Evening all! I have a question for y’all. Has anyone had any experience with those “carbon infused” plastic lowers? A friend replaced it, and gave it to me. I plan to use it at least until I can get a replacement, but currently with rds, light, and fully assembled it’s a hair under 5.5lbs. I know the lower takes less stress normally, and I’ve seen monolithic lowers of similar material, but any input would be appreciated. Thanks!
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We had a discussion on billet vs. forged awhile back, and @Craig6 ,who seems the voice of experience on AR builds, mentioned plastic lowers, lack of stress allowing that material.I came close to buying an 80 percent plastic lower some years back, but ran out of time before my state put the kibosh on that. I’ve been eyeballing a CZ scorpion as my next gun, looks like it’d be a hoot on falling plates, and though only a 9mm, the frame is polymer, and seems to be solid.
Best thing is shoot it and see what ya’ think. At least half the fun imo.
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Personally I would not want a blowback caliber on a plastic lower. I’d rather have any of the calibers that use the rotating bolt. The lugs on the bolt contain the worst of the forces until the pressure drops enough to let it unlock.
I’d recommend a set of the anti-rotation trigger and hammer pins for it. Otherwise I bet it would take way more than you think to wear it out. And I’m not really a fan of plastic.
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I have a set of anti rotation pins on the way so I can use the spare RA drop in that I bought. I am thinking it’ll definitely wear faster than an aluminum one, but we’ll see
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I’ve been eyeing those scorpions myself, but I have to start saving for Christmas stuff, so my firearm purchase plans are postponed lol. I’m going to give it a chance. My chief worry is the takedown and pivot pin holes. Those areas take a brunt of the force. I will say that the fitment of the upper to the lower is currently tight with zero slack 
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My take is a good old forged aluminum AR lower is $70-$110 and that’s all I need to know
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Free is better than $70 though 
. I’ll get one in January, and if this Lego one works out, that just means I have to do another build:wink:
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Thinking the same and perhaps the next version would sleeve the holes if that became a common issue.
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Metal shop all my life, including forging M16 and M4 receivers. . Definitely a fan of forged. We were running a 1600 ton press, 2 dies, pre and finish. Set your die wrong, it’d be smashed. We got the Canadian mil contract around 1994. New set up, I noted it didn’t look right, boss told me to stfu. Next day, customer comes in, dog and pony show, and first hit smashed the die.
I ever mention how much I love being retar…uh retired?
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I’ve been thinking about making steel sleeves for the inside of the receiver. That way if I notice the holes start to wear funny, I can strip away a little material off the inside and epoxy the sleeves in? Maybe too much work for a lower that’s probably $30, but the work is half the fun. I prefer forged myself. The style improvement and possible weight savings aren’t worth it for me. Previous statement excluding those sharps bros. lowers lol
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Hey @mattm !!
I played with the carbon plastic lowers and I have found them to be NOT wanting. They are slightly lighter as an upside. Other than that they act just like an aluminum lower, that said I have no experience trying them with the 50 Beowolf or similar but for a GP run of the mill build I wouldn’t have an issue with them. The caveat would be the pin holes … ALL of them. Hammer fisted gun plumbers don’t pre-line the holes and solve sticky pins with hammers which WILL fracture/chip the plastic as it will also do to the aluminum versions. The “plastic” AR lowers are built on the same concept of Glock/S&W/Walther/HK/SA pick your flavor of plastic pistol. The gas system of the AR takes all the hammering normally derived in a rifle and pretty much negates it. If it was free I’d run it just to see what happens, you might learn something or you might find out that there is nothing to learn.
Cheers,
Craig6
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I appreciate the insight. I’ll probably go ahead and work on pin sleeves as a preventative measure, and fit for the trigger and hammer pins was perfect… actually fit for everything was better than some forged lowers I’ve had! It’s mostly for the truck and house, so won’t see much action outside of zeroing and range practice.
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@Levi2 The only thing I would really be mindful of is dropping the hammer with the receiver open depending on your hammer. I have seen fractured frames (aluminum) from dropping the hammer without a block when someone was trying to “adjust” a trigger and doing it repeatedly.
Cheers,
Craig6
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For anyone that might need it, PSA has a lower parts kit (minus fcg), buffer assembly, Magpul MOE grip and stock for $89…lol with fcg is 100, iirc.
@Craig6 I’ve seen that myself, and am mindful to avoid doing that. The time I saw it, the person was just cocking the trigger and letting it slam forward repeatedly 
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Spring for their EPT kit. The enhanced polished trigger is night and better than the basic kit and only a few dollars more.
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I have heard that that trigger group is nice. Optics planet frequently has the RA drop in’s for $ 90-100. I save up the op bucks and use them for that. The spare drop in I have only cost me $50… those got me spoiled
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RA? Rheumatoid arthritis?
Geissele is my preference for any platform they make a trigger to fit.
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Rise Armament lol. I like Geissele triggers, but they are too proud of them. The Rise triggers do all I need them to for a much better price. I really like some of the hiperfire options friends have, and may get one of those. I’ll have to talk myself into forking over that much for it
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They still cost less than two full tanks of diesel fuel.
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True story! When you put it that way, it doesn’t seem that bad 
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