I've only assembled a couple dozen from kits. I have not bought a complete AR-15 rifle in over 20 years. I can assemble from a kit, or usually hand selected parts a lot better gun than you can buy for the price. Zero issues with reliability. I even recommend that 1st time AR buyers buy a stripped receiver and then order the parts so I can help them assemble it, you learn a lot about Americas rifle that way, come out ahead on price and don't have a drawer of replaced parts you will never use again.
Notice how I say 'assemble' as opposed to build. For the vast majority of folks they will assemble a parts kit on a complete lower. A few will build from a 80% lower (I have done this as well), but it is not a 'build' as if you were putting together an AK from a flat and a surplus parts kit-------that is a build.
The skills and tools needed are easy to come buy and it is not that hard to do. Did a half dozen or so for myself in the 6 months before the election, and helped another 5 folks assemble some of theirs during that time frame. Just wish I could have gotten today's prices then.
Palmetto State Armory is probably the most popular source of parts for this. Primary Arms is good, as are a number of other folks.
I have experience with Outdoorsportsusa, they send out a pretty good kit for a real value price. If you are budget conscience they are not a bad choice for a range toy, truck gun, knock about gun, hedge against a ban or for an occasional shooter. Another value is 22mods4all.com, you can get good price from them as well, just remember you don't get a BCG with their kits, must add it on. Those are the only people that regularly offer a .223 Wylde chamber in their kits. (For those that don't know, the .223 Wylde is the best choice for a chamber if you intend to shoot both 5.56 NATO and .223 Rem from your rifle.)
Buyer beware in whatever used gun you buy, doesn't matter if 'bubba' did it or some other 'gunsmith', lemons are out there in every category. No matter what you hear, it is not that hard to assemble on correctly, and the basic tool kit needed is not that hard to get. I had to repair an AR-10 last week that was last worked on by a professional gunsmith, he did a boneheaded job on the rifle for a LEO buddy.
If you are considering it, don't let the naysayers scare you off. The hard part (and safety issues) are already taken care of in the design, or by the way parts are sold these days. No need to worry about headspacing, etc. when buying quality parts. If a part is bad or not in spec. every company I have used will swap it out for a good one.
We have a business near me that assembly of ARs is what they do. They are a big parts house. You as a customer bring in your stripped receiver, and they help you select parts and assemble the rifle on their workbench using their tools for free. At the end, they tally up all the parts on an invoice. That way every part is exactly what you want at that time. Good news is they are now getting into AR-10s, 80% Glock clones and 80% 1911s as well.
Kevin, I respectfully disagree with you final sentence, they are good guns. Normal folks can assemble very good guns from parts kits. I don't buy manufactured guns not because of the lack of quality, there are some outstanding rifles being sold these days, but due to other reasons. Colt, Daniel Defense, FN, LaRue, Noveske, Sig all make high quality rifles. Viet Nam was decades ago, they have made lots of improvements. Look at all the countries that are going to the stoner design these days, it's a different rifle from what you had to deal with. The deficiencies and issues with it's initial deployment have been well documented and addressed.
Some would call my SBR a bubba gun (I prefer 'Custom Made'), I carefully selected each and every part on that gun and took extreme care and patience when assembling it to my exact need. I have never had a failure with it, and I trust it as my go to rifle for any emergency.
Oh, one more thing, I will never buy or recommend someone buy anything from Cheaper Than Dirt after all the less than ethical things they have done over the years. Before their shenanigans I did shop their store in Fort Worth, but never again will I darken their door.
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