I have a 20" bull barrel and I am going to change to amodel 1 lightweight contour 16". How much will I have to change? Gas tube - cutable or will I have to buy new, Handgaurd - will I have to buy a carbine or will the standard still fit.Can I take the front sight off and just use a regular gas block?
Anything else you guys can think of that might need changed?

You will need a new gas tube and new handguards. You can take the front sight off and use a regular gas block.

You may have a few options. Are you running a rail or tube on the 20" bull with the standard gas block (high profile with rail on top)? Does your 16" have the standard sight tower/sight or a gas block?

My gun is an olympic k8.It has a gas tube .The new barrel says sight and block included,I have'nt orderd it yet but that is the description in midway usa.Thanks for your time.

I don't understand if your swapping out a barrel assy or an upper? Could you link me to the unit your looking at? I think I know what you have but don't know what your looking at. Thanks

Is it this one?

http://www.midwayusa.com/viewproduct/?productnumber=777573

If it is then you will need,

A carbine lenght gas tube.

A carbine lenght handgaurd.

You can cut the front sight down and shape it to look real nice and continue to use that as your gas block OR buy one of the gas blocks made for the lightweight barrel.

ALSO, if you're planning on swapping the barrel out yourself, there are a few items/tools that are almost mandatory to do the job correctly and without flubbing something up. Two that come to mind are...

A GOOD action block. It is almost a must have for the barrel change. I like this style the best.
http://www.midwayusa.com/viewproduct/?productnumber=593549
Brownells also sells one very simular to the one Midway sells.

A barrel nut wrench is also very handy.

No big deal, but you do realize that Model 1 barrel (assuming we're talking about the same one) is not set up for a free float hand guard when you receive it?

Good luck.

That barrel is a 16" Superlite, it is chrome moly and unlined, it is chambered for the 223, standard front sight tower/gas block and it is threaded for a muzzle device. It also has the front handguard retainer plate which will be discarded if you use a float tube.
1. should you choose to use this barrel with the 2 piece snap in plastic handguards you will need the carbine length handguards, carbine length gas tube, gas tube roll, pin you will also need the Delta assy which consists of the retaining ring,slip ring spring,and handguard slip ring (the barrel nut is already on the barrel)and a brake or flash hider.
2. I think this is what your after. If you choose to use this with a float tube you will need to remove the front sight tower/gas block and remove and discard the barrel nut and the front handguard retainer plate from the new barrel (this will also eliminate the Delta assy). You will install and torque the barrel with the barrel nut used with your float tube at this point you can install a new carine length float tube or cut yours back to seven inches and use it (they are fairly inexpensive, personally I wouldn't go to the trouble to cut one down), this will allow you to keep your front sight abd bayo lug intact, if you know you don't want a front sight (and never will) you can shave the front sight and go over it with your rifle lenth tube. You can see an example of this shaved gas block if you have a Bushmater V Match with shaved gas block or a S&W M&P 15 T as they both do this.

That is the barrel I was looking at. I would like the change to be as easy as possible. So what about the oly barrel#680269from Midway? Would that one be easier to swap?
Im not set on anything yet but i do want to gat rid of the bull its just too heavy to carry all day.If you guys have a suggestion on which one to get please let me know.I dont know much about ar's so I could use all the help I can get.

If you are going to use a float tube either barrel will require the same process. If you use the standard carbine handguards rather than a float tube it becomes a simple barrel swap(it eliminates removing and reinstalling the front sight/gas block).

You may consider buying a new upper configured as you want it and selling the old one.

Thanks for everybodys input.After reading it all a second time it does'nt sound too complicated, just have to buy the right parts.Is there someplace else to order these parts from or is midway as good as any?

don't waste your time and money on FF a 16" barrel, keep the standard handguards and buy ammo!

FF it. You won't regret it.

I agree with Curt. I built my LW 16" barreled AR with a FF tube. It does make a difference. MI VHNTR