View Full Version : AR assembly techniques.
I have currently built a few uppers/lowers at this point, but by no means consider myself to be an expert/armorer. And, I'm always interested in hearing/seeing how others go about their builds and the techniques, insights, etc. So, recently I was watching somebody build a BCM 9" .300/blk upper (however, the video is now gone for some reason). This video was of particular interest since I'm about to build my BCM 11.5 upper. Anyway, in the video, the guy building it used compressed air to clean any particles, dust, or debris that may have been in the barrel nut, feed ramps, and receiver threads. How critical or important is this? This guy was the only person I've ever seen do this, and he was pretty adamant about how important of a step it was (I do have a compressor and can utilize this technique if it's beneficial). In the same sort of vein, is soaking threads of various parts in acetone critical/required or pointless? The acetone cleaning I have seen in quite a few videos, but not in all of them. Sorry for the long winded post!
RobertTheTexan
10-30-17, 14:29
I don’t soak my parts in acetone. Wasn’t even aware that was done. In the video, were all the parts brand new? If so, then I think the only time I would use compressed air was if I was lapping my upper receiver or some other activity that left metal particles that could come into contact with threads or threaded surfaces. I do clean the threads on the upper and wipe down the inside threads on the barrel nut before applying aeroshell.
I’m not an expert either, but that’s the way I do it.
I think if I let my OCD run wild I could see myself using my air compressor to blow out whatever particles, real or imaginary.
Sent from my iPhone using Tapatalk
I've built one upper and lower
It was pretty easy
All the videos I researched most made a point of proper torque
Proper degrease then regrease or loctite as appropriate any threads
The most difficult for me was installing the trigger
It kept uncocking
I don’t soak my parts in acetone. Wasn’t even aware that was done. In the video, were all the parts brand new? If so, then I think the only time I would use compressed air was if I was lapping my upper receiver or some other activity that left metal particles that could come into contact with threads or threaded surfaces. I do clean the threads on the upper and wipe down the inside threads on the barrel nut before applying aeroshell.
I’m not an expert either, but that’s the way I do it.
I think if I let my OCD run wild I could see myself using my air compressor to blow out whatever particles, real or imaginary.
Sent from my iPhone using Tapatalk
Yup! Brand new right out of the packaging. The guy was saying basically if any little bits of debris get into those areas they could really mess with the function of the rifle. And maybe "soak" wasn't a good word. For instance, Surefire put out a muzzle device installation video a few years ago. And the guy in the video poured acetone on the muzzle threads and barrel thread, cleaned with a Q-tip until the Q-tips had no visible anything on them, then he proceeded to install the muzzle device. It seems like a good practice, but it doesn't seem to be the "standard"?
SomeOtherGuy
10-30-17, 14:43
Not an expert. I have never used compressed air or acetone. If a part appears to have dirt or production grit I clean it with something compatible with its ultimate use - typically gun CLP for parts that will have CLP or grease on them, or water-based spray degreaser for parts that will be dry in use, or are getting painted.
Again, not an expert.
I think compressed air is massively over-used though. It's the absolute best way to put your contaminated grit or oily residue into the shop air, so it can slowly settle on EVERYTHING in the shop and make a much bigger mess. If there's enough grit that you can't wipe it away or blow it with your breath, try a shop-vac.
I've built one upper and lower
It was pretty easy
All the videos I researched most made a point of proper torque
Proper degrease then regrease or loctite as appropriate any threads
The most difficult for me was installing the trigger
It kept uncocking
Yes, torquing is definitely important and yes triggers can be a pain in the ass haha. You never cleaned your threads with acetone before installing or used compressed air?
Yup! Brand new right out of the packaging. The guy was saying basically if any little bits of debris get into those areas they could really mess with the function of the rifle. And maybe "soak" wasn't a good word. For instance, Surefire put out a muzzle device installation video a few years ago. And the guy in the video poured acetone on the muzzle threads and barrel thread, cleaned with a Q-tip until the Q-tips had no visible anything on them, then he proceeded to install the muzzle device. It seems like a good practice, but it doesn't seem to be the "standard"?
Threads for a silencer mount need to be cleaned completely with solvent. Same for anything getting thread locker.
The biggest mistake I see is failing to torque the barrel nut to max, then loosen several times before final torque setting.
Threads for a silencer mount need to be cleaned completely with solvent. Same for anything getting thread locker.
The biggest mistake I see is failing to torque the barrel nut to max, then loosen several times before final torque setting.
Yup, I don't think I've ever seen somebody not do that. Who knows what people do in the privacy of their own garage, though.
Yes forgot to mention the breaking in and seasoning of torque on the barrel nut is very important
Second to the trigger assembly clocking the barrel nut was also a bit of a pain
Threads for a silencer mount need to be cleaned completely with solvent. Same for anything getting thread locker.
The biggest mistake I see is failing to torque the barrel nut to max, then loosen several times before final torque setting.
Who goes to the maximum (80 foot pound) torque spec for the tighten/tighten/loosen routine?
The tighten/loosen routine is supposed to be done with the minimum (30 foot pound) torque spec, not the maximum.
Also, I have always hosed down every metal part with CRC non chlorinated brake cleaner and then I use an air compressor to dry the parts prior to assembly.
All plastic parts get hand washed with hot/warm soapy water and then they get the air compressor.
Yes, my skin will crawl if I happen to see someone skip these steps. :fie:
Who goes to the maximum (80 foot pound) torque spec for the tighten/tighten/loosen routine?
The tighten/loosen routine is supposed to be done with the minimum (30 foot pound) torque spec, not the maximum.
Also, I have always hosed down every metal part with CRC non chlorinated brake cleaner and then I use an air compressor to dry the parts prior to assembly.
All plastic parts get hand washed with hot/warm soapy water and then they get the air compressor.
Yes, my skin will crawl if I happen to see someone skip these steps. :fie:
Thank you! This is what I wanted to know. So you do this even if the parts are all sealed up and only exposed once they're ready to be installed? I never torque down to the maximum. Every set of directions I've seen that comes with a rail specifically says not to torque to the maximum, but I'm sure there are plenty of people that fail to read the directions 🤔
Thank you! This is what I wanted to know. So you do this even if the parts are all sealed up and only exposed once they're ready to be installed? I never torque down to the maximum. Every set of directions I've seen that comes with a rail specifically says not to torque to the maximum, but I'm sure there are plenty of people that fail to read the directions ��
Yes, I even clean parts that came to me all sealed up direct from the factory. Metal parts are usually covered in some type of preservative oil or grease.
However, I do keep in mind that they do not preform my OCD clean routine at any of my favorite firearms manufacturing companies. :no:
I think this is an excellent idea for a thread.
Does everybody apply aeroshell to all the threads? I usually do - barrel nut and castle nut/receiver extension.
I have more aeroshell than I could use in a lifetime it feels like. I bought like 14 oz.
Who goes to the maximum (80 foot pound) torque spec for the tighten/tighten/loosen routine?
The tighten/loosen routine is supposed to be done with the minimum (30 foot pound) torque spec, not the maximum.
Also, I have always hosed down every metal part with CRC non chlorinated brake cleaner and then I use an air compressor to dry the parts prior to assembly.
All plastic parts get hand washed with hot/warm soapy water and then they get the air compressor.
Yes, my skin will crawl if I happen to see someone skip these steps. :fie:
I would just let the brake cleaner evaporate.
I had an engine shop teacher in high school who was adamant you don't use shop air to clean/dry parts because most compressors don't have air dryers on them. Don't know that it's that big a deal.
When torquing I go to slightly below the minimum for my seasoning torques, then clean the aeroshell off with a rag and lightly reapply for final torque. Don't know if that's right, but it is what I do, grease is cheap.
I also oil roll pins, on my next assembly I'll probably use Giessele 0000 Grease. I figure since I push a drill bit into paraffin or soap before drill hardwood, it can't hurt to lube a roll pin.
Yes, I even clean parts that came to me all sealed up direct from the factory. Metal parts are usually covered in some type of preservative oil or grease.
However, I do keep in mind that they do not preform my OCD clean routine at any of my favorite firearms manufacturing companies. :no:
I suspect it would be next to impossible to do so. Unless they ran the place NASA when it builds satellites!
I think this is an excellent idea for a thread.
Does everybody apply aeroshell to all the threads? I usually do - barrel nut and castle nut/receiver extension.
I have more aeroshell than I could use in a lifetime it feels like. I bought like 14 oz.
Yep, I apply moly grease/paste to the upper receiver/barrel nut threads, castle nut/receiver extension threads and muzzle device/barrel threads.
I would just let the brake cleaner evaporate.
I had an engine shop teacher in high school who was adamant you don't use shop air to clean/dry parts because most compressors don't have air dryers on them. Don't know that it's that big a deal.
When torquing I go to slightly below the minimum for my seasoning torques, then clean the aeroshell off with a rag and lightly reapply for final torque. Don't know if that's right, but it is what I do, grease is cheap.
I also oil roll pins, on my next assembly I'll probably use Giessele 0000 Grease. I figure since I push a drill bit into paraffin or soap before drill hardwood, it can't hurt to lube a roll pin.
I actually use a condensation catcher to capture any moisture that may be coming down the air hose from the tank.
I also dip my roll pins in Slip 2000 EWL before installation... Same with taper pins, it works great.
I think this is an excellent idea for a thread.
Does everybody apply aeroshell to all the threads? I usually do - barrel nut and castle nut/receiver extension.
I have more aeroshell than I could use in a lifetime it feels like. I bought like 14 oz.
I appreciate the compliment. I aeroshell the hell out of everything. What's the worst that's going to happen if there's a little bit too much? I do the same thing w/ lubrication.
I think this is an excellent idea for a thread.
Does everybody apply aeroshell to all the threads? I usually do - barrel nut and castle nut/receiver extension.
I have more aeroshell than I could use in a lifetime it feels like. I bought like 14 oz.
I took apart my PSA upper this weekend because I couldnt see any grease around the barrel but (like all of my BCM uppers show) I was completely shocked (sarcasm) that it didn't have any grease and it was completely dry.
So I greased the hell out of it and put it all back together. I doubt it'll change anything but I sure do feel better knowing it has the right grease on it now.
I hand torque, to somewhere near max to get any possible stretch out before hitting final torque. I don't trust the minimum to do that if I end up near the maximum for final.
A bit of grease on the threads, but there is way more need for it on the front of the barrel extension. Everything should be clean and free of any grit or metal particles. Air is fine if you have a dryer or good trap.
I saw a Ballistic Advantage video where an armorer (believe it was Hanson) was assembling an Upper with the then new Hanson profile barrel.
He did NOT use a torque wrench on the barrel nut- explaining he never did (use one).
Apparently "the Force" was guiding him.
Watching this I had to try it.
My next Upper I just used a 1/2" drive, "seasoned" the threads thrice, tightened it up and called it good.
No problems were experienced by doing this. Accuracy was 1.5 MOA per normal.
Anyone NOT use a torque wrench?
Yup! Brand new right out of the packaging. The guy was saying basically if any little bits of debris get into those areas they could really mess with the function of the rifle. And maybe "soak" wasn't a good word. For instance, Surefire put out a muzzle device installation video a few years ago. And the guy in the video poured acetone on the muzzle threads and barrel thread, cleaned with a Q-tip until the Q-tips had no visible anything on them, then he proceeded to install the muzzle device. It seems like a good practice, but it doesn't seem to be the "standard"?
This makes sense if using a a mount that gets rock set. Critical, probably not, but it can only help adhesion.
I saw a Ballistic Advantage video where an armorer (believe it was Hanson) was assembling an Upper with the then new Hanson profile barrel.
He did NOT use a torque wrench on the barrel nut- explaining he never did (use one).
Apparently "the Force" was guiding him.
Watching this I had to try it.
My next Upper I just used a 1/2" drive, "seasoned" the threads thrice, tightened it up and called it good.
No problems were experienced by doing this. Accuracy was 1.5 MOA per normal.
Anyone NOT use a torque wrench?
Guys always tell me how much experience they have and how calibrated they are and don’t need a torque wrench.
They always mess up once in a while. A torque wrench removes all doubt. There is no reason not to use one, IMO.
This makes sense if using a a mount that gets rock set. Critical, probably not, but it can only help adhesion.
Good point. He was using rocksett.
fishindogwood
10-30-17, 21:43
So do you think my Daniel Defense M4v7 has the Aeroshell or grease on the threads from the factory? Not able to check at the moment.
I hand torque, to somewhere near max to get any possible stretch out before hitting final torque. I don't trust the minimum to do that if I end up near the maximum for final.
A bit of grease on the threads, but there is way more need for it on the front of the barrel extension. Everything should be clean and free of any grit or metal particles. Air is fine if you have a dryer or good trap.
I always assumed that you need some amount of thread stretch still available to achieve alignment of timed barrel nuts.
I'm glad that you brought up greasing the front facing side of the barrel extension flange as I forgot to mention it... Greasing the flange is a very important step in the assembly process.
The last 3 PSA uppers I have disassembled in my courses have all had much less than the minimum of torque, and were as dry as Hillary's V spot.
The last 3 PSA uppers I have disassembled in my courses have all had much less than the minimum of torque, and were as dry as Hillary's V spot.
Enough to give you nightmares!
I use a 1/4 clevis pin from Home Depot to install the pivot. Cheaper than the dedicated tool and saves me launching springs and detents across the garage. This discovery was a revelation for me.
A gunsmith friend of mine wipes down every part with a nylon brush and a rag. Sometimes I've seen him use a hair dryer on the lowest setting to blow out any junk.
I've usually just wiped down with a rag and then install if they look dirty.
The last 3 PSA uppers I have disassembled in my courses have all had much less than the minimum of torque, and were as dry as Hillary's V spot.
Now I am sick to my stomach! Old "Crusty Cunt" comes to mind!!
Some tips on AR assembly, picked up over my eight years of building them:
- Barrel nut torque: I use barrel nut shims to time the nut for gas tube clearance (article found at http://ar15barrels.com/data/barrel-nut-index.pdf. I've checked torque on several after install, and find that method yields a torque value of around 40 ft-lbs, and no drama. As a footnote, grease on the upper receiver threads will yield an actual torque higher than perceived, due to reduction of thread friction by the grease.
- Upper receiver threads: Aeroshell 64 MoS2 grease on the threads, to reduce the possibility of bi-metal corrosion.
- Trigger install: to ease aligning all the parts of trigger and hammer, I use Hiperfire's Assembly Drift Pin (link here: https://www.hiperfire.com/product/assembly-drift-pin/), a $10 tool that stays in my range bag until needed. Geissele also sells a tool with which to line up trigger parts.
- Trigger "break-in": mil-spec trigger sears are typically not micro-polished, which is why they can feel "gritty" until many thousands of rounds are fired. I clean the sear surfaces, and install the FCG into the lower "dry"; using a bench vise and lower block, I cock the trigger and apply upward force to it with a finger, to increase the load on the sears, and press the trigger. I take care to not let the hammer impact the mag catch, and dry-fire the trigger 50~100 times to polish the sears. I then apply Mobil 28 grease to the sear surfaces for use. This yields a mil-spec trigger that feels like it's seen lots of breaks. Of course, if I'm building a higher-end unit with an aftermarket trigger, it's not necessary.
- Selector detent spring capture: I use a 4-40 tap to make threads about a quarter inch into the selector spring well at the back of the receiver, and matching set screw. I cut the end of the spring flush with the receiver, and install the set screw, and never again need to wrangle the spring if I need to change the buffer tube.
I hope these tips help, OP.
Some tips on AR assembly, picked up over my eight years of building them:
- Barrel nut torque: I use barrel nut shims to time the nut for gas tube clearance (article found at http://ar15barrels.com/data/barrel-nut-index.pdf. I've checked torque on several after install, and find that method yields a torque value of around 40 ft-lbs, and no drama. As a footnote, grease on the upper receiver threads will yield an actual torque higher than perceived, due to reduction of thread friction by the grease.
- Upper receiver threads: Aeroshell 64 MoS2 grease on the threads, to reduce the possibility of bi-metal corrosion.
- Trigger install: to ease aligning all the parts of trigger and hammer, I use Hiperfire's Assembly Drift Pin (link here: https://www.hiperfire.com/product/assembly-drift-pin/), a $10 tool that stays in my range bag until needed. Geissele also sells a tool with which to line up trigger parts.
- Trigger "break-in": mil-spec trigger sears are typically not micro-polished, which is why they can feel "gritty" until many thousands of rounds are fired. I clean the sear surfaces, and install the FCG into the lower "dry"; using a bench vise and lower block, I cock the trigger and apply upward force to it with a finger, to increase the load on the sears, and press the trigger. I take care to not let the hammer impact the mag catch, and dry-fire the trigger 50~100 times to polish the sears. I then apply Mobil 28 grease to the sear surfaces for use. This yields a mil-spec trigger that feels like it's seen lots of breaks. Of course, if I'm building a higher-end unit with an aftermarket trigger, it's not necessary.
- Selector detent spring capture: I use a 4-40 tap to make threads about a quarter inch into the selector spring well at the back of the receiver, and matching set screw. I cut the end of the spring flush with the receiver, and install the set screw, and never again need to wrangle the spring if I need to change the buffer tube.
I hope these tips help, OP.
I appreciate the info man! Especially your point about breaking a mil-spec trigger in. Unfortunately (or maybe it's fortunately), all my lowers either have an Geissele SDC, ALG, or BCM nickel teflon FCG at this point. Next time I buy an assembled lower, though, I'll be sure to try your method first before I swap it out!
There are good reasons to build with a mil-spec. As a civilian/non-LEO, the edge being primarily legal - in that altered trigger break weight cannot be used against you as evidence that you had "intent" in altering your rifle's performance, and a moral oblige to adhere to a stiff, mil-spec break weight as a last line of defense against an improper shooting. Paper may not always be your target, and when it isn't, you don't want to be on the existential side of the discussion.
- Selector detent spring capture: I use a 4-40 tap to make threads about a quarter inch into the selector spring well at the back of the receiver, and matching set screw. I cut the end of the spring flush with the receiver, and install the set screw, and never again need to wrangle the spring if I need to change the buffer tube.
I hope these tips help, OP.
Do you do both the selector and the take down pin this way?
I've never seen the selector detent done this way, is there any chance of the set screw backing out into the hole in the grip?
This is typically done (when done) on the takedown pin, not the selector. I believe Spike's Tactical lowers come pre-tapped for this. It's a gimmick.
Do you do both the selector and the take down pin this way?
I've never seen the selector detent done this way, is there any chance of the set screw backing out into the hole in the grip?
How did I miss this?
Wait. You're saying a "good shoot" can be overturned by merely bending your springs? I call BS, sir. Please cite some examples....
There are good reasons to build with a mil-spec. As a civilian/non-LEO, the edge being primarily legal - in that altered trigger break weight cannot be used against you as evidence that you had "intent" in altering your rifle's performance, and a moral oblige to adhere to a stiff, mil-spec break weight as a last line of defense against an improper shooting. Paper may not always be your target, and when it isn't, you don't want to be on the existential side of the discussion.
Do you do both the selector and the take down pin this way?
I've never seen the selector detent done this way, is there any chance of the set screw backing out into the hole in the grip?
Lemme get the egg off my face and correct this: I wrote "selector" when what I meant to say was "takedown pin spring". I know better than to post while consuming adult beverages. Nothing needs done with the selector detent spring. Sorry.
RobertTheTexan
11-01-17, 13:00
Do you do both the selector and the take down pin this way?
I've never seen the selector detent done this way, is there any chance of the set screw backing out into the hole in the grip?
This sounds like how the Aero 308 lower takedown pin is set up. Basically the same as the selector switch. The hole is right next to it. I take my dremel and drill out a very small hole, just an indent really to secure the spring. In the end it’s basically like the selector switch, once you remove the pistol grip the spring and detent are free. But so far the pistol grip holds it in place just fine.
I’d love to see AR-15 lower manufacturers adopt this same method. If some already haven’t. Keeps me from having to use my razor blade to hold the spring in place between the end plate and lower.
Sent from my iPhone using Tapatalk
Yeah guys, I knew about the take down pin set screw, he said selector, which he corrected.
Robert, I didn't understand what you posted.
How did I miss this?
Wait. You're saying a "good shoot" can be overturned by merely bending your springs? I call BS, sir. Please cite some examples....
And God help you if you practice!
:nono:
There are good reasons to build with a mil-spec. As a civilian/non-LEO, the edge being primarily legal - in that altered trigger break weight cannot be used against you as evidence that you had "intent" in altering your rifle's performance, and a moral oblige to adhere to a stiff, mil-spec break weight as a last line of defense against an improper shooting. Paper may not always be your target, and when it isn't, you don't want to be on the existential side of the discussion.
If the shoot is bad is ain't gonna matter much what you used or what mods you did. If the shoot is righteous then it is righteous, no one cares accept perhaps the civil side, and that is a different situation.
I would also request any actual case law showing that legal mods to the firearms actually were used in an actual prosecution. I have yet to see any in a righteous self defense case.
If the shoot is bad is ain't gonna matter much what you used or what mods you did. If the shoot is righteous then it is righteous, no one cares accept perhaps the civil side, and that is a different situation.
I would also request any actual case law showing that legal mods to the firearms actually were used in an actual prosecution. I have yet to see any in a righteous self defense case.
I agree with you 100% on this. Idk where this idea came into people's heads about modifying the gun puts you under more scrutiny. Maybe somebody has a lighter trigger in their gun because they have arthritis, or maybe a female that doesn't have the grip strength to feel comfortable with a standard trigger pull. Lots of valid reasons for modifying your guns, on top of the fact that trumps all others, which is, it's completely legal to modify your gun!
...It's a gimmick.
Using a set screw to hold the detent pin & spring in place may be a gimmick, but it's one that makes assembly and disassembly much easier.
I've never had a problem with losing or kinking the spring. For the time and effort to tap threads and trim the spring, I'd have the stock or end plate already installed. To each his own.
I've never had a problem with losing or kinking the spring. For the time and effort to tap threads and trim the spring, I'd have the stock or end plate already installed. To each his own.
It would be quite easily to do this during the manufacturing process. I don't know if it would save time during initial assembly. It would probably be quicker for someone who puts together dozens at a time to use a shim (as opposed to the razor blade us amateurs use) to hold the spring in place than it would be to install the shorter spring and set screw.
All that being said, it is a nice 'extra' touch if the weapon comes that way. However, as you mention - for the time and effort to tap threads and trim the spring, I'd have the stock or end plate already installed. But damn, I wax the inside of the trunk lid on my 91 Mustang.
If you like this mod, Spike's pre-taps their lower for this. The up side being the threads are anodized. Not sure if any others do.
If you like this mod, Spike's pre-taps their lower for this. The up side being the threads are anodized. Not sure if any others do.
Aero Precision does this as well.
I've never had a problem with losing or kinking the spring. For the time and effort to tap threads and trim the spring, I'd have the stock or end plate already installed. To each his own.
Some of us ain't so deft. I pulled an RE, forgetting about the detent spring and spent awhile hunting for it. I have one lower I installed the set screw on out of necessity and it has saved me hassling with the spring when swapping the RE as that AR evolves.
Point is, having a set screw makes more sense than not having one.
Outlander Systems
11-05-17, 08:13
Since its somewhat relevant.
I've assembled something around 30 lowers.
The last two I did, I struggled MIGHTILY with the bolt catch roll pin.
Any hacks/tips/tricks?
Since its somewhat relevant.
I've assembled something around 30 lowers.
The last two I did, I struggled MIGHTILY with the bolt catch roll pin.
Any hacks/tips/tricks?
I tape up all over my receiver w/ electrical tape, bought an extended roll pin starter/punch from eBay, the punches were quite long and heavy. But just a few taps w/ a heavy ball-peen hammer and that damn Colt bolt catch was out (which was stiff as hell) and the Geissele bolt catch was in. I think it would've been 10x hard w/o those punches and my lower would've been scratched.
Outlander Systems
11-05-17, 08:33
Roger. Thanks.
I've been using a dead blow for these last two assemblies and that may be the common denominator here...
nightchief
11-05-17, 08:39
Since its somewhat relevant.
I've assembled something around 30 lowers.
The last two I did, I struggled MIGHTILY with the bolt catch roll pin.
Any hacks/tips/tricks?
This single use tool works well...
https://littlecrowgunworks.com/product/bct-bolt-catch-assembly-tool/?v=7516fd43adaa
Worth $18 plus shipping? YMMV
Outlander Systems
11-05-17, 08:43
I've said, "never again" at least ten times now, so I might as well get a proper tool for the job.
This single use tool works well...
https://littlecrowgunworks.com/product/bct-bolt-catch-assembly-tool/?v=7516fd43adaa
Worth $18 plus shipping? YMMV
I've said, "never again" at least ten times now, so I might as well get a proper tool for the job.
There are a few tools that make bolt catch roll pin installation and removal very easy.
For installation...
https://rguns.net/shop/r-guns-role-pin-punch/
https://rguns.net/shop/r-guns-extended-role-pin-punch/
For removal...
https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/bolt-tools/dissassembly-tools/bolt-catch-pin-punch-prod26484.aspx
To help support and hold everything together...
https://brdengineering.com/products/bolt-stop-slave-pin
http://www.crosstac.com/shop-all-products/ar-15-armorer-block-full-kit-with-hammer-block-and-roll-pin-punch/
I've said, "never again" at least ten times now, so I might as well get a proper tool for the job.
That is pretty much what I was talking about. The ones that I have are flat, though. So they can get closer to the receiver and be more in-line w/ the pin. I believe both punches were $9/shipped just in case $18 is too rich for your blood lol.
For the bolt catch, I use a dedicated roll pin punch and starter punch. Lube the pin and receiver bosses. I start the pin just so it is flush internally, then use a slave pin (or hex wrench) to hold the bolt catch in place. Then I drive the pin, which displaced the slave pin, to it's home position. I'll check for progress to make sure the holes are aligned.
I've just used the bolt catch punch from Brownells plus a slave (usually a small hex wrench or punch). I've found that installing bolt catch isn't too bad, I struggle more with the trigger guard roll pin.
Outlander Systems
11-05-17, 11:04
Roger. Maybe it's been a tolerance stacking thing, or the improper hammer, but the last two I've dealt with have been absolutely difficult. On the lower before last, I thought I was going to crack the receiver I had to beat so hard on it. I finally got it in, but it was, by far, the most stubborn receiver I've ever death with.
I've done some shade-tree, makeshift assemblies with improper tools in the past that went smoother than my last two.
ETA: on the last lower I did this past week, once I had the pin through the bolt catch, I used channel locks to finish. It worked well enough that I may attempt that stunt again.
For the bolt catch, I use a dedicated roll pin punch and starter punch. Lube the pin and receiver bosses. I start the pin just so it is flush internally, then use a slave pin (or hex wrench) to hold the bolt catch in place. Then I drive the pin, which displaced the slave pin, to it's home position. I'll check for progress to make sure the holes are aligned.
Roger. Maybe it's been a tolerance stacking thing, or the improper hammer, but the last two I've dealt with have been absolutely difficult. On the lower before last, I thought I was going to crack the receiver I had to beat so hard on it. I finally got it in, but it was, by far, the most stubborn receiver I've ever death with.
I've done some shade-tree, makeshift assemblies with improper tools in the past that went smoother than my last two.
ETA: on the last lower I did this past week, once I had the pin through the bolt catch, I used channel locks to finish. It worked well enough that I may attempt that stunt again.
Who's lowers and roll pins were you you using?
...once I had the pin through the bolt catch, I used channel locks to finish. It worked well enough that I may attempt that stunt again.
Let me suggest using these Knipex pliers instead. Jaws stay parallel and are smooth to reduce the chance of marring your receiver. They also have good feed back as you're pressing a pin in place.
https://www.thehighroad.org/index.php?attachments/kpx8603150-jpg.767156/
I use vice grips to crimp the rollpin and slowly work it in. Has worked well in my very limited number of builds.
As a matter of course, I recommend against using Vise grips. They've got aggressive teeth and it's too easy to leave marks. I particularly like the Knipex for pressing the trigger guard roll pin. One jaw supports the opposite ear and minimizes the risk of the ear breaking.
I am another one to tape the receiver, roll pin punch with ball pein hammer and use a hex key for a slave. I also file down the sharp leading edge of the roll pin to help it start. Better than crimping with vice grips!
For clarity: I compress the pin(I think it seems easier to start). I don’t crimp the end as my previous post suggested.
I use lube on pin, in the hole and a starter punch. A small allen wrench holds the bolt catch in place and use the starter punch as far as it will go in without marring the surface by making contact. I then switch to a roll pin punch and drive that punch with another standard punch to get around the length issue. Kind of a pain but it works without needing to tape anything or marring the finish.
I saw a Ballistic Advantage video where an armorer (believe it was Hanson) was assembling an Upper with the then new Hanson profile barrel.
He did NOT use a torque wrench on the barrel nut- explaining he never did (use one).
Apparently "the Force" was guiding him.
Watching this I had to try it.
My next Upper I just used a 1/2" drive, "seasoned" the threads thrice, tightened it up and called it good.
No problems were experienced by doing this. Accuracy was 1.5 MOA per normal.
Anyone NOT use a torque wrench?On typical AR barrel nuts, you're torquing until things line up (and are in a very broad torque range), rather than torquing to a specific torque value. I use a torque wrench, but I don't see anything really wrong with not using one.
Guys always tell me how much experience they have and how calibrated they are and don’t need a torque wrench.
They always mess up once in a while. A torque wrench removes all doubt. There is no reason not to use one, IMO.I've seen plenty of torque wrenches that weren't very accurate.
Some tips on AR assembly, picked up over my eight years of building them:
- Barrel nut torque: I use barrel nut shims to time the nut for gas tube clearance (article found at http://ar15barrels.com/data/barrel-nut-index.pdf. I've checked torque on several after install, and find that method yields a torque value of around 40 ft-lbs, and no drama. As a footnote, grease on the upper receiver threads will yield an actual torque higher than perceived, due to reduction of thread friction by the grease.
- Upper receiver threads: Aeroshell 64 MoS2 grease on the threads, to reduce the possibility of bi-metal corrosion.
- Trigger install: to ease aligning all the parts of trigger and hammer, I use Hiperfire's Assembly Drift Pin (link here: https://www.hiperfire.com/product/assembly-drift-pin/), a $10 tool that stays in my range bag until needed. Geissele also sells a tool with which to line up trigger parts.
- Trigger "break-in": mil-spec trigger sears are typically not micro-polished, which is why they can feel "gritty" until many thousands of rounds are fired. I clean the sear surfaces, and install the FCG into the lower "dry"; using a bench vise and lower block, I cock the trigger and apply upward force to it with a finger, to increase the load on the sears, and press the trigger. I take care to not let the hammer impact the mag catch, and dry-fire the trigger 50~100 times to polish the sears. I then apply Mobil 28 grease to the sear surfaces for use. This yields a mil-spec trigger that feels like it's seen lots of breaks. Of course, if I'm building a higher-end unit with an aftermarket trigger, it's not necessary.
- Selector detent spring capture: I use a 4-40 tap to make threads about a quarter inch into the selector spring well at the back of the receiver, and matching set screw. I cut the end of the spring flush with the receiver, and install the set screw, and never again need to wrangle the spring if I need to change the buffer tube.
I hope these tips help, OP.Shims are very convenient. I currently like ALG handguards, which come with a few shims (and I keep the ones I don't use).
This is typically done (when done) on the takedown pin, not the selector. I believe Spike's Tactical lowers come pre-tapped for this. It's a gimmick.Spikes isn't the only one who does it, Aero does too, and some others.
If you're likely to be swapping the buffer tube (or nut, or plate) at some point, it's worth it IMO.
I've never had a problem with losing or kinking the spring. For the time and effort to tap threads and trim the spring, I'd have the stock or end plate already installed. To each his own.I haven't lost it, but I have pulled one apart to find it kinked when I was positive I did it right.
Since its somewhat relevant.
I've assembled something around 30 lowers.
The last two I did, I struggled MIGHTILY with the bolt catch roll pin.
Any hacks/tips/tricks?You can get kits to thread the bolt catch roll pin. I haven't tried doing it myself, but it's certainly been convenient on lowers I've bought already that way. The issue that I see is that you'd need a VERY skinny tap handle or a VERY long tap to tap the hole straight.
If you're likely to be swapping the buffer tube (or nut, or plate) at some point, it's worth it IMO.
You can get kits to thread the bolt catch roll pin. I haven't tried doing it myself, but it's certainly been convenient on lowers I've bought already that way. The issue that I see is that you'd need a VERY skinny tap handle or a VERY long tap to tap the hole straight.
I agree that it may be a desirable feature on a purchased lower. However, unless you just like tinkering, and there is nothing wrong with that, you have to ask yourself if it is worth the time and effort to do the modification yourself.
My thought is that unless you are changing bolt catches, buffer or end plates on the same rifle over and over, it isn't worth it.
I change bolt catches every now and again, for example I installed a Giessele Maritime catch on a lower only to find it did not work with a Forward Controls EMR-A. For that reason I have a Brownell's flat punch marked for the depth that the roll pin releases the bolt catch yet is still in the boss. For the reinstall I use a piece of stem from a wooden q-tip as a blind slave pin and parallel jaw pliers. Once the pin is far enough in that it retains the bolt catch I remove the q-tip stem and finish.
I figure I could probably make a swap like that several times before I would equal the time spent tapping the bolt catch boss.
On the receiver extension, once you've done a couple you should have developed a method that I believe would not be slower than fiddling with inserting and compressing the spring to insert the set screw.
Once again, just my thoughts.
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