Sunday, February 07, 2021

Putting Together a Lower

 A buddy of mine showed up today for lunch with a mostly-stripped lower, and a complete parts kit.  I've never put one together, but I happen to have a grandson who eats at my table, ad is a school-trained Small Arms Repairer, MOS 91F.  It took a bit over an hour, and there was a learning curve.  It appears that in MOS school, they never started with a stripped lower.  But, we got it all together.

There seems to be a problem wit the bolt hold-open.  My buddy believes that he got a defective part in the kit.  I don't know.  But, we put my upper on it and ran three rounds though it.  It goes bang, and that's done.

I wished I had taken pictures, but I didn't think about it unit the chore was over.

I see that there are some tools that would have made the job a bit easier, so I went over to Brownells and ordered the kid an Armorers Essential Kit. and a set of screwdrivers.  He's worth it, and it would have made this job a whole lot easier.

That's how I spent my Sunday afternoon.  


Wayne said...

Take a look at some of the other AR-15 tools at Brownells - the Avid AR-15 Pivot Tool, for example - $10 and worth 3 times that much. Makes the front pivot pin detent and spring a 10 second job. The Magpul Armorer's wrench - $75 - is the best AR assembly wrench on the market. A good set of long shank gunsmith punches saves time and makes the job easier (get an extra long shank 1/8 punch, it's the "trigger and hammer assembly tool"). A barrel extension and a upper receiver vise block are great for working on uppers. With a few specialty tools and some practice you can assemble a lower from scratch in 20 minutes, an upper in 30. Uppers are more complicated than lowers because alignment and torque wrenching take more time and have to be done just right.

robert said...

The kid has a lifetime of income after learning this trade . Many sheckles have I gladly forked over to my local Smithy . The guy can bullet proof anything .

Bob said...

sounds like a buffer to heavy in weight or buffer spring to stiff, not letting the bolt completely cycle back. check spent brass for unusual wear or case mouth bent.Especially any barrel length longer than 16 inches. it is a touchy thing with gas operated cycling systems to get the dwell to match.

RHT447 said...

Well done. I graduated Small Arms Repair School in '74 at Aberdeen Proving Grounds. MOS 45B. Got my FFL in '93 and started building custom AR-15's. My class was the last one to be trained to repair the 3.5-inch rocket launcher--aka Bazooka.

Old NFO said...

Agree with Robert! He'll have a job for life if he wants it!