Bought AR Lower Kit - Any Fluff-n-Buff Needed Before Assembly?

Nope I bought of of their lowers put it together and slapped an upper on it and boom it was gtg good to go

If you're a polish the trigger surfaces guy, you should do that up front... but, otherwise, you're good to go.

General advice: make sure to clean lint and crud out from the pivot and takedown pin spring holes by hand with an appropriately sized drill bit. Just get any metal shavings or lint out. Drill bits between thumb and finger work great for that.

Double-check that "PTAC" trigger group. Make sure it works correctly in a function check. I've heard of one person in the last week who had either a trigger or hammer (or both) out of spec. The hammer dropped when the trigger was released. Of course, regardless of how much you spend on the LPK, function check it.

Easy installation of a Timney Trigger assembly would be nice but they cost about nearly as much as the lower.

Stock AR trigger group parts often do not do well when "fluffed 'n buffed". They have a sallow surface hardening that is easy to cut through. Better to run them as is or replace with better quality parts. ALG has a nice inexpensive kit that produces a great improvement over the feel of the stock parts. It comes in two versions. That kit is great for general use such as a duty rifle. From there, the sky is the limit. Lots of match grade kits out there. Some moderately expensive and some very expensive. Some of good quality and some not so much. Part of how I define quality is customer service after the sale for stuff that breaks.

It's a good idea to have a dedicated roll-pin punch set. It's easy to damage the finish of the lower -- or worse -- when installing the roll pins. The roll pin for the trigger guard is the trickiest. People have been known to break off the tab on the lower when applying too much force to that pin. If you encounter too much resistance getting that pin started, you should taper the end of the pin using a small file and/or ream the hole slightly.

AlexanderA said:

It's a good idea to have a dedicated roll-pin punch set. It's easy to damage the finish of the lower -- or worse -- when installing the roll pins. The roll pin for the trigger guard is the trickiest. People have been known to break off the tab on the lower when applying too much force to that pin. If you encounter too much resistance getting that pin started, you should taper the end of the pin using a small file and/or ream the hole slightly.

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This. Put a block of wood or something under the trigger guard when you're driving the pin to keep it from breaking. Also, use tape to protect the finish when you're driving the roll pin for the bolt release. Finally, some people tap the hole for the detent for the rear takedown pin. Tapping it and using a set screw to hold the spring and detent in place keeps them from going flying if you every decide to remove/swap stocks.

With this particular PTAC LPK, just a couple swipes of the hammer engagement surface and sear across the stones was all that was required for me. There was some brown crud on the engagement surfaces that was probably some kind of dried preservative or packing grease but didn't come off with the CLP brushing I gave the parts before installation. Not a big deal at all.

Other than that, it installed and works the same as any other LPK that I've ever used.

I dull the tips of the 3 detents a little on a stone - makes the pins and selector easier to move. A dab of grease on the selector detent spring keeps it from sliding out of the grip when installing. I clip about 1/8" off the hinge pin detent spring - makes the detent easier to start in the hole and still provides plenty of tension. Start the hammer pin in with the non-grooved end - that way the first groove (center one) will be the only one that hits the J retainer clip.

look at ALG Defense. 45 and 65 bucks for something you may like. Aimsurplus and many others carry them. Highly thought of.

Russellc

BTW, as a point of information, when Colt was factory-assembling the lowers for the early AR-15 SP1's, they weren't too careful installing the roll pins for the bolt catch and/or trigger guard. They would cover the resulting nicks in the anodized finish with dabs of black paint. Ironically, the presence of these dabs of black paint is a mark of authenticity for todays' collectors of SP1's. If you have one of these guns, don't clean off the dabs of black paint! They're practically necessary, for example, if you're claiming that the gun is new in the box. (And the paint is a specific consistency, being neither matte nor glossy. If you've seen a few originals, you'll know if it's correct.)

I polish all the roll pins before assembly, and lubricate the pins before driving them in. Makes them much easier to install.

Checking the pin holes in your stripped lower with the appropriate drill bit is a very good idea.

Just my .02,
LeonCarr