Second AR build

[MetGel]

I was wondering if you could help? I'm doing my second AR build, and you were very helpful with the first. This time I was thinking of doing a 300 blackout with an 18" barrel and fixed stock. What do I need to know as far as the buffer weight and gas system? Can I use the same as my first one it's 16" with mid length gas.
And I've noticed that a lot of 300 blackouts tend to be SBR, why? Is there an advantage to a shorter barrel with the 300? I may get my tax stamp for this build.

 

[NyleRN]

The 300blk gains nothing past 9". That's why you see all the 300blk SBRs and pistols. I most certainly wouldn't do an 18" in 300blk. Very much diminishing returns. Unless you reload I wouldn't even mess with 300blk. 308 is cheaper. And carbine length gas system only for 300blk if you go 16"rifle setup.

 

[MetGel]

Okay, thanks. I guess I'll try filling out a form 1.

 

[markiemark]

As mentioned earlier, the 300 blk burns out at 9" inches. Really no big benefit in velocity afterwards. I built a 16" due to a good deal on a barrel. The only benefit possibly is the extra iron sight radius and rail space. I am currently waiting on my Nfa trust to be completed to put a sbr together.

 

[sgreen3]

I had a 16" 300 back when the caliber started to get real popular. I didn't keep it long as to me it really didn't do anything more for than my 5.56 rifles did at a cheaper price to feed. Now with that said fast forward to today I have a suppressed form 1 300blk SBR that's a ton of fun! Moral of the story if you want it cause you want it, more power to ya, but anything over about a 9" barrel is not really what the caliber was developed for.