new build - SLR sentry 7 adj GB issue

[tb-av]

Went out to shoot a new build today.

11.5" mid Faxon
Sentry 7 SLR Adj. gas block.

Loaded 1 round fired everything felt and sounded good. Even with a non-zeroed RDS it was on 2" off POA. Things are looking good.

Then I realized oh wait, it didn't eject. It then hits me that I have the AGB and just need to dial in a little more gas. I forgot my wrench. No prob says my friend he goes up to the house and gets some allen wrenches. My other friend ends with the wrenches and I said just turn it until you feel maybe two clicks and I can't remember which way to turn it but you feel it click. He figures it's probably CCW. So he turns it and says, I don't feel any clicking. So I try it and I don't feel any clicks now either. We turned it both ways and at one point for one round got a round to eject which was really just a tumble out. Best thing we really every got was the bolt going about half way back.

I distinctly remember when I installed it, it clicked. I mean the directions were very clear and I set it about where they said to put it. I absolutely remember the clicks. It absolutely will not click now. The screw just turns out.

It's under a BCM KMR-A and aside from the adjustment screw, all others are blocked except one of the mounting set screws. I --might-- with a really thin screw driver and some tweezers be able to get that leaf spring loose but that doesn't look easy by any means.

So two questions.
1. Has anyone seen this happen and what the situation is going to be with the SLR S7?
--- the only thing I can see on the GB is that the leaf spring is sitting proud of the side surface of the GB at the front ( opposite end of it's retaining screw ). I honestly can't recall if it was always that way or not. I don't know if this is some freak accident or what. Just basic 55G range ammo. I think it was PMC

2. To get that KMR off, I'm supposed to give it the heat gun treatment and try to patiently tap/pull it off?

[jerrysimons]

Tighten it until you feel the detent clicks. You might have to put more pressure downward on the screw while tightening than you would expect if you have loosened it so much the detent came off the threads entirely. But I am betting that if you shot the gun and the adjustment screw is still in the gas-block that you backed the adjustment screw too far off and are in the inbetween portion of the threads on the adjustment screw where the detent nib is out of the detent channels but the adjustment screw is still engaged with the threads in the gas-block. Tighten it all the way. You should also see the detent move up and down between clicks.

[tb-av]

I can tighten it down until it's bottomed out just like a normal screw. I can screw it out until it would normally fall out but the crush washer for the flash hider is in the way. So basically it is totally loose to totally tight.. no clicks.

I can easily see the channels in the screw. Also the front edge of that spring is sitting out a good 1/8".

I tried to back the screw out and then push in on it while trying to screw back in.... still nothing.

[jerrysimons]

Ok. So something is wrong with the detent. It sounds like the detent is stuck up which is surprising. You don't see it move up and down? Is there a gap at any part of it with the gas block?

Best way to get a KMR off is to, like you seem to have in mind, heat it up with the heat gun at the barrel nut and the tap it off with a rubber hobby hammer using the edge of an attachment alternating on opposing sides of the rail to get it off straight. Reheat as necessary careful not to rock the rail on the barrel nut too much and gouge it.

[SOTAR]

I can tighten it down until it's bottomed out just like a normal screw. I can screw it out until it would normally fall out but the crush washer for the flash hider is in the way. So basically it is totally loose to totally tight.. no clicks.

I can easily see the channels in the screw. Also the front edge of that spring is sitting out a good 1/8".

I tried to back the screw out and then push in on it while trying to screw back in.... still nothing.

It is possible that if he turned the adjuster too far towards the muzzle that it unseated the detent. When this happens you will lose the clicks.

To fix this you have to remove the leaf spring screw and the leaf spring to re-seat the detent. Make sure the adjuster screw is installed fully when you do this.

You need to be VERY careful with with leaf spring screw, some have loctite holding them and you can strip the screw head. Dont use a torch as you can heat the leaf spring and ruin the leaf spring. A soldering iron tip on the screw head can transfer adequate heat to the screw to allow it to come loose.

Reinstall the leaf spring and you should have clicks again.

SLR has superb customer service and will help you if you have problems.

[jerrysimons]

You can completely remove the adjustment screw and replace it in the SLR design without removing the leaf spring, you just have to push hard enough on the adjustment screw, while tightening it, to overcome the hump of the detent over the threads, the detentnit self should then drop down into the channels in the screw once it is tightened enough. If the op can tighten and loosen the adhustment screw all the way in both directions without feeling the detent channels click then the spring is not providing tension against the screw properly.

[tb-av]

Ok. So something is wrong with the detent. It sounds like the detent is stuck up which is surprising. You don't see it move up and down? Is there a gap at any part of it with the gas block?

I don't see anything moving and no gaps. Again, when I first did this, it had clicks. As to him adjusting it. I was holding the upper and he/we only moved it small bit. He said I don;t feel a click. Then I tried it and said that's odd, I don't feel a click either. But we didn't turn it far. Plus we figured if we go ccw first and nothing happens, the next would be cw. So we basically went 1/4 turn ccw the back 1/2 turn cw.

Is the end of the spring supposed to sitting up off the face of the block? I mean it's not subtle and I don't recall that. I thought it was basically flush with the block.

@clandestine ... will do on all that. I'll heat the screw a bit just to be on safe side and make sure I have the right sized bit for it.


ETA: I'm using a 6/64 ball end driver and that's just about how far the spring sits out from the side face of the GB.. maybe 5/64ths

[jerrysimons]

The leaf spring has a nub that sits inside one of the channels on the adjustment screw and the bottom edge should be sealed against the body of the gas block, that is no gaps between the bottom side and the gas block. The top edge of the spring does not sit flush. You should be able to watch the leaf spring hop up over the threads and settle down into the next channel or adjustment setting. If you are not getting the "click" or feeling the detent hop and drop into the next setting something must have jammed it open/up, possibly.

Btw if the adjustment screw is still threaded into the gas block and was mostly open, the rifle should still functiion (keep in mind 11.5" mid is an unconventional configuration too). But since we are talking a potential obstruction in the leaf spring (could be deformation though) it would also make since that the rifle was not cycling if the gas block was also obstructed.

[opngrnd]

This is probably completely unhelpful, but anytime I adjust mine after firing it, I don't feel clicks at first. It's almost like the soot needs to be worn off of the screw. So I turn mine all the way in and then open it up to where I want it. By thr time I'm opening it back up again i can feel the clicks. I haven't adjusted it more than a few times, so it's a pretty small pool.of experience I'm drawing from. Again, just one guy's experience.

[jerrysimons]

I just realized you said you were shooting 55gr pmc, bronze? Suppressed? If unsuppressed I wouldn't be surprised if the gun would fail to cycle with that gas/barrel configuration and the ammo with the GB fully open.

Even stil you should feel some resistance between adjustment settings when turning the screw.