I'm putting together an SPR'ish AR15. It will have an 18" barrel with a mid length gas system. I will probably shoot suppressed (AAC M4/SPR) about half the time. Will I be good with a plain gas block, or should I look at getting an adjustable?
Will I need an adjustable gas block?
- Thread starter Cerebus
- Start date
Re: Will I need an adjustable gas block?
You will be good without it but better with it. The adjustable blocks will run on the suppressed setting and on the full open setting while suppressed. The SPR/M4 is supposed to enherently have less blowback but I can't tell the difference from the M42K while shooting or at least haven't ever thought about it...
You may actually find yourself using the off setting with an 18".
1 more thing to consider - if it's the Switchblock for the 18" that you are looking at, keep in mind that it is setup for an odd length gas tube. It will confine you to very specific front end stuff.
You will be good without it but better with it. The adjustable blocks will run on the suppressed setting and on the full open setting while suppressed. The SPR/M4 is supposed to enherently have less blowback but I can't tell the difference from the M42K while shooting or at least haven't ever thought about it...
You may actually find yourself using the off setting with an 18".
1 more thing to consider - if it's the Switchblock for the 18" that you are looking at, keep in mind that it is setup for an odd length gas tube. It will confine you to very specific front end stuff.
Re: Will I need an adjustable gas block?
I'm looking at the JP Enterprises adjustable block. I am however very open if there is something cheaper and at least just as good out there. It's about $75, so a little salty.
I'm looking at the JP Enterprises adjustable block. I am however very open if there is something cheaper and at least just as good out there. It's about $75, so a little salty.
Re: Will I need an adjustable gas block?
I noticed that SI Defense had one at the SHOT Show.
It looked similar to JPs.
I dont remember the price. Good luck.
Mike.
I noticed that SI Defense had one at the SHOT Show.
It looked similar to JPs.
I dont remember the price. Good luck.
Mike.
Re: Will I need an adjustable gas block?
I have a JP adjustable gas block on a mid length 18" bbl and IMO its way better than a switchblock. With the JP (and others as well I assume) the gas is controlled by a set screw so you can fine tune it to whatever you are running on the muzzle. I shot a switchblock equipped rifle and it would have been nice to have that extra adjustability while running a very short supressor. In that particular rifle anyway it was either over or under gassed.
I have a JP adjustable gas block on a mid length 18" bbl and IMO its way better than a switchblock. With the JP (and others as well I assume) the gas is controlled by a set screw so you can fine tune it to whatever you are running on the muzzle. I shot a switchblock equipped rifle and it would have been nice to have that extra adjustability while running a very short supressor. In that particular rifle anyway it was either over or under gassed.
