AR Barrel

[Dutchbat]

Hello All
I am starting a project to replace the barrel on my 20 inch AR to a 16 inch M4 style.  I have all the parts, instructions and am currently gathering all the proper tools to get the job done.  My question is for those who have done this type of project.  What are some common problems I could run into or should look out for?  I am new to the forum and anything and everything will help.  Thanks!

[gunman42782]

Welcome.  First of all, I would suggest you go over to ar15.com and read the great picture tutorials they have over on that site.  They explain step by step how to put an AR together from scratch.  Personally, the hardest thing I have found on swapping barrels is getting the gas tube lined up through the delta ring, and the only advice I can give you is be patient and you will eventually get it done.  Also, a good DVD is a world of help.  I have the Bushmaster Armorer DVD, but many folks put out one showing you how it is done.  These DVDs are great! 

[m25operator]

I pretty well mirror Gunmans recommendations, but you left out a few things I would like to know before you start.

1) are you going back with standard handguards or going to a free float system, if the answer is free float, is it one piece or two piece?

2) are you reusing your front sight base, if so, measure the diameter of the barrel at the sight base, and compare it to what you have purchased. maybe your new barrel comes with a matching sight base or gas manifold.

3) since your going from a 20' to a 16", this is fundamental, but does your new barrel come with a matching handguard?

4) once you've completed the installation, have the headspace checked, it's usually ok if your using premium parts, but you don't want to fire it to find out.

5) standard front sight base pins are tapered and should only go in one way, and come out one way. If unsure, measure the pins on both sides of the barrel. Drive the pins out from the little end, once again fundamental, but can cause a lot of frustration if done wrong.

Good Luck

[Dutchbat]

My thanks to m25operator and gunman 42782  for there info.  To answer m25s questions, I have ordered the complete DPMS barrel kit from Del-Ton, so it has everything forward of the upper including standard handguards.  I also have the combo wrench and upper reciever block as well, am borrowing the other tools.  So at this point I am not re-using any of the parts from my old barrel.  Great tip on the front sight base pins, did not know that, much better than finding out the hard way.  Again thanks guys and keep the info coming everyone.

[tombogan03884]

Is there a reason not to just get a16 inch upper? then you have the option of switching back.Imay not have thought that through completely but as they say, the only dumb question is the one you don't ask.

[Sponsor]

[Dutchbat]

Well to let everyone know, the project is done except for the test fire.  I'll let you in on the problem I had.  I had purchased a GI type wrench for the project, to remove the barrel nut I hooked up a 18 inch breaker bar.  You guessed it, it broke...one of the prongs on the GI wrench.  Once I got the barrel nut off I found that it had been cross-threaded to begin with, the parts kit was purchased with the complete upper.  I cleaned up the threads on the upper and hoped for the best.  Today when my DPMS Multi Tool arrived I had the job done in about 45 minutes.  To answer TOMBOGAN's question, I wanted to change the barrel myself for the "fun" and experience of it, because in the long run after buying the tools to do it with it was not cheaper.  Thanks everyone for the guidance, we'll see how she does down range.

[m25operator]

4 weeks ago at the gun show I ran into a friend who is a top 3 gun shooter, Who is on team DPMS, at his table were 3 Stainless Shilen 8r ( ratchet rifled ) 24" barrels, for 100 bucks apiece   I asked him the skinny, and he was given the barrels for testing, he installed them and ran 50 rounds apiece through them, said they shot very well, and gave his report to Shilen and he was left with the barrels, which he cannot use, as he must use all DPMS stuff. So I bought one, thought of rebarreling one of my current rifles and decided I like what I have the way they're set up now. Ordered a DPMS LOW PRO upper reciever, bolt carrier assembly,a 4 rail gas block, JP free float forend with accessorie rails, they back ordered the forend but it should arrive tomorrow. I will assemble and take some pics.  After a little consideration, I said self, you can't buy a cheap AR barrel for a hundred bucks, so I called friend and asked if he still had the other barrels? One was left, so I get it this weekend, I think I might make that one into a DCM GUN.

[kilopaparomeo]

If you haven't already, I highly recommend reading and printing out the "Assembling an AR15 from Parts for Dummies" sticky thread over at AR15.com

http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782