Thread: Newbie AR owner question.......

What should I look out for when putting an upper and lower together that didnt come new with eachother? Should the buffer tube from the collapseable stock be touching or be depressed in any way, with the rear of the bolt assembly when put together? Should there be any gaps between the mating edges of the upper and lower? ANY info would be helpful. Thanks!

Originally Posted by treemanx

What should I look out for when putting an upper and lower together that didnt come new with eachother? Should the buffer tube from the collapseable stock be touching or be depressed in any way, with the rear of the bolt assembly when put together? Should there be any gaps between the mating edges of the upper and lower? ANY info would be helpful. Thanks!

Its as easy as just putting them together. Generally they will fit just fine if you buffer is all the way pushed in and "snapped" behind the pin so it doesn't fly out. Then just put the two pieces together and push to two take-down pins in. run the action a few times. Sometimes if they are older there can be some play in the lower and upper but for the most part newer setups tend to be pretty snug.

What if the rear of the bolt on the upper is pushing the buffer tube in a bit when the gun is closed up, even with the buffer tube behind the little pin? Does that matter?And how tight should they fit together? Should you not be able to see any light between the two recievers? Or is a little light here nad there ok?

Originally Posted by treemanx

What if the rear of the bolt on the upper is pushing the buffer tube in a bit when the gun is closed up, even with the buffer tube behind the little pin? Does that matter?And how tight should they fit together? Should you not be able to see any light between the two recievers? Or is a little light here nad there ok?

that shouldn't matter at all there will be a slight pressure there and that is good so there isn't any slap of the bolt carrier against the buffer. Some you can see light through and some you can't. My m16 in the Army actually shook some and it was fine. Mine now is tighter but you can slightly see through in parts they all tend to have their own "personalities".

So its ok if the buffer tube is depressed a bit when the upper is closed down on the lower. Thanks for clearing that up for me, I have a lot I need to learn! What is headspace??

Originally Posted by treemanx

So its ok if the buffer tube is depressed a bit when the upper is closed down on the lower. Thanks for clearing that up for me, I have a lot I need to learn! What is headspace??

yup totally okay. Its really hard to mess these rifles up and if you do its fairly obvious even to the novice.

head-spacing I have never really worried about with my AR, but you can read more about it here.

http://www.fulton-armory.com/headspace.htm

One needs to have head-space checked when using a different bolt assembly than what came with the rifle.

OK, so the head spacing is the distance between where the primer end of the bullet casing sits, to the shoulder of the bullet casing, when the bolt is closed. Right? So why do peopleorry about that? Shouldnt that be all good from the tight AR specs/tolerances?

Originally Posted by wichaka

One needs to have head-space checked when using a different bolt assembly than what came with the rifle.

I can see where if you had an old barrel this may matter, but I know plenty of people that change bolts around on many different rifles and have no issues at all. I guess if you were going for extreme accuracy for match on something?

All you need is one out of spec bolt....or the combo of under spec chamber and bolt and you will never forget that spectacular moment in your life.

All AR's come with a nominal spec tolerances, except the upper end brands they are made more precision to specs. Anyway, most all will interchange with no problem. But as I said, all one needs is one or both out of spec....and watch the fireworks.

if you bought the upper as a kit the manufactuer should have checked it (but not always the case just depends on who made the kit)

it is very rare to have new parts be out of spec but in that 1 in a million chance it may be worth checking it out if you value your hands and the side of you face

since your in clack area if i have some time i can bring over some head space guages and check it if you would like and give it a look over to make sure its all together

right not sure what you mean by the buffer tube depressing it . the tube should not at all protrude into the upper receiver and infact should not come into any contact with the upper if i understand you correctly you may not have installed the buffer retainer and screwed your tube in too deep and if thats the case where is the buffer

or you are refering to the buffer and not the buffer tube the buffer is to rest behind the buffer retainer and it also should not protrude into the upper receiver it should be close to flush with it though as the buffer should not hinder the upper from closing onto the lower

as far as gap some have it some don't if it has slop you can get a $5 accue wedge to fix the slop

I have a newb AR question as well. How do I get the front foregrips off?

Stand rifle on it's butt& pull down on the ring at the back of the fore grips.Some have higher spring pressure than others & may be more difficult. They make a simple tool for this but I have never needed it.The grips will come out in 2 pieces (top&bottom)You can pull out one & then the other.

I tried that and boy was it difficult. I will just have to try a little harder I guess. Thanks

Two people will make this easier. If grips are loose fit they will drop down w/ring. May be easier to stand on barrel as the rear of grip needs to lift out first.

The buffer itself may contact the bolt carrier. This is normal with many AR's, and not a problem.

To get the hand guards off, yep.....just try harder.

Thanks for all the replies!! OK--so what do you guys reccomend to use for lube? Oil or grease? Ive talked to some people who swear by white lithium grease, and some oil, which is better and how much do you use?

the headspace is actually the distance between the end of the case and the breech face of the bolt, on a case with a shoulder it is usually measured from the shoulder on the cartidge. As far as lubrication goes, I like militec 1, you need to either bake it on, or fire the gun until warm to make it work well, once it impregnates the metal, you wipe off the excess and it self lubricates for a few thousand rounds.

Any type of grease lube would be good. If you use oil, and store it muzzle up...the oil will flow down into the extension tube and will eventually leave the carrier dry.

For general use & storage, go with a grease. If you happen to shoot a few hundred rounds, keep a small bottle of Mobil 1 handy to keep the carrier and bolt wet.

Contrary to popular belief, AR's wont jam if they are dirty. Can run mine for 2-3,000 rounds without a cleaning. They will run longer, and actually push the grime out as long as the carrier stays wet. They don't like to run dry.

mobil 1? like car oil? really I have not heard of using that as a gun lube.