KAC SBR overgassed [Archive] - M4Carbine.net Forums

jaybirdritenour2

06-12-13, 20:10

My factory Knights 11.5 is comming back from Knights Armament with an H3 buffer installed from them. Not all too happy. They have all been very helpful though. I guess my rifle is way overgassed as they dont even make an H3 buffer.

Trying to look on the bright side of things. Since my rifle is getting so much gas would it work more reliable on underpowered ammo? Say SHTF situation it would cycle low powered ammo if that were all there was? Or even if there is one underpowered round made its way in a box of good ammo by accident?

Or will it all be negated by the H3 buffer?

***edit***I want everyone to know Knights has great customer service and is a great company with great products. I know the problem I am having is a rare problem. Please don't take anything differently from reading this thread.

E-man930

06-12-13, 20:21

VLTOR A5 kit w/ H4 buffer and SpringCo green rifle spring + LMT enhanced bolt carrier (gen 4 or 5) and you will be impressed.

jaybirdritenour2

06-12-13, 20:27

They say its working good now with the suppressor. But They dont make H3 buffers because their guns dont need them. But mine does? All the parts including the suppressor are Knights. Which means my gun is not running as it was designed to.

I am not knocking Knights. I love Knights products. Just not happy with this situation and hoping to find a bright side to the issue.

davidjinks

06-12-13, 20:31

Unless I've reached some type of parallel universe, H3 buffers are made and can be bought just about anywhere.

Just so it's clear, you sent the rifle in to KAC, they fixed the issue and you're not happy with them fixing the issue?

My factory Knights 11.5 is comming back from Knights Armament with an H3 buffer installed from them. Not all too happy. They have all been very helpful though. I guess my rifle is way overgassed as they dont even make an H3 buffer.

Trying to look on the bright side of things. Since my rifle is getting so much gas would it work more reliable on underpowered ammo? Say SHTF situation it would cycle low powered ammo if that were all there was? Or even if there is one underpowered round made its way in a box of good ammo by accident?

Or will it all be negated by the H3 buffer?

jaybirdritenour2

06-12-13, 20:37

Knights doesn't make H3 buffers because their rifles do not need them. That means my rifle is not running the way it is supposed to. I was just told today from them that it is very far from the norm for them to do that. First off that means they are opening an H2 buffer and putting the tungsten weight inside to make it an H3. How would you feel if all the other Knights rifles are running different than yours. Must be something wrong with all those rifles?

I am not unhappy with Knights. Just trying to be happy with the situation in general. I have a rifle not preforming how it is supposed too. Was just hoping to turn that in a good direction . Thats all.

davidjinks

06-12-13, 20:44

Okay, so what is it not doing correctly?

Knights doesn't make H3 buffers because their rifles do not need them. That means my rifle is not running the way it is supposed to. I was just told today from them that it is very far from the norm for them to do that. First off that means they are opening an H2 buffer and putting the tungsten weight inside to make it an H3. How would you feel if all the other Knights rifles are running different than yours. Must be something wrong with all those rifles?

I am not unhappy with Knights. Just trying to be happy with the situation in general. I have a rifle not preforming how it is supposed too. Was just hoping to turn that in a good direction . Thats all.

jaybirdritenour2

06-12-13, 20:49

Don't know yet but the heavier the buffer the more chance I might have problems with the suppressor removed. Maybe recoil and impulse. Either way the rifle isn't right. I do get what your saying if it works then it works it doesn't matter how it gets there right? A good answer to your question would be it is getting to much gas(allowing to much through). Is it a crime to want the gas system to work correctly on a rifle I payed almost 3000.00 for. Instead of making adjustments for something that isnt working correctly?

rjacobs

06-12-13, 20:49

I would venture a guess that the gun ran like a top unsuppressed right?

Most guns that run great when unsuppressed are magically "overgassed" when you put a can on it. I know my 10.5" LMT runs like a top, has perfect ejection, etc... when running unsuppressed. Put a can on it and it ejects to 1 oclock. Not LMT's issue that the gun suddenly has a ton more gas due to the can.

It sounds to me that the gas port was a bit large and should have been a bit smaller to begin with. Did KAC put a new barrel on it or say what the gas port measured?

When running gas guns with cans this is one of the side effects.

scoutfsu99

06-12-13, 21:06

Exactly what was wrong with your rifle in the first place? Overgassed with a suppressor?:confused:

saddlerocker

06-12-13, 21:06

Lets start from the beginning....

What was happening that led you to send the rifle in to KAC?

jaybirdritenour2

06-12-13, 21:06

No they didn't. But the gun first went in for issues with the suppressor making to gun almost underpowered. I know it sound crazy but it really was. One of them said it might have has a leak somewhere. When I received the gun back it was a crazy difference in pressure compared to before but Right away I had 8 or 9 stoppages in 50+ rounds because of how fast it was cycling . so I sent it back and that is what they did to fix it. I think they may have opened up my port without telling me the first time around.

jaybirdritenour2

06-12-13, 21:10

Lets start from the beginning....

What was happening that led you to send the rifle in to KAC?

Gun felt underpowered with suppressor attached and was not locking back suppressed. Second time was as soon as I got it back. And it had 8 or 9 stoppages with gas related problems in 50+ round straight back from the factory.

Split66

06-12-13, 21:18

jaybirdritenour2

06-12-13, 21:19

Exactly what was wrong with your rifle in the first place? Overgassed with a suppressor?:confused:

Lol. Yea.

jaybirdritenour2

06-12-13, 21:23

Perhaps you should contact KAC again instead of venting. Tell them it still isnt right. Tell them you dont feel right about the fix. As much as it sucks, I'm 1000 % sure that will get you alot further in the process of correcting the rifle than posting here.

Was not venting. Nor did I even want to explain all this to you guys. But I was made feel like I needed to defend myself about the post. I just wanted to know if it would work better with underpowered ammo or will the effect be negated because of the h3. I don't think the rifle can be corrected short of a new barrel. And they don't make my barrel anymore. So I might be stuck.

I dont want anyone to take bad away from the this about Knights. They have been very helpful with everything. Great customer service. Great company. Great products. What is happening with my rifle is very rare.

scoutfsu99

06-12-13, 21:35

The weapon functioned correctly without the can?

jaybirdritenour2

06-12-13, 21:40

Worked flawlessly without the can. I didn't understand either how it seemed to get less gas at first.

scoutfsu99

06-12-13, 22:14

hjmpanzr

06-12-13, 23:08

Since my rifle is getting so much gas would it work more reliable on underpowered ammo? Say SHTF situation it would cycle low powered ammo if that were all there was? Or even if there is one underpowered round made its way in a box of good ammo by accident?

Or will it all be negated by the H3 buffer?

***edit***I want everyone to know Knights has great customer service and is a great company with great products. I know the problem I am having is a rare problem. Please don't take anything differently from reading this thread.

Sounds like you've got some odd issues but to your question about lower powered ammo.... Im shooting BHA .223 77 gr and i haven't experienced any issues whatsoever on my KAC 14.5 which features a vltor A5. I've been shooting it suppressed and non since January mostly using that ammo and no problems. From time to time, I run xm193 or mk 262 mod 1 thru it (again no problems).

Even so, people keep telling me that I should be having problems because the ammo is too slow and the buffer too heavy for the intermediate gas system. All I know is that it runs very smooth;)

jaybirdritenour2

06-13-13, 06:34

I just can't see how it would have less gas WITH a can. If there was a leak, I would think the increased back pressure would highlight where it was escaping.

And not to pick but if you could lay out one big post highlighting the original problem, the fix(es), what you/they did, all the variables,etc - we wouldn't have to play 20 questions. I feel like we're having to pull information out of you.

Sorry. I wasnt looking for a solution. Was just asking a question. I have no idea why it was getting less gas. It doesn't make sense. But trust me when I got it back it was getting way way more gas. Night and Day difference.

davidjinks

06-13-13, 06:40

So I'm still just not tracking...

They either fixed or it or didn't fix it. Which one is it? If it runs like a champ unsuppressed but not when suppressed and you send it in and they fix it...what's the problem?

Lets say they did open up your gas port. So what? You did send it to them to fix the issues you're having correct? Now you say too much gas and send it back. They then add an H3 buffer, problem fixed correct?

But below you stated you don't even know yet?

Don't know yet but the heavier the buffer the more chance I might have problems with the suppressor removed. Maybe recoil and impulse. Either way the rifle isn't right. I do get what your saying if it works then it works it doesn't matter how it gets there right? A good answer to your question would be it is getting to much gas(allowing to much through). Is it a crime to want the gas system to work correctly on a rifle I payed almost 3000.00 for. Instead of making adjustments for something that isnt working correctly?

midSCarolina

06-13-13, 09:34

Gun felt underpowered with suppressor attached and was not locking back suppressed. Second time was as soon as I got it back. And it had 8 or 9 stoppages with gas related problems in 50+ round straight back from the factory.

I am kinda confused by this right here... if the gun ran 100% without the suppressor I don't see how adding the can would magically suck gas out of the gas system since the gas entering the suppressor would just be getting expelled from the end of the barrel otherwise.

Anyways, if you say the gun is overgassed, there are 3 things you can really do since you can't reduce the port size. 1... VLTOR H4 buffer
2... Stiffer spring
3... LMT enhanced carrier

The LMT enhanced carrier will port off some of that extra gas prior to the bolt beginning to cycle back and the spring and buffer will slow the system.

Other than this you can call KAC and see what they will do with it.