I'd like to replace my 14.5" M4 barrel (with permanent FH) with an 18" barrel.

What are my options? and what do I need to mount it on my M4 receiver?

Are the gas tubes the same? what of the gas opening? gas block?

Thanks!

A 18" barrel with a carbione length gas tube is an immense waste of effort. You want to run a longer mid or even rifle length tube so that you get a smoother, less violent action. The lower port pressure means the bolt unlocks a little less violently, which is good both for control and also relilability.

The rifle length tube will give you the best 'feel'.

You will however need a rifle length HG.

Simon

I really like the Noveske SPR upper. But I don't have the $1K ... I can afford the barrel, so how do I build the rest myself?

Thanks!

What do you want gun to do? If you are going to be shooting surplus like XM193PD and Wolf out your gun, you will never approach the accuracy potential of a premium match grade barrel like the Noveske which will shoot 0.5MOA WITH MATCH AMMO.

If you want to max out your accuracy, you'll need a Free Float handguard. That can run from $150 for the YHM tubes to $350 for a DD or PRI.

With a rifle length gas system, you don't have to run a low-pro block. Do you want a standard FSB or are you after something else like a block mounted flip up or a railed block.

Are you equipped to build an upper? Do you have tools and equipment for the job.

Simon

Several dealers here sell Noveske barrels and build uppers, why not let one of them do it for you?

If you want an 'SPR' upper, you're not gonna get much back from the grand with a Noveske barrel and brand name rail.

That's why I ask just what you want this upper for.

Simon

CMMG has chrome lined 'SPR' barrels.

Just buy the Noveske barrel, midlength gas tube, Larue FF tube and low-pro gas block. Build it on your current upper. Cost you less than 1K.

Thanks all! I'll research the parts mentioned.