I found some threads here and on ARFcom discussing this but I’m still confused.
How do I determine the correct/optimal rail to use on a given upper?
Back before folding sights, everyone was running a fixed front sight base gas blocks that was connected to the gas tube. And If that’s what you’re using, your gas tube length is determined by the barrel, and I don’t think it can be changed. If it’s a carbine length gas tube setup, you’re running a 7” rail, period. Right?
Since the invention of low profile gas blocks that can fit under the rail, my assumption is that you want to use the longest possible rail that still gives you access to the flash hider so you can mount a suppressor. This lets you mount more stuff and grab the gun further down. The trade off being the overweight weight is heavier on a longer rail. Is this right?
Curious to hear if my two assumptions are correct and to help anyone else reading this thread with general info.
Now onto the specifics of my use case:
Currently half of my uppers have front site gas blocks and I actually love those. As a survivalist LARPer, the small amount of vision that’s obscured by the fixed front site seems minuscule compared to the benefit of having an always up and durable front site. Also, lately I’ve been switching over to the 2.26” aimpoint micro heights and the fixed front site doesn’t obscure anything.
Question) So I’m wondering, if I have a carbine length gas tube system using a fixed sight block currently, on a 11.5” barrel, can I install a low profile gas block so I can use longer than a 7” rail that feels cramped for a light and laser (running NODs in my LARPing), and then have a gunsmith reinstall the fixed front site on the barrel further down, even though it’s not connected to the gas tube anymore, to have the durability of an always-on front site? Would pair great with the always-on built in unity tactical rear sight inside the 2.26” aimpoint mount.
Or am I better off using a backup front iron site that is fixed and mounting that to the rail? I’ve seen those before, seems like it couldn’t be as durable as the front site mounted to the barrel, but perhaps it’s even more durable since I don’t really know how tightly the fixed barrel front site is?
Question) What’s the correct appropriate rail to use for the following four barrel lengths: 9”, 11.5”, 12.5”, and 14.5”?