AR15 Lower Receiver Build Part I

Before you can start assembling your lower receiver, you have to make a few choices on what direction you want to go. There are countless configurations of grips, build groups, bolt carriers, and other parts out there. This lower is built to host large bore SBR uppers so we opted for a military style trigger and robust build group from Daniel Defense. You can get this kit from Midway, but with free shipping you can sometimes find it cheaper here: Daniel Defense DD.21007 Lower Kit. The only substitution I made was to the grip. I have the CAA UPG-16 on all my builds. With all the potential combinations it should suit just about anyone. The best price at the time of this article is Midway if you are already ordering, or from here due to free shipping: CAA UPG-16 Grip.

Daniel Defense Build Kit And CAA UPG16
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The night before you plan to start the assembly, place all the metal build parts on a baking sheet covered in foil and lightly coat them with Militec-1 or something similar. Then heat them to 160 degrees F for approximately 20 minutes. This treatment gives you a good starting point for maintenance as well as protecting the parts from skin oils during assembly. Once the parts have cooled off, wipe off any excess oil and set them aside. Through all of these steps you are working with springs under pressure. For that reason, safety glasses should always be worn. With all of the prep out of the way, the first thing to install should be the magazine release. This will allow you to use a magazine vice block in the later steps should you need one. To begin, install the magazine catch through the left side of the weapon as shown below.

Magazine catch install
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Now flip the weapon over while holding the magazine catch in place. Install the the magazine catch spring over the the threaded portion of the catch as seen below. While holding the catch flush with the receiver, press the magazine release button down onto the spring and get a few threads started. Once you have a few threads of engagement, you can let go of the magazine catch. Now position the button into its recess and press it as far into the receiver as you can. While holding the button in, you can screw the catch in the rest of the way from the opposite side. Use care not to scratch the receiver. Using a space magazine, now preform a function test.

screw on magazine catch button

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While the next step is not difficult, it is where the most people damage the finish on their receiver. The bolt catch can be tricky, you just need to be patient. With the receiver resting on its right side, drop in the bolt catch spring followed by the plunger as shown below. If you have a threaded receiver, you can hold the bolt catch in place and screw in the set pin. If you have a traditional receiver, you need to insert your magazine vice block and place the weapon face down in a vice. Get your roll pin started before placing the bolt catch. Once the pin is started, you can either hammer it directly, or use a 12" 1/8th punch to drive it into place. The punch is the better method as it will help prevent scratches. This is one of the reasons I prefer to convert to screw in pins over roll pins for the bolt catch.

bolt release
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The following pivot pin installation procedure is hands down my least favorite step. While straight forward, it is tedious with new springs. Start by placing the detent spring in its recess as shown below. From here you will need to press the detent into place and hold it flush with a razor blade. With the detent held in place with the razor, install the pivot pin from right to left. Once the pin is started you can remove the razor. I usually perform this step someplace where I can easily find the spring, should it go flying.

pivot pin
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Because of the numerous trigger combinations and install methods, I am going to skim over this step covering the key points. If you have a drop in trigger, it just sits in place while you press in the trigger and hammer pins. The pins usually will press in by hand. If you are using a military style trigger, insure the disconnector spring is installed with the wider side down. If you are using the Daniel Defense kit, the disconnector spring is the green spring. With the trigger and disconnector set up, you can simply press them into place and install the trigger pin. Follow this with the hammer and hammer spring, which is also secured with a pin.

trigger spring
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Now cock the hammer back. With the hammer in the back position, you can insert the fire selector in the fire position. With the selector in place, turn it to safe. While holding the hammer pull the trigger. The selector should prevent the hammer from falling. If it does not, review the previous steps to identify the problem. Now set the selector to fire. While holding the hammer pull the trigger. The trigger should try to fall. While still holding the trigger in lower the hammer and recock it. The disconnector should catch the hammer and prevent it from falling a second time on a semi-auto weapon.

insert fire selector
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After you have confirmed a properly functioning fire selector, you can finish installing it. This is done by flipping the weapon over as shown below. Now drop in the safety selector detent. On the grip locate the small hole on the top right side. Drop the safety spring into this hole. Set the grip aside. Before installing the grip you need to confirm if your take down pin is installed from the bottom, or the traditional way in front of the buffer tube. In the example below you can see a tiny set screw just behind the install brass safety detent. If you have this style, insert the take down pin, followed by a detent, then reinstall the tiny set screw. If you have the traditional style the take down pin procedure will be addressed in part two of this review. Now install the lock washer over the grip screw. Even though the screw has a washer, I still like to use a small amount of Guntite on the screw. With the screw and washer ready, press the grip down onto the spring and get the screw started as shown below.

safety spring and detent
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Slowly tighten the grip screw while confirming that the spring is being pressed into the recess and not kinking over on itself. Once the grip is installed, go back and confirm that the fire selector switch is functioning correctly. Take care not to drop the hammer, as it will strike the bolt release with no upper in place.

Install grip
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At this point you will have a few extra pieces. You should have the trigger guard, split pin, set screw, two springs, buffer retainer, and a detent left. The trigger guard was not used in this build, but should you need to install it, it is just snapped into place on one side then secured with the set screw on the other. If your take down pin was the traditional style, you cannot install it till the second part of this guide when the buffer tube and stock get installed. The same goes for the buffer spring and detent.

Here is a short movie to help you with the first few steps:

In the next guide we will cover the completion of the lower, and the final inspection and function test. While these guides seem simple enough, you should consult a licensed gunsmith if you have any questions or doubts about your work. Even if you put everything together and it seems to work fine, there is no harm in having someone double check your work.

Big Bore Rifle Dust Cover Modification

At the time of this article, there is no dust cover door that will fit a Satern modified Beowulf/SOCOM/Bushmaster upper receiver. This leaves you either running no dust cover at all, or dropping a lot of money to have one custom stamped. There is another option however. With a little time you can move the standard detent up, to make the MIL-SPEC cover work with your large bore rifle.

Standard ar15 dust cover
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With the dust cover removed, start by drilling out the roll pin. This is not as easy as it sounds due to the fact the pin is steel and the surrounding area is aluminum. With that said, take your time here. There is nothing you can hurt, but patience will save you a lot of frustration.

Drill out roll pin and repin
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In the images above you can see the detent removed. Be careful not to lose the spring that is behind it. Now, on the opposite side of the cover drill another hole for a new roll pin 1mm or .04" higher than the original hole. Reinstall the spring, followed by the detent, then set the new roll pin.

Sight gap on beowulf upper by satern
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Because the only modifications were done to aluminum pieces there is no need to touch up with any cold bluing. The image above was shot at a downward angle to over emphasize the gap, but it is there. For this reason I consider this a work around until someone produces a proper dust cover. Having said that, the cover does function exactly as it would on a standard rifle. It is not going to bounce open and is very secure.

Intro Guide To Polishing Brass For Reloading

The first stage for reloading cartridges (Pistol or Rifle) is cleaning the brass. If you are using virgin brass you can skip this step, but otherwise this much debated topic is your starting point. Your first and foremost concern should be safety. You are working with dangerous components that require care when handling and a well ventilated area. Before we get started, lets talk about a few reasons to clean and polish your brass, prior to reloading. The two primary reasons are for inspection and reducing friction in the reloading process. Whenever reusing a case, you need to insure it does not show signs of excessive pressure or over use. We will discuss warning signs in another article. The next reason is wear and tear on the reloading machine. Clean brass puts less wear on dies and requires less friction to load, providing a more consistent finish. Just how clean does it need to be? That is a matter of personal preference and highly debated. Some people use a multiple step process to render the brass spotless with a mirror finish. Others say just wash the dirt off and go for it. From our experience the best answer is somewhere in between. The goal is clean brass with no signs of carbon build up and minimal, to no tarnish.

Brass after tumbling
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Above, you can see a typical example of spent shell casings. They have a dull finish with signs of carbon around the case mouth and a layer of carbon inside the case. The first step in our process involves washing the brass. If it is a small quantity, simply place the brass into a one gallon Ziploc bag. Fill the bag half full with hot water and a single pump of Dawn dish soap. Agitate the bag a few times and let the brass soak 5-10 minutes before rinsing with fresh water. The reason for this step is to help minimize the release of airborne lead. While many people will debate the need for this step, we insist that it is a necessary precaution that only takes a few seconds. If you reload, we highly suggest you periodically test for lead contamination in your work area. A simple kit such as this 3M lead kit, will either put your mind at ease that your work station cleaning procedure is adequate, or tell you that you need to improve your cleaning regimen and be more careful in the future.

Washing brass before reloading
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With the brass finished soaking, now is the time to lay it out to dry. If you do not wear gloves for this step, wash your hands immediately after finishing. It should also be stated that smoking and eating should always be avoided whenever handling casings, as there is an increased risk of transferring lead from your hands to your lungs or stomach. I usually place the casings I want to reload in old ammo trays. This allows me to easily inspect the brass while at the same time confirming its caliber. In the image below, you cans see that there are a few 10mm rounds mixed in with the bulk of the rounds, which are .40. Now is the time you want to find this out, not when sitting at your press dealing with some form of equipment malfunction.

Dry brass
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While the brass is drying, start preparing your tumbler. I suggest doing this outside for the lead concerns stated above. So far, our favorite mix is one liter of crushed walnuts and two tablespoons Mothers PowerMetal. The crushed walnut can be purchased at your local pet store in different sizes and is usually marketed for bedding use. The polish is not that difficult to find in most areas, but can be ordered off-line here for less. The reason we suggest this polish, other than in our opinion it works awesome, is that it is ammonia free and will not weaken the brass. With the polish added to the media, turn on the tumbler for 5-10 minutes to distribute the polish evenly.

Load up vibrasonic tumbler
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With the polished mixed in, now add the shells. We recommend leaving the spent primers in the casings for this step. This prevents any of the media from entering the flash hole of the primer pocket, which you will have to dig out later. A common question is how many shells should you polish at once. This depends on the size and power of your tumbler and the finish you are seeking. If you add excess brass to the point that it bangs against itself, you will end up with a satin finish. While this will not hurt performance, it may not yield the mirror finish some are looking for. I have had good results keeping the ratio of shells to media to a 1:3 by volume ratio. Your ratio may need to be adjusted based on the power and size of your tumbler.

Load brass into tumbler
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If you are using crushed walnut, 45 minutes to an hour will give you the results shown below. It is best described as a gloss satin finish. If you want something with more of a mirror finish, you can run the brass for an additional hour in a  crushed corn cob media. While you can start with the corn media, this will increase the total polishing time. As is usually the case, polishing is best done in steps. If you do opt for the one step corn cob method, reported typical tumbling times are usually around 4 hours. If you do use corn, be aware that the crushed cob you typically find at most pet stores will not work very well. It contains chaff and other bits, not just the pit. If you use corn media, it needs to be blast media, not pet bedding.

Dirty brass prior to tumbling and after washing
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While several companies offer media separators, we have found that fryer baskets, such as this one work just as well. They also allow us to have several inexpensive baskets around for different media. Again, keep in mind safety in this step. The media will be loaded with lead dust. Once you have removed your casings, you can set aside the media for reuse later.

Brass tumbled in dry walnut media no corn
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A lot of people have reported that tumbling their casings does not clean out the inside of the shells. Above, you can see shells that were tumbled for one hour in crushed walnut and as reported, the insides are not clean. For pistol and non-precision loading they are clean enough, but there are cases where you may want the insides cleaned also. To accomplish this, there is a simple trick, water. Once you have loaded the media into the tumbler along with the polish, add water until all of the media is wet and a thin layer will float out on the top when the tumbler is on. The casings below were run in this way for one hour in the media, followed by 5 minutes using only dry walnut media to remove the film left by the water and polish. You can clearly see the difference inside the shells.

Brass tumbled in wed slurry media
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Whatever method you decide to use, exercise care and safety for both yourself and those around you. If you are not comfortable with a step, ask a more experienced reloader, or post it up on our forums. Have fun, and let us know if you find any other tips for polishing or secret recipes for polishing media.

Polished with rice and media
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After seeing a lot of talk about using brown rice as a polishing media, we decided to test it. We also tested Flourite as a faster option to walnut shells. In the above side by side image, you can see that both media produced a satin blasted finish not a shiny one. Some people prefer this finish, so it does have its place. Both batches were run 1 hour in a vibrasonic tumbler. The rice was run dry and the Flourite was run with 2 cups of water in 4cups of Flourite. The Flourite media had the added benefit of cleaning the inside of the case as well as cleaning up very easily. Although it is more expensive than walnut shells, it would make a great one step polishing media if you are looking for a satin finish.  The rice on the other hand did little to the inside of the case other than coat it with a layer of powdered rice and plug up the flash hole even though the rounds had not been de-capped. If there is anything else you would like tosee tested let us know.

Magpul P-Mag Modifications For Large Bore Rifles

One of the top selling points of the .458 SOCOM and 12.7x42mm rifles are that they share so many components with their parent platform the 5.56mm. Right out of the box most magazine will work with no issues. That does not mean that there is not room for improvement. I wanted to have a few magazine to work on, but was not ordering from my usual suppliers any time soon. For that reason I picked up these from Amazon to take advantage of free shipping here: Magpul PMAG Magazines.

Magpul Pmag modification for .458socom, 50 beowulf
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From the start I noticed a few things. The much larger case of the big bore rounds prevented them from having an ideal feeding angle. While not an issue with pointed and FMJ rounds, this was an issue as usually is on the open hollow points. The first few go arounds involved jigs and power tools. Only later did I realize this process is faster by hand.

Pmag magpul taken apart
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Start by removing the baseplate, spring, and follower. Now tightly wrap a small strip of 200 grit sandpaper around the shank of a 1/2" drill bit. This gives you a sanding mandrel that is almost the exact size of the rounds we are developing for here. This process goes quickly so use care not to remove too much material. If you are applying even pressure to both sides the width of the sanding marks will be uniform. From what I have seen the best angle to sand at is around 30 degrees in relation to the magazine.

Feed lips opened up
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The other that needs addressed is the front of the magazine. In the un-modified magazine below, you can see the sharp point at he front which causes hollow point to hang up. This can be radius off, which solves the problem. Remember the goal here is not to remove the ridge, and stop, but to slightly change its profile. This process may take some trial and error on the first few magazine to get everything "just right". Once you are happy with the function, take a cotton swap and lightly wipe down the area you sanded with MEK. This will melt the plastic and remove any sign that the magazine was ever modified.

Follower modded for extra round
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This step has nothing to do with reliability, but will allow you to load one additional round into the magazine, and still be able to use it even with the bolt forward. The goal here is to sand the follower flat. You will also need to radius the rear of the follow to allow it to come all the way up to the top of the magazine body.

New angle
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In profile you can clearly see that the follower sits a few hundredths higher now. If you correctly radius the rear of the follower everything should work 100% reliably with an extra round. If the bolt catch does not work after this modification, you need to radius the rear of the follower more.

Here is a short movie to help you with the first few steps:

Lower Receiver Safety Indicator Painting

We have all seen the H&K style painted safety indicators, and I have to admit they do look kinda nice. I am not sure they serve any real purpose though, as anyone familiar with the M16/M4 platform should be preforming by feel. Having said that, I do find myself at the range from time to time in an instructor capacity. Anyone in this position will see it happen at least once per day. Someone goes to pull the trigger and nothing happens. It is probably that the safety is on, but from a distance there is no way to be sure, so if they do not catch it on their own you are forced to assure they keep the weapon pointed down range and go look. Having the indicator painted helps identify this problem from a distance even with eyes and ears on.


Clean receiver with solvent
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This DIY is for a Teflon or painted firearm. If your receiver is only hard anodized, ignore all the steps except the ones which are red throughout the article. For supplies you are going to need:

All said and done the paint will be about ten dollars shipped. Worth a mention is if you are filling back in after an NFA engraving, you will want Testors 1749 Flat Black. With all your supplies gathered up, start my applying a light coat of solvent to the area on the receiver you will be working in. Wipe any excess solvent off, and wait a few minutes to assure that there is no solvent remaining as this can tint your paint.

apply medium coat of paint to ar15 receiver
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If you have a painted receiver mix in 2ml of thinner with 1/4 oz of the Insignia Red and shake for 60 seconds. Now using a cotton swab apply a medium coat of paint to the fire position indicator. Try not to make more of a mess than you have to, but a little excess is not going to matter.

If you have a anodized receiver mix your paint 3:1 with the thinner and shake. If you are using an insulin syringe draw up ~10 units of paint. Using the syringe as a sort of quill pen, slowly lay paint into the grooves of the fire indicator. No matter how much care you use, there will be some out side the lines.

dab painted area to keep paint damp
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Wait sixty seconds then with a solvent dampened paper towel lightly dab the area once. Do not keep blotting. All you are trying to do is keep the excess paint from curing while giving the intended are time to set up a little more. Wait another thirty seconds and and blot once more with a new paper towel. Then flip the paper towel to the clean side and wipe the area once. Use as little pressure as you can. The wait of the paper towel is enough. Repeat the steps until all excess paint is removed.

Use the same steps as above, but do not use a paper towel. Use a cotton swab with solvent on it. Do not use a lot of pressure of you will end up buffing the area.

Close up of painted safety indicator after cleaned
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From this point on the steps are the same for both types of receivers. After twenty to thirty minutes you can do back and lightly wipe down the entire receiver with solvent on a rag. Again do not use a lot of pressure. Now you can repeat the above steps for the white areas. Do the white last other wise transfer from the red will leave the white pink. After a day of curing pretty much nothing you do will remove the paint. Unlike whiteout or crayons, this is pretty much permanent. I have seen a ton of reviews on-line where this turns out looking good..... from 10 feet, or with a blurry camera. The ones that were not using the ten foot rule had noticeable buffing marks around the painted areas. Don't be a rookie. Do this right. If you still need more help check out the video below on AR15 receiver painting.

Nickel Boron Plated Desert Eagle

Since there is already a primer on Nickel Boron platings in the Fail Zero review, we can jump right into this. Wanting to see how well nickel boron holds up in a heavy wear environment, I decided we needed to coat a pistol. Unlike most people I actually fire my Desert Eagle, and it hands down had one of the roughest finishes I had ever seen on a weapon.

Desert Eagle frame stripped all the way down including magazine release
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While I was not looking for a high polish chrome finish, I did not want something that did not try and pit and rust every time the weather took a turn towards the rainy side. Above you can see the stripped frame showing some holster wear as well as some wear under the grips. Even well oiled this weapons would show surface rust on humid days.

NIckel boron coated desert eagle frame
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After a solvent hot dip and an HCL bath, the remainder of the bluing was gone along with any light surface rust. On the beaver tail and above the grips there was some light pitting which I removed with a wire brush and 400 grit sand paper before giving it a quick media blasting and one last acid bath.

.440 desert eagle with boron coating
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Plated out to 0.0005" the frame looked completly plated. However on the frame itself I continued to plate out to 0.0010" as this is a high wear location and there were no clearance issues. On the rest of the weapon plating was stopped at 0.0005". The barrel and gas ports were plugged to prevent any issues there.

Deagle .50ae chrome, nope. Better its nickel boron coated
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After a light polish you can see the end results above. The finish came out uniform, and had the flat appearance I wanted thanks to media blasted finish of the metal. If a bright finish is desired that can be done also. Longterm follow ups will show how well this holds up. Operation wise the weapon is extremely slick feeling even with no lube. Cleaning it up now is a breeze and more importantly it shoes no desire to flash rust when it is humid.