First not-totally-crap polymer lower?

[discreet]

The problem is that companies take a part designed to be made out of aluminum, and substitute plastic, without modifying the design to take into account the properties of the material it's being made out of. A piston won't fix that. A piston just gives you a new set of problems, different than your old set of problems, plastic lower or not.

The reason it doesn't make sense to build on another platform is because you end up having to build the entire gun, not just the lower. Ain't nobody got time fo' dat.

A piston in a gun like a SCAR or ar18 relocates moving mass to an entirely different point. From there there doesn't need to be any conventional receiver extension design thus eliminating the main weak point of polymer lowers. That was my point. That is why the Scar lower handles so much abuse as well, as it's not in anyway a point of major stress as by design all the stress is un the upper it's self.

Same thing with the Masada etc. Issue is the conventional ar15 system and bcg just isn't polymer friendly due to the enherant design of weight moving so far back past the receiver further stressing that thin/smaller part of the receiver.

Unless the polymer lowered gun offers something really different, such as folding stocks, ambi controls, and supporting a matched upper with different system and quick change barrel etc, there really isn't a point in using polymer to begin with. The cost savings now are so miniscule. I really have no idea why new polymer lowers are even coming out. It's nothing like the polymer pistol market. You don't see people trying to push polymer 1911's, you see them pushing glocks etc. New design new gun rather than trying to reinvent the wheel.

[Snipe315]

I have YET to see a Polymer Lower that anyone in their right mind would consider worthy of being SBR'd or registered as a MG.

/thread

[CRAMBONE]

Please someone help me:

A stripped polymer (PLASTIC - not some hitech ninja space age ubercomposite) lower - list $70 priced to sell $45/55
Average price quality 7075 alloy garden variety lower $69/79

What am I missing?

I don't get it either. PSA sells blemish lowers for $60, I've seen them as low as $50.

[Dead Man]

I don't get it either. PSA sells blemish lowers for $60, I've seen them as low as $50.

But if you're looking for a poly, how is this better?

Low price is just icing on the cake, if you have a chub for a poly piece.

[CRAMBONE]

But if you're looking for a poly, how is this better?

Low price is just icing on the cake, if you have a chub for a poly piece.

Why would you be looking for a plastic over aluminum? For less than $10s usually, you can get a far superior product.

[polydeuces]

But if you're looking for a poly, how is this better?

Low price is just icing on the cake, if you have a chub for a poly piece.

Which i guess is what it is about-the chubby part i mean.
Since there is absolutely no real practical reason, nor does it even come close in quality and last but not least it really is not cheaper.....therefore it is nothing short if a novelty item. They make it because
A- its soooooooooo easy to make, and,
B- someone will buy it.
Buying one i did, so i speak from experience, see my earlier post.
But hey, never get between a fool and his money...;-)

[Dead Man]

The difference between the guy that has 40lbs of kit and the guy next to him with 20lbs is the selection and even modification of every single piece of kit; with weight being highest priority.

My last SBR build came in at 5lbs 8oz with T1/mount, backup sights, and a sling. With some of the poly lowers, I could have gotten that down to less than 5lbs unloaded. What does your lightest carbine weigh? Probably around 7-7.5lbs. I've paid hundreds more for a piece of gear that will not last as long, for the purpose of shaving less weight than that.

Till you've done ultralite, you will never understand!

[markm]

Why would you be looking for a plastic over aluminum?

A rimfire build would be the only reason I could imagine. For a 5.56, the trade off isn't worth it to me.

[orionz06]

The problem is that companies take a part designed to be made out of aluminum, and substitute plastic, without modifying the design to take into account the properties of the material it's being made out of. A piston won't fix that. A piston just gives you a new set of problems, different than your old set of problems, plastic lower or not.

The reason it doesn't make sense to build on another platform is because you end up having to build the entire gun, not just the lower. Ain't nobody got time fo' dat.

Words from my mouth.

[discreet]

I've paid hundreds more for a piece of gear that will not last as long, for the purpose of shaving less weight than that.

Till you've done ultralite, you will never understand!

That's the whole issue. Replacing strength and durability to save weight.

The issue with polymer lowers is you aren't gaining anything. By the time you beef them up in all the key spots, add metal inserts here and there, do all this refining and R&D work, you really aren't far off a normal lower in terms of weight and cost. That is where the Cav lower at least comes out decent, but still, being stuck with the same grip and stock, one something known to eventually crack or warp, it really just boils down to preference I guess.