Friday, December 01, 2006

cARnaby-15 Build Part Duex

I got the AR lower together last night while watching, ahem, Grey's Anatomy and ER with my wife. Went together pretty well. I'm definitely impressed with the RB Precision first time builder's AR lower parts kit. They stick all the springs on the trigger and hammer assemblies, so you can see how it's done, and they bag all the sub assemblies separately in little ziplock bags, that is SUPER helpful.

A couple notes though that would have helped ahead of time. The spring/plunger bit for the bolt release mechanism... DO NOT put it in its little hole and push down all the way. The stupid thing gets stuck. Fortunately, I put the spring on first and did not test it without the spring. Searching the web shows that this is not that uncommon, and if you at least leave the spring in, you can have the plunger out in five minutes by heating the upper in the oven at 200 deg F, until you hear the thing pop out onto the cookie sheet. See, the upper is aluminum, and the plunger is steel, so they have different coefficients of thermal expansion (fortunately, Aluminum expands more than Steel).

Secondly, the holes in my Mega lower for the trigger and hammer pins were undersized. After twiddling with it for a while, and re-reading the directions on arfcom, it was clear that they had to be opened up a bit. I've got some good drill bits, and the back end of the 5/32 drill had a perfect slide fit through the trigger set, just like the trigger pin, so I ran that, by hand (well, with a pair of pliers) through the holes in the lower. Perfecto!

I'll post a pic of the lower all saddled up this evening, cuz, you know, nobody here knows what an AR lower looks like. Or is it that no matter how many you've seen, you always like to see more?


Anonymous triticale said...

Get one of those little drill chucks with a hex shank, made to use in a power screwdriver. That is the best way to grip a drillbit when putting it thru by hand is all about control.

12/02/2006 2:39 PM  

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