Re 80% lowers

[tackdriver]

I finally decided to do one before it's too late. Is there any pro/con between an aluminum lower vs a poly? Do all makers require the same type of prep work or are some easier than others?

Thx!!

[CK_32]

Yea there is huge differences between poly and alumi.

There is 3 different alumi metals, billet, T7075 and 6066.

Same for polymer, they have different designs and strengths via the plastic used. I'm not a poly pro so thats about as much as I can elaborate via structure and make up. But with poly lowers they definintly seem to be hit or miss, for me personally, at this stage would stay away. The tech still has much to be desired IMO.

Right now any polymer lower that stays together through a good amount of rounds (Couple thousands) is a GREAT lower. Which again says a lot that most can't even handle basic cycling with out breaking apart and they are still being revamped and in beta testing for the most part.

So I vote alimi, standard 7076 T6.

I my self have 3 finished and ready to be topped off.

[junior40er]

Dont get a polu lower. If you're going to do an 80% that will last you your lifetime then go with aluminum. Do it right the first time.

[BigPimping]

What about those ATI Omni Hybrids? I myself will stake my Cav 15 complete lower against any aluminum or forged lower.

[tackdriver]

Will the aluminum cut/drill as easy as the poly?

[WartHog]

Was going to tell the OP to consult our resident expert on Poly/Aluminum Lowers but then I remembered Sikvenem got banned 😁

Sent via my Nokia Lumia 520 with Tapatalk

[tackdriver]

Well heck, I just now got the smarts and looked it up on youtube. I didn't realize I'd need a jig to do the mill work. What's another $150 eh? Oh well, it was just a thought. Thx anyway guys!!

[LONGRANGER777]

Check Tactical Machining....i just got a few there .....great deal ...add an upper for $28 and jig was $69 ...

[CK_32]

Will the aluminum cut/drill as easy as the poly?

If you buy the correct tools yes.


If your looking to dremel it for $20 no. Both will show how much affort, time and money you put into it. Just because polymer is easier to cut into doesn't mean it's easier to finish.

[edgerly779]

Never get a poly. I mill out aluminum ar lowers and 1911 steel lowers when I am bored and don't like the structural integrity that a poly displays. If I could i would make all my 80% out of titanium then they would be around for a millenia.

[Cannon-Arms]

Yea there is huge differences between poly and alumi.

There is 3 different alumi metals, billet, T7075 and 6066.

Same for polymer, they have different designs and strengths via the plastic used. I'm not a poly pro so thats about as much as I can elaborate via structure and make up. But with poly lowers they definintly seem to be hit or miss, for me personally, at this stage would stay away. The tech still has much to be desired IMO.

Right now any polymer lower that stays together through a good amount of rounds (Couple thousands) is a GREAT lower. Which again says a lot that most can't even handle basic cycling with out breaking apart and they are still being revamped and in beta testing for the most part.

So I vote alimi, standard 7076 T6.

I my self have 3 finished and ready to be topped off.

Not trying to niggle, just want the facts correct.

There are...

Machined forged lowers of either 6061-O or T or 7075-T.
Machined billet lowers of either 6061-O or T or 7075-T.

A forged lower will be stronger than a billet.
7075 will have higher tensile strength than 6061.
6061 will be more corrosion resistant than 7075.
6061 is weldable, 7075 is generally not thought of as weldable, some have been successful with minor repairs.
I believe all Military M-16s are 6061. I know older M-16s are.

Machined billets can have many nice features or details programmed into the CNC machine and the final product.
Forged lowers generally follow the blueprint mil. spec. standard.

In my opinion, any Billet or forged Aluminum lower you chose is GTG!


I clarified my opinion above, noted in red.

[CK_32]

Not even mad. ^^

Great info!

[tackdriver]

Geez, nothing's ever simple...As usual, thx for the help guys!!

[jaymz]

Get aluminum. Poly's are still too hit & miss from what I've read. And jigs are for people that don't know how to use the proper measuring tools, or to increase production in volume. You don't need a jig to cut a lower or two.

[MrElectric03]

I have over 3,000 rounds through my home built ar15 using a poly lower. Granted it wasn't an 80% build. That being said if I were to do it over again, 80% or not, I'd go with aluminum. I want to do some 80% myself before they go away but I'm really questioning how well I could pull it off and I'm a perfectionist. Trying to find a good cheap mill.