Thoughts on a polymer SBR

[Caster]

Thoughts?
I already have a polymer lower. It's a Tennessee Arms Co. lower and not your typical cheap crap. It has threaded inserts and is quite well made. We're it not for the fact I alrady have it, I wouldn't consider it but I DO have it and I am.

Now that my trust is done, me and the wife were looking over some things. Her AR is very nice. She spared no expense. But it's godawful heavy ESPECIALLY for her. I was thinking of doing an SBR since she's on the trust too. Shedding every ounce possible, I could fix her up a 12" suppressed AR with an Eotech that would be minute of man accurate to a couple hundred yards and be VERY light.

I'm just curious of the implications with engraving polymer.

[hipower]

Go for it!!!

[MacGyver]

You save a little less than 3 ounces on the lower considering the stripped TN Arms Co. lower weighs 5.6 oz and a regular mil spec 7075 lower comes in around 8.5 oz.  The threaded inserts aleviate some of the concerns, but I think in the grand scheme of things I still might step up to aluminum receiver.

 

That said, with the weight difference, you basically offset the weight of an Aimpoint T1.

[Caster]

I knew the savings were marginal at best. The real savings for me would be the fact that it's already here and paid for and he assembled rifle it's a part of is nothing more than a glorified "oops, I broke my good one" back up.

[Caster]

My biggest concerns are the actual engraving.
First, engraving plastic is a bit shifty.

Second, I wanna say I've heard the ATF wants the engraving done on metal....but I can't substantiate that.


I only paid $50 for the lower, Brand New. I care very little about it. I might get a sixer in my liver one afternoon and break out the wood burning kit. If it turns out nice, register it. If not, put it back where it is now, a back up...just in case.

[Jct1911]

My biggest concerns are the actual engraving.
First, engraving plastic is a bit shifty.

Second, I wanna say I've heard the ATF wants the engraving done on metal....but I can't substantiate that.


I only paid $50 for the lower, Brand New. I care very little about it. I might get a sixer in my liver one afternoon and break out the wood burning kit. If it turns out nice, register it. If not, put it back where it is now, a back up...just in case.

I'm in the "what if" crowd. I've seen his lowers, he's about 25mins from my house but I'm still leery about breakage($200 risk). Aimsurplus has anderson lowers for $39 if so inclined. My form ones have been of known quality, just in case

[MacGyver]

I'm pretty sure only the serial number is required to be on metal. I've seen polymer lowers done with a rotary engraver. They looked just fine to me.

[Lumber_Jack]

I would buy a new stripped aluminum receiver. They are a dime a dozen now a days.

[Lumber_Jack]

Joebobs has Anderson lowers for $45

http://www.joeboboutfitters.com/Anderson_Manufacturing_AR15_Lower_Receiver_Multi_C_p/ander-lower.htm

[TrickyNicky]

I'd probably go for a new stripped lower personally, but the TNarms co lowers do seem like a cut above the standard poly lower.

 

Related question; If Caster where to go ahead and SBR his poly lower and something breaks, SHOULD Tn Arms co consider it under warranty, would Caster get a new lower with the same serial number, and if so would he need to do any reregistering on the new lower? If that would be the safe Id say get the wood burner and a sixes and start filing out paperwork, otherwise I'd sell the poly lower and buy a aluminum one. Or just buy an aluminum one.

[KKing]

I'd just get a mil spec aluminum. I see what you're getting at, but it's literally an extra $125 to have a complete lower. With the game you're playing (NFA), that can't make the difference.

I have no problems with polymer lowers. But with this being on a trust, and something that should get passed down, the thought of a breakage with a polymer lower down the road would be another $200 stamp plus another lower to fix.

$125 now, or $200+ if the polymer breaks down the road. To me it's a no brainer Edited April 21, 2015 by KKing

[samson7x]

I'd go with an aluminum.  They are super cheap right now, so why risk it with a poly lower?

[John Wells]

You could also SBR her existing lower and build a lightweight upper for it.  Since she already owns that lower, that's the same cost savings you're talking about with the poly lower.  Just a thought.

[Oh Shoot]

Having had a polymer lower that broke, I would never consider throwing an extra 2 bills at one. Especially since if it ever craps out, it's another 2 bills to replace.

 

- OS

[Luke E.]

I don't think there is anything that says that the trust info has to be engraved into metal. I know a guy that has an Scar that he sbr'd and unless he swapped out the lower with an aftermarket aluminum unit, it has it's engraving done on polymer. That being said, the Scar was designed to run a poly lower where the AR is not. I just can't see risking $200 with as many poly lowers as I hear about breaking. 

[shotgunshooter]

Out of curiosity do you have to be 21 to fill out a Form 1 in Tennessee? I understand what the NFA says but I didn't know if TN state law would prevent me from having an SBR when under 21. I hope this makes sense. I'm just looking for answers.

[Caster]

I don't know for fact and for certain, but I'm gonna say yes.  

[shotgunshooter]

Here a what I did find. http://3gn.ar15.com/archive/topic.html?b=6&f=17&t=319777

[Luke E.]

Out of curiosity do you have to be 21 to fill out a Form 1 in Tennessee? I understand what the NFA says but I didn't know if TN state law would prevent me from having an SBR when under 21. I hope this makes sense. I'm just looking for answers.

Typically, as residents of TN, the federal laws are going to be the aggravating factor. I can't say for sure but if federal law allows it I would think that TN would as well.

[shotgunshooter]

Typically, as residents of TN, the federal laws are going to be the aggravating factor. I can't say for sure but if federal law allows it I would think that TN would as well.

Based on my understanding I can build or buy an NFA item from an individual before turning 21. But I'll continue to look into it. I haven't found any state law that says I can't.

[Dolomite_supafly]

The only guns that a dealer may sell to someone under 21 is long guns. A silencer, and any other NFA item, is not considered to be a long gun so dealers cannot sell those to anyone under 21 either. But, just like pistols, NFA items may be sold by an individual as long as the buyer is 18 or older. But because a dealer cannot transfer the NFA item to anyone under 21 the sale of the NFA item must be to someone within the same state.

[shotgunshooter]

The only guns that a dealer may sell to someone under 21 is long guns. A silencer, and any other NFA item, is not considered to be a long gun so dealers cannot sell those to anyone under 21 either. But, just like pistols, NFA items may be sold by an individual as long as the buyer is 18 or older. But because a dealer cannot transfer the NFA item to anyone under 21 the sale of the NFA item must be to someone within the same state.

So I can fill out a Form 1.

[Dolomite_supafly]

So I can fill out a Form 1.

Yep, or buy from another individual in the same state.

[shotgunshooter]

Well I already started on my paperwork last night.

[Luke E.]

Well I already started on my paperwork last night.

Sounds like you're good to go! I hope you have a quick turn around and you're approved.