80% lower finished

[CamoDeafie]

I have the ATI Omni Maxx hybrid lower on my 2nd budget AR15 16" carbine build. Haven't tested it out yet though.. it has a zinc alloy reinforcement in the buffer tube extension and rear takedown pin area.

 

[Diamondback]

The other thing is... while I prefer them on *all* my builds, I *will not* do a poly without KNS pins--I like the extra structure of the FCG having it's own "frame within the frame."

 

[Caveman Jim]

I had not considered a polymer lower for the AR platform but do like my high capacity plastic handgun though.... lol

 

[CamoDeafie]

I had not considered a polymer lower for the AR platform but do like my high capacity plastic handgun though.... lol

The biggest single issue with AR polymer lowers is where the buffer extension goes... on a non-reinforced one that is the place for the majority of failures and cracks.
So a polymer lower with metal reinforcement in that key area is more likely to last longer than the old Plum Crazy lower. Cav Arms lower I think has metal reinforcement in that area too but only around the pin... that lower has an integrated A2 stock molded into it so theres very little risk of snapping it apart.
Honestly though if someone came out with a skeletal magnesium lower that has polymer over molded on it, it could sell pretty well.. lightweight and sturdy in key points.
I have heard of the trigger pins developing cracks and wearing into oval shapes on polymer lowers that an anti-walk trigger pin is in the future for my ATI Omni lower.

 

[Diamondback]

If I was designing a hybrid lower, I'd start with an aluminum, titanium or magnesium "ring"--basically a thin band including the pivot pin lugs and spring hole, running down to form the bolt-catch pocket, possibly a couple plates back into the FCG-pin area, then otherwise going skinny back to the takedown-pin and buffer tower, which would have threaded metal for the tube.

After that, everything would be plastic, with the buffer tower/TD-pin area bulked up to the maximum extent that most jigs and beavertail grips would allow. Possibly even go all the way to a metal back-half with just a polymer magwell--the main thing is you want strength concentrated in the "load-path" resisting recoil back to the stock and grip-mount.

 

[5D Tactical]

Followup: Is it possible to arrange to have the buffer-tower slot cut a little bigger to clear poly towers at time of order, or is it always a matter of having to do multi-step shipping? Or, if lower-in-hand is required--and I'd understand if it is--could you hold the order there and have me either ship the lower from here or have it drop-shipped from the manufacturer straight to your site as "me C/O you"? (I'm trying to save us *both* a few bucks on shipping. )

If I am understanding you correctly, we're not able to customize the jig per order. If a particular poly lower doesn't fit, and we receive enough requests to make it fit, we will certainly give it a shot. We are very happy with the design of our jig right now, and poly lowers are a far deviation from a Mil-Spec lower. Designing the jig to fit all metal lowers was a monumental task, and the polys are a whole other challenge in themselves. Since most customers are purchasing our jig for metal lowers, we have honestly not received very much feedback on the polys.

 

[Caveman Jim]

The other thing is... while I prefer them on *all* my builds, I *will not* do a poly without KNS pins--I like the extra structure of the FCG having it's own "frame within the frame."

Do polymer lowers actually save any weight to the build? If it does then it must be marginal, say 6-8 oz, that's not enough to warrant using one in a build in my book.....
Sorry, just my opinion.

 

[Diamondback]

Jim, I meant "prefer KNS pins on *all* builds"--poly is just easier to work on the blanks, you can get away with mill bits in a handheld drill rather than drill-press or router.

 

[PiratePast40]

Caveman - thanks again for sharing. You're making some fantastic contributions to the forum.

 

[Caveman Jim]

Well folks, thanks for all the votes of confidence and for your contributions as well that have helped me so much.
We are the Borg, a collective of gun owners that have been assimilated.....

But don't expect any sloppy wet kisses or group hugs at get togethers....

 

[Capn Jack]

I GOTTA GET A BIGGER SAFE !!!

 

[Caveman Jim]

I GOTTA GET A BIGGER SAFE !!!

Same here brother!!!!

 

[11Charlie]

+1 on the bigger safe and I just bought a bigger safe



Edit: What I really need to do is get my ammo out of the safe and put it in my old smaller safe.

 

[Caveman Jim]

Just an update as I picked up another Noreen 80% lower for...












$30...

 

[Squidly]

+1 on the bigger safe and I just bought a bigger safe



Edit: What I really need to do is get my ammo out of the safe and put it in my old smaller safe.

I bought a used, slightly dented and beat up Knack box for my ammo, The cabinet type. I think it's a model 109. I wanted a 139, but they were all gone. Not as secure as a safe, but good enough to keep the in-laws out of it.

 

[DirectDrive]

... good enough to keep the in-laws out of it.

 

[Squidly]

... good enough to keep the in-laws out of it.

Actually, it's the adult step children, but "in-laws" rolls of the tongue better. (creative license)

 

[JD42]

After doing several poly 80 glocks. I just finished 2 off the AR15 and 1 off the new AR10 warhog lowers. Very easy and so far both .223 and .308 are running well. About 300rds on the .223 and 150 or so on the .308. I will post pictures when I can. Would like to try the 5D jig.

 

[Caveman Jim]

UPDATE!!! Another fine milling job completed on the 5D jig.
Definitely need a new endmill and guide block after the 5th lower.

 

[Flymph]

You're making it dificult for me to get a pocket pistol...
How are you going to "finish" this one?
This is extremely cool, seems like you can be a lot more proud shooting your gun this way.
So it's good for about 5 lowers, you say?