I want to replace my 20" inch barrel with a 16" incher. Can I just get a wrench and do it myself or would I be better off paying some one at the gunshop to do it?
What is the most importan factor? Proper alignment?
Thanks,
muz

TM-ManualDownload the TM manual and all the info you need to change the barrel will be listed.

dont you also need a heacspace guage for that operation?

What is the most importan factor? Proper alignment?

As rn45 suggested, you'll need a GOOD barrel wrench (beware of the cheapo ones)and a Armorers Action Block similar to this:



A good vise w/ brass inserts are helpful, (for holding upper by the barrel if necessary).

Pair of small vise grips, small punch and small ball pee hammer (for gas tube removal and re-installation)

Alignment is generally not a problem as barrel has an indexing pin and there is a notch in upper receiver which pin fits in.

Be sure an use some type of anti-seize compound or lube on threads prior to re-installation of the barrel nut. Also alignment of handguard snap-ring, weld spring and barrel-nut is necessary when re-installing the gas tube.

As to head-spacing if barrel your installing has been fired with a bolt/carrier and you use that combination, headspacing should not be necessary, but if new bolt/carrier is used with the 16" barrel to be installed then you should check it to be on the safe side.

Mike  

well thanks all. I'm thinking it might be less expensive to have the shop do it. I did not realize I would need so many additional tools.

Get the stuff and do it yourself. The investment in tools will pay off when you want to build different uppers. If you have an AR and don't have different uppers for different purposes, then you are missing out on the beauty of the AR design.

Variations include:
M4
16 CAR
24 A3 varmint
20 A2
20 DCM
26 Space gun

By do-it-yourself, the cost for those uppers is a fraction of what you would pay to have someone build them for you.

muzlblast,

if you are a younger person i highly recomend buying the tools, because in the future you will become such an AR addict that you will want to build a rifle, then another & another & b4 long you are totaly helpless..., $100 - $150 worth of tools will be all you will need, i have a built in torque wrench in my elbow so for me they are not needed.........