new to AR thinking of putting one together

Nov 2012
27
0
Aloha, OR
so ive been doing a bit of research on the AR-15 lately and im far from finished but i did find a few things that i think i like. the idea of building my own is to learn the weapon inside and out before i ever take it to the range. also would give me something to do in my off time.

At this point these are some things i was thinking about:

.223/5.56

No Lower chosen so far (other than DPMS trigger group, i like the light trigger pull without having to go too far into different spring choices, still not a firm choice)

A3 upper, no particular brand chosen at this point (for the flat top and still has the forward assist and dust cover)

18" 4150 chrome moly barrel, 1/7 twist (the twist is a bit tight, sacrificing range for accuracy if i have my information right, may still go 20" with 1/8 though)

direct gas impingement with picatinny front sight rail (direct gas because it is the most common, no extra moving parts for reliability and its cheaper)

adjustable stock, still no firm choice past that

a couple questions still:

i like the enlarged feed ramp of the M4 configuration. how do i make sure that when i buy that BCG, it will match up to the other parts? (im still not sure if it is part of the barrel or the upper receiver, having trouble getting a look at that in pics and videos) i know its not entirely necessary, so long as i keep my rifle clean but i like that small extra that doesn't cost any extra.

also ive seen a lot of people having different opinions on the gas system length. some say the mid length gas system is best for overall performance and others say that at 20" you should only use the long gas system length.
What are the facts about this?

does anyone see any problem with the rough build plans ive laid out so far? is there something i did wrong or will i mop myself into a corner at any point?

also for those nwf refugees i posted a similar thread there a couple days ago but i have gotten a bit further with my reading.
 
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Jan 2013
3
0
Battle Ground
Every thing looks good.

1. Make sure you get a 5.56 barrel and not a .223 one. You can shoot .223 in a 5.56 barrel with no problems. But there is a small chance you could have problems with a 5.56 cartridge in a .223 chamber.

2. Most parts for BCG and upper are standard across the industry. I've never had an issue with any builds with a BCG not working in an upper. Just be very sure that the gas tube and the BCG come together with very little resistance.

3. Over all my builds I haven't really seen to much of a differance between carbine and mid-length gas systems. I think barrel, trigger, sighting system will be more important. The length of the gas system has not been a limiting factor in how well I shoot.

You really can't go to wrong with AR parts, as its the lego of the gun world and almost everything will fit.
 
Nov 2012
27
0
Aloha, OR
i get the part with the caliber sizes, something to do with a small difference in brass size which makes a lot of since when it comes to machined sizes. also i think you really gave me all the confirmation i needed when it comes to the gas system.

the only thing that didn't quite get to what i was looking for was the BCG. reading what i posted again sort of shows the lack of knowledge i have and how to ask the question. what i was really trying to get to was the feed ramp grooves on the bolt carrier and what part the grooves match up to. is it all part of the BCG or the barrel? i want it to look like the "good" illustration on the top right. i may also be getting my parts mixed up here too.

images
 
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Jan 2009
845
0
Renton, WA
i get the part with the caliber sizes, something to do with a small difference in brass size which makes a lot of since when it comes to machined sizes. also i think you really gave me all the confirmation i needed when it comes to the gas system.

the only thing that didn't quite get to what i was looking for was the BCG. reading what i posted again sort of shows the lack of knowledge i have and how to ask the question. what i was really trying to get to was the feed ramp grooves on the bolt carrier and what part the grooves match up to. is it all part of the BCG or the barrel? i want it to look like the "good" illustration on the top right. i may also be getting my parts mixed up here too.

images

Pic is a bit small, but pretty sure M4 style feed ramps are what you're after, and what looks to be in the 'good' pic. The 'bad' pic looks like a sad attempt at M4 style, but to the point of being worse than not doing it all.
 
Nov 2012
27
0
Aloha, OR
found a much better image of the feed ramp i like the look of. so is that where the barrel meets the upper receiver or is that bolt carrier meets upper? also what do i look for to make sure i will be getting that?
6809066489_bcd5e49b0a_b.jpg
 
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Jan 2013
6
0
Bellingham,WA
sounds good so far, just make sure you use all mil spec. components on your build as opposed to a mish mash of mil spec and civi. as far as feed ramps go just ask for m4 bolt carrier group and extended feedramp m4 barrel. I just used a LMT complete upper with m4 feedramps, (GTG).
 
Jan 2009
845
0
Renton, WA
Yes that is M4 style feed ramps. If you think about the relationship of the tip of the bullet as it leaves the magazine and heads for the chamber, that extra relief gives room for the round to feed more reliably. IIRC this modification came about when the M4 was introduced (hence the name) and had to do with the reduced dwell time on the shorter M4 barrels causing some feeding issues, or something along those lines.
 
Nov 2012
27
0
Aloha, OR
awesome, that pretty much settles me on a couple choices. M4 BCG, mil spec; for the more sturdy and even carrier and extended feed ramp M4 barrel. now as for the upper, will i need to be specific with choosing for the grooves in the feed ramps to be completed or am i looking at the pic wrong? will that mean that an A3 upper will get in the way of completing that type of feed ramp?
 
Jan 2013
6
0
Bellingham,WA
any upper you want, you just want m4 feedramps, when I ordered mine I asked for extended feedramps in the upper. they match up almost perfectly with my bolt feedramps. Ive had no feeding issues except for the very first round chambered, I did not let the bolt fly, and I should have . Now it eats anything including steel wolf ammo all day long.
 
Jan 2013
4
0
Vancouver
Good luck finding the parts right now. I have an AR pistol up for trade in the classifieds and I am being flooded with requests to part it out instead. I didn't go to all that trouble building it to take it apart again. :)
 
Nov 2012
27
0
Aloha, OR
thats exactly what ive seen every where ive looked. even my local dealer want $580 for a generic stripped lower. this is going to be a long term project, that at this time i will only be investing time into.
 
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