Why Free Float a Carbine Rail System?

[MX5]

Primarily, free-floating allows secure attachment of accessories without play or movement. Vertical fore grips are secure, optics remain zeroed, bipods won't have any effect on accuracy. Most carbines with non-free floating handguards are still more accurate than their owners/shooters. Depends on your usage and what level of 'cool' you aspire.

[markm]

Yeah. If you were running an Eotech way out front I could see wanting a FF.

But as far as VFGs and Lights, the KAC mounts up really tight. I know some of the Cheapo 2 piecers wiggle though.

[toddackerman]

For me, it allows me to "Quick Change" barrels on my LMT MRP upper. Release two "TorX Screws" and off it comes, and on goes the other. Nothing is touching the barrel other than the gas tube.

Tack

[Paulinski]

I also like the free floated set ups. My rails of choice are DD.

Although I do admit that my latest build KISS (my version of it) has standard handguards.

Basically LMT 16" upper with troy buis on stag lower.

[KevinB]

back,

I beleive that even a steel bbl nut affixed onto the rail will act as a heatsink to some extent.
The advantages to the FF system (depending on mount type) can allieviate the pressure on the barrel from a vert grip etc.
All weight on the barrel will contribute to forcing the barrel/barrel extension slightly out of alignment - thus forcing more pressure on one side of the bolt - especially on unlocking the locking lugs of the bolt will have unequal pressure exterted upon them - and thus lead to reduced bolt life.

With a more uniform pressure/lock, this then decreases wear and inturn leads to great life and reliability. Additionally this is another place where thin barrels with suppressors suffer greater bolt failure than thicker barrels.

Crane had a metric ton of data on this stuff for those with access who are curious.


For me - popping a FSB is a minor issue - and I feel the added benifits of a FF rail are worth the few extra dollar for the rail, and the few minutes to pull the FSB and barrel to replace the nut etc.

[C4IGrant]

Yeah. If you were running an Eotech way out front I could see wanting a FF.

But as far as VFGs and Lights, the KAC mounts up really tight. I know some of the Cheapo 2 piecers wiggle though.

The KAC RAS is a very good rails system. The thing to remember though is that it is more money then most of the 1 piece FF rails on the market and they don't give you the benefit of less stress on the barrel.


C4

[markm]

Good point, Grant.

[onmilo]

I know the Crane geek speak and it all really applies to full auto carbines.
Even burst fire guns don't have near the problems the full auto guns do and those problems are mainly caused by operators insisting on using the carbines as light machine guns.

The excessive heat with bolt failures rarely occurs with semi auto guns.
Bolt failures on semi auto guns are generally associated with out of specification bolts.
I have yet to see a semi auto carbine pop a barrel and I do repairs an many match used rifles and carbines.

Free float forearms generally make an accurate rifle even more so by relieving the already noted stresses on the barrel.
If you aren't trying to make a Match gun out of a semi auto version of a burst fire/full auto battle carbine then a standard, tight fitting, delta ring mounted rail forearm will work just fine and you have the advantage of switching the forearm out for standard handguards anytime you desire to do so.

[AR15barrels]

I'm just curious why there are so many Free Floated Carbine Rail systems available. To me a FF is what you want on a precision gun or an SPR or whatever. Why go to the trouble and expense of a FF on a CQB/Mid range weapon?

Grant already beat me to the point, but here are some real numbers...

Knights RAS from Operation Parts: $316
LaRue 7.0 from about Anywhere: $250
DD M4 7.0 from about anywhere: $275 (includes 3 rail covers)
Installation of a freefloat handguard by a gunsmith: $25 to $50

So, you can buy a LaRue or DD handguard AND pay someone to install it cheaper than you can buy the Knights RAS that you install yourself.
The dedicated freefloat will be more solid than any system that snaps-on with the delta ring.

[docsherm]

I have had allot of "play" with every Knights RAS I have had. My PEQ2 was always messed up. I only go with FF rails now.