Hey guys I am starting on building another AR but a "pistol" this time.  I have 3 16"(2 5.56/1 2.23 Wylde) and 1 18"(2.23 Wylde) rifle I built already so figured its time to go shorter!  The barrel length I am considering is between 10.5" to 13.7"ish.  I really like the Ballistic Advantage Hanson series barrels and how they offer strange lengths to match hand guard choices.  I'm leaning towards the 11.3" Hanson because I would like to run a 12" HG and don't know if the 10.5" would be too short even if I run a 2.25" linear comp.  What size barrel do you guys prefer to run with a 12" HG that measures 12 1/4" actual length?  Also do you think going with a barrel with a .625 port VS a .750 is better for the shorter length barrel?

They list the barrel length and any decent handguard manufacturer should list the ACTUAL overall length of the handguard itself. With that info you should be able to use a tape measure and see which combo works best for you in your opinion.

I prefer a long handguard (extending just before the muzzle device) unless I intend to often remove and reinstall muzzle devices or direct thread suppressor for whatever reason. That is because I do not currently own an action rod so I would have to remove the handguard in order to clamp the barrel to remove/install a muzzle device. An action rod would be the solution, but I haven't felt the need to buy one 'yet'.

The rail needs to be an inch less then the barrel. 12 inch rail you'll want a 13.7 or 14.5. Not really worth it. Build a 11.5 or 10.3.

The threaded portion of the barrel 9/16" needs to be subtracted from the length and the same for the muzzle devise.  Your 11.3" barrel is about 10.75" to the end of muzzle threads, add a 2.25 comp and it's 12.44" long give or take.

Thanks LastRites thats pretty much what I'm going for looks wise.  I want the muzzle device to stick out only about 1/2 or 1/3 of the way past the HG.

Anyone have any input on the gas port size of .625 VS .750?

That is not gas port size, that is the diameter of the barrel where you put the gas block/sight tower. .625 is normally used on the lightweight barrels, and .750 is the common size.
.750 = 3/4 inch. There is no gas port that big on any AR.

Thanks for clarifying that for me.  What is the purpose of the different sizes then if its not the actual gas port hole size?  Ive seen a lot of talk about .625 and .720 VS .750, it doesn't seem all that important to me if its just the diameter of the barrel where the gas block sits.  It makes more sense to me that the profile of the barrel would be more important than the diameter of the gas block area?  So for my purposes which is just a "fun gun" either would work and I will buy whichever barrel is in stock at the time.

I have a 11.5 BA barrel under a 13" rail and a flash can makes up difference in length to clear the hand guard.  I really like the look and its a handy firearm.

Hey Neal what is the length of the flash can you have?

I ended up buying a 10.3" BA barrel.  It is 416 stainless steel with a nitride finish and nickel boron coated feed ramps/chamber.  I went with an AT3 tactical 9" hand guard that measures 9.25" actual length.  I ordered a Kaw Valley Precision linear comp as well.  I didn't end up "tucking" the muzzle device but the barrel/M.D. should only stick out about 1.5-2" past the H.G. so it should look good.  Ill post some pics if the parts ever show up, 1 week late and counting!