Never built a gun before, need some advise so this doesn't cost me an arm and a leg. (if this is wrong sub-forum, mods please move)
First thing: decide is on a stripped lower.
Should I spend the $200-$300 on a name brand lower, or will a generic $100 lower perform just the same. Is this where I save the most money, or do the cheap ones have known issues (FTF and other misfires). Any manufacturer I should avoid.
If I plan on getting the .22 LR conversion kit, does it make a difference which lower I choose.
How much money can I expect to save over a pre-assembled from the gun-shop - How much did you save ?
I build AR's for extra money, and I'm a military trained Armor, (Marines, 2112 Armorers, Quantico, Va.),
So I've built them for everything from lead spraying to tack drivers.
You can't confirm this on the internet, so take what I have to say with a grain of salt, ask around, confirm what I'm telling you...
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The first thing I do when trying to assemble mis-matched components is put the front break down spring, retaining pin, and 'Shotgun' pin in the lower.
Then I find the rear (Break Down) pin, and I mate the upper receiver with the lower receiver, install the take down pins, front and rear.
The idea is to find out if the upper and lower MATE TIGHTLY.
If they DO NOT mate tightly, the rifle will NEVER be accurate,
The UPPER RECEIVER will move around on the LOWER RECEIVER every time you pull the trigger and the hammer falls,
Before the round exits the barrel, the upper will move on the lower, and you will ALWAYS have a loose, rattling, inaccurate rifle.
You can hone off a little on an overly tight assembly, but you CAN NOT add material to one that has gaps all along the sides of the upper/lower and letting the upper rattle around on the lower...
There are 'Gadgets' to tighten up this fit between upper and lower,
Everything from off set bushings for the pin holes to rubber wedges that go under the locking lugs (Accu-Wedge), but the best thing you can do is get Upper/Lower that FITS in the first place!
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Once I find a set that MATES TIGHTLY, then you need to TRUE the upper receiver bore.
The hole the bolt/carrier rides in is often OBSTRUCTED by excessive coating, bad machining, ect.
It needs to be sized correctly if the bolt/carrier is ever going to cycle correctly in the bore.
There are SEVERAL ways to true the upper receiver, but the most simple is to use a trueing tool that sizes/trues the bore and the front barrel nut facing at the same time.
They are relatively inexpensive and easy to use, just don't take more off than you have to...
LINK:
BROWNELLS : AR-15/M16 UPPER RECEIVER LAPPING TOOL - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools
Link Removed
This tool sizes the bolt carrier bore and squares the barrel nut face with that bore.
This action aligns the rear sights with the barrel, sizes the bore for the bolt carrier, and keeps your rifle shooting STRAIGHT for a change!
99% of the rifles I true for accuracy have excessive and uneven coatings inside the bore,
And the front facing that aligns the barrel with the bolt are uneven, so the barrel is cocked in the upper,
Your sights will NEVER align at various ranges with the barrel cocked in the upper since the rear sight is mounted on the Upper, and this tool takes care of it.
It's MANDATORY if you want a rifle that shoots straight at all ranges.
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When doing match rifles, I usually put them on the lathe, but for everything BUT long/various range match rifle where EVERYTHING has to be EXACTLY RIGHT, this tool shown will do you just fine...
I've used the crap out of mine, and it works GREAT. Highly recommended!
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Now that you can put your barrel in the upper SQUARE,
Remember NOT to torque the retaining nut in more than 35 Ft.Lbs.!
Most guys OVER TORQUE that retaining nut, and you WILL distort the front threads if you do!
there is a TON of contact with the threads there due to the large diameter of the bore,
So 35 Ft.Lbs is PLENTY.
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If you are using (or switch to) a full floating tube Barrel Retaining/Forward Hand Grip nut later,
Then feel free to hone a little more off the front of the upper receiver to get the barrel nut gas tube hole to line up with the upper.
Take the material off in VERY SMALL increments so the barrel nut lines up with the gas tube inlet on the upper.
This DOES NOT effect your head spacing! (some people say it will, but it DOES NOT)
The bolt carrier still shoulders on the barrel extension, and the bolt still locks into place in the same relative position inside the barrel extension, so taking a little extra material off to get the barrel nut to center up on the gas tube isn't an issue.
Since the bolt carrier contacts the barrel extension, and the head space is determined from that point,
Moving the barrel/barrel extension backwards in the receiver will NOT effect your head spacing.
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When putting together a lower, it's really an 'Erector Set', not much to it, and not much you have to do except for install the parts.
Assembling your own lets you get EXACTLY what you want, so I recommend you put your own together now,
Then add 'Extras' later as your needs change.
Just keep in mind there are different recoil buffer springs and recoil buffers for 'Carbine' and full size rifles, and they DO NOT interchange.
Carbine rifles MUST have carbine springs and buffers,
Full size rifles MUST have full size springs and buffers.
Keep in mind there isn't a ton of difference between stock and 'Aftermarket' triggers.
You CAN tune a factory trigger to work very well for a 'Field' rifle, and amateur target rifles,
AND STILL BE SAFE!.
DO NOT try and mess with trigger action unless you know EXACTLY what you are doing!
Making a rifle that is unsafe isn't worth the danger it becomes, so go with 'Stock' AR-15 trigger group until you get some experience and understand how it works...
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If you have a choice between Taper Pins that hold the front gas block/sights on and Roll pins to hold it on,
ALWAYS GO WITH THE TAPER PINS!
Roll pins will let the front sight move around and cause the rifle to be inaccurate.
Taper pins will hold the front sight/gas block on CORRECTLY, but recent manufacturers like the roll pins since they are much cheaper to machine the holes and install.
Since I build FIELD RIFLES most times... I like REDUNDANCY & SIMPLICITY.
If you are going with optics, then a flat front gas block might be the way to go.
Personally, I like the idea of having iron sights as a back up in case the optics fail or get damaged...
Many a hunt has been saved (although been limited in range) by defaulting to iron sights for me,
So REDUNDANCY is a big part of what I do with these rifles...
There are a lot of manufacturers that make blocks you can attach/remover front sights,
And there are some that make 'Fold Down' front sights that simply fold down and lock into place.
(Same with rear 'Iron' sights), and they have saved my hunts/shoots before, so I recommend them.
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.22LR conversion makes your rifle a ton more useful.
I have a dedicated upper I mostly use the .22 conversion in (Better twist rate for the little bullet) but I also shoot, quite accurately, through the .223 barrels also.
DO NOT buy a 'Cheap' conversion! Make sure you can get extra magazines for the conversion,
And see if you can get extra springs, firing pin for the conversion for future use...
(you never know how long they are going to be in business, so get replacement 'Wear' parts now!)
Magazine lips wear out, springs break, finding pins get hammered flat, ect.
And the conversion companies come and go, and little interchanges between companies.
Always good to have 'Field Parts' when something fails, and every thing fails eventually!
BOY! Do I get looks when I'm squirrel hunting with a full size AR! :biggrin:
Makes you a target for every game warden to check out!
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As for 'Raining On Your Purchase''...
I just sold a Bushmaster AR Carbine (new in box) for $1,200, so you found a pretty good deal in my opinion.
I know you can buy them for less, but this guy just HAD to have the rifle, ponied up the bucks, so I sold it!
You CAN find deals, but they aren't as plentiful as they once were...