Hello, first post on the forums. Hope I am putting this in the right section. I am looking to upgrade my ar15 in the near future. Would like put a whole new upper assembly on it. Something with a quad rail. Anyone have any ideas or suggestions? I was looking at the Yankee Hill Machine Black Diamond series of “top-ends” with a 1:9 twist.
Thank you.
Welcome. You can’t go wrong with Yankee Hill. They make excellent uppers.
Thanks. WOuld you recommend a 1:7 twist or 1:9?
I would go with the 1-7. It will help stabilize heavier bullets if you want to use them. That is a subject that will draw a lot of opinion.
Alright. I have looked up the differences between he two twist rates and could never get a straight answer. thank you though.
@CDW15 It depends on your use case. I have bought some YHM kit and it is consistently good. What caliber will you be running? My 5.56 16" has a 1:7 and does well with 68-76 gr bullets. The only way I can afford them is by reloading. A 1:8 twist would be more middle-of-the-pack. Most ammo off the shelf is 55 gr and 62 gr. The length of the barrel has some say in bullet stabilization. Short pistol barrels need to do a lot of work quickly to stabilize the bullet.
I am looking at a standard 16 inch rifle barrel. shooting your typical 55 grain 5.56. What would you recommend?
You are welcome. Theory being that it does not hurt to overspin a lighter round. But under spinning a heavier round will cause it to be less stable. I am sure other members can offer more detail. Have a good night sir.
My $0.02… Shooting 5.56/.223 always go with a 1/7 twist. It allows you to take advantage of the full range of commonly available weights from the heaviest 77gr down to the lightest 40gr varmint rounds. (there are some boutique rounds outside that range but i wouldnt worry about those).
A “slower” twist of 1/8, 1/9, or 1/12 will generally have trouble stabilizing the heavier bullets but will be fine for the lighter bullets. If you go with one of these, just be aware of what you can/can’t shoot through them.
I have seen people on the internet saying they’ve seen other people on the internet saying you can spin the lighter bullets “too much”, but i’ve personally never seen any evidence of that in person or otherwise.
As far as brands for a completed upper, these would be my recommendations that I have some experience with:
Sons of Liberty Gunworks
Daniel Defense
Bravo Company
By reputation, I’d also recommend a look at
Aero Precision
Midwest Industries
Radian
I’m not familiar with Yankee Hill Machines specifically, but there are lot’s of good manufacturers making good equipment (and also some junkers). Do a good bit of googling online for reviews, or Youtube reviews by known firearms reviewers as they can put it through it’s paces better than most of us ever will.
I’d also add… are you sure you want a quad rail? They are typically noticeably heavier than MLOK (or KeyMod) and MLOK can give you similar number of mounting points.
I just got back from the Elite Shooting Range in Manassas tonight. Took my son out for his birthday so he could shoot his M4E1 and FNS-9. I shot my M4E1 using 55 gr at 100 yds. 20 rounds. All my 62 gr was SS109 so bought 55 gr range ammo. Group was not great but I had to shoot it in under a minute. My son used up the hour and I squeezed in a magazine after asking to run over-time. The range officer was cool.
Last year with 68 gr reloads at 100 yds:
One of these days we’re going to bump into each other… I was at Elite last week!
Their 100yrd range is great
@Harvey We need to link up, brother! Love the range. It is a bit of a drive but well worth it. I live next door to the Fredericksburg Rod & Gun Club but don’t have a membership anymore. Get to go with my neighbor on occasion…
Thank you for the feedback and the suggestions. I will be sure to check those brands out. I was wanting quad rail for the mounting. If MLOK provides right around the same amount of mounting points, I might go with that. I like the look of MLOK anyways.
Quad rail was the original (?) free floating rail system. It has four picatinny rails running along the length. It gives the advantage of virtually unlimited mounting positions since the grooves of the picatinny rails are like 1/2" (or so) apart and the rails are at 12, 3, 6, 9 oclock. The mounting system is extremely secure and has been thoroughly tested in military use for decades.
KeyMod and MLOK came along later and are noticeably lighter. Note that they will all have a picatinny rail all along the top (12 oclock) so the KeyMod/MLOK rails are at 3, 6, 9 oclock. There are slightly less mounting options because they are spaced farther apart, but unless you are planning to have a ton of things mounted on your rails it is more than plenty. I actually cant think of anything you wouldnt have room for using KeyMod/MLOK. BackUp Iron Sights (BUIS), scope/red dot, offset sights, light, laser, activation switches, foregrip, bipod mount… all that will fit on KeyMod/MLOK.
KeyMod fell out of favor a bit as testing by USSOCOM found that KeyMod would break loose more often than MLOK in repeated drop tests. My 16" is running KeyMod and I’ve been more than happy with it, and I havent had anything ever loosen but I am far from a high round count shooter and I’m not running around chasing insurgents so YMMV.
Not all rail manufacturers offer the choice of KeyMod or MLOK. Some will offer only one or the other so if you want a specific manufacturer you may be limited to whichever mounting tech they’ve gone with. If you have the choice, and cost/availability is the same… MLOK > KeyMod > Quad.
I’m wondering if there is enough of us in/near NoVA to do a meetup at Elite… 
@Harvey I’m game. Good analysis on the handguard. We called the quad rail a cheese grater. As you can see in the photos I have an M4E1 upper from AeroPrecision (AP) with Keymod attachment points. Didn’t know why keymod lost popularity but I don’t run multiple attachments and drop test my gear. I’m convinced AP has designed one of the best uppers because of this:
Now I understand why the military is concerned about mounting points:
The PEQ-16B ($2,000.00) alone costs more than my M5 with Vortex Viper PST. Add a AN/PVS-15 Gen 4 ($8,249.00) to work with the PEQ and you can own my entire firearms collection, reloading gear and spare set of wheels and tires for my Wrangler (all 5).
Call me old fashioned, but I am still rocking a quad rail on my carbine. I dont mind the weight and enjoy the versatility. I did get the Magpul ladder rail covers for the unused rails. I suppose I grew used to them on my issued M4 back in the day.
Yeah, I dont mean to imply Quads are obsolete & useless. If you need 100% rock solid lockup, or you need (almost) infinitely adjustable mounting positions, or you love the look (pretty much every M4 ever shown on a movie screen sports quad rails), and you dont mind the weight (and we’re talking ounces heavier, not pounds) then Quads are 
For me and my usage, the weight savings alone is reason for me to look at KeyMod/MLOK.
At the end of the day, the answer is… “it depends” 
