Upgrading Polymer Lower Durability

[williamcm]

I'm going to finally start my build and had some thoughts on increasing the durability of some polymer lowers I got awhile back. I'm not worried about weight or looks, but has anyone had similar Ideas?

-Powder coat
-carbon fiber wrapped (I have a friend that has all the machines/materials)
-Some kind of enamel
-rubber coated/sprayed

I know the obvious answer would be to just get a forged lower, but it's fun to tinker. These builds will only probably see .22lr. Was also thinking of attempting a bullpup config for fun.

Weird/funny ideas welcome.

[Mitch]

You can't powder coat a plastic lower.

The other suggestions seem like a lot more trouble than they can possibly be worth. If you are sticking with .22LR, you should be good to go. The weak point on a polymer lower is the receiver extension tower, and even then mostly when used for AR pistols (when the stock is not supported against the shooter's body), or those featureless builds with wonky stocks that don't support the buffer tube.

With a .22LR, the buffer tube is under far less stress than with a full power 5.56mm.

[williamcm]

Yeah, I kinda knew that powder coat only works on conductive metals, but just wanted to get the neurons firing.

The .22 build will be ready to accept 5.56/.223, but only if emergency, and an excuse to get more spare parts. My buddy does carbon bike repair so I may take it up to him and see if he can find a way to beef up the buffer tube assembly with some high vacuum, strong resin, carbon fiber.

I hope to post some pics.

[davidb]

if its a polymer 80% just make sure the dremeling/parts fitment is done right and like above^ a rifle build is probably the best bet for a poly lower

i have a strong feeling a lot of the broken poly lowers floating around werent put together correctly

[bksa]

if its a polymer 80% just make sure the dremeling/parts fitment is done right and like above^ a rifle build is probably the best bet for a poly lower

i have a strong feeling a lot of the broken poly lowers floating around werent put together correctly

The buffer tube snapping off has nothing to do with how a 80% was completed. All of the rear section past the rear takedown pin has been already completed pre-sale, there is nothing a finisher would be doing to decrease the strength of the buffer tube/rear takedown pin area.

[davidb]

ive put together several and on each one the buffer tube wanted to go in crooked, at different degrees, one wanted to go slightly crooked while others wanted to go more noticably crooked... pretty sure a crooked buffer tube would either put awkward stress on the tower or below the tower or even allow the bcg to hit somewhere along its travel if crooked enough

i just made sure the ones i put together went in straight. ive trying to intentionally be rough on one i built, only firing hotter 5.56, rough handeling it, bump firing with no support on buffer tube/stock...only 300 rnds so far but its doing good so far but we'll see


im not claiming anything on long term durability, just have a suspicion the ones that fail at a really low round count werent put together right

[HighWildFree]

You already said it, go buy something aluminum. I was going to buy some polymer lowers, heck on sale for like $35, but I wanted something stronger. Also why buy cheap? and weaker? in your mind (and mine), when in the end it is going to be part of something that costs you over $500 and is going to be containing an explosion next to your face.

[TheExiled]

ive put together several and on each one the buffer tube wanted to go in crooked, at different degrees, one wanted to go slightly crooked while others wanted to go more noticably crooked... pretty sure a crooked buffer tube would either put awkward stress on the tower or below the tower or even allow the bcg to hit somewhere along its travel if crooked enough

i just made sure the ones i put together went in straight. ive trying to intentionally be rough on one i built, only firing hotter 5.56, rough handeling it, bump firing with no support on buffer tube/stock...only 300 rnds so far but its doing good so far but we'll see


im not claiming anything on long term durability, just have a suspicion the ones that fail at a really low round count werent put together right

Ive done the same on one of my pistols with around a thousand rounds of 5.56 so far, no issues

[williamcm]

Yeah, my assumption is that the mean failure rate of polymer lowers is just higher than metal. I'm making this a .22 build, 10" barrel, 1:9 to 12 twist, but The option for 5.56 and having extra parts is the goal. I'll machine a metal pistol after some practice on these polymers.

Side note; anyone foresee major limitations to the barrel and twist I'm going for? Really a middle road pistol. I figure it could hit man sized targets at 100yd with any caliber/weight.