For those of you who build them, if you have every part and tool on the bench, how long does it take you to complete?

A stripped lower can be built in ~15 minutes, depending on how much of a pain in the ass the front takedown pin detent and the bolt catch roll pin decide to be that day. Lowers are fairly simple and straightforward.

Building out a stripped upper take a bit longer, since it's more complicated and it has more steps that require precision like torquing to spec. Also considering there's much greater variation in upper parts and accessories like handguards and muzzle devices, the time to build will vary greater than with a lower which are all effectively the same for the most part. But it still won't involve hours of work. Figure ~30 minutes for the average stripped upper. Maybe a little more if you're having to do stuff like time a muzzle brake with shims, or you have a complicated handguard assembly or one that's a very tight friction fit to the barrel nut and that requires things like applying heat and percussion in order to inch it in place a little bit at a time.

If you have all the parts and tools in place, and know what you're doing without having to constantly stop and re-reference that tutorial video you're watching, you can easily build a complete AR from parts and stripped upper/lower receivers in under an hour.

If you're more of a beginner, the sweet spot is to build your own lower using a stripped lower and a lower parts kit, but then buy a complete upper to slap on it with 2 pins. This removes all the complicated parts of upper assembly and the need for specialized tools beyond basic roll pin punches and a castle nut wrench for the lower, but you still benefit from the cost savings over buying a complete pre-assembled AR. Plus everything but the stripped lower receiver (which is the serialized "firearm" portion of the build) can be shipped right to your doorstep.

I have all the tools and have built several now. I rarely have every part on hand when I start. I usually do a little bit at a time as parts come in. I don't get in a hurry about anything, if I had all the parts it would take an afternoon for me.

Rogue's point about timing a muzzle break is accurate, I might have to take it on/ off a dozen times to get the shim stack right. Oh, and I send one spring flying across the room every time. I usually find it, but buy a $9 oops kit upfront.

Lowers are easy, and don't require much in the way of tools. Planning and building is as much fun as going to the range for me. I'm picking up some more stripped lowers at my FFL tomorrow so I won't run out of projects anytime soon.

Building an upper takes me longer than it should because I struggle with the dust cover spring. Sometimes I hate having sausage fingers

quote:

Originally posted by darthfuster:
Building an upper takes me longer than it should because I struggle with the dust cover spring. Sometimes I hate having sausage fingers

That is why God invented Magpul dust covers. Sooooooooooo much easier than messing with the GI style. I agree though that the dust cover installation is my least favorite part of the process.

https://www.scheels.com/p/8131...ing_19%20-%20Hunting



You'll thank me later.

Well, I took that thread title too literally and was expecting a building full of ARs. Hehehe!

Something like this:

Are we having a contest?

If we are, I know who’s winning.

I have built probably half of the ARs I own from scratch. However, I am meticulous in how I do things and take much longer so I couldn’t even give a time.

All I can say, it definitely isn’t hard to assemble a lower compared to an upper as it can get more complicated. Most times I have built the lower and taken the upper parts to a gunsmith.

10=15 minutes depending a little bit on what trigger is involved. But that assumes you have all the little cheating tools around like a the takedown pin cheater pin and the bolt catch cheater roll pin tool etc. All in with the parts and tools nearby should be less than an hour from parts to a functioning gun upper and lower. Depends a little bit on the upper how much work you do for example I always check the headspace which adds a bit.

I haven’t built a AR. I have built a couple Garands and a semi auto M1919A6. The trigger group on the Garand was the pain. Rest of it was pretty easy. I am in the gathering of parts phase to build another Garand.

Building and tuning a Frankenstein 1911 is the hold-my-beer of gun building.

I will echo the muzzle device sentiment. Timing muzzle devices absolutely infuriates me. I hate it. Especially when the barrel doesn't have a great shoulder, or the shims aren't especially precise in their ID.

The type of handguard (because it dictates the barrel nut) can have a huge impact too. The barrel-to-receiver fit is a big deal on multiple fronts. Ideally the fit is snug. Another thing on top of that is the feed ramp alignment. If the tip of a dental pick catches the edge of the barrel extension ramp, I don't like it.

The gas block is another thing that can significantly change your time line, depending on what sort it is: pin(s), set screw, clamp, etc.

I'll give another recommendation for Magpul dust covers.

Like everyone else said... Lowers are easy compared to uppers. Staking the castle nut is likely the most aggravating part of a lower, depending on what trigger you have. Also, if your end plate is something like a Magpul, it may be VERY difficult to stake. My staking method is not advanced enough to do them; the metal is so much harder than "GI" plates.

So many variables in terms of parts and complexity, but there is a special tool for about every step of the build that not only saves time but also decrease the level of frustration. Some are pure luxuries as the job can be done without them and others are absolutely essential. Having different styles and type of vice blocks also aid in upper assembly as well. While I have never raced to build one, I’m sure I can do a complete rifle in 30-40 minutes +/- depending on the complexity. I would take longer on a precision build than I would on a general battle rifle.

I’ve only built 3 from scratch (2 other started as complete rifles but were torn down and built back up, giving me a little more experience with some of the parts) and my last one probably came in around 2 hours. I don’t have any “cheater” pins like for the front pivot pin dent and spring. I always set up a loose blanket to catch my multiple failed attempts at securing the detent and spring. I also don’t have the hockey puck for the gas block so that bugs me. My last two muzzle devices didn’t need to be timed so I guess I got lucky there. Nothing else really gave me grief that I can recall, but I’m on the slower side and generally refer to videos just to make sure I have the right spring, but overall I think at this point I could probably get it done without video. If CA hadn’t just passed that online parts restrictions I’d consider building one just to try it without video haha.

ETA That 2 hours is a guess, but the build before that I took a picture of all the parts on the floor and then another picture of the complete rifle for a friend. The time stamp difference between the two was about 2.5hrs. I again took my time and think I cleaned up some stuff before the complete picture.

It kind of depends on what "Building from scratch" means.

If there's no drilling or aligning to do and you're just slapping parts together, the whole thing can be built in 30 minutes or less.

This would require the barrel to be complete with the front sight or gas block pre-installed and the barrel pre-chambered and headspaced with the barrel extension installed.

If you have to align the free-float tube, drill and pin a front sight base, or thread a barrel for a barrel extension and cut a chamber, then it can take hours.

If you want the upper receiver face lapped and trued, that adds 15 minutes to an hour, depending how aggressive you attack it and how many iterations you need to get it done. Then you have to clean the residue off completely so the glue can get a good hold on the surfaces.

For my Geissle hand guard, I want the rails to be perfectly aligned with the top of the receiver. There's a little bit of extra time required to get them aligned properly.

The gas block can be tricky or easy. If it's a classic front sight base that needs to be installed, you have to make sure the port is aligned and that the post is perpendicular with the receiver and getting the front sight rotation adjusted can take time. I use opposing set screws in place of taper pins to adjust the rotation of the front sight so that my rear sight is set to mechanical zero and my rifle is zeroed.

If it's a low-profile gas block that is concealed under a free-float tube, that can be a bit easier, but you still have to take time to ensure that you're over the gas port. A borescope can help with this step.

If you're installing a scope that uses rings, there's time required to get the scope set up to the proper eye-relief and proper rotation, and the proper torque. Bubble levels and plumb bobs help with this step.

Admittedly, I've built way more M14's than I have AR's. I can build a M14 in a couple of hours if there's no bedding required and if the barrel is short-chambered. There are way more tools required (including a lathe) to build a M14 than an AR. For a full M14 build with chamber cutting and bedding can take me few hours to do the mechanical work but two more days of epoxy work with curing time.

I have a saying. You build M14's, you assemble AR's.

I could have assembled a basic AR in the time it took me to brainstorm and write this post.

Tony.

I am surprised nobody has mentioned the "trick" of installing detent pins inside a clear plastic bag so when they do go sproing, you have a limited search area.

quote:

Originally posted by architect:
I am surprised nobody has mentioned the "trick" of installing detent pins inside a clear plastic bag so when they do go sproing, you have a limited search area.

I used that the first few times, and it's a great trick for a beginner. But now I have done it enough times I just use a square Exacto blade to depress the detent and then insert a large Allen wrench through the pin holes to hold the detent in place before I slide the actual pin in and push the Allen wrench aside, and I have yet to have a detent go flying.

Buying and using one of the various dedicated front detent tools would likely be even more foolproof.

Around 20-30 minutes for a basic M-4 type.
For higher-end customizations just depends upon how 'unique' certain parts are or, if it has idiosyncrasies where certain items don't match up cleanly and need some 'adjusting'