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renaissanceman

Cycling issues -- 20" Ballistic Advantage 308 barrel, rifle length gas (high frame rate video included)

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27 minutes ago, Matt.Cross said:

I wouldn't advise it. You need to keep changes to a minimum, drilling your gas port might cause issues you could've avoided. If the correct buffer and spring fix your issue, you're done. If not, drilling up is the next logical step.

Yep, one step at a time, but like you, I am a little impatient, and I would be tempted, but the voice of reason says to fix one issue at a time, you probably will be drilling up soon, but if its too much, then you'll be buying a new adjustable gas block... these gents will get you there, keep us in the loop, I for one am very interested to hear the "end of the story"!

Whoops! you've already got one of those, lol.

Edited by billymagg

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renaissanceman,

Do you know which gen PSA lower you have? I just picked up a complete gen 3 lower and was planning on using an aero upper - but now I'm concerned. I had heard they fixed some of their issues with gen 3, but perhaps not...

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27 minutes ago, Entebbe07 said:

renaissanceman,

Do you know which gen PSA lower you have? I just picked up a complete gen 3 lower and was planning on using an aero upper - but now I'm concerned. I had heard they fixed some of their issues with gen 3, but perhaps not...

my sugestion would be to get a psa upper to go with lower. psa has history of not playing well with other receivers 

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6 minutes ago, Entebbe07 said:

I'm new here and don't want to hijack further. But now I'm reading all the other PA10 threads and... Yikes.

I may still try for the aero upper so at least half my system is viable.

Welcome, and feel free to create a thread to discuss anything you want to about what you're working on and trying to accomplish.

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2 hours ago, unforgiven said:

Give back the PSA lower and get a Aero lower you will be happier.

No returns accepted I'm afraid. I think I'll proceed with the aero upper. When it inevitably doesn't work, I'll build out an aero lower to match.

 

Still curious to hear specific parts and how things resolve for the OP here. Could be I swap out the recoil system and get lucky.

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I finally got around to ordering the heavy buffer.  The first time the site's payment gateway was down, and then holidays hit and that was that.  

Looking forward to getting this thing running.  

Edited by renaissanceman

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On 1/13/2021 at 6:19 PM, renaissanceman said:

I finally got around to ordering the heavy buffer.  The first time the site's payment gateway was down, and then holidays hit and that was that.  

Looking forward to getting this thing running.  

I hear you, my 37 coil flat wire spring from Wilson Combat came in today, I tried to run my small frame 300 Ham'r on what used to be their hot set up 40 coil flat wire, and wasn't even getting it to lock back... so standard spring and H2 buffer, Bill asked me why I was running an H2 buffer, it wouldn't pick up the second round off the top of the mag.  any way, they are going to 37 coils, and have one for small frame and one for large frame.. I'll save that 40 coil for a spare for my large frame rifle. Thanks for giving us an update, I still think you are going to have to drill that gas port, but as the experts reminded us, one thing at a time, LOL.

Oh and Wilson has gone to a mid length gas port on their 18" 300 Ham'r barrels, as they were undergassed with the 13.25" intermediate length gas tube...

 

Edited by billymagg

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16 minutes ago, billymagg said:

Oh and Wilson has gone to a mid length gas port on their 18" 300 Ham'r barrels, as they were undergassed with the 13.25" intermediate length gas tube...

^^^  There's something else going on there, and it's not "under-gassed."  Midlength gas tubes are 11.750" long.  Armalite AR-10 "Carbine" gas tubes are 12 1/16" long...   Longer than AR15
"midlength" gas tubes...   The Wilson Intermediate gas system is a brand new animal, for everyone, at 13.250" long. 

If they "shrunk" the gas tube length, stating it's under-gassed at 13.25" - then there wasn't enough dwell time in that barrel config.  Gas port diameter needed to go up, on that 13.25" gas tube, to make it run right.  Or, keep the same barrel gas port diameter, and shorten the gas tube... UP the dwell time to make the pressure needed...

There's more to that story, and I wish I had both barrel configs, to see what it really is... Someone's not being told the truth, here...

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On 1/21/2021 at 2:22 PM, renaissanceman said:

The heavy buffer and spring arrived.  Now to get to the range to test it.  

No change.  That 0.086" port is probably the culprit, as originally suspected.  Any suggestions on what size to drill to?  3/32" (0.0938") perhaps?

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11 hours ago, renaissanceman said:

No change.  That 0.086" port is probably the culprit, as originally suspected.  Any suggestions on what size to drill to?  3/32" (0.0938") perhaps?

Probably the culprit...

On 11/20/2020 at 3:49 PM, renaissanceman said:

-20" ballistic advantage barrel, rifle length gas/0.086" port

20" Rifle Gas on a .308AR barrel with a 0.750" gas block diameter should be 0.093"~0.096" to run right.

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41 minutes ago, 98Z5V said:

Probably the culprit...

20" Rifle Gas on a .308AR barrel with a 0.750" gas block diameter should be 0.093"~0.096" to run right.

I'll take a drill bit to it soon -- I've done one in the past with a hand drill and a 3d printed guide to keep it straight and a 3d printed insert to keep the bit from going all the way through and into the opposite side.  Sort of shady, but lacking a drill press...whatcha gonna do?  Kinda strange that a rather large and reputable company (Aero) would under-drill a port -- I'm thinking a lot of AR10s are undergassed, despite everyone online seeming to think overgassing is the issue that causes chronic cycling headaches.  Of all my buddies who have built one, I've still never seen one just run without issues.

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50 minutes ago, renaissanceman said:

Of all my buddies who have built one, I've still never seen one just run without issues.

One word.

Armalite.

Oh, and I'm the Armalite guy by the way. So, no bias or anything. :lmao:

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55 minutes ago, renaissanceman said:

I'll take a drill bit to it soon -- I've done one in the past with a hand drill and a 3d printed guide to keep it straight and a 3d printed insert to keep the bit from going all the way through and into the opposite side.  Sort of shady, but lacking a drill press...whatcha gonna do?  Kinda strange that a rather large and reputable company (Aero) would under-drill a port -- I'm thinking a lot of AR10s are undergassed, despite everyone online seeming to think overgassing is the issue that causes chronic cycling headaches.  Of all my buddies who have built one, I've still never seen one just run without issues.

Hand drill is perfectly fine, and I've stated this before - you're not drilling a new hole, that has to be perfect. You have a guide for your new hole, right there - it's the original hole.  It's hard to fuk that up, no offense intended.  You're just making a smaller hole, well, larger.  The template is already there.  Stick a 1/4" (0..250") diameter wooden dowel down the barrel, to prevent you from pushing too hard and hitting the other side of the barrel.  Which leads me to something else that I've recommended before...

Use SLOW drill speed with a variable speed drill, and LIGHT pressure on the drill - and just let the drill bit eat. Let it do it's job.  You won't hit the other side, when you "break through" if you're using light pressure, and slow speed on the bit.

I drilled up one of these things (a 6.5 Creedmoor barrel) out in the desert a couple months ago, and got the gun running.  Right then.  At night, with a headlamp and a work light around.  Dude's gun wasn't running, we looked at it, someone had a drill, someone looked up drill bit sizes on their phone - and I said "THAT is the bit we need!"  Everyone was all nervous, and I said "Give me the drill and the bit, and stand back - I don't know how big this thing is gonna get!"   :banana:

Two minutes, DONE.  Gas block back in place, and he's shooting, and it works now.

 

This isn't Rocket Science, and you don't need alot of fancy protective parts to do this.  You're just up-sizing a hole that's already there.  :thumbup:

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Here's directly where I've stated this before:

When I have to punch a gas port, I do it free-hand, with a hand-held drill.  Either a Makita or Milwaukee, but the drill brand doesn't matter, as long as it's variable speed trigger on that thing.  Keep the speed slow, and light pressure - don't push it hard - let the bit eat. 

This is determining how you affect an explosion, mere inches from your own face when you pull the trigger - but it isn't Rocket Science.  It's just drilling a hole in a piece of metal, larger, where there's already a hole to base this from.  It's easy to do, and you don't need specialized equipment to pull this off.  Under-paid workers and trained monkeys could do this all day long, and PSA proves this every single day. 

Don't over-think it. It's a simple operation. You already have the pilot hole, right there in front of you.

[/quote}

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1 hour ago, renaissanceman said:

  Of all my buddies who have built one, I've still never seen one just run without issues.

For what it's worth, I have a very large handful of larger-than-normal-caliber ARs. The only one I had to fuk with the gas port on was my .260 Remington.  The barrel shipped from a very reputable manufacturer with a 0.070" gas port.  That gas port needed to be 0.080" to run right.  That's the size it is now, and it runs great.  I only discovered that when I tried to feed it some factory match ammunition, and it wouldn't cycle with it. It always worked fine with my handloads, before that.  Now, it works even better.  Punch the gas port, don't overthink it, and don't sweat it. 

EDIT - That same barrel manufacturer now ships this exact same barrel with a...  yep.  0.080" gas port diameter.  :thumbup:

Edited by 98Z5V

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3 minutes ago, 98Z5V said:

For what it's worth, I have a very large handful of larger-than-normal-caliber ARs. The only one I had to fuk with the gas port on was my .260 Remington.  The barrel shipped from a very reputable manufacturer with a 0.070" gas port.  That gas port needed to be 0.080" to run right.  That's the size it is now, and it runs great.  I only discovered that when I tried to feed it some factory match ammunition, and it wouldn't cycle with it. It always worked fine with my handloads, before that.  Now, it works even better.  Punch the gas port, don't overthink it, and don't sweat it. 

Will do.  Last time I used a high grade bit and it kept grabbing the soft stainless and chipped all to hell on the cutting edges.  This time I'll just use a crappy dewalt 3/32 bit on my cordless variable speed drill and take it slower with no guides or any other overthinking shenanigans.  It'll probably work without drama and I'll be up and running tomorrow.  

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Super easy to do, man - really.  You're right on the softer stainless.  Light pressure, oil the hole and bit, and just go slow.  Let the bit eat - it'll do it's job.  :thumbup:

Someone recently stated that they were worried about a burr in the inside of the barrel after drilling...   First bullet that leaves that barrel after drilling - will eliminate any burr that might have been there...

Edited by 98Z5V

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16 hours ago, renaissanceman said:

but lacking a drill press...whatcha gonna do?

I hit them with a hand held cordless and a 1/4 inch dowel in the bore to stop the bit from bottoming out. 

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Drilled to 0.938".  First crappy dewalt bit couldn't handle it, second (new) one cut it smoothly and easily.  Kissed it with a 0.125" bit afterwards for a bit of a chamfer to deburr.  Bore cleaned and ready to roll, hopefully I'll get cycling and not have to give it another thought.  

signal-2021-01-26-145338.jpeg

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All cycling issues have resolved -- it now cycles any ammo you feed it with bolt lockback every time.  The recoil is quite mild and the empty cases land at the 4'oclock position about 5 feet from the rifle in a neat little pile.  

How's that for a happy ending? 

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