in the bull pin, 80% ar15 build

[corey012778]

I ordered a lower receiver and the finishing jig. both are on the way. these will be my boldest build of any gun yet. won't start until I finish my mn project. hoping for sometime to finish in the next few weeks.


couple of questions


I am thinking of practicing the milling and drilling on as wood stock.. would that be ok? think it would be cheaper then metal both on trail an error and on bits.

would it be better to have someone do the work for me? (have someone already in mind I know that would be able to do it for free)

[captain-03]

....would it be better to have someone do the work for me? (have someone already in mind I know that would be able to do it for free)


May wish to look closely at the legal aspects of this!!

[lefty o]

you have to do your own work on an 80% , otherwise whoever does it for you becomes a manufacturer, needs an FFL, and needs to add a ser# to it.

[Bzcraig]

The advise above is solid, however you can ask your friend to teach you how to use his machine to mill the lower yourself.

[corey012778]

Disclaimer: A provision in the Gun Control Act of 1968 (http://www.atf.gov/firearms/faq/firearms-technology.html#commercial-parts-assembly), 18 U.S.C, Chapter 44 states that an unlicensed individual can make a firearm for personal use, but not for the intent of sale or distribution. Said firearm must conform to N.F.A standards and you must be legally able to be in possession of a firearm. Should you desire to create a Short Barreled Rifle or a Machine gun the BATFE is going to require additional paperwork. If down the road you desire to sell your rifle you will have to put a serial number on it and transfer it via a Federal Firearms License holder. If you never intend to transfer or sell the firearm it must be destroyed upon you giving up possession of the firearm. Granted this is the generally accepted translation of 18 U.S.C, Chapter 44 you should still check local and Federal laws before attempting to build your own personal firearm. Technically you can sell a rifle you have made but you cannot simply make a rifle then immediately decide to turn around and sell it.

could not find anything under va law about these
these will be for person use. if I am wrong. I will delete the first post and ask for it to be locked.

[corey012778]

been doing a lot of research on these. that is way I want to practice on a something that cost a lot less and wont make me go into a corner and cry about screwing up.

[corey012778]

May wish to look closely at the legal aspects of this!!

miss read the first part. new computer and have not got the font size set where I want it yet. so to sound defensive

[oldred]

Not sure how you took the legal warning but the whole thing "in a nut-shell" is you can legally build the rifle but YOU have to do the work and you can not farm it out to someone else! "Oh but he was just showing me how to do it" will not save the builder from prosecution if the actual parts used in the gun are what is being made, if you get someone else to make these parts or do the machine work for you on the ACTUAL PARTS USED both you and the machinist could be in deep,,,,,,well you know!

The reason I am so sure of this is that when I built my first rifle I got conflicting advice when I started asking around, not wanting to run the risk of committing a very serious federal offense based on arm chair law experts on the internet I spent the money to discuss this with a real lawyer ($75 for 10 minutes to sit and ask a few questions might seem a waste but it's darn good peace of mind!). Yes a machinist can "show you how" but they had better not be showing you on the actual parts that will be used, it matters not to the feds if someone is showing you how the bottom line is they are manufacturing the parts that will be used without the proper license. If someone wants to disagree with this then go ahead it's your **** but the lawyer I asked is well familiar with gun laws and is a frequent visitor to the local gun range, he is well known to the local shooters and that's how I connected up with him.



Now as far as practicing on wood, no IMHO. Wood is a terrible practice medium for a machinist because not only can you not practice holding close tolerances but the dimensions often change by quite a bit even over a period of just a few minutes. If you are going to screw up most likely it will be by exceeding tolerances by a few thousandths, this is probably the most common mistake and wood will not let you work to anywhere near the precision you need to learn!

One good practice medium can be plastic auto body filler (Bondo), I use it sometimes for making prototype parts and it machines cleanly as long as it has had time to cure properly (at least 48 hours). I know it seems to harden in a matter of minutes but only to a point and it will remain too soft for at least a couple of days, the cheapest fillers are the best and get a lot harder than the premium easier to work body fillers. You can mold this stuff into the general shape of the part you want to practice or just cast it into blocks and start from there but either way if you give it the proper setting times it will machine to fairly close dimensions and cut cleanly. Of course if you are talking about practicing general machine procedures then it too is not going to help you very much, it may help you learn how to stay within working tolerances and learn a specific procedure to make a certain part but will be of little or no help with other critical things you will need to know, for instance climb cutting and backlash is not a problem at all with a material like Bondo but just try it on steel and see what happens! That's just one of many examples and working with soft materials like body filler or wood can actually be counterproductive because it can instill false confidence by making the operator think he has it down when in fact they may be using techniques and methods that are not possible or extremely risky when used with harder materials, for instance climb cutting against backlash will work just fine with body filler or wood but can easily result in some exciting episodes and broken tools when machining metal!

[corey012778]

Not sure how you took the legal warning but the whole thing "in a nut-shell" is you can legally build the rifle but YOU have to do the work and you can not farm it out to someone else! "Oh but he was just showing me how to do it" will not save the builder from prosecution if the actual parts used in the gun are what is being made, if you get someone else to make these parts or do the machine work for you on the ACTUAL PARTS USED both you and the machinist could be in deep,,,,,,well you know!

The reason I am so sure of this is that when I built my first rifle I got conflicting advice when I started asking around, not wanting to run the risk of committing a very serious federal offense based on arm chair law experts on the internet I spent the money to discuss this with a real lawyer ($75 for 10 minutes to sit and ask a few questions might seem a waste but it's darn good peace of mind!). Yes a machinist can "show you how" but they had better not be showing you on the actual parts that will be used, it matters not to the feds if someone is showing you how the bottom line is they are manufacturing the parts that will be used without the proper license. If someone wants to disagree with this then go ahead it's your **** but the lawyer I asked is well familiar with gun laws and is a frequent visitor to the local gun range, he is well known to the local shooters and that's how I connected up with him.



Now as far as practicing on wood, no IMHO. Wood is a terrible practice medium for a machinist because not only can you not practice holding close tolerances but the dimensions often change by quite a bit even over a period of just a few minutes. If you are going to screw up most likely it will be by exceeding tolerances by a few thousandths, this is probably the most common mistake and wood will not let you work to anywhere near the precision you need to learn!

One good practice medium can be plastic auto body filler (Bondo), I use it sometimes for making prototype parts and it machines cleanly as long as it has had time to cure properly (at least 48 hours). I know it seems to harden in a matter of minutes but only to a point and it will remain too soft for at least a couple of days, the cheapest fillers are the best and get a lot harder than the premium easier to work body fillers. You can mold this stuff into the general shape of the part you want to practice or just cast it into blocks and start from there but either way if you give it the proper setting times it will machine to fairly close dimensions and cut cleanly. Of course if you are talking about practicing general machine procedures then it too is not going to help you very much, it may help you learn how to stay within working tolerances and learn a specific procedure to make a certain part but will be of little or no help with other critical things you will need to know, for instance climb cutting and backlash is not a problem at all with a material like Bondo but just try it on steel and see what happens! That's just one of many examples and working with soft materials like body filler or wood can actually be counterproductive because it can instill false confidence by making the operator think he has it down when in fact they may be using techniques and methods that are not possible or extremely risky when used with harder materials, for instance climb cutting against backlash will work just fine with body filler or wood but can easily result in some exciting episodes and broken tools when machining metal!

so in a nutshell. find scrap aluminum or other metals and practice the operations on that. or a see how good my art skills are and mold a close to the shape.

[Handloader109]

Go to Ar15.com and there are a lot of discussions about 80% building. I ordered a pair of lowers and a jig last year and used my drill press to mill out pockets. I've a heavy-duty floor press and it worked out OK. Mill would be better, but I don't have a mill. It is easy if you follow directions.

[corey012778]

The more I look at sites and YouTube vids. Starting to think that this part is not as bad as I am thinking. Sadly I don't have a floor model drill press. Have two table press. (Bought one brand new the other was bought at auction for $25) also have an x-y vise.

[xacex]

The more I look at sites and YouTube vids. Starting to think that this part is not as bad as I am thinking. Sadly I don't have a floor model drill press. Have two table press. (Bought one brand new the other was bought at auction for $25) also have an x-y vise.
There is a great jig available now for using a router. If you have one of those they come out better than a drill press. I did the drill press thing once, and was not impressed. Ended up buying a mill, and well the rest is history. The mill cost was made up rather quickly. But, then again I have done more than a few lowers. It gets used for many things now. Saving up to cnc the darn thing now. It is just a little X2 mini mill, but it works.

[xacex]

Here is the router jig I was talking about. http://www.80percentarms.com/products/80-ar-15-easy-jig

[corey012778]

I know the one your talking about. Looking at it I don't see why you could not pull it off with out that jig. Other then (if it is the one I am thinking about , looked at so many jigs) the cool depth gauges.

[LAGS]

I was given some Out of spec Handgun receiver parts, that were not machined.
I contacted BATF to verify that what I was building was not an AOW.
They said the receivers qualified as a Handgun, but I could make it for myself, but they reserved the right to ask me to demonstrate that I had the tools and skills to Machine and build it myself.
IE, I had to be the one who actually did the Machining and assembly.
And if other pistols started showing up with out serial numbers, they would ask the owners to demonstrate that they actually built the handgun also, so they were sure I was not turning un machined receivers out , selling them with a parts kit and letting someone else say, I Built it for myself, so It Doesnt need a serial number.

[xacex]

I know the one your talking about. Looking at it I don't see why you could not pull it off with out that jig. Other then (if it is the one I am thinking about , looked at so many jigs) the cool depth gauges.
There is a fellow that did one of Pirate4x4 with just a standard jig, and a router. This one just looked easier with less drilling. The drilling can be a bear, and if the small starter bit wanders when you drill the 3/8th holes they will be off slightly. That was my experience doing one with a drill press. There were small marks on the side walls that were where the 3/8th bit was centered. Still totally functional, but is was not up to my expectation of quality as far as being blem free on the inside when done. I cant say any method outside of using an actual mill would make me happy, and I have no clue if that router jig is worth it, but it is an option that does not look to bad. I paid a bunch more for the mill than that jig, but the jig is a one trick pony. Not the best investment of tool money if you ask me.

[bld451]

So this year they came out with a guideline that says if you have a business you cannot loan your tools to someone to finish their receiver....... If you have a business, own the tools and someone else uses them to finish a receiver, you have de-facto manufactured a receiver for them. This all started with the build fests where someone would set up outside a cooperating CNC shop and sell someone an 80% receiver with a coupon for 15 minutes of machine time on the CNC. The customer would walk into the shop and give the coupon. A nice machine operator would either give instruction on how to load into the fixture, (or load them himself) and the customer would put the piece in the CNC and push the button. Voila! Ar 15. Now, the ATF didn't like this, of course, and decided to "clarify". I was just preparing to tutor my neighbor and let him use my mill to complete his 80% lower. Bummer for him, it didn't happen as the guidelines came out just before we went to work..... As it turns out, I could not loan him my machine, as I have a home based business. This is from the ATF letter...

"Held, any person (including any corporation or other legal entity) engaged in the business of performing machining, molding, casting, forging, printing (additive manufacturing) or other manufacturing process to create a firearm frame or receiver, or to make a frame or receiver suitable for use as part of a “weapon … which will or is designed to or may readily be converted to expel a projectile by the action of an explosive,” i.e., a “firearm,” must be licensed as a manufacturer under the GCA; identify (mark) any such firearm; and maintain required manufacturer’s records.Held further, a business (including an association or society) may not avoid the manufacturing license, marking, and recordkeeping requirements of the GCA by allowing persons to perform manufacturing processes on blanks or incomplete firearms (including frames or receivers) using machinery, tools, or equipment under its dominion and control where that business controls access to, and use of, such machinery, tools, or equipment.
Held further, this ruling is limited to an interpretation of the requirements imposed on persons under the GCA, and does not interpret the requirements of the National Firearms Act, 26 U.S.C. 5801 et. seq."

So, be careful about borrowing or loaning equipment if the loaner has a business (any business). Also, what would constitute "under its dominion or control? The clarification includes "equipment and tools", so if they wanted to press the issue, (when have they ever prosecuted anyone to LESS than the limit of the law??) does that mean I can't loan out my hand drill and file to my neighbor to finish his receiver. I suppose I could but the mill is stationary in my garage.... Some folks are buying the little "Ghost Gunner" tabletop CNC, and agreeing with friends (we'll say 10) to sell the mill to the next in line at a 10% reduction, so at the end, they can all have purchased their own tool at 10% of the cost of the whole thing, then, when finished, sell it to the next group and recoup most of their investment.

[oldred]

Some folks are buying the little "Ghost Gunner" tabletop CNC, and agreeing with friends (we'll say 10) to sell the mill to the next in line at a 10% reduction, so at the end, they can all have purchased their own tool at 10% of the cost of the whole thing, then, when finished, sell it to the next group and recoup most of their investment.


Something like may (or may not!) work but I would "assume" that as long as the builder him/herself was doing all the work it would probably be ok. The problem is things of this nature are in the proverbial "Grey area" and judges are not very tolerant of clever little tricks obviously meant to circumvent the law, common (but very often mistaken) ideas of what is ok could land a person in serious hotwater, things such as "he was just showing me how to do it". If the laws were that easy to get around they would be meaningless, an example is that CNC shop trick you mentioned. The main subjects of that incident, there were several of these shops in operation, got into some very serious legal troubles and a number of customers lost their projects but were lucky not to be charged with possession of an illegal weapon.

The bottom line is the BATF frowns on us building guns at home, as of right now they can't do much about it but they certainly would if they could, and if a person is charged they had better be in FULL compliance with the law TO THE LETTER and no federal prosecutor is going to fall for any "clever" little tricks to get around these laws!

[corey012778]

kinda a double good news, my lower came in today and looks like less work. looks like I just have to mill the trigger house pocket. thought 80% lowers you had to do the trigger pocket and the pocket behind it?

[Vann]

I've finished two 80% lowers using the router jig from 80 Percent Arms, and they both came out great. I've never tried milling one with a drill press, so I can't advise you there. I only used a drill press to do all of the drilling on the receivers. If you go the drill press route be sure to square up your vice to the chuck.

[oldred]

BE WARNED!!!!! A drill press is not a mill! Some folks have obviously done this and gotten away with it but there are several things wrong with trying to use a drill press for a mill, two in particular. First a drill press is not nearly rigid enough but if using a small end mill just for Aluminum it can often be made to work, albeit not to really close tolerances. The worst problem is the very real danger of the drill chuck falling off while trying to apply a side load in order to use the end mill, a drill chuck is held only by friction on a taper shaft and side loading WILL cause this to work loose. It's not a matter of if but rather when it will fall off, it may (or may not) hold long enough to finish a job such as this but the loosening effect is cumulative as the chuck spins while side loaded and it WILL eventually fall off. If this happens it can damage the part or ruin the end mill or both, if it comes off at the right time you could easily find yourself being chased around the shop by a rapidly spinning metal top with very sharp teeth! There are some rather eye-opening stories out there from folks who didn't get away with doing this and while some have (so far anyway) it's a very risky practice that can ruin your parts or YOU!

[corey012778]

I've finished two 80% lowers using the router jig from 80 Percent Arms, and they both came out great. I've never tried milling one with a drill press, so I can't advise you there. I only used a drill press to do all of the drilling on the receivers. If you go the drill press route be sure to square up your vice to the chuck.
I will be making sure 100% it is lined up. may end up using a router. since I already have a jig coming in I am not willing to fork out an more money on a second at these time. but I see where you can order just the router plate debating on ordering that and seeing if I can adapt that to work. worst case, use it as a template.

I stand corrected on that bolded statement. they sell the spacer not the plate in the replacement section. that went that idea for now.


BE WARNED!!!!! A drill press is not a mill! Some folks have obviously done this and gotten away with it but there are several things wrong with trying to use a drill press for a mill, two in particular. First a drill press is not nearly rigid enough but if using a small end mill just for Aluminum it can often be made to work, albeit not to really close tolerances. The worst problem is the very danger of the drill chuck falling off while trying to apply a side load in order to use the end mill, a drill chuck is held only by friction on a taper shaft and side loading WILL cause this to work loose. It's not a matter of if but rather when it will fall off, it may (or may not) hold long enough to finish a job such as this but the loosening effect is cumulative as the chuck spins while side loaded and it WILL eventually fall off. If this happens it can damage the part or ruin the end mill or both, if it comes off at the right time you could easily find yourself being chased around the shop by a rapidly spinning metal top with very sharp teeth! There are some rather eye-opening stories out there from folks who didn't get away with doing this and while some have (so far anyway) it's a very risky practice that ruin your parts or YOU!

I have seen where people have made a shaft to be used for milling. really not wanting to go thru all the work to adapt one of the two drill I have for that. once again I wish I just broke down and got the easy jig. it is what it is.

sadly I may have to still fork out some money for a new router. my larger router is die barely used it and have a hf small router. every thing I have read and watched said to use higher end "laminate" routers. porter cable ect.

I am still in the early stages of these and have to finish another project first. luckily is in the final stages. another two weeks (I hope) on it.

[corey012778]

the jig came in, the ar book I ordered came in. I could just got all the info off the internet but nothing like a paper copy to have for a quick reference. checked the jig with my hf trim/laminate router. it will ride on the templates but will hit the buffer tube area. I would have to mod the finance to make it work right. I will figure it out , I have sometime. have a few things I want to do in my shop before I even start these project.

[rtracy2001]

I just finished my 80% on a little HF tabletop drill press (all I had). It really wan't as hard as I feared, but I did learn a couple things:

Gratuitous disclaimer: I am an engineer NOT a machinist. These are my observations and your mileage may vary.

1. Two flute end mills are generally preferred for aluminum BUT, when using a drill press they chatter A LOT! I found that using a 4 flute end mill and going slow produced much more satisfactory results.
2. It bears repeating that not all end mills are created equal. Buy US made from a reputable dealer. The Chinese junk just won't cut it for end mills. Do NOT buy cheap end mills from Amazon.
3. Because the drill press doesn't have the same rigidity as a mill, a special technique is required.
Mill down the center of the cut first, leaving plenty of room between the edge of the cut and the jig.
Once the cutting flutes are below the level of the jig, mill out the excess material until you can use the jig as a secondary contact point. This avoids chewing up the jig and seems to give a better finish to the part.
4. Use a quality cutting oil like "Tap Magic" or similar.
5. Clean chips often. I used a chunk of 1/2" plastic conduit taped to my shop vac hose to create a small nozzle to pick up stubborn chips.

With a little time you can get a nice looking receiver, even with junk tools.
145776
(yeah, I still have a few chips to clean out in the photo above.)

It works just fine:
145778

[nicholst55]

Also realize that every single 80% lower that I have examined (10-15), are slightly undersized according to the drawings. The receiver is generally .010-.020" thinner than spec. - sometimes more.

[Handloader109]

Also realize that every single 80% lower that I have examined (10-15), are slightly undersized according to the drawings. The receiver is generally .010-.020" thinner than spec. - sometimes more. And really no big deal, way stronger than polymer lowers

]

[Handloader109]

kinda a double good news, my lower came in today and looks like less work. looks like I just have to mill the trigger house pocket. thought 80% lowers you had to do the trigger pocket and the pocket behind it?


Just depends on the lower, my rear pocket was machined also. I actually left a Web of material between the two, no reason to mill all the way out, nothing but one pin thru that area

[plus1hdcp]

I just finished my 80% on a little HF tabletop drill press (all I had). It really wan't as hard as I feared, but I did learn a couple things:

Gratuitous disclaimer: I am an engineer NOT a machinist. These are my observations and your mileage may vary.

1. Two flute end mills are generally preferred for aluminum BUT, when using a drill press they chatter A LOT! I found that using a 4 flute end mill and going slow produced much more satisfactory results.
2. It bears repeating that not all end mills are created equal. Buy US made from a reputable dealer. The Chinese junk just won't cut it for end mills. Do NOT buy cheap end mills from Amazon.
3. Because the drill press doesn't have the same rigidity as a mill, a special technique is required.
Mill down the center of the cut first, leaving plenty of room between the edge of the cut and the jig.
Once the cutting flutes are below the level of the jig, mill out the excess material until you can use the jig as a secondary contact point. This avoids chewing up the jig and seems to give a better finish to the part.
4. Use a quality cutting oil like "Tap Magic" or similar.
5. Clean chips often. I used a chunk of 1/2" plastic conduit taped to my shop vac hose to create a small nozzle to pick up stubborn chips.

With a little time you can get a nice looking receiver, even with junk tools.
145776
(yeah, I still have a few chips to clean out in the photo above.)

It works just fine:
145778

Nicely done sir

[Sticky]

Also realize that every single 80% lower that I have examined (10-15), are slightly undersized according to the drawings. The receiver is generally .010-.020" thinner than spec. - sometimes more.

Forged lowers will always vary a little, CNC'd not so much. When using a mill, one first determines the centerline of that particular lower and works from that. It really doesn't matter if they are a little skinny or fat, as long as the trigger components all clear inside and the critical holes are properly located.

I have seen some pretty rough ones (done with a drill press and dremel tool) that looked pukey inside, but worked just fine.. LOL

[corey012778]

Just depends on the lower, my rear pocket was machined also. I actually left a Web of material between the two, no reason to mill all the way out, nothing but one pin thru that area
I made sure it meets all the measurements I had, it did. so it did happy about that. taped the drill holes in that area already. after a missed typed on a search. found some drill press mills accidents. I have already have had a meat saw accident. lucky to still have my trigger finger. still leaning to using a router option. think I could pull it off with the jig I have.

[LAGS]

I have a Question;
Why does everyone want to build their own AR out of an 80% receiver ?
Is it in some way better or really cheaper to get an AR this way.
But no matter how little or how much you spend, You legally cant sell it ?

[lefty o]

2 main reasons people build 80%ers, 1 some guys just want to do it themselves. 2 some want to build it so the gvmnt doesnt know they have it. for those that do it for #2 and ask or post about it on the net, it kinda negates the whole deal lol! #1 isnt a bad reason, but for me currently you can find completely machined ready to go quality rcvrs for $39-$49, so your not saving money doing it.

[LAGS]

I too like to build my own guns, and if I wanted Big Brother not knowing what I have, then I just buy something in a private sale, and there is no government transfer.
But I have run into Local Issues of having an Unregistered or Unserial numbered receiver.
The Feds say you can build Have and shoot it, but your Local authorities can step in if they want, and in the long run not be able to arrest you for having a unregistered gun, but can confiscate it, and hold it for however long they want to.
But my reason for wanting to build my own is so I can make one Better than what is out on the market.
I am not kidding myself and think that can really happen, especially without having the Proper Tools to do it Better.
But I aplaude the guys who like building their own stuff, and wish them luck with their project.
I have seen some fine Home Builds, but have never seen one that will outperform an off the shelf rifle.

[corey012778]

I enjoy doing a gun build. done a number of muzzleloader builds. just got bored of doing them. I am just, want to do something different. really should be done with the current project in next week or so. getting a break from the on the go. have 3 or 4 little projects. mainly to get ready for these project

[LAGS]

What Upper are you going to use, and what Caliber are you going with ?

[corey012778]

leaning to the 556/223 but after talking about state hunting caliber min. thinking about 6.5mm Grendel. maybe 7.62x39. most likely stay with the 556/223. maybe I do a another build down the road depends how these one turns out.

[corey012778]

little update,

have not finished my other project yet nor cleaned up my shop. (bad me). have most the drill bits and end mills bought or on order I will need for the project including something I never used in the past namely I wear glasses and never felt or found a pair of safety glasses that fits.

I printed out two sets of drill/milling instructions, going to decide what parts of each I am going to use. there very alike in many of the steps but one or two of that. there so close it is just minor steps. did get a pdf file from the company I got the jig from. but when I upgraded to windows 10 the file got deleted before I got my printer working again.

lags, private sale on ar15 can be shady. they don't resale them cheap. most will say they will put 1200 worth of after market parts into the gun and ask that price. then you buy it and find out you have stock $550 gun.

figuring I will put $500 to 600 more into these gun. I got some time before I will finish it. think I my wife said the rest of the parts for Christmas. that is ok. going to be spending most the fall looking for a very nice buck that is on the land I help take care of. big boy is at 6 points now and looks like he is going to split a little more.

[corey012778]

started on the build. the small holes are going faster then I thought they would. I am taking my time. two reasons, one, these is my first build not wanting to try to rush things. taking my time making sure it is right. second, taking it easy on the drill press I am using. I am using an x-y vise. helping a lot. drilling a little short.

I am thinking when I have it done have the guy I know double check my work. I am known to be off on my measurements. second eye would not be bad.