I am getting ready to start the plunge to build my first SBR AR15. I have basically every other part planned out, just trying to figure out the upper. I am either gonna do 10.5", 11.5" or 12". Maybe a suppressor in the future, no plans for one now, but I want the upper to be ready for one. I am not a LEO so this gun will be relegated to range time, class’s, and home defense. Probably will run ~5k rounds a year through the gun.
I see lots of guys running regular DI 10.5" and 11.5" guns with H2 buffers and no issues. I also see other guys running the same setups that say they have issues.
Noveske’s switchblock looks to be an intermediate step between regular DI and a piston system, but is it worth the cost and does it really help fix some of the issues inherent to the SBR design? I know it is really designed for suppressor use, but it does have the side benefits of helping control the gas which can get out of control in SBR’s.
Piston uppers seem to be the way to go on an SBR for all of the reasons mentioned above, but the cost seems to be way up there, almost double what a regular DI upper costs.
For my uses is a piston overkill when the switchblock would work? Is the switchblock overkill when a regular DI gun would work?
The uppers I am looking at are Noveske 10.5" N4 Light Shorty(regular and switchblock), BCM 11.5", LMT CQB MRP 10.5 & 12", and I think I have looked at a few more(my mind is drawing a blank). Any other suggestions on uppers while were at it, I am all ears.
I have an 11.5" that I assembled with all the stuff coming from Bravo Company. I fire it suppressed and un-suppressed and I have had zero issues. I am running an H2 buffer and full auto BCG.
I also have a carbine that I assembled using a 16" barrel w/ Switchblock, but I have yet to shoot it. If you assemble the gun with the correct parts and know the variables then you will be good to go.
Thanks,
I guess I am just trying to decide if its worth it to spend the extra 300-500 on either a switchblock or piston upper when a DI upper will suit me just fine. I think a DI upper would be fine, but I dont want to buy one and then go “damn I shoulda bought a piston”.
I’ve got a Noveske Switchblock 12.5 upper and ran it with an AAC SPR/M4. It ran great, got some gas blow back. I haven’t compared it to regular DI or Piston upper but I plan on it…I don’t think you can go wrong either way. I really like my LWRC after running a mag through it on full auto the bolt remains cool to the touch.
If you get a good DI you shouldn’t have problems. I am sure that the Switchblock works as advertised, I just don’t have any real experience with it. As for a psiton gun. I have a piston upper and it works 99% of the time, suppressed and un-suppressed. But, if I had to grab something and go and would be my DI gun.
I can’t speak for the piston uppers, but if you aren’t going to run a suppressor there’s no reason to get a switchblock. I haven’t fired mine sans can with the switch set to the suppressed setting, but I’d be concerned about not having enough gas to function the action correctly.
If you’re going to suppress it, I’d definitely consider a switchblock upper. The extra cost is part of the Noveske quality you’d be getting, not just the block itself. If I were going suppressed, I wouldn’t go piston as I hear they’re louder due to excess gas bleed off in the system.
With an unsuppressed SBR, I’d either go piston or H2/H3, FA BCG and good springs. Either way you should be fine.
Yea I am leaning towards either the 10.5 Noveske DI, non switchblock or a 11.5" BCM with the CHF barrel and some type of rail, most likely Daniel Defense. Or I may try to get Grant to build me an upper with a Daniel Defense 10.3" and some type of DD rail as well. I think a DI upper with a H2 buffer and FA carrier will work just fine for what I am wanting to do.
If you aren’t running a can a switch block does nothing for you. You will need to run it wide open - regular DI, in order for it to function with the widest variety of ammo. If you have a can, you move it to the middle setting in order to reduce the amount of gas flowing through the system. Here it shines. It is a soft shooter and even with a standard CH that does not have any silicone I do not notice any gas in the face. The third setting shuts the gas off. For a suppressed 5.56 gun it is still loud so - this is something that is really never going to be used. Running a can and the middle setting keeps the chamber a little cleaner just b/c less crap is flowing back into it. Here is where the comparison to a piston comes into play.
I have a 14.5" Noveske Switchblock and an 11.5" Colt 6933. Based on the setups you’re leaning towards, I’d go for the 11.5" BCM based on quality vs. cost ratio (Unless Grant can do the DD for around what the BCM is). I don’t think you’d be unhappy at all.
If you are considering a piston type sbr, the sig p556 is a very good way to start…there arent as many after market parts, but it is an easy way to get to where you want to get to…makes it easy to have a folder also…no buffer tube…
IMHO I would say if your going to do a 10.5" at all make it a Gas Piston Gun. If its a DI setup I would say stick to 11.5" and higher. Its amazing what 1" can do for reliability. I’m not saying 10.5" uppers arent or can’t be built for reliability but its seems they tend to have more issues. I think a 10.5" Gas Piston would be best. Thats what Im building now to be run suppresed all the time. I figure its 10.5", its Gas Piston so not as many issues running SBR unsuppressed and when u do get a suppressor just turn it over to run suppressed and your GTG.