I'm Blaming Y'all for This...

[blue109]

Mine only ran good brass ammo until I opened up the port...and would still fail to lock on an empty mag on occasion. Wouldnt cycle steel cased ammo at all. 

 

Runs perfect with the bigger port. Didnt lose any smoothness.  

[COBrien]

3 hours ago, blue109 said:

Mine only ran good brass ammo until I opened up the port...and would still fail to lock on an empty mag on occasion. Wouldnt cycle steel cased ammo at all. 

 

Runs perfect with the bigger port. Didnt lose any smoothness.  

Do you recall what you opened the port up to? I want to say I’ve seen that the Del-Ton port is .092”, but I could be mis-remembering that. 

[blue109]

Check out my "blue builds a dissy" thread. Numbers are all in there. Im a little sauced right now or id dig it out for you lol. 

[98Z5V]

 

^^^  Page 5 in that thread.

 

16" rifle gas 5.56 Dissipator = 0.110"...

[COBrien]

11 hours ago, 98Z5V said:

 

^^^  Page 5 in that thread.

 

16" rifle gas 5.56 Dissipator = 0.110"...

Excellent. Thank you, sir! I was about to go through that thread right now, until I noticed you'd posted here.

I've already ordered an H2 buffer for the wife's rifle, so I'll try swapping some weights from that standard carbine buffer into my rifle buffer and see how that works out. I mean, hell, it's free and easy, right? If I can't get it to run that way, I'll open up the port and consider it resolved.

[98Z5V]

1 hour ago, COBrien said:

Excellent. Thank you, sir! I was about to go through that thread right now, until I noticed you'd posted here.

I've already ordered an H2 buffer for the wife's rifle, so I'll try swapping some weights from that standard carbine buffer into my rifle buffer and see how that works out.

You can do that if you want, but it's just going to give you practice in taking buffers apart - the same guts are in both.

(photo from ARF)

[COBrien]

Ah. Damn. I should have known it was too good to be true. I was under the impression there were some (at least 1...) tungsten weights in a rifle buffer.

I guess I could always rig up a lightweight spacer(s) and start removing steel weights.

OR I could just grab myself some 3/16" dowel rod, run it in the bore, and open up my port to 7/64"...

[COBrien]

Just wanted to swing back through and update this thread.

I learned my way around my new-to-me drill press, bought a better vise for it, and picked up a #35 drill bit. At low RPM, it went right though, like butter.

Got 'er all put back together, with my A.R.M.S. 41-B folding FSB.

Now to find a day when I can get out to the range...

[COBrien]

So... I got out to the range on July 4. Wasn't pretty.

Running American Eagle (Federal?) XM193. Short-stroking, wouldn't even eject spent casings. Having no other ideas except to re-position the gas block, that's what I did. Fiddle-fvcked around with it for 30 minutes or so, and finally got it ejecting. But it was still short-stroking and wouldn't pick up the next round in the mag. Got annoyed (and hot... 102°ish that day) and packed it up. This rifle, along with my CSASS which turned out to have headspace issues, was all I'd brought.

I'm focusing on the CSASS now, will dig out the green Diss(appointment)y once the CSASS upper is shipped out to Criterion.

Thinking a combination of gas block alignment and a "tight spot" in either the upper or the buffer tube is to blame here. There's always been a bit of a rub when cycling the BCG by hand, so I've always just kept the BCG wetter than I'd like, hoping she'd clearance herself out...

[98Z5V]

On 1/16/2017 at 2:55 PM, COBrien said:

DTI Dissy Barrel

This is a true Dissipator, right?  Rifle gas on a 16" barrel?

7 hours ago, COBrien said:

So... I got out to the range on July 4. Wasn't pretty.

Running American Eagle (Federal?) XM193. Short-stroking, wouldn't even eject spent casings. Having no other ideas except to re-position the gas block, that's what I did. Fiddle-fvcked around with it for 30 minutes or so, and finally got it ejecting. But it was still short-stroking and wouldn't pick up the next round in the mag. Got annoyed (and hot... 102°ish that day) and packed it up. This rifle, along with my CSASS which turned out to have headspace issues, was all I'd brought.

I'm focusing on the CSASS now, will dig out the green Diss(appointment)y once the CSASS upper is shipped out to Criterion.

Thinking a combination of gas block alignment and a "tight spot" in either the upper or the buffer tube is to blame here. There's always been a bit of a rub when cycling the BCG by hand, so I've always just kept the BCG wetter than I'd like, hoping she'd clearance herself out...

This is a gas issue.  Like, not enough gas, from a small gas port diameter.

But, what do I know, since I'm not a real Gunsmith...  

[COBrien]

31 minutes ago, 98Z5V said:

This is a true Dissipator, right?  Rifle gas on a 16" barrel?

This is a gas issue.  Like, not enough gas, from a small gas port diameter.

But, what do I know, since I'm not a real Gunsmith...  

Yes sir, true Dissipator. 

At Br. Blue’s suggestion, I opened the gas port to .110”. It ran worse after that...

What’s this about “not a gunsmith?” Have I missed a dramatic thread somewhere??

Edited August 3, 2019 by COBrien

[98Z5V]

Very dramatic, IMHO...  Much drama...  

[98Z5V]

4 minutes ago, COBrien said:

Yes sir, true Dissipator. 

At Br. Blue’s suggestion, I opened the gas port to .110”. It ran worse after that...

What’s this about “not a gunsmith?” Have I missed a dramatic thread somewhere??

What was the diameter before you opened it up?  FWIW, you're close, at 0.110, based on what you're saying it's doing.  Max you can go is 0.125", because that's the max opening in a gas tube  - anything bigger gains you nothing, becaise the gas tube becomes the restriction.

What buffer are you running (weight)?...   What's your recoil system look like, as far as parts go...  carbine, rifle, specific parts, etc...

[COBrien]

2 minutes ago, 98Z5V said:

What was the diameter before you opened it up?  FWIW, you're close, at 0.110, based on what you're saying it's doing.  Max you can go is 0.125", because that's the max opening in a gas tube  - anything bigger gains you nothing, becaise the gas tube becomes the restriction.

What buffer are you running (weight)?...   What's your recoil system look like, as far as parts go...  carbine, rifle, specific parts, etc...

IIRC, it was .088” originally. 

Fulton Armory A2 recoil system (buffer, tube, and spring), PA NiB M16 BCG. 

 

...got a link to the butthurt?

[98Z5V]

Just now, COBrien said:

IIRC, it was .088” originally. 

Fulton Armory A2 recoil system (buffer, tube, and spring), PA NiB M16 BCG. 

 

...got a link to the butthurt?

That is KILLIN' YA, right there.   That's a 5.4oz rifle buffer.  That's your problem.

Drop to any AR15 carbine buffer, with a spacer, and that thing will RUUUUUUUUN!...   I think Spike's tactical makes a spacer, but I'm sure others do to.  You need to take up enough internal depth to go from a 9 11/16" internal depth of a rifle receiver extension, to 7.000" internal deoth of the standard AR15 carbine extension, and just plop any regular AR15 carbine buffer in there. 

[COBrien]

1 minute ago, 98Z5V said:

That is KILLIN' YA, right there.   That's a 5.4oz rifle buffer.  That's your problem.

Drop to any AR15 carbine buffer, with a spacer, and that thing will RUUUUUUUUN!...   I think Spike's tactical makes a spacer, but I'm sure others do to.  You need to take up enough internal depth to go from a 9 11/16" internal depth of a rifle receiver extension, to 7.000" internal deoth of the standard AR15 carbine extension, and just plop any regular AR15 carbine buffer in there. 

Y’know what...

I’ve got an Armaspec CAR to A2 spacer lying around (planned to run a Stealth recoil spring) that should do exactly that...

[98Z5V]

Here's your "functional test" right here.  That thing needs to take up 2 11/16" of space in the receiver extension, in order to "make a rifle extension = an AR15 Carbine extension."  Measure it.  If you had to stack quarters, that's about 38 or 39 quarters to test this.... 

Carbine buffer, carbine buffer spring...   Don't use the rifle buffer spring...

[COBrien]

I have a standard CAR buffer, but no spring. I suppose I could “borrow” the one from the wife’s patrol rifle (she’s on maternity leave til September, so she won’t miss it for one range trip). 

Or I could just drop the Stealth spring in it...

[blue109]

Just had mine out the other day. Still running beautiful with the standard rifle buffer. Want to make sure you did not use the little spacer that came with the arms fsgb right?  Give the carbine buffer a shot but it shouldnt matter. You should be able to go either way on that and not notice a huge difference. 

[98Z5V]

1 minute ago, blue109 said:

Just had mine out the other day. Still running beautiful with the standard rifle buffer. Want to make sure you did not use the little spacer that came with the arms fsgb right?  Give the carbine buffer a shot but it shouldnt matter. You should be able to go either way on that and not notice a huge difference. 

You're on a 0.110" gas port, right brother?

From his cycling description, he is SO CLOSE to full-function...

Edited August 3, 2019 by 98Z5V

[COBrien]

1 minute ago, blue109 said:

Just had mine out the other day. Still running beautiful with the standard rifle buffer. Want to make sure you did not use the little spacer that came with the arms fsgb right?  Give the carbine buffer a shot but it shouldnt matter. You should be able to go either way on that and not notice a huge difference. 

See, I thought I remembered you running a rifle buffer.

No, I didn’t run the .030” gas block shim — I have a handguard cap for that. Lol!

Your experience is leading me to believe I have something else going on...

[blue109]

14 minutes ago, 98Z5V said:

You're on a 0.110" gas port, right brother?

From his cycling description, he is SO CLOSE to full-function...

Correct...but if the gun is so sensitive that a few extra oz in the rifle buffer cripples it, than even if it works with the carbine buffer it would have to be right on the edge of failure. Seems like something else is going on. Maybe get it out there with a known strong rifle and start swapping uppers/lowers/guts to see if you can isolate an issue. 

I was mag dumping crappy ammo into a chunk of plywood until the barrel smoked and the handguard was too hot to hold so I know that gas port diameter is plenty big for that setup. 

Edited August 3, 2019 by blue109

[98Z5V]

I wanna see 3.0oz carbine buffer to see if it's "cured."  It might be harsh as hell to shoot like that, kick like a pissed-off ex-wife, carbine buffer and 0.110" gas port - but if it works...  

Then that gun just isn't liking the 5.4oz rifle buffer, or that spring tension.  Take a steel weight outta that buffer, and insert a piece of 1/2" delrin in it's place, problem might be solved - drop that buffer weight just a tad, in his gun...  Or, punch that 0.110" gas port to 0.112"?...   He's so close.  It's one of the other, based on his failure descriptions...

Dissipators - TRUE Dissipators - are fucking unicorns...  There's no magic formula, but there's damn sure a baseline to start getting them to work.  They'll all be different, in some way... 

[COBrien]

On 8/2/2019 at 11:46 PM, 98Z5V said:

I wanna see 3.0oz carbine buffer to see if it's "cured."  It might be harsh as hell to shoot like that, kick like a pissed-off ex-wife, carbine buffer and 0.110" gas port - but if it works...  

Then that gun just isn't liking the 5.4oz rifle buffer, or that spring tension.  Take a steel weight outta that buffer, and insert a piece of 1/2" delrin in it's place, problem might be solved - drop that buffer weight just a tad, in his gun...  Or, punch that 0.110" gas port to 0.112"?...   He's so close.  It's one of the other, based on his failure descriptions...

Dissipators - TRUE Dissipators - are fucking unicorns...  There's no magic formula, but there's damn sure a baseline to start getting them to work.  They'll all be different, in some way... 

Before I go buying more parts, which will leave parts lying around in a drawer (and we all know that parts lying in a drawer get lonely and bored, so they start breeding more parts...), I'll try this Armaspec SRS I have on-hand (H2, 4.7 oz.). I figure it's 0.7 oz. lighter, so surely it has to work at least a little bit better, right?

Also, since I've decided to send the CSASS upper off to Criterion for "hand-fitting" of a bolt, I'll start digging into the Dissy diagnosis.

Last night, I pulled her apart. Pulled CH and BCG, and decided to run the BCG by itself, by hand, back and forth through the upper. There's a bit of "grab" just aft of the ejection port, and a corresponding mark inside the upper. As it was, uhh, 0100 when I was doing this, I don't have any pics to show. I also pulled the buffer and spring and checked them, as well as the inside of the buffer tube, for any interference. None to be found, so I re-oiled the spring with some Mobil 1 15W-50 and re-installed.

I'd planned to pull the gas block and get it all aligned with my Gas Block Genie, but ran out of energy (2 y/o + 2 m/o + exhausted wife = wore out Daddy). I'll get around to that tonight. Or, at least, that's the plan.

I'm also contemplating going back to basics. 98Z5V's words ring in my head -- "Don't complicate shiit with complicated shiit!" The rifle ran better with the DTI pinned FSB and .088" port than it did with the A.R.M.S. folding FSB and .110" port. So, maybe I swap back to the DTI FSB, leave the A2 buffer and spring in place, and see what she does with a .110" port. If no joy, then swap in the H2 SRS. If still no joy, then I'll start piddling around with carbine buffers and springs.

EDIT: I just remembered, I have a handful of aluminum buffer weights sitting on my bench. Before I decided to hog out the gas port, I thought I'd just lighten this rifle buffer, one weight at a time, until she ran like I wanted. That is still an option, at this point...

Edited August 7, 2019 by COBrien

[98Z5V]

11 hours ago, COBrien said:

EDIT: I just remembered, I have a handful of aluminum buffer weights sitting on my bench. Before I decided to hog out the gas port, I thought I'd just lighten this rifle buffer, one weight at a time, until she ran like I wanted. That is still an option, at this point...

That is still a completely viable option, brother - that will work.