Ballistic Advantage DMR barrrel "gassed for a Carbine system"?

[SDW]

Hi all. I'm putting together a 6.5G upper and I bought a BA 20" DMR barrel to use with it. I have seen a reference or two on this board that this barrel is "gassed for a carbine buffer system", but I don't know what that means exactly. It's a rifle-length gas setup. I assume the only thing that can vary would be the port's size. I couldn't find anywhere on BA's web site that discusses this. I assume that since it's a rifle-length gas setup that it ought to work with a rifle buffer system, which happens to be my plan.

So I guess my question is, is there any reason why this barrel wouldn't work fine with my lower, without fiddling, messing with an adjustable gas block (I don't have one), and so forth?

[Popeye212]

I have the exact same setup and it is run with a carbine buffer and spring. That is what is was designed to run. I have a standard clamp on gas block (Vltor). It ejects at 3:00. It means the barrels ported for a carbine buffer system. Rifle buffer systems use a heavier buffer and spring set up.

[Popeye212]

And Welcome from the Republic of Texas

[A5BLASTER]

So it has rifle length gas system but port cut to carbine size, so it will run better with carbine stocks.


That is the dumbess thing I have heard yet.

To my knowledge their has never been a problem running rifle length gas with correct rifle port size on either a rifle or carbine length buffer and stock.

But now you take a rifle length gas system and cut the port to match a carbine port size too aka better work with carbine stock and buffer system and my thinking is it won't work worth a crap with a rifle stock and buffer system now.

I had look at this barrel for my rebarrel I'm going to do but it's off my list now.

This is just stupid period, problem looking for a answer is what it is.

[Kswhitetails]

Basically, they've adjusted the gas down for you. Okay. But this leaves the end user with potential problems that can't be adjusted later. And I would think it would limit load options. If it works though, I don't see any reason to throw it away.

Grendel runs great on RLGS and a carbine buffer, with the normal port size. I don't know what the impetus was to change anything. I suppose some were having issues with over gassed 20" barrels on carbine buffer systems, but to that I would say get an AGB and leave yourself the option later, if you do something that a little more gas would wind up beneficial.

I'd guess there's not too many folks looking to run subs in a 20" barrel though. Heh... the things that necessity invents.

[A5BLASTER]

Basically, they've adjusted the gas down for you. Okay. But this leaves the end user with potential problems that can't be adjusted later. And I would think it would limit load options. If it works though, I don't see any reason to throw it away.

Grendel runs great on RLGS and a carbine buffer, with the normal port size. I don't know what the impetus was to change anything. I suppose some were having issues with over gassed 20" barrels on carbine buffer systems, but to that I would say get an AGB and leave yourself the option later, if you do something that a little more gas would wind up beneficial.

I'd guess there's not too many folks looking to run subs in a 20" barrel though. Heh... the things that necessity invents.

All good points but here is where I'm at with this.

And you can bet your paycheck very soon someone is going to buy that barrel without looking and thinking about it, wanting rifle gas on a rifle stock and buffer and when it won't run properly what's the first thing they will do.

Come online to all the forums they know about and say my grendel want run it's junk don't spend your money on a grendel it's junk.

That's what will happen with this stupid idea.

[SDW]

All good points but here is where I'm at with this.

And you can bet your paycheck very soon someone is going to buy that barrel without looking and thinking about it, wanting rifle gas on a rifle stock and buffer and when it won't run properly what's the first thing they will do.

Come online to all the forums they know about and say my grendel want run it's junk don't spend your money on a grendel it's junk.

That's what will happen with this stupid idea.

Hmm. I'm not sure if you are talking about me. This isn't quite what's happening.

Well I've built a few 5.56 uppers and both rifle and carbine lowers. I'm familiar with the differences between the two and have never had an issue swapping between the two systems and having them run. So this caught me by surprise. But just to emphasize my original point, this info didn't come from BA to me directly. I've only seen it mentioned here. BA didn't publish any warning on the page about which system should be used. I bought the barrel assuming that because it's a rifle length gas system it ought to work with a rifle buffer system. If it's common knowledge that this won't work with the 6.5G BA barrel then my bad. None of their lit I could find even discusses rifle/carbine combos. BTW, my rifle's not fully together yet. I could use it with one of my carbine lowers if need be. Just wouldn't be how I'd planned to do it.

So the gas port on the barrel, I couldn't measure it very precisely, but I did find that it's between 0.095" and 0.10". Seems to be of respectable size. LOL It certainly doesn't look "small" to me, which I imagine is what would be required for running a light buffer and spring. But I have nothing to compare it with except 5.56 barrels. Seems I have a few things to learn still.

It was just and impulse to ask you guys about this, to see if anyone can back up this... I guess you might call it hearsay at this point. I think my next move it so call BA and get the info from the source.

[A5BLASTER]

Hmm. I'm not sure if you are talking about me. This isn't quite what's happening.

Well I've built a few 5.56 uppers and both rifle and carbine lowers. I'm familiar with the differences between the two and have never had an issue swapping between the two systems and having them run. So this caught me by surprise. But just to emphasize my original point, this info didn't come from BA to me directly. I've only seen it mentioned here. BA didn't publish any warning on the page about which system should be used. I bought the barrel assuming that because it's a rifle length gas system it ought to work with a rifle buffer system. If it's common knowledge that this won't work with the 6.5G BA barrel then my bad. None of their lit I could find even discusses rifle/carbine combos. BTW, my rifle's not fully together yet. I could use it with one of my carbine lowers if need be. Just wouldn't be how I'd planned to do it.

So the gas port on the barrel, I couldn't measure it very precisely, but I did find that it's between 0.095" and 0.10". Seems to be of respectable size. LOL It certainly doesn't look "small" to me, which I imagine is what would be required for running a light buffer and spring. But I have nothing to compare it with except 5.56 barrels. Seems I have a few things to learn still.

It was just and impulse to ask you guys about this, to see if anyone can back up this... I guess you might call it hearsay at this point. I think my next move it so call BA and get the info from the source.

No sir not directed at you personally at all.

Just stating what I think about the info given.

And if true it's stupid to port a rifle gas barrel in such away.

I'm not sure how well know this info is or if it's true or not it's the first I have heard of it.

But if your gas port measured .95 its a rifle gas port.

Carbine sized gas port is like .70 if I remember correctly.

Again nothing I posted was directed at you sir, merely towards the info give and at BA if said info is true.

Making changes to known specs like that if they did that is just asking for problems and a bad rep to follow.

Sorry if I caused any confusion sir.

[SDW]

My apologies. I should not have posted without at least including a reference to where I read this "ported for carbine" thing. I believe this post from a gent about a month ago is where I first saw it:

http://www.65grendel.com/forum/showthread.php?15696-My-Ballistic-Advantage-build&p=199390&viewfull=1#post199390

Perhaps it was the only place I read it and for some reason it loomed large in my mind.

It would be interesting to find out that I might need to either use a different lower or swap out my spring and buffer for carbine pieces to use this upper on my rifle lower. My preference is to use it on the rifle lower because it's got my Guissele SSA-E trigger, which is my "best" target trigger to date.

[SDW]

I might as well post a pic of the rifle. I did have it together last week but I was having handguard issues. What's on in the pic is spare one I'd planned to use for this project. A UTG Pro. It's actually a beautifully made and finished HG that's hamstrung by a really crummy mounting system. I decided it's much too wobbly. So I've added to the budget and bought another HG. Waiting for it to arrive.

6.5-Grendel-mineresize.jpg

[A5BLASTER]

I might as well post a pic of the rifle. I did have it together last week but I was having handguard issues. What's on in the pic is spare one I'd planned to use for this project. A UTG Pro. It's actually a beautifully made and finished HG that's hamstrung by a really crummy mounting system. I decided it's much too wobbly. So I've added to the budget and bought another HG. Waiting for it to arrive.

[ATTACH=CONFIG]12428[/ATTACH]

Looks good sir.

I use the seekins sp3rv3 on my longer barreled grendels and now a matrix Victor on my 16 inch I just finished yesterday.

Like the matrix simple install and very strong attachment method for the handguard.

If the barrels gas port measured around the .95 size I would put a adjustable gas block on it.

Fail it in and it will be super soft shooting, I use adjustable gas blocks on every barrel they just do so much for you.

Makes the gun run cleaner for sure and helps with recoil a lil as well.

Both my jp barreled grendels use rifle gas with adjustable gas blocks and jp scs systems but I can open them up pull it out and put in a standard rifle buffer and spring and they don't skip a beat.

[SDW]

And Welcome from the Republic of Texas

Sorry, I meant to say thanks. Glad to be here. I'm a big fan of your state. My family's actually from the San Antonio area mostly.

Looks good sir.

I use the seekins sp3rv3 on my longer barreled grendels and now a matrix Victor on my 16 inch I just finished yesterday.

Like the matrix simple install and very strong attachment method for the handguard.

If the barrels gas port measured around the .95 size I would put a adjustable gas block on it.

Fail it in and it will be super soft shooting, I use adjustable gas blocks on every barrel they just do so much for you.

Makes the gun run cleaner for sure and helps with recoil a lil as well.

Both my jp barreled grendels use rifle gas with adjustable gas blocks and jp scs systems but I can open them up pull it out and put in a standard rifle buffer and spring and they don't skip a beat.

It'll be interesting. I decided to see if it'll run with the standard non-adjustable GB first. The price wasn't too bad from BA for their pinned GB. Since you're suggesting an adjustable, I assume that I might have more than enough gas pressure rather than not enough (as would be the case if "gassed for carbine system")? That would be nice. But... I've considered going to an adjustable GB if necessary. Lighter recoil would be welcomed. As you can see from the pic, I've decided not to use a brake. I just don't want to deal with the extra noise, for more than any other reason.

FWIW, that lower is using a standard rifle buffer with a David Tubb flat-wire spring. All I can say is that it works fine for 5.56 on a 20" rifle gas setup. I won't try to guess how it might work with a 6.5. Worse case scenario I could try a standard spring. Or the aforementioned carbine buffer.

For the new handguard I decided to get a KMR Alpha rail. They seem like they fit on very solid, no flex. The price is about middle of the field. I thought about going with something M-Lok, but I already have a bunch of Keymod HGs (SLR HGs) on other rifles, so it'd be nice to keep my stuff standardized. Plus, the KMR is already Ceracoted in FDE so it saves me the trouble of Duracoating it like all my other parts. Not that I mind painting. Heck, it's kinda fun. But why do it if I don't have to.

[A5BLASTER]

Sorry, I meant to say thanks. Glad to be here. I'm a big fan of your state. My family's actually from the San Antonio area mostly.


It'll be interesting. I decided to see if it'll run with the standard non-adjustable GB first. The price wasn't too bad from BA for their pinned GB. Since you're suggesting an adjustable, I assume that I might have more than enough gas pressure rather than not enough (as would be the case if "gassed for carbine system")? That would be nice. But... I've considered going to an adjustable GB if necessary. Lighter recoil would be welcomed. As you can see from the pic, I've decided not to use a brake. I just don't want to deal with the extra noise, for more than any other reason.

FWIW, that lower is using a standard rifle buffer with a David Tubb flat-wire spring. All I can say is that it works fine for 5.56 on a 20" rifle gas setup. I won't try to guess how it might work with a 6.5. Worse case scenario I could try a standard spring. Or the aforementioned carbine buffer.

For the new handguard I decided to get a KMR Alpha rail. They seem like they fit on very solid, no flex. The price is about middle of the field. I thought about going with something M-Lok, but I already have a bunch of Keymod HGs (SLR HGs) on other rifles, so it'd be nice to keep my stuff standardized. Plus, the KMR is already Ceracoted in FDE so it saves me the trouble of Duracoating it like all my other parts. Not that I mind painting. Heck, it's kinda fun. But why do it if I don't have to.

Your spring and buffer should work fine.

With the gas port size it has you will have plenty of gas.

I'm use to jp barrels they cut their gas ports huge, but jp designs his products to run adjustable gas and lowmass parts so that's why their gas port is so large.

[ricsmall]

SDW

your rig should run fine with rifle weight buffer if gas port is around .094-.098 with 20” pipe. If you end up undergassed, you could run a lighter buffer but this should not be the case. Shouldn’t be over gassed either unless your port is getting close to the .100” mark or bigger. Measure port with drill bit if available.

[kcb38]

I had my BA barreled rifle (from the thread mentioned above) to the range again today. I thought I had the cycling issues fixed but apparently I don't. I've had issues from partially open on the gas block to full open. At this point I have 2 options: change the buffer & spring or disassemble it yet again and inspect and possibly enlarge the gas port. I just had the darned thing apart messing with the handguard issue I had and didn't look at the port because I thought that problem was fixed. Between the cycling and my seeming inability to shoot this rifle with any consistency, I'm frustrated to the point where I'm about to stick it back in the safe and not pull it out again until I have the time to diagnose it (and my shooting) properly. I was really hoping to use it in an event coming up in 3 weeks, shooting 6 to 1 MOA steel at distances to 427 yards. No way that's happening, short of a quick fix and an epiphany on my part.