I have an armalite M15A4 16" carbine. The length of the standard handgurds are 8". Could someone please tell me what free float tube or free float hand guard would fit on my rifle in the 50-75.00 range without alot of gunsmithing. Thank you again

Does it have the recoil check/muzzle brake
on it ?

If so that has to be removed.
( Because you have to take off the gas block
             to install the tube )

DPMS has a carbine float tube for  $50

[url]http://www.shooterstore.com/acb/showdetl.cfm?&DID=90&Product_ID=6286&CATID=494[/url]

Does your Armalite AR15 have one of their brakes on the end of the barrel?
If it does then putting a free flaot tube on that barrel will be very difficult. The brake is permanently attached.

Any tube you decide on will need minimal gunsmithing to remove the front sight and barrel nut as well as install the tube. If you have the proper tools it is a job that should take half an hour to an hour. If you don't have the tools you will need to pay to have the tube installed and it would probably cost about $60-$75 just to have the work done.

I have a Hogue free float tube on one of my AR-15 rifles and like it alot. The rubber gripping surface really does offer a better hand hold than a regular metal tube. It will cost approx $75.
[url]http://www.hogueinc.com/getgrip/merchant.ihtml?pid=159&lastcatid=16&step=4[/url]

There are float tubes offered by others also which range in prices. Here are just a few:

Bushmaster:
[url]http://www.bushmaster.com/shopping/handguards/hgd-02.asp[/url]

DPMS:
[url]http://www.shooterstore.com/acb/showprod.cfm?&DID=90&CATID=494&ObjectGroup_ID=1365[/url]

DSArms:
[url]http://www.dsarms.com/item-detail.cfm?ID=FTUBEC&storeid=1&image=ARfreefloattube.gif[/url]

Aren't there two piece float tubes?

Yes, but they still go on the same way.

check with Tommy at Georgia precision he gave me a price from rock river for there midlength free float tube it and shipping was around $60.00 hope this helped us mid length guys gotta stick together

You can also get the Olympic FIRSH midlength free floating quad rail tube.

arbud, the act of installing a free float tube is not hard, but getting that Armalite recoil check out is.  For float tube, you might have go the route others had suggested, get a full length tube and cut it down to fit.  DPMS tubes are very reasonable, specially with discount from Brownells.