What would be "behaving normally" compared to how it's acting now?
I was under the impression that the ejection pattern I described is that of a rifle in good working order given proper spec'd springs, headspace, etc.
What am I missing?
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Less recoil, less pressure, less heat, less debry in the chamber, etc.
Ejection patterns are really nothing to pay attention to when trying to identify if your gun is over gassed or not. Measuring the GP size does that.
As far as buffer springs go, we measure those as well. ;)
C4
So far none of these seem to be an issue. As in I havn't noticed an increase in recoil, never measured it's heat so I have no idea, and the fouling has been consistent thus far.
With any machine, observing "behavioral patterns" is usually how we figure out if a machine is going "out of spec". Given all things being equal (bufer spring is within spec, ejector spring is within spec, extractor is in good condition with proper spring, insert and Crane O ring, gas tube is within spec, Carrier key is fully tightened and staked, the gun headspaces properly, etc.) the gun *should* work within a standard.Quote:
Ejection patterns are really nothing to pay attention to when trying to identify if your gun is over gassed or not. Measuring the GP size does that.
To date, the best indicator of this standard is ejection pattern, given all known parts being within spec.
Are you saying this is not the case?
I have always used machinery until its behavior patterns change, then based on those changes, the machine is maintinenced and returned to as close to original operating specs as possible and then put back into use.
To date, this gun has not exhibited any of the issues that comes with an over gassed gun. No excessive BCG speed, fouling is "normal", the buffer is not showing excessive wear on the nylon buffer insert. Recoil spring is within tolerance(replaced less then 2K rounds ago actually).
Once again, what am I missing?
As do I. Been doing it for well over a decade. Been building AR's since 1996 in some form or another. This is nothing new to me. This thread was an observational thread about the FZ BCG, not a trouble shooting thread for my gun. Just because it had a few unexplainable issues that weren't really "big deal" issues to begin with doesn't mean i'm worried about the gun, expecially considering what I had put it through before it started acting like that and the fact that it continues to work properly once cleaned..... ;)Quote:
As far as buffer springs go, we measure those as well. ;)
C4
That being said, I would really like to understand exactly how this "over gassed" stuff works. In my experience, gas port erosion starts on the portion of the gas port on the inside of the barrel, and as it grows it starts working its way through the barrel wall towards the gas block.
This being the case, the important dimension here is the size of the gas port on the outside diameter of the barrel where it opens into the gas block. While gas port erosion on the inside diameter of the barrel is primarily where the most damage is done, so long as the exit of the port on the OD of the barrel remains within spec, the amount of gas getting into the system will remain consistent.
I'm getting really tempted to punch off my FSB just to measure now because of all of this.
How would you know what is standard and what isn't?? How many mil-spec AR's have you owned?
Since you live in WA, your knowledge about suppressors and how they affect AR's is going to be pretty limited.
You can only notice differences IF you have a good frame of reference.
There are SO MANY things that can change the ejection pattern that it really is a waste of time to use this as an identifier of ANYTHING.Quote:
With any machine, observing "behavioral patterns" is usually how we figure out if a machine is going "out of spec". Given all things being equal (bufer spring is within spec, ejector spring is within spec, extractor is in good condition with proper spring, insert and Crane O ring, gas tube is within spec, Carrier key is fully tightened and staked, the gun headspaces properly, etc.) the gun *should* work within a standard.
To date, the best indicator of this standard is ejection pattern, given all known parts being within spec.
Some of the things that will affect this is:
1. Ammo selection.
2. Extractor tension (both the extractor insert and extractor spring).
3. Extractor wear.
4. Buffer weight.
5. Buffer spring tension and length.
Just so you know, NOTHING about your BM is "within spec." BM doesn't follow a set standard. So back again to establishing a known standard.
From day one, your "machine" AKA BM AR, has been assembled incorrectly. So if it it all the sudden became "in spec" the difference in it would make you think something is wrong.Quote:
I have always used machinery until its behavior patterns change, then based on those changes, the machine is maintinenced and returned to as close to original operating specs as possible and then put back into use.
Really? Are you sure? To start, the amount of carbon build up you have is much greater than if you owned a Colt. The amount of heat and pressure exerted onto the bolt are much higher. So your definitions of "normal" are not the correct version of normal.Quote:
To date, this gun has not exhibited any of the issues that comes with an over gassed gun. No excessive BCG speed, fouling is "normal", the buffer is not showing excessive wear on the nylon buffer insert. Recoil spring is within tolerance(replaced less then 2K rounds ago actually).
You BCG failed to lock back on the last round. That generally means that it is going to fast.
Have any the AR's you have had experience with (for over a decade) been mil-spec? Suppressed?Quote:
As do I. Been doing it for well over a decade. Been building AR's since 1996 in some form or another. This is nothing new to me. This thread was an observational thread about the FZ BCG, not a trouble shooting thread for my gun. Just because it had a few unexplainable issues that weren't really "big deal" issues to begin with doesn't mean i'm worried about the gun, expecially considering what I had put it through before it started acting like that and the fact that it continues to work properly once cleaned..... ;)
Having ANY issues with a gun IS an issue, especially if you are going to bet your life on it. So I would be concerned and would be getting to the bottom of these problems REAL QUICK. This is why myself and some of the others have gone to great lengths to explain that your gun is WAY over gassed and then you added a suppressor for good measure (just in case you did not have enough gas in the system).
I can get a lot of crappy AR's to "work." They are far from ideal though and would not use them for anything other than shooting dirt.
No GP erosion even needs to take place on your gun. You see, BM made sure that your gun had an out of spec GP size from DAY ONE!Quote:
That being said, I would really like to understand exactly how this "over gassed" stuff works. In my experience, gas port erosion starts on the portion of the gas port on the inside of the barrel, and as it grows it starts working its way through the barrel wall towards the gas block.
It is also true that larger than spec GP sizes open up faster than in spec GP's so in as short as a few thousand rounds, your GP has already started to erode (FYI).
One last comment about using a BM barrel for suppressed use. Besides the simple fact that this is a horrible idea, the MAJOR issue is that the threads on BM barrels tend to NOT BE concentric to the bore line. This means that the chances of you having a baffle strike is MUCH greater than if you were using say a Colt, BCM, DD, Noveske, etc. The majority of all baffle strikes I have witness or read about were on BM barrels.
C4
Colt and LMT.
WA only limited the use, not ownership. Been in the supressor game for three years now. Both rifle and pistol.Quote:
Since you live in WA, your knowledge about suppressors and how they affect AR's is going to be pretty limited.
You're assuming I don't. Remember that whole "ass-u-me" thing.Quote:
You can only notice differences IF you have a good frame of reference.
Which is why we have base standards. I.E. Mil spec M193 Nato ammunition which is the benchmark. Some also use M855, I do not.Quote:
There are SO MANY things that can change the ejection pattern that it really is a waste of time to use this as an identifier of ANYTHING.
Some of the things that will affect this is:
1. Ammo selection.
Already covered this. Regular PMCS on the rifle and replacement with milspec parts as necessary.Quote:
2. Extractor tension (both the extractor insert and extractor spring).
SameQuote:
3. Extractor wear.
Same.Quote:
4. Buffer weight.
Same.Quote:
5. Buffer spring tension and length.
It's not a Bushmaster gun. Only the barrel.Quote:
Just so you know, NOTHING about your BM is "within spec." BM doesn't follow a set standard. So back again to establishing a known standard.
But that's neither really here nor there. There is an easy known standard. That standard is a mil-spec gun shooting mil-spec ammunition. Of which I've owned a few and shot that mil spec ammunition through them.
Ths gun behaves exactly the same. Hence, I have a benchmark performance set, and this gun matches it.
Quote:
From day one, your "machine" AKA BM AR, has been assembled incorrectly. So if it it all the sudden became "in spec" the difference in it would make you think something is wrong.
Oh really? Did you actually bother to read what I wrote or are you simply assuming that my low post count means I am a noob with zero experience or that I didn't bother to follow the Mil-spec for assembling a rifle? I mean, it's not like that information is difficult to find out there in the great intarwebs.
Through several personally owned colts, and at least 15 other personally owned rifles of various flavors, not to mention the countless other rifles I have built or troubleshooted and repaired for others, I *think* I have a pretty good idea of what is "normal".Quote:
Really? Are you sure? To start, the amount of carbon build up you have is much greater than if you owned a Colt. The amount of heat and pressure exerted onto the bolt are much higher. So your definitions of "normal" are not the correct version of normal.
There are other possibilities as well. Dirty magazines, excessivly fouled gun, weak ammunition, or a combination of all of the above.Quote:
You BCG failed to lock back on the last round. That generally means that it is going to fast.
Given that the issues occoured near the end of the shooting session when the gun was at its dirtiest, rather then when it was freshly cleaned and lubed, I am very reluctant to say that was the issue. While I would most definitly consider excessive bolt speed as a culprit, there are too many other possible variables for me to choose that as the answer with any certianty.
Grant, Let me start by saying that I do respect your knowledge, your work put into this website, and the fact that you're trying to "help".Quote:
Have any the AR's you have had experience with (for over a decade) been mil-spec? Suppressed?
Having ANY issues with a gun IS an issue, especially if you are going to bet your life on it. So I would be concerned and would be getting to the bottom of these problems REAL QUICK. This is why myself and some of the others have gone to great lengths to explain that your gun is WAY over gassed and then you added a suppressor for good measure (just in case you did not have enough gas in the system).
At the same time, I would love to know how it's possible to diagnose a rifle from across the country without looking at the actual rifle. You've already shown that you understand that there are a LOT of different variables that can affect the behavior of a rifle, but you automatically jump to the assumption that because it's a bushmaster barrel and a supressor, that the issue is gross over gassing of the gun.
Not to be a dick, but that'd be like asking a doctor halfway across the country to diagnose a medical problem without having actually looked at the patient.
I have owned a rifle that was grossly overgassed. It was so bad that the ejecting brass was deflecting off of the brass deflector, bouncing forward and impacting the aluminum free-float handguard. It also exhibited the same behavior of excessive bolt speed and failed to lock back on the last round as you describe. THAT'S way over gassed. A Fulton ARmory adjustable gas tube fixed that issue.
Call it what you will. I'd happily stand this "crappy" gun up against a milspec gun any day of the week. I have not ever had to tweak it to get it to work, i've never had to do anything except regular PMCS and it performs under any condition that i've placed it in.Quote:
I can get a lot of crappy AR's to "work." They are far from ideal though and would not use them for anything other than shooting dirt.
If this makes it a "crappy" rifle in your eyes, so be it.
Yet it still acts just like any milspec gun i've ever owned. Interesting.Quote:
No GP erosion even needs to take place on your gun. You see, BM made sure that your gun had an out of spec GP size from DAY ONE!
No argument there. That stands to reason.Quote:
It is also true that larger than spec GP sizes open up faster than in spec GP's so in as short as a few thousand rounds, your GP has already started to erode (FYI).
Quote:
One last comment about using a BM barrel for suppressed use. Besides the simple fact that this is a horrible idea, the MAJOR issue is that the threads on BM barrels tend to NOT BE concentric to the bore line. This means that the chances of you having a baffle strike is MUCH greater than if you were using say a Colt, BCM, DD, Noveske, etc. The majority of all baffle strikes I have witness or read about were on BM barrels.C4
Assumption time again. And completely irrelevant to the topic at hand. Not only that but I had the shoulder trued prior to bi-lock install and verified boreline to supressor after install.
As it were, the baffle strikes that were caused on this supressor by it's previous owner who works for a supressor manufacturer (1 stike), by me on an over heated LMT Mk18 pistol clone (two strikes). All strikes are minor although noticable, but do not affect performance to the naked ear. I have yet to test with equipment.
For what it's worth, I mean to be argumentative. There is much to be learned, and i'd hate to miss something possibly important because I just settled for an answer that is just one of many possibilities when there are other possibilites avalible.
Grumpy,
I not going to tit for tat respond to all of your points. However, I will say this. Those of us who have had experience with Bushmaster carbines can usually diagnose things about them even if we were on Venus.
The simple fact is that their strong point is the consistency in which they fail to do things. I have used a Hawkeye borescoper and scoped out a few BM barrels in my time. They were siginificantly larger than others I had seen.
It is a well known fact that BM gas ports are considerably larger than Colt, DD, LMT, Noveske and BCM.
So for example- when Grant states that it most likely is the gas port this assumption is based upon well know repeated variables and experience with their products and a particular set up.
Your "strawman" argument about running your set up against a "milspec" AR any day of the week is just that. An out of the box Colt 6920 will also run against yours without modification. So would a Daniel Defense and probably an LMT as well.
To be honest I am surprised that you are have fallen into the "I'm defending my choice of a crappy AR" camp.
Well stated.
To add, why anyone in their right mind would use a BM barrel (especially suppressed) is retarded. Especially given the fact that you SAY you have owned an LMT and Colt. If you did in fact own those two guns, why in the world would you not use them??????????????????
Just Sayin...
C4
So now i'm a retard for having a gun that works?
Like the old saying goes, even a blind squirrel finds an acorn every now and then. Would I expect this performance out of any BM barrel I came across? Absolutly not! I do believe that I just got lucky and i'm going to run with it until it stops working.
Divorce and child support are a bitch.Quote:
Especially given the fact that you SAY you have owned an LMT and Colt. If you did in fact own those two guns, why in the world would you not use them??????????????????
That and this rifle performed better then at least one of the Colt guns that I owned, so I decided to keep it instead.
I understand where you're coming from. I really do. I am normally very much into the "Buy a Colt from the beginning and do it right" camp under normal circumstances. Were it not for the stellar performance of *this* rifle, we wouldn't be having this conversation at all.Quote:
Just Sayin...
C4
That being said, is performance not the standard by which things are judged? This rifle performs. That's why I have it. If it didn't, I wouldn't. I have no desire for "project" guns that I have to **** with just to get them working properly. Last time I did that was with some speshul weapons/bobcat MP5 clones and I vowed never to do it again. Luckily I ended up breaking even on those when I got rid of them.
In the end, what we are really discussing are longevity issues. Since the rifle has always and is currently performing as well as any mil-spec gun, I'll keep using it. I understand that I probably have less then 5k rounds left on barrel life and i'm not worried about it. I planned on replacing it before then anyways. I've been looking at a Centurion barrel. How do you feel about those?
But this rifle is still working right now, and doing very well at it. It shoots around 3moa which while nothing to write home about, is acceptable "combat" accuracy. It goes bang every time I pull the trigger and the only issues i've ever had with it are at times when i'm well past the "use" stage and into the "abuse" stage. Yet even then it continues to actually work and once I clean it, the small issues go away and it works fine just like it's supposed to.
If we really want to get into comparisons, please feel free to do the same thing with a milspec gun and report how it performed. I'd frankly love to see the results. Not because I think it will choke up, but simply because I like having a performance benchmark. Especially since I've never done anything like what what I did this weekend with a milspec gun.
And i'm absolutly not arguing this or disagreeing with it. I understand what you are saying and understand that my gun probably has the same issue.
What I am saying is that in this particular gun, this issue has not affected performance....yet. I'm expecting it in the future, but it has yet to manifest itself.
This is where we diverge. Understanding that BMs have oversized ports to begin with and that this rifle has 8 to 10K rounds down the pipe, I can easily see the logic behind what you're saying.Quote:
It is a well known fact that BM gas ports are considerably larger than Colt, DD, LMT, Noveske and BCM.
So for example- when Grant states that it most likely is the gas port this assumption is based upon well know repeated variables and experience with their products and a particular set up.
But that doesn't explain why it doesn't have this issue when it's freshly cleaned and the bolt speed is even greater (still using the suppressor). Because of this, the "most likely" explination is cast into doubt.
It's that one factor that's sticking in my craw and making me say "I can't bring myself to definitivly say this is the issue".
To be honest, right now i'm leaning more towards the ammunition (BVAC) as the culprit simply because of the dirty performance compared to clean performance.
I don't see how saying that this gun running as well as a Milspec gun counts as a straw man argument. It's merely a statement of fact. I've run my own Colts, my own LMT, and i've run next to plenty of those guns owned by others. This gun has kept up with them all and has actually done better the a few.Quote:
Your "strawman" argument about running your set up against a "milspec" AR any day of the week is just that. An out of the box Colt 6920 will also run against yours without modification. So would a Daniel Defense and probably an LMT as well.
Havn't "had" to modify this gun either. It ran fine before the FZ BCG too. Matter of fact, I had the original BCG in my gear this weekend in case the FZ ****ed up. I want my gun to run like it did before and was ready to replace it with my original parts if the FZ BCG did fail.
No, i'm not defending crappy guns as a whole especially bushmaster, i'm defending *this* crappy gun because it continues to perform, even when I do stupid shit like not clean it for 1100 rounds and shoot over half those rounds with a suppressor attached.Quote:
To be honest I am surprised that you are have fallen into the "I'm defending my choice of a crappy AR" camp.
I agree, and to be honest this is a defense of my crappy rifle thread, so much so the original topic is no longer in play. Only thing left is people stating why his rifle is having problems and him defending every explanation that gets stated. This same thing happend in another thread that turned into grumpy defending crappy rifles again. IMHO I think we've all heard enough of why this particular rifle is having problems but there's no way it could be the shitty barrel.
This thread can be closed at any point.