Questions: Floating Quad Rail for AR-15

[SS_N_NE]

Getting to the end of an AR build with a 80% lower and SS 16" .300 BLK barrel with a carbine gas system using a low profile gas block. Last parts are ejection port cover, barrel nut and forearm.

Decided I want a free floating rail and have begun leaning towards and Ergo Z floating rail. This is a somewhat narrow profile rail handguard and price is somewhat less than some other offerings but better USA version than some of the junk rails out there.

So some questions for our experienced members:

Could use a carbine length rail, but I have a low profile gas block and could install a rifle length rail over the block. Would have the benefit of a longer rail for MBUS sites I have. Any thoughts on handguard length?

Since this is a .300 BLK would there be some benefit from using an adjustable gas block? Will most likely only shoot super-sonic handloads from this rifle, so short barrel cycling on sub-sonic loads is not much of a concern. I think and adjustable block could be hidden under a longer rail. 

[RobertH]

I would check out ALG Defense, they have great high quality stuff. Or Midwest Industries.

I would go with longer rails, looks cooler, longer iron sight radius and covers up gas block, etc. It wont add a lot of weight if you buy good light weight rails.

[tstuart34]

Getting to the end of an AR build with a 80% lower and SS 16" .300 BLK barrel with a carbine gas system using a low profile gas block. Last parts are ejection port cover, barrel nut and forearm.

Decided I want a free floating rail and have begun leaning towards and Ergo Z floating rail. This is a somewhat narrow profile rail handguard and price is somewhat less than some other offerings but better USA version than some of the junk rails out there.

So some questions for our experienced members:

Could use a carbine length rail, but I have a low profile gas block and could install a rifle length rail over the block. Would have the benefit of a longer rail for MBUS sites I have. Any thoughts on handguard length?

Since this is a .300 BLK would there be some benefit from using an adjustable gas block? Will most likely only shoot super-sonic handloads from this rifle, so short barrel cycling on sub-sonic loads is not much of a concern. I think and adjustable block could be hidden under a longer rail. 

You said no SBR but what about a suppressor? If you not going to run a can I would skip the cost on adjustable gas block and buy a quality gas block. One thing to not is make sure you have clearance on smaller tubular rails. I burned myself when I bought a YHM clamp on gas block and my rail did fit. Luckly I tested a fitted everything before I pin and welded the comp in place.

I am a fan of longer rails. I have 13" troy Alpha. Like Rob said ALG and Midwest have some nice stuff. My dad has the MW Keymod and the older style I like both when i shot his rifles.

Pallet Racking For SHOOTER!!!!

[SS_N_NE]

I did a little web searching on adjustable GB use. Seems a lot of benefit to it for standard 5.56 so the shift to .300 and carbine length might be worthwhile as well as some buffer tuning. Just guessing at this point since I have zero experience.

Here is a pic of the build. The lower and upper were "in the white". With the stainless barrel, there is a black/silver/black thing going on that I kind of like. Just going to polish the "white" stuff for now. I know this might offend some of the black gun aficionados but it is my build. 

[SS_N_NE]

Thanks for some of the ideas.