I have a shot out 20 inch light weight barrel that I would like to play with.  I want to use this to make dedicated 22lr upper.  I want to move the sight post back to accept carbine handguards (22lr no gasport needed) and shorten the barrel.  What I need to know is how to recrown and thread the barrel for a flash hider.  I would like to use a standard A2 flash hider and need to know the thread size.  I have the standard garage type power tools but need to know where to buy tools to actually thread the barrel.  

I know it would be easier to have this done by a professional so if anyone else has done this and failed miserably let me know so I just go and buy a new barrel.  

Buy a new barrel.  First, the 22LR is .222 diameter which makes it kinda loose in a .223 bore in good condition.  It would be very loose in a shot out barrel.  Not to mention it's the wrong twist.  I doubt you'd get 4 - 6" at 50 yrds.  Second, while Brownells sells a die for cutting the muzzle for a flash suppressor, you'd still have to have the muzzle turned down to the correct diameter.  Third, Brownells also sells a handheld crowning cutter, but it indexes off the bore.  If your barrel is shot out then you wouldn't get a very accuate cut.  By the time you bought the dies and cutters and risk screwing the whole thing up, you prolly be half way to buying a new barrel just as you want.  I would imagine you could get a 22lr barrel for $100 to $150.  Diligent shopping would get you closer to the $100 mark or less.  Try eBay.

Couple ways to go about it.

You might be better off relining the old barrel with a rimfire liner.  They come in lenghs around 26", about .312 diameter.  I've never tried to drill out a chrome bore, and it might take a couple bits to do it.  I've done this on a old marlin 1892 and it is a pretty slick method.

You can buy 10/22 barrels for 10-15 bucks on Ebay.  These are already chambered and cheap to play with.  The diameter and length is a bit short, but make for good practice.

A used Win52 barrel should be on ebay every now and then.  It is the chamber end that goes, and cutting a bit off a 28" barrel and rechambering shouldn't be a problem.  A machine shop could do simple contouring in a couple hours....

:)  You really need serious guy tools.