“All AR-15s are parts guns” – I don’t know how many times I’ve heard that statement. I’ll even admit to thinking that way once. It is, now that I’ve had time to think about my sins, wrong.
What the people who say such things don’t realize – or choose not to realize – is that the person who put the weapon together has a tremendous impact on the overall quality of the weapon.
While the process of assembling one may seem really simple, it’s also very simple to screw up. When combined with cheap parts, this is a recipe for disaster (see the threads on various forums that start out with questions such as “I built an AR using a grab bag of cheap parts, and it ‘jams’, what should I do?”). Even if quality stuff is involved, the weapon will not perform to its full potential, and may not function at all.
Case in point: a used upper assembly that I recently tore down (no, I didn’t put it together). Here are some of the issues I encountered:
– PRi front sight/gas block was not properly aligned with the gas port. It was both canted and too far back towards the receiver. This was a relatively easy fix. Carbon marks on the barrel indicated that the gas block had probably not moved since it was first fired, though the screws that clamped the gas block to the barrel were barely tight.
– Because the front sight base was canted, the gas tube was crooked in the receiver, and contacted one side of the gas key on the bolt carrier. The gas tube was replaced as a precautionary measure.
– Loctite was used thoroughly on the heads (not the threads) of non-essential screws on the PRi handguard, which serves no real purpose – if you’re going to use Loctite, put it on the threads.
– No grease was used on the large nut that secures the handguard to the barrel nut, resulting in galling of the threads.
– The barrel nut was damaged, most likely by wrench teeth that slipped out of their “holes” – the direction and location of the damage indicates that this was done during installation, and by a two-pronged wrench. The nut required over 150 ft/lbs (a conservative estimate on my part – I had to use a 1/2″ breaker bar attached to the armorer’s wrench, with an extension attached to the breaker bar) of force to come loose. I’m not the strongest guy in the world, but I’ve never had to go to such lengths to remove a barrel nut. When it did break loose, there was a loud “cracking” sound – nothing was permanently damaged, this was the noise that results from two threaded pieces that have been stuck together for a long time suddenly coming loose. In other words, no grease was used on the threads.
– The dowel pin in the receiver extension was damaged/deformed, possibly when the extension was being attached.
– An unidentified substance was applied to the barrel extension where it interfaces with the receiver, making barrel removal very difficult. I would almost describe it as some sort of epoxy. If this was some sort of attempt to increase accuracy, it was probably negated by the overtorqued barrel nut.
The parts used in the build were all pretty expensive and high quality – but the person who put them together either hadn’t built many uppers before, or was having a really bad day. Retail value of the parts used was approximately $1300 – and yet the quality of the work involved was nowhere near that level.
Now, many people only care if bullets come out the front end of the barrel and make round (or nearly round) holes on paper at 25 or 50 yards. The previous owner did not indicate that there were any functional issues. I believe that the issues I saw would have had some effect on the weapon at some point, especially if the gas tube was allowed to be damaged even further, and the overtorqued barrel nut may have had an effect on accuracy. A good hit to the barely tightened gas block might have moved it further out of alignment – it was already on the ragged edge of being misaligned.
When one pays big bucks for an AR upper, don’t they deserve to have a weapon that was assembled properly and with high attention to detail? Frankly, shouldn’t that apply to pretty much every upper out there, at any price range?
Note: The upper in question was acquired secondhand – not received for T&E. It has no connection to any product (or company) that I have reviewed before. I will not entertain questions as to the origin of the upper.
So I’ve been doing it wrong all these years by putting loctite on the threads? 🙂
There’s two ways that people can learn how to properly put together an AR upper.
1) Learn from mistakes
2) Get advice and follow instructions from people who know what they are doing. Then, learn from fewer mistakes.
Everyone has to learn somehow.
Even the assemblers at Colt and BCM started out not knowing what they were doing.
Perhaps we should then start on Blackthorne kits to avoid damaging quality parts! :p
Sure, but hopefully those assemblers “learned” before they started working for a company that sold assembled weapon components, or at least someone checked their work before it went out the door.
Andrew,
I have built my lowers because its such an easy process, but in the back of my mind I always feel like they are sub-par. Do you see any weaknesses in lower receiver builds done at home vs. those put together by professionals? Is is more than they either work or not? Thanks for the solid blog and informative posts.
Take Care,
MRA
Well, part of the problem is that a lot of home built lowers use cheap parts kits (or cheap lowers that may be machined incorrectly). But assuming that you’re using a really good lower parts kit and an in-spec lower, and you follow some good directions, the lower is much more plug-and-play than the upper. One thing that a lot of people leave out is staking the castle nut on the receiver extension tube, if a collapsible stock is used. Do a function check when you’re done.
To compare building a lower to some of the things I saw on the upper described in the post – maybe stuff like dinging the receiver with the slip of a punch, or breaking off one of the trigger guard “ears”. Simple things that can be avoided if you follow a good checklist.