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View Full Version : Polymer Lowers. Trying to get the lightest build


Solidux
04-19-2012, 4:02 PM
I wasn't completely sold on New frontier's polymer lowers for AR15s until I saw their #3 torture test.

http://www.youtube.com/watch?v=CEAYW_2y4VU

Anyone have personal experience with these? Are they as sturdy as standard forged lowers?

Any tips on making my next ar15 the lightest as can be?

jasonnorcal
04-19-2012, 5:25 PM
BCM pencil barrel (Lightweight\LW) upper. Carbine or midlength gas system. 14.5" if your hardcore. I'd stick with a basic M4 stock or Magpul MOE\CTR. Magpul MOE handguard and the obligatory Aimpoint micro. I'd also stick with an aluminium lower as it's not that much heavier. Most of your weight is in the upper, optic package, and stock

drifter2be
04-19-2012, 5:29 PM
I have one, its a love-hate relationship. The factory LPK sucks (almost entirely plastic), so I chose to look at it as a stripped lower with a buffer assembly. Bought a metal LPK, a lot of it required me to file the openings in the lower (accepts any milspec LPK my @$$). The lower itself seems relatively sturdy, I have about 300 rounds through mine so far and it is holding up well. Personally I would only recommend buying one if you are trying to go for the absolute lightest build possible, because the only advantage of this lower is saving you a few ounces of weight, probably less if you put a real LPK in it.

a1fabweld
04-19-2012, 5:53 PM
An aluminum lower is too heavy? Really? I guess I'm getting old because I notice myself avoiding plastic plats these days.:oji:

chrisf
04-19-2012, 5:56 PM
I have a plumcrazy lower thats been nothing but reliable through thousands of rounds. I did replace the parts in the lower with metal parts. Something about a plastic hammer.........

6doubleR
04-19-2012, 6:01 PM
No issues at all with my New Frontier. Great value for the price.

GettoPhilosopher
04-19-2012, 6:19 PM
BCM pencil barrel (Lightweight\LW) upper. Carbine or midlength gas system. 14.5" if your hardcore. I'd stick with a basic M4 stock or Magpul MOE\CTR. Magpul MOE handguard and the obligatory Aimpoint micro. I'd also stick with an aluminium lower as it's not that much heavier. Most of your weight is in the upper, optic package, and stock

Grab a Spikes/Seekins Precision SAR rail. Lighter than the MOE handguards. :eek:

https://spreadsheets.google.com/pub?key=pwswheghNQsFnUZMkZNF2DQ&output=html

Also, here's another great resource for planning build weights, though I can't vouch for accuracy:

https://spreadsheets.google.com/pub?key=tsU_kAjONKoGGfkDPaQZX1Q&single=true&gid=0&output=html

Solidux
04-19-2012, 6:56 PM
I have one, its a love-hate relationship. The factory LPK sucks (almost entirely plastic), so I chose to look at it as a stripped lower with a buffer assembly. Bought a metal LPK, a lot of it required me to file the openings in the lower (accepts any milspec LPK my @$$). The lower itself seems relatively sturdy, I have about 300 rounds through mine so far and it is holding up well. Personally I would only recommend buying one if you are trying to go for the absolute lightest build possible, because the only advantage of this lower is saving you a few ounces of weight, probably less if you put a real LPK in it.


In what way does the plastic LPK suck? I read a bunch of people using a metal LPK, but isnt making metal rub against plastic no good? Lightest build possible is my goal.

Cucv
04-19-2012, 7:09 PM
I love my lw15 lower

Reverend Clint
04-19-2012, 7:12 PM
ive got a plum crazy with a DPMS Sportical Upper with magpul moe handguard. weighs like 6-6.5 lbs. Ive got like 1k rounds through it with no problems.

drifter2be
04-19-2012, 11:52 PM
In what way does the plastic LPK suck? I read a bunch of people using a metal LPK, but isnt making metal rub against plastic no good? Lightest build possible is my goal.

Crappy FCG with a trigger that has to be pressed forward to reset...enough said. (to be fair, supposedly they have fixed that problem, but I am not going to risk having issues with a rifle because a company wants to put a plastic fire control group in their lower)

If that wasnt enough, the pins were garbage, the pivot pin on mine broke the first time I went to remove my upper from the lower, and don't get me started on how you can put it on safe without the hammer being back...really instills confidence when they cheap out on the LPK and it doesn't even work right..

If metal rubbing on plastic was no good wouldn't we see a LOT of failed Glocks, Springfield XDs and other polymer framed guns?

jkonquer
04-20-2012, 12:07 AM
yeah look into lightweight barrel, barrel makes 80% of the weight

Speedpower
04-20-2012, 12:09 AM
My PlumCrazy with all original FCG have never failed me, shot 800+ rounds through it, I love the plastic FCG, the best trigger I ever had, Crisp, breaks clean like glass! I have separated the upper apart so many times and everything holds in place, I love it!

freonr22
04-20-2012, 12:11 AM
Maybe someone can do a polymer upper with a metal rifled liner? That may save a little

Solidux
04-20-2012, 12:27 AM
Another question is: will the cleaning solvents used on the rifle somehow corrode/ damage the polymer? Example being, coating it in gun oil for long term storage

echo1
04-20-2012, 12:31 AM
I bought a NF lower on price alone, but my upper ducats got side tracked on some more interesting iron. I'm building mine based on cost and I'm already second guessing that decision, to build one at all. I'm going to be hard pressed to throw lead down range in an all new AR for under $700, which is a fortune to me. So far I'm into the NF lower and 10 mags for $232, and the least exspensive complete upper I've found, that's configured to my liking, will set me back another $500 bucks or more. I still haven't got a clue on the twist rate or barrel length I should go with (16" 1:9?). PAX

Solidux
04-20-2012, 12:36 AM
1:9 is fine for standard 55gr 62gr rounds. If you wish to shoot anything higher, then a 1:7 twist is recommended

echo1
04-20-2012, 12:46 AM
1:9 it is then. Thanks, PAX

KandyRedCoi
04-20-2012, 1:00 AM
sub'd

looking to build a lightweight ar as well but with "off the shelf" parts, nothing custom...thanks

Speedpower
04-20-2012, 9:29 AM
Another question is: will the cleaning solvents used on the rifle somehow corrode/ damage the polymer? Example being, coating it in gun oil for long term storage

Doesn't most of the solvent for cleaning your guns come in plastic containers? :facepalm: