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Jpyle 02-09-2010 03:19 AM

JP builds an AR - pics added
Ok decided to take the plunge and join the "I built my own AR" community here. Gonna start slow one component at a time.

First up...lower. Have my eye on a receiver that R Guns has on clearance at $55. Have read that a receiver is a receiver is a receiver but is that true in all cases? Heres a pic:

Also going with the following parts kit:

Total cost about $130 with shipping.

Anyone thinking these are bad choices please feel free to comment. I'll try to update this thread as I progress with the build and post some pics as I go along.

Really looking forward to this...

Dillinger 02-09-2010 03:31 AM

First off, let me say welcome to the build community, you are among friends. :D

Second, I am the one who said that a receiver is a receiver. :p

Here's the deal, unless you are buying from some guy named Cleatus who just got done chiseling it out of an old engine block his brother blew up in 9th grade autoshop, you are probably alright.

Look, there are three classes of receiver.

Cheap, chinese pot metal. Usually super cheap and definitely easy to spot.

Aluminum, usually CNC machined and banged out in droves. Totally safe and what everyone is buying...

Custom Machined Billet - You are paying for someone's name on the side and it's probably 10%-15% better ( tops 20% ) than the "middle of the road" receiver.

DPMS makes a great kit, you should have zero problems....

PM me if you have any troubles.

SLO - You have anything to add?

Jpyle 07-06-2010 04:24 AM

Getting re-engaged in the AR build as a summer project. Have acquired an upper and want to remove the existing gas block and mount either a railed gas block for removable, fold-down BUIS or permanently affixed fold-down sights. I have a few questions.

1. What is the diameter of a Colt A1 style barrel as shown, .625. .750?
2. Do I need a medium or low profile sight to keep below the free float tube. Are there particular measurements or numbers that refer to the appropriate heights so that the front and rear sights remain on the same plane? Maybe I am making this too complicated but how do I know the front and rear sights will line up properly?

For example if I were to order this sight would I need to specify a height as well as a mounting diameter?


Dillinger 07-06-2010 02:18 PM

^^ What Slo said. :)


mjkeat 07-06-2010 04:41 PM

I agree that the DPMS lpk will work and that most lowers are created = although some lowers are made from different materials and differ slightly in color (all stated above). I have heard of Sharps but have no experience w/ them. The gas block is fairly simple to remove. Some have tappered pins and some dont. For me it was a trial and error moment. Mine ended up being tappered. Personaly I like the Mbus sights used on a rail that extends past the lo-pro gas block. Thats all just personal preference though. The hooded stem is cool looking. Build what YOU want and what makes YOU happy. Because in the long run if youre not happy youll end up selling it and will never be able to fully enjoy your creation. Then again ARs are perfect for guys like me who have changing taste. Ive heard it refered to as "adult legos". Good luck Jpyle and keep us updated.

Jpyle 11-12-2010 06:18 AM

Build update
Well its been a long term project but I finally got the AR 98% completed. Went with a YHM lower and the DPMS parts kit. Completing the lower was fairly easy with only a few flying detents and one oh shizz moment when I had a spring left over. Fortunately it was only the disconnector spring so taking it apart to install the spring was not a major PITA. Note: Trigger and hammer work just fine without the spring, not sure what would have happened with the upper in place, possibly a doubler or a fully auto AR or just a trigger that won't reset :eek:

Next up is the gas block replacement and installation of the BUIS, acquiring a decent scope and a trip to the range for a shake down...:D

Only problem of note is a very loose rear take down pin, so loose in fact that the upper and lower separate. Will an accu wedge fix that or should I replace the pin entirely? :(

Thanks again to everyone for the help and suggestions, it was really not that difficult and the knowledge gained was worth the extra effort.

Dillinger 11-12-2010 02:22 PM

I would try the Accu-Wedge first, as it will tighten the overall fit between the upper and lower, before you go replacing parts.

Can you post a couple of pictures of the problem?

dog2000tj 11-12-2010 02:51 PM

Pyle, I have a couple wedges laying around. if you want to try it let me know and I can mail you one.

Jpyle 11-12-2010 03:18 PM


Originally Posted by Dillinger (Post 384985)
I would try the Accu-Wedge first, as it will tighten the overall fit between the upper and lower, before you go replacing parts.

Can you post a couple of pictures of the problem?

JD...Thats sorta what I was thinking, I'll take off the stock, reseat the detent and spring and see if that tightens things up a bit. I'll post some pics as soon as I can but in a nutshell what happens is that the rear pin slides freely through the upper and lower rear holes allowing the upper to pivot up and away from the lower. Can't imagine that would be a good thing while firing. :eek:


Originally Posted by dog2000tj (Post 385000)
Pyle, I have a couple wedges laying around. if you want to try it let me know and I can mail you one.

Thanks Dog...I'll see if I can pick it up locally and let you know, appreciate the offer.

Dillinger 11-12-2010 03:23 PM

Jpyle - That is not uncommon, but it is less common these days. I know that upper and know it hasn't been abused and is not a colt large pin, so we can discount that as a possible. ;)

My first thought would an out of spec take down ( rear ) pin, as the front pivot pin fits correctly and does it's job, correct?

An Accuwedge was basically designed to take that play out of the upper to lower receiver match. It essentially adds upward pressure to the tang that holds the take down pin, but if the pin going through is so loose it rattles, that is a point of concern for me.

Do you have a dial caliper that you can mic the pins in question?

An Accuwedge will run about $3-$5 at most places, so it's a pretty easy and cheap solution, but in the meantime if you want to try something to see if it will work, try a cigarette butt or a foam ear plug.
They will essentially do the same thing.

Now I am curious....

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