial strike. 

[3] Finished view

As you can see, definitely enough material displaced to sufficiently retain the castle nut.

A sharpie adds the finishing touch.

Final notes. It's not a question of whether "to stake or not to stake", because the castle nut has small notches specifically dedicated for displaced material from staking the end plate. So, while some may decide to forego staking or use Loctite, there really should be no excuse for not staking down the castle nut to maintain a reliable platform. And, that is exactly what you are doing, you are eliminating a possible point of failure to ensure your primary firearm is always ready. Whereas, by not securing the castle nut you are allowing various scenarios to possibly unfold. Consider what would happen while if you were firing the weapon or even while in transit, the takedown pin spring being retained beneath the end plate could easily be lost if that section were to loosen up & come apart. Now you have an AR-club (still illegal in CA) in your hands that could separate (lower from upper) at any given second. You could MacGruber it and put some duct tape over the retaining pin cap (if spring is lost) to hold it in place, but would you really want that? Of course not. Additionally, consider if you were firing the weapon and, as the BCG was moving back, the takedown pin comes loose, thus allowing the upper to separate from the lower. Not a good situation, basically a catastrophic failure that would render the weapon useless, nevermind the BCG implanting itself into your forehead or being ejected 15 ft away from you. A ridiculous scenario, maybe, a possibility, yes, an avoidable scenario, definitely.

As stated previously, if you are having trouble using a nail to stake your castle nut, you may have a CNC machined harden steel end plate as opposed to an aluminum end plate. The CNC end plate will usually have a very smooth machined side surface. A tapered center punch will do the job.

Lastly,  if you were ever to decide that you needed to remove your buffer tube, say to install a Magpul UBR, it is easy to unstake the castle nut with the right tools, a roll pin punch and a Dremel tool.