Build a 9mm AR-15: Part II: cheap and cheaper!
In the first installment of this series, I built a 16-inch barreled 9mm AR-15 carbine. Excluding the Slide Fire stock, when the basic project was complete I had about $725 in it. This shot a very big hole in my $1,000-51,200 budget that I had allotted to build two 9mm AR-15s. I still had the pistol project to build and it was doubtful that I could make a 9mm AR pistol for a mere $300.
In this installment, I will document the build process and parts acquisitions I used in attempting to meet my budget goal. Some of the prices I paid for parts are very low. In fact, some readers may question if I really got parts as cheap as I say I did. Let me assure you that the prices I report in this article are the prices I actually paid for the parts. I had to do a lot of searching and expend a fair amount of time to find these bargain priced parts.
I started my parts search by looking for a budget priced lower receiver. There was no doubt my receiver choice would be the very economical yet high quality Anderson receiver. This would be a standard dedicated 9mm AR-15 receiver. Anderson receivers are available from many vendors at the $50- $80 price point. While searching through some of the large online AR parts vendors I found my bargain price. Copes Distributing (www.copesdistributing.com) had several variations of Anderson receivers listed on their website. The lowest priced option was a cosmetic defect receiver. This forged Mil-Spec receiver was priced at only $34.95.1 jumped on this deal and had three of them sent to my local dealer for this and future projects. I have bought several of these cosmetic defect receivers over the last few years and I can seldom find a major defect in the finish. The defects are usually so minimal that they are not a concern to anyone except the manufacturer. For only $35 I can live with a little imperfection.
I now needed to find a bargain upper receiver. CMMG is one of the companies usually in attendance at the Knob Creek Machine Gun shoot. At their display they had several tote bins full of odd color AR-15 parts. These were surplus parts from special order production runs where the customer wanted non-standard color AR-15 rifles. The gold colored stripped AR uppers were only $20 each. At this low price I decided to buy several.
While still at the show I found that AR-15 rifle and parts company J+T Distributing / Double Star was also set up. They were offering production over run charging handles for $10 each, another bargain.
At the Century Arms display they had boxes full of the braces that were private labeled as Century braces rather than Sig-Tac brand. The braces were un-boxed, came with no Velcro straps, and had no instructions. The braces were priced at only $25 each! Normal price for a Sig-Tac brace is $125--SI 50. Obviously there had to be a catch at this low price. When I asked why they were so cheap the sales person said there was something wrong with them but he didn't know what. I looked over several and other than some minor cosmetic issues I couldn't see what was wrong with them. For this low price I decided to take a chance and buy one for my project. Later when I tried to install this item I found the reason for the incredibly low price.
I needed several other parts for my project and turned to the Internet to find them at good prices. I needed a pistol-type buffer tube and found one for $35 (#STKPBT) at the JSE Surplus website (www.jsesurplus.com). While on the JSE website I found that they had 32-round C-Products 9mm AR-15 magazines (#MAGC9M32) for $18 each. They also had 20-round magazines (#MAGC9M20) for $18.1 found one more magazine even cheaper at JSE and that was a 30-round Bushmaster brand (#MAGBFI930) for $15 each. I ordered the buffer tube and all three magazines for my project.
I now moved on to the CDNN Sports website (www. cdnnsports.com) for more needed items. CDNN Sports is a very large distributor of economical firearms, parts, magazines and accessories. Their prices are very good and I have been buying items from them for many years. I ordered my favorite AR grip from CDNN. This is advertised as the IMI Defense Israeli AR-15 grip (#AR15G) and is priced at $15. I really like the styling and feel of this grip and have it on several of my AR-15s. I also ordered an extended charging handle release (#TAR214). This $8.99 release works as well as those costing 2-3 times as much.
Since I had ordered my carbine parts kit from Palmetto State Armory (PSA) I knew they had many of the parts I would need to complete my pistol project. I needed a 9mm buffer for my pistol so I ordered one from PSA. This buffer (#482667) is priced at $14.99. This buffer is made of steel and is almost twice as heavy as a standard carbine buffer. I needed a 9mm bolt carrier and PSA had the best price on those at the time I did this project. My carbine kit came with the same carrier so I knew it was good to go. This 9mm bolt (#505089) was listed as being on sale for $94.99. The regular price was listed at $169, which was the same price as their premium bolt, so I am skeptical that this price was really a sale price. I can't say for sure but it looks more like creative marketing to me.
While on the subject of 9mm bolt carriers and the versions PSA offers, I will give you a little supplemental information. PSA, and some other parts vendors, offer two types of carriers. One is called a ramped bolt and the other is known as an un-ramped bolt carrier. They are identical except for one feature. The ramped version features a shallow bevel on the bottom that allows the hammer to be cocked in a more gradual manner and allows it to slide over the hammer easier. Supposedly the non-ramped version places more stress on the hammer and its pin than the ramped version. Experienced 9mm AR builders claim that you will eventually break the hammer pin if you use the un-ramped version. I don't know if this is true or not because many 9mm AR kits come with non-ramped carriers. PSA list the non-ramped version at $94.99 and the ramped version at $169. To save money I ordered the non-ramped version for my project. Since I have a well-equipped shop I figured I could ramp the bolt myself and save $75.
Because I would be using a standard 5.56 AR-15 receiver for the pistol project, I would need a magazine well adapter. I found that Brownells had Pro-Mag brand adapters (#687-000-033) for $44 so I ordered one before I knew I would be using a dedicated 9mm receiver on my carbine project. Better planning would have saved me over $80!
The Pro-Mag plastic adapter is less than half the price of its nearest competitor. I found that adapter blocks run from a low of $35 all the way to more than $200. The best price I found for an aluminum adapter block was the PSA offering for $99.99. This is the same one that came in my carbine parts kit used on the previous project.
One thing I would need to complete my project was a lower parts kit (LPK) to complete the Anderson lower receiver. Typically name brand LPKs run $45-$75. Earlier this year I stocked up on LPKs when I found a bargain price on them. PSA had what was listed as Black Hawk brand LPKs on sale for the unbelievably low price of $29.95. These budget priced kits were advertised as being Mil-Spec and came with an ergonomically styled pistol grip. Since they were so cheap I ordered several of them for future projects. Other than having some less-than-stellar machining on the triggers, they worked fine. As long as they work I figure one can't be too picky at the $29.95 price.
For my pistol project I would need either a pistol handguard or a carbine-length handguard depending on the length of barrel I would be using. A brand new handguard would stress my budget so 1 would need a cheap alternative. You might assume that the cheapest option would be to pick up a used set of carbine handguards that I routinely buy for less than $10. Unfortunately the cost of the parts needed to mount those $10 hand guards would cost several times more than $10. To mount cheap used carbine handguards I would need a GI barrel nut ($10), a delta ring assembly ($20), a front hand guard cap ($3), and a front sight base/gas block ($35). It would take about $70 worth of parts to utilize those $10 hand guards. That isn't very budget friendly. Fortunately I had a simple solution that would solve all my problems. At a previous Knob Creek show, J+T Distributing had a bin full of cosmetic defect parts, customer returns, used parts and other items that could not be offered as new first-rate products. In this junk box I found several carbine-length round handguards that had minor problems that could be overlooked or repaired. These round handguards came with their own special barrel nut that the hand guards screwed onto. There were several handguards in the box and they were priced at only $20 each, including the barrel nut. By utilizing these $20 parts I could remove the need for $70 worth of associated parts. I bought several of the best reject parts to use for this and other projects.
Now it was time to consider the largest expense for the pistol project, the 9mm barrel. My research indicated that 9mm AR-15 barrels run from about $125 to well over $200. Rather than buying a factory barrel that would bust my budget, I decide to fabricate one myself. If you have a metal lathe and some basic machining skills the cost of a barrel can be reduced by 75%.
To make my own 9mm AR barrel I would need either a 9mm barrel blank or a new or used existing 9mm barrel from some other gun. All I needed was a barrel or barrel blank that was at least 3/4" in diameter and 10 inches or so in length. Fortunately I had several options already in my parts bin. I had some Green Mountain brand 4140 9mm barrel blanks that were 24 inches in length. These were purchased through the Green Mountain website for $40 each. Just a few months before starting this project Firearms News advertiser SARCO was advertising 18- to 20-inch long stainless steel 9mm barrel blanks for $34.95 each or 3 for $90.1 bought some for future projects. What I eventually used was even cheaper. A few years ago Firearms News advertiser Centerfire Systems was selling M31 Suomi parts kits for $49.95 each. I had bought several of these sub-machinegun parts kits to build dummy guns. When I built the dummy guns I used a piece of pipe for dummy barrels and saved the excellent condition barrels for future projects. I figured that the barrels represented about half the kit cost so these barrels cost me about $25 each. The almost-new condition barrels were just a little over 3/4" diameter at the breech and tapered to just a little under 3/4" at the muzzle. These 12.5 inch barrels would be perfect raw material for my 9mm AR-15 barrel.
Because the most important part was the cost cutting self-made barrel I decided to start there. I will briefly explain how I turned an inexpensive barrel into a 9mm AR barrel. This will just be an overview of the methods I used. The reader who decides to take on their own project will have to supplement the information presented here with their own gunsmithing skills and knowledge. Making this barrel is very easy and the lathe work required is basic lathe operation.
It is best to size your parts to your individual needs but you still need a starting point. To get a rough idea of the size of parts you will be making, a print is helpful. Fortunately one is available free on the Internet. Go to the Green Mountain Barrels website and click on the tab that list military gun barrels. There are several 9mm AR15 barrels listed for sale there. Some, but not all of them, have a tab listed as "technical specifications". If you click on that tab you will get a very basic barrel diagram that list several important dimensions. These prints don't have all the dimensions but they do have enough to get a good idea of the size of the breech end that will slide into the AR upper receiver. You can use this diagram as a rough guide to fabricate an adapter that will allow the Suomi barrel or a barrel blank to be fitted to an AR receiver.
The first part of making the Suomi barrel fit an AR upper is to fabricate an adapter. I will give some of the dimensions I used but you should fine-tune the dimensions to fit your individual needs. I have made a lot of these adapter bushings since I have done a lot of special AR projects that featured self-made barrels. The bushing should be made of steel since the bolt will impact the bushing when it reciprocates in the receiver. The size of the hole in the front of an AR upper receiver is 1.00" plus or minus .005". I size my bushings to only have a couple thousandths clearance for a nice tight fit. I typically start with a piece of material that is about 2'A" long and about 1 3/16," to 1 1/4" in diameter. This diameter is required for flange formation. I chuck this piece up in my lathe and turn part of it to 1.00" diameter. The part I turn to 1" is 1 foot long. Ahead of this 1" X 1" section I turn it to 1.170" diameter. The 1.170" section needs to only be about 1/4" long. This will leave more than enough length to form a 1/8" wide flange later. Exact diameter of this flange portion is not critical as long as you stay within a few thousandths of the stated size. I got this dimensions by measuring several slightly varying barrel flanges. Before I remove the partially shaped bushing to form the other end, I drill it for cutting 3/4"-16 tpi threads. The correct drill size for 3/4"-16 threads is 11/16" (.687"). This hole needs to be very close to size so that the barrel will fit snugly in the bushing. Drill it in several stages to prevent drilling over size. You will need to drill all the way through your bushing. I drill 3 inches deep to be sure that I am all the way through the 2.5" bushing. Part of this 11/16" hole will be threaded later and part of it will be opened up to 3/4". Once the 11/16" hole is drilled the bushing can be turned around and the front end turned to size. The front portion of the bushing is turned to .950" diameter. This portion is turned all the way up to where the flange will be formed. The 1.170" diameter flange will be .125" (1/8") wide so turn the .950" portion to create that size of flange. The reason
I make my adapter bushing long rather than stopping right in front of the flange is to add more support to the barrel. Once you have the exterior of the bushing turned to final size the hole in the center needs some more work. The hole in the front portion of the bushing (the .950" portion) needs to be enlarged to exactly 3/4" (.750"). I drill the front portion to a depth of roughly 1.25". This will leave about half (the other 1.25") the bushing for forming threads. The hole needs to be sized to fit your barrel diameter very closely to offer support on the front end of the bushing. An oversize hole will offer no support. Now that you have a bushing with a 3/4" hole in one end the 11/16" (.687") portion can be threaded with a 3/4"-16 tap. The tapping will be done by sliding the tap into the 3/4" hole till it encounters the 11/16" section. The 3/4" hole will in effect be a tapping guide so that the tap cuts the threads precisely square. If you tap from the other end it would be very easy to cut the threads crooked since you have no support on the sides of the tap. I usually leave the bushings in the lathe chuck for tapping since the chuck grips the bushing better than if you took it out and set it up in a bench vise. Once the threads are formed the adapter bushing is done. When fabricating this part precise lathe set up is very important. Poor lathe set up can result in off-center holes or threads that can cause sight alignment issues later. Make sure all machining operations are square and concentric for the best made part.
Now the barrel needs to be sized to fit the adapter bushing. If you are using a barrel blank, it needs to be turned down to .750" its complete length (or as much of it as you will be using). Since my M31 Suomi barrel was just a little over .750" most of its length I turned the oversize portion to .750". Once the breech end was sized it was time to thread it 3/4" 16. This threading should be done on a lathe with a single point thread cutting tool for maximum accuracy. Trying to thread the barrel with a hand held die holder will result in crooked threads no matter how good you think you can thread by hand. Alignment doesn't just have to look straight it must be straight! This is precision threading, not general purpose threading that can be a little off with no consequences.
I set my lathe up to cut 16 threads per inch and then set up my 60 degree threading bit in a tool holder. I threaded about 1.5" of the breech end of my barrel. I used my bushing as a guide to determine thread fit. The threads on the bushing and barrel need to fit together very snugly for precise alignment. The loose fit like you have between a nut and bolt is too loose for this application. Since this article is not a lathe operation article I won't go into detail on how to thread on a lathe. Once you get close to finish size you need to take very small amounts off on each threading pass to prevent going overly deep. Remember you want a tight thread fit and if you take off to much material you can't put it back on. When test fitting tight threads make sure you keep lubrication on the threads to prevent any chance for galling that could lock the parts together.
Once I had my barrel threaded to tightly fit my bushing, I removed it from the lathe so I could decide how long I wanted the length to be. After test fitting my barrel to the upper receiver and installing the handguard, I decided to shorten the handguard by about 1.5" and then to shorten the barrel to roughly 8 inches in length. After I cut the barrel, I set it up in the lathe and squared up the muzzle and formed a crown on the barrel with 60-degree counter sink.
While certainly not needed on a 9mm AR with an 8-inch barrel, I wanted some type of flash suppressor simply for appearances. A lot of 9mm AR barrels are threaded 1/2"-36 to accept a special 9mm-sized flash suppressor. Considering that a 9mm barrel has a bore size of about 3/8", this only leaves a wall thickness of about 1/16". I personally feel this is too thin. Since this is my project I figured I could make my muzzle threads any size I wanted. I decided to go with 5/8 "-24 muzzle threads. This is a common size for .308 AR barrel muzzles. This would allow me to utilize modified .308 muzzle attachments that are available at reasonable prices.
I turned the last .700" of my muzzle down to 5/8" (.625") and then set my lathe up to cut 24 threads per inch. While I prefer to lathe cut my muzzle threads, you may be able to use a die and hand-held die holder to cut your threads. If, and only if, you are going to use a muzzle attachment that is forgiving of thread alignment you might be able to get by hand-threading with a die. I personally prefer the precision of lathe cut threads. Once I had my threads formed, I installed a YHM Phantom flash suppressor. This unit has a very distinctive appearance that I really like. If you are going to utilize a .308 type muzzle attachment it is imperative that you remember to modify it for the passage of the larger 9mm bullet. I drilled the YHM unit out to 7/16" which would give plenty of clearance. The reason 9mm barrels feature special size threads are specifically to keep people from installing under sized muzzle attachments. Trying to force a .355" bullet through a .308" hole will likely result in severe damage to the gun and operator. If you decide to go with non-standard muzzle threads it is your responsibility to make sure you install a properly sized muzzle attachment.
Later on I was figuring up how much I was spending on my project and decided I needed to remove some cost from the project to meet my budget goal. Because the YHM flash suppressor was priced just a little over $30 I figured I could remove it and replace it with a self-made unit that might cost nothing. To keep cost down I fabricated a faux flash suppressor out of a piece of scrap steel.
Once I had my barrel done I needed to determine how it would fit in my adapter bushing. Barrel depth in the bushing will determine the headspace setting on the assembly. Even though this project features unlocked blowback operation, you still should make some effort to get some type of headspace setting. The unlocked bolt of this gun could be considered to be in the closed position when the bolt face is all the way up against the bushing since this is as far forward as the bolt can go. If the chamber depth is too shallow the bolt will be pushed away from the bushing when a cartridge is in the chamber. While this probably would not affect functioning, it would possibly cause the cases to be smashed by the bolt when it comes forward at speed. If on the other hand the chamber was too deep the cases might be seated so deep in the barrel that the firing pin could not reach the primer when the gun is fired. While headspace is not as critical in this design as it would be in a locked breech gun we still need it to be close for good functioning. Because the chamber depth is already set by the existing chamber in the Suomi barrel I will set depth by screwing the barrel in or out of the hushing
While I have in the past used nothing more than cartridges as improvised headspace gages, you really should utilize real headspace gages for this job. These are available from Brownells. You will need a "GO" gage (#513-100-340) and a "NO GO" gage (#513-100-341). These are priced at about $30 each. Just for your reference a "GO" gage is .755" long and "NO GO" gage is .776" long. This leaves a tolerance of .021". This is an unusually wide range that you typically don't see on high pressure locked breech designs.
I started by screwing my barrel into the bushing till the rear of the barrel was flush with the edge of the bushing. I placed the "GO" gage on the bolt face and inserted it into the chamber. The bolt would go all the way up against the bushing. This indicated that there was at least enough room for a cartridge. I then placed the "NO GO" on the bolt face and inserted it into the chamber. The bolt would now not go quite all the way up to the bushing. There was a very thin gap between the bolt and the bushing. This indicated that there was not excessive space for a cartridge. These two tests indicated that with the barrel flush with the edge of the bushing that there was enough head space for a round but not too much. If the bolt would have touched the rear of the bushing that would have indicated that the chamber was too deep. If you were chambering a barrel blank, you would use a chambering reamer to cut the chamber to the correct depth. Since I was using an existing barrel that already had the chamber cut, the depth was controlled by how far it was screwed into the bushing.
Once the correct depth has been determined, the barrel can be locked into that position in the bushing. Do not lock the barrel in place until you are absolutely sure you will not need to remove the barrel from the bushing for anymore work. Using a Suomi barrel with a pre-cut chamber makes this project a lot easier and cheaper than if you use a barrel blank. If you use a barrel blank you will need to buy a chambering reamer to form the chamber and those are pricey ($75-$100).
The threads on the barrel and bushing will lock the parts together but some means must be used to prevent the parts from screwing apart during use. There are several ways to do this and I will name a few ways to do it. I will start with the most difficult method first. This method is used my many manufacturers. This method is to drill a cross pin hole right at the seam between the barrel and the bushing and then press in a tight fitting cross pin. With this method you must precisely locate the hole so that you drill right at the seam between the parts and not drill off location and completely miss the seam or in a worst case scenario drill into the bore of the barrel. If the parts are flat this method is very easy to do but in this case the bushing is round and getting the drill started in the right place and keeping it from deflecting off course can be difficult. On round work you usually have to machine a flat for a drill starting point so it drills straight.
An easier method is to solder the parts together. You can solder the front joint between the bushing and barrel just like you would on a copper pipe fitting. You rough up the metal and then apply flux to the parts followed by heating with a propane torch. Once the parts are hot enough you apply the solder and it will wick down into the joint. You can also run a little bead around the seam for extra strength. Since the soldering will be done at a relatively low temperature (about 600 degrees) you will not damage the parts if you do it correctly. The best solder for this job is referred to as silver solder. This type of solder is typically made from 96% tin and 4% silver. The best source for this solder is Brownells. Their version is called Hi-Force 44. It is available with or without a flux core. It is very easy to use and even the novice can make a good solder joint with it. I mention Hi-Force 44 specifically because there are other solders marketed as silver solders that may or may not contain the correct amounts of tin and silver to create a strong joint. Brownells Hi-Force 44 is a product of known quality and composition so there is no use in using mystery solders made of who knows what material.
The last method that I will mention is to use a set screw to lock the parts in place. I use this method quite often and used it on this project. The set screw will pass though the bushing and extend a little ways into the barrel. You must be sure to drill to the correct depth to prevent drilling into the bore of the barrel. To use this method you start with the barrel in the correct position in the bushing. Then use a #3 drill bit to drill a tap hole through the wall of the bushing and a very short distance into the barrel wall. You only drill into the barrel far enough to form a shallow dimple in the barrel. When you drill this hole place it where it will be on the inside of the receiver and make sure it will not interfere with installing a locating pin in the bushing later. Once you have the #3 hole through the bushing and have a shallow dimple in the barrel, disassemble the parts and use a 1/4"--28 tap to thread the hole in the bushing. You will use a short 1/4"-28 high-quality set screw in the threaded hole. When you re-assemble the parts the set screw point will extend into the dimple and prevent the parts from rotating out of position. When you have the set screw torqued down tight you grind off any extending above the surface so that the bushing will still slide into the receiver. When using the set screw method I always apply a liberal dose of permanent thread locker (such as Loctite #271) to the barrel, bushing and screw threads so that the parts are "glued" together as well as being retained with the set screw. Be aware that when the thread locker has set up the parts will be extremely difficult to get apart without the application of a lot of heat. Do not assemble the parts with thread locker till you are absolutely sure you will not need to disassemble them later.
Once the barrel is locked into final position in the bushing, there is one last thing that, needs done before the barrel work is complete. The bushing needs to have an indexing pin installed just like the kind you see on a regular AR barrel. This indexing pin will prevent the barrel assembly from turning when the barrel nut is tightened down and also allow the barrel to be indexed in the same place each time it is removed and re-installed. The AR upper receiver features a 1/8-inch slot in the top for this pin so the pin needs to match this diameter. On my Suomi based barrel assembly, I determined the correct location for this pin by aligning the extractor slot in the rear of the barrel with the extractor in the bolt. I also used the feed ramp on the barrel as a location guide by placing it at the bottom. These two indicators did not align together just right so I kind of split the difference between the two. I had to rework the left side of the feed ramp a little to get the ramp centered on the bottom of the receiver. I just widened the feed ramp on the left side with a needle file and then polished the ramp with sand paper and a polishing wheel on a Dremel tool. With the feed ramp and extractor slot in about the right places, I marked the bushing through the top slot in the receiver for the location of the index pin.
The pin hole must be drilled to a precise size so that the 1/8" pin can be press fitted in place. Ideally you would drill the pin hole a few thousandths under size and then use a precision reamer to bring the hole up to exactly .1245". This would allow for a press fit with a .125" short precision dowel pin. I realize that most hobbyist don't have access to precision reamers nor do they have a bin full of precision dowel pins so I will give you an improvised method. This method may require some trial and error fitting but it will work. This method works because drill bits are not made for drilling precisely sized holes. They are generally under the stated size by a thousandth or so and will drill holes under size if you drill the right way. The first thing to do is to purchase a #30 (.1285") drill bit. This .1285" bit will likely drill a hole that is about .1265-. 1275". Also buy a #31 (.120") drill bit and a 1/8" (.125") bit. Number drills are available at most well-equipped hardware stores such as ACE Hardware stores. Drill your locator pin hole with the #31 (.120") bit first. You will only be drilling 5/32"-3/16" deep to prevent drilling into the bore of the barrel within the bushing. After you drill the .120" hole 5/32"-3/16" deep follow up by drilling the same hole with the 1/8" (.125) bit. Since the 1/8" bit is not really .125" in diameter your finished hole size will likely be around .1245". You now need a pin that is about 1/2 thousandth (.0005") over hole size to create a tight press fit. Cut off 1/2"-3/4" of the #30 drill bit's shank. This will be your pin material. Place the piece of #30 drill bit in the chuck of a drill and spin it. Use a fine cut file on the spinning piece of drill shank to reduce the shank down to the size needed for your pin hole. If your hole is about .125" you will need a .1255"-. 126" pin. Once you get close to the size you need remove the bit from the drill and drive it into the hole with a hammer. Be sure to drive it in straight. Once the pin is securely press fitted in the hole cut off the excess pin. The length of the pin needs to be short enough to clear the threads on the receiver and barrel nut but long enough to prevent the barrel from rotating in the receiver. The reason I said you may need some trial and error fitting is because most hobbyist don't have a means of precisely measuring the pin or pin hole in the bushing. This is where you will have to do some guessing. Experienced machinist or gunsmiths can easily gage the size of the hole with measuring tools or even by educated guessing. In the absence of precision measuring tools and practical experience, the hobbyist will just have to do some guesswork gunsmithing. If you don't want to guess fitting this pin you could hire the job out to a machinist. All you have to do is tell him that you need a 1/8 precision dowel pin press fitted into a 5/32"-3/16" deep hole where you have it marked. The machinist will be able to figure out the details. If your 1/8" pin fits too tight in the receiver slot a couple strokes with a file will open up the slot enough for easy insertion. Once you have the pin tight in the bushing and trimmed to length your barrel work is done. If you got your parts close to the price I paid you have a $150 barrel for the expenditure of only about $25. Hobby gunsmithing can save big bucks!
In the next and final installment, I'll affix the barrel, assemble everything and head to the range.
I think you'll like the results. Stay tuned!
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|Date:||Jan 20, 2016|
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