SLR Sentry7 adjustable gasblock

I’ve been looking for a while for an adjustable AR15 gas block that has adjustment with “clicks” to measure the setting and also keep the adjustment without any thread-lock.

So far I have found two manufacturers with such products, SLR Rifleworks and Syrac Ordnance.

Now I finally got my hands on one, the SLR Sentry 7 Clamp On model.

picture taken with a potato

The actual model is SLR Rifleworks Adjustable Sentry 7 Stainless Steel .750″ Gas Block with Melonite QPQ Finish (SA7-SS-CN).

The package included the gas block with gas tube pin, adjustment hex-tool, manual and an SLR Rifleworks sticker. The hex-tool is nice to have and I was really impressed about the small size, low weight (manufacturer states 1.3oz / 36.9g, but I haven’t got a proper scale to verify) and the high level on finishing of the gas block itself.

Contents of the Sentry7 package

The “manual” contained simple but enough instructions for installation, usage/adjustment and maintenance.

SLR Sentry7 manual’

Manual states about 15 useable positions with 0/1 being fully closed. I measured 16 clicks from 0 to fully open, as depicted below by the pictures.

The adjustment has three clicks / revolution and this is enforced with a leaf spring, a plunger (as stated in the manual, I didn’t find small enough hex-tool to take the block apart) and the adjustment screw has three grooves machined on its sides, 1/3rev apart.

As you can see from the pictures below, the actual gas adjustment part of the adjustment screw, is a clean cylinder with no thread to get dirty and stuck.

gas adjustment fully closed


gas adjustment 5 clicks open


gas adjustment 10 clicks open


gas adjustment 15 click open


gas adjustment 16 clicks open

The gas block is supposed to be a part of my IPSC Open Division rifle build and as it is currently the only part in the build, I currently have no actual hand-on tests, only pictures about the block itself.

**** UPDATE on 2015-07-01 ****

Apparently it is recommended to close the gas adjustment during cleaning. I did some shooting-in for my new barrel, which required a lot of cleaning solvents. After shoot-in + around 1000 rounds I noticed that the *clicks* were barely noticeable on the adjustment and I took the block apart.

SLR Gasblock small parts, fouled adjustment screw on the left and cleaned on the right
SLR Gasblock small parts, fouled adjustment screw on the left and cleaned on the right

As you can see, there was a lot of fouling in the adjustment rifts. After cleaning, the *clicks* were again well noticeable.

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