Originally Posted by RustyDaleShackleford
A few days ago I bought a stripped AR-15 lower online from Palmetto State Armory when they went on sale for $49.99 plus $7 FFL shipping. I've never built an AR-15, but I've been wanting to for a long time, and knew I had to buy since the price was right. I've been doing a lot of reading online and watching videos on building your own, but still have a few questions. I want to build a decent quality, all-around good rifle.
From my reading, here's what I think I want:
- 16" barrel, non-fluted, chrome-lined, 4150
- M4 extended feed ramp cuts
- chambered in 5.56 NATO
- 6-position adjustable stock, mil-spec buffer tube
- forged front sight base, f-marked, parkerized, tapered pins
- MP tested, pressure tested, shot-peened bolt
- flat-top upper receiver, T-marks on rail
- staked gas keys
- non-staked castle nut you want this staked
Now here's what I'm still a little hazy on:
1. I've read piston gas system guns run cooler and cleaner, but I've also read that it results in the same dirtiness, just in a different part of the gun. Which would you recommend? And what's the difference in cost to build a DI upper vs. a piston upper? If I decide on a piston gun, what additional parts would I need to obtain?
Do some reading. This horse has been beaten to death many many times.
2. Is a midlength gas system, with a 16" barrel and 9" handguards the only setup which allows for the attachment of the M9 bayonet? Even if I never use it, it'd be a cool feature to have. And do you have to have a standard A2 front sight base to use it?
Not, sure. Never even thought of using a bayonet but any with a bayo lug should work.
3. I've heard about fully shrouded firing pins. What does this feature do, does it cost more, and is it worth it?
Not a huge deal either way. If memory serves it's a feature of FA BCG's which most are these days.
4. Are M4 collapsible/adjustable stocks made out of different materials, and if so, which would you recommend?
There are a ton out there. For cheap I like Magpul MOE stocks.
5. Should you definitely buy your barrel and bolt-carrier group from the same place and at the same time? I've read this ensures accurate headspace. And how do you know if this is correct otherwise?
As long as both are new it should be fine. Buying from the same company doesn't gain you a lot. There are gauges you can buy to ensure it but as long as both are new and from quality companies don't stress to much.
6. I'd like to get a chrome-lined barrel for better functioning and longevity, so is there anything else that can be chrome-lined for better quality, and any that you would recommend?
No. There are BCG coating out there but it doesn't extend life, just makes them slicker.
7. I know that slower barrel twist rates (like 1:12) can handle lighter bullets, that faster rates (like 1:7) can handle heavier bullets, and that 1:9 is very common and is a good compromise. But should I get a 1:7 rate twist barrel, knowing it will let me reliably shoot any ammo, from light to heavy? Are there any drawbacks, or should I stick with my 1:9 plan?
I prefer 1/7, it will shoot 55gr and up. Unless your building a varmit gun for really light bullets stick with the 1:7 or 1:9. Either of the two are fine but most quality barrels are 1:7.
8. Somebody told me that since I'm a noob to this, I should buy a lower parts kit and a stock kit to finish up my lower, and just buy a complete upper and pin it on. I'd rather build my rifle one part at a time (or one group at a time), as I browse the internet and find deals, which would also allow more customization and familiarization with my weapon. What do you think?
Building a lower is pretty simple and only needs basic tools. Building an upper is a whole different ball of wax. It requires skill and specialized tools. It can save you money down the road but with the expense of the tools it's going to cost you more than just buying.
Thanks in advance!