new build - SLR sentry 7 adj GB issue

[Fatorangecat]

SLR has awesome customer service. I lost the detent at one point and called them to request an extra. SLR sent me an extra detent along with an extra spring and replacement screws and didn't even charge shipping. If you end up having to contact them I have no doubt they will take care of you.

[jerrysimons]

SLR has awesome customer service. I lost the detent at one point and called them to request an extra. SLR sent me an extra detent along with an extra spring and replacement screws and didn't even charge shipping. If you end up having to contact them I have no doubt they will take care of you.

This. OP, get new parts for free, no reason not too.

SLR adjustable gas block for bomb proof go-to-war gun? I am tending toward gas-port inserts if not barrel porting. But for defense in Urban CONUS/ LEO patrol capacity. SLR adjustable seems just fine.

[tom12.7]

I'm not gonna speak for the other guys but that's not what I'm saying here.
You're advocating a buffer swap to compensate for an overgassed situation for when a can is added. I disagree with that completely. It's when a can is added to a properly gassed barrel that I prefer an AGB to throttle the gas vs compensating with a buffer swap.
I don't think anyone here prefers an overgassed barrel as the baseline. Mark has especially made that clear many times.
No offense but it seems you're so inside your head with this gas port/reciprocating mass/buffer stuff that you can't see the forest through the trees.

Maybe it would be better to ask your opinion as to what over gassing actually is, perhaps my view is flawed?
A span of function for use has many timing events that we could look into. Some of these can induce additional stresses and strains, some of these can induce reliability issues. If we take the total span in range of function, then look into a cap on stresses/strains and a limit on timing for some events, we can end up in a narrower range than what we consider for function for a a more desired combination.
There is a given that is known, that porting for the carbine H2 action and the base rifle action systems can be an overall standard to compare these. Not saying that all carbine actions require an H2 for proper function, or a rifle like action, they just happen to be in a place that can suit the span width well within the confines of reduced stresses and more optimal timing for reliability.
So is the carbine action H1 and H3 bad when looking at this? No, they aren't necessarily that way, both have an operational overlap that is just offset compared to the H2. Either could be looked at deeper, much of this operation does overlap, their prefered operation may be a little lower in span, but nothing dramatic for most unless you end up in either extreme of the margin, that's not the best place to be in.
In looking at rifle actions, or the rifle like actions, you can end up with finer increments for a buffer mass alternative and a better span when looking at the timing events. Basically, a base with a carbine action with a H2 is a more course adjustment to a H1 or H3 than a A5H2 to a A5H1 or A5H3.
I would tend to prefer a porting that aligns with the carbine H2 or more so with the A5H2. While this may seem unpopular here for some, remember that I'm looking at the span of function and further limiting that to a reduced range that maintains reliability and durability.
Components consume and wear with use, throats, ports, tubes, keys, etc.. Sometimes wear can be a compliment, sometimes to a detriment, depending on specific situations that we can look at further.
For a base 5.56 AR, I would tend to prefer a fixed proper gas port for that application than an adjustable one for non suppressed use only with the A5H2. I'm not sure what gains that most would get by using a larger barrel's base port with an added adjustable gas block. I can really only see negatives, mostly with the erosive gasses.
For a base 5.56 AR, I would tend to prefer a fixed proper gas port for that application than an adjustable one for suppressed only with the A5H2. Still not sure what you would gain with erosion at a higher level than a dedicated port.
For a base 5.56 AR, I may find something that could be suppressed for only half the time. As I may have decided that the can needs to be there or not for whatever reasons. Either application does not need a dedicated gas adjustment on top of an oversized port. There are circumstances that could be had with a single sized port, this size may overlap either for function for either usage. For that scenario, a dedicated port can be used with a reduced overall span of function for both combined, but not ideal for either. A pair of buffer masses may be required to widen the span of desired use for either pretty well. Larger increments are not really needed for most, but when one step up or down maybe needed, it's not much overall.
There are ways to suit a combination's action mass with confidence with the porting. When will the adjustable gas block get the micrometer indications for repeatability?
There's a lot more that could be brought up, from the base combinations to changes.

[tb-av]

Well gang, I'm still banging my head on the table over this one.


Here is the review and update.

11" midlength gas.
Adjustable gas block SLR Snentry
A5 lower w/ A5-3 and Sprinco GREEN

Ok, so it would not eject brass nor cycle fully.

So I took everything apart and thought I found a little issue with the spring. Flipped it over due to tight fit otherwise. Now it clicks fine.

Back to range with clicks set to 7 I think. No workie. So I swap out the bolt assembly and charging handle from the BCM 16" .. .still didn't work, but my friend says he recalls it just barely ejecting the shell but couldn't feed the next round. This was several weeks ago. At that time I think ok, give it more gas. But I forgot my wrench...... so it's still a mystery.

We go back out today. Swapped back the original bolt and charging handle. Gas set to 7. One round in mag. Bang. no cycle. I open up the gas. We can now actually feel and hear the gas block clicking no problem. Bang! Bolt is locked back and the shell is just laying in the ejection port on top of the empty magazine. Aligned to barrel.. not sticking out the side or anything of that nature.

So I close the gas off. Bang! bolt does not open. I pull the charging handle and the shell goes zinging across the table. Open the gas to 7. Bang! Bolt is closed. Pull charging handle, shell casing zings across table. Open gas to 9. Bang! Bolt is locked back, shell is laying on top of empty magazine. Close gas to 7. Bolt does not open, Open to 8 clicks. Bolt locks back and shell case is laying on top of empty magazine.

So the gas is working and it's right in the range near 7 clicks where others say they operate non suppressed.

We see no marks, dents, strangeness of any sort.

So here s what we don't know.

1. There is no O-Ring in the bolt carrier extractor. Should there be?
2. Could the A5-3 + GREEN be having any impact.

We are both down to thinking it must be ejector related but why does it eject manually when the gas is cut off and I cycle it with the charging handle.

These bolts had O-Rings, and I took them out because I thought that was the standard setup.

We are now thinking ok, -maybe- the BCM group I installed would have worked if I had opened the gas.... but it doesn't have an o-ring. It's stays in the 16" BCM upper. Even the little bit of ejecting it did was more like fall out the port type ejection and not sling the case away ejection.

My friend -thinks- he sees the shell case being extracted. IOW, I fire the shot, hold the rifle and then he says.... 'nope, it's just laying on the magazine'... So IOW, I'm not elevating the muzzle after the shot and having the shell just fall back. When the shot is over, the shell is just laying there. Lined up like it's ready to feed back in the chamber.

So we feel like the whole gas amount issue is eliminated. We can alter gas to lock back the bolt which we assume should be enough to eject the case. also when I manually eject by charging handle, there is no binding or anything of that nature. It just cycles very easily and flips the case a good long way like it's doing what it's supposed to.

any ideas? We are down to .. set this bolt assembly aside. Take two more, put an o-ring in one. Try both and see what does or doesn't work. But we don't know why or what should or should not work. that's just our last point of possibility.

[MistWolf]

tb-av, you have an extractor issue. Most likely a new extractor spring will fix the issue. I had the same problem trying to tune the gas flow on an AR pistol. Try a Colt extractor spring with black insert, no O ring. I recommend the Colt spring because Colt designed it to fix the extraction issue and it works. Another reason is because I've been using Colt extractor springs and they have been trouble free. I had PSA springs and a generic spring and they all failed after a few hundred rounds. I have never tried Sprinco springs

[Hero]

Bolt locks back and shell case is laying on top of empty magazine.

I've had this happen twice before, two different rifles. Not enough extractor tension. As Mistwolf says above, both times the malfunction was remedied by replacing the extractor spring. Adding the black o-ring fixed the issues as well, but I've read from some that that's more of a band-aid than a true fix.

[tb-av]

Fantastic... this is a relief to hear. My friend had concluded it had to be extractor related but he was thinking maybe it was just a defect. I figured it had to be the o-ring. I never realized there were so many different springs and inserts. I just did a quick search and found a picture of about 7 different spring + insert pairs... and the o-ring.

So just to be clear... the "Colt" spring I want is the copper colored one?

http://www.specializedarmament.com/a...assembly-colt/

[MistWolf]

That's the one. I got mine from Brownell's

[tb-av]

Success!!!!

It ejects everything at about 4 O'Clock and sends them about 7-8 feet. Basically someone could stand there with a red Solo cup and catch every case.

I can dial the gas block from 7, I think it was, for no bolt open, to 9 with full lock back. Non-suppressed. Still waiting on a muzzle device to mount the suppressor.

The gas block is clicking very clearly. I would describe it as a steep wide lobe with well defined valley steps. So no more of that 'is it clicking?' type deal.

The spring that came out of the BCG was silver with black insert but the wire looked thinner. Looked to be just about the same length though.

Thanks again.

TB

[FaxonNathan]

Success!!!!

It ejects everything at about 4 O'Clock and sends them about 7-8 feet. Basically someone could stand there with a red Solo cup and catch every case.

I can dial the gas block from 7, I think it was, for no bolt open, to 9 with full lock back. Non-suppressed. Still waiting on a muzzle device to mount the suppressor.

The gas block is clicking very clearly. I would describe it as a steep wide lobe with well defined valley steps. So no more of that 'is it clicking?' type deal.

The spring that came out of the BCG was silver with black insert but the wire looked thinner. Looked to be just about the same length though.

Thanks again.

TB

Glad to hear you are up and running!