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Posted: 8/18/2017 6:42:44 PM EST
On my first build (16" carbine) everything extracted similar. I shot my new pistol build for the first time the other day and the .223 62 gr tulammo steel casing were very consistent at 5 o'clock. The 5.56 55 gr American eagle were almost straight back reflecting off the base of the brass deflector and bounced forward about 2 o'clock.

Specs: 10.5" barrel, carbine gas, phase 5 buffer assembly, toolcraft ni-bo bcg
Link Posted: 8/18/2017 6:52:55 PM EST
Not to be rude.. you mean ejection, yes? Extraction is straight back out of the chamber...
Link Posted: 8/18/2017 7:02:58 PM EST
[Last Edit: 8/18/2017 7:05:30 PM EST by HighpowerRifleBrony]
BCG velocity (controlled by ammo load, gas system, recoil system), extractor depth and case rim thickness, ejector spring tension.

Tula is relatively weak, driving the BCG slower, giving the ejector more time to flick the case around the extractor and out the ejection port, past the case deflector.

ETA: watch AR15 slomos.
Link Posted: 8/18/2017 8:11:25 PM EST
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Originally Posted By BDA:
Not to be rude.. you mean ejection, yes? Extraction is straight back out of the chamber...
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Yes, ejection
Link Posted: 8/18/2017 9:57:03 PM EST
[Last Edit: 8/18/2017 10:01:32 PM EST by AZgun4runner]
.223 Tula is a weak load. Nato 5.56 is a lot hotter providing a higher port pressure and increasing the cycle rate. A heavier buffer will resolve the 5-6 oclock ejection of the hotter 5.56 but may cause issue with lower powered ammo like Tula, bolt might no lock back after last round and/or ejecting at 1-2 oclock. Ammo, buffer wieght, gas system length, gas port size all play a role on your rifles ejection pattern. Sounds like your rifle is a little over gassed, which is common, larger gas ports to ensure full function with low powered .223 loads. Uss the heaviest buffer that will lock your bolt back on last round with the lowest power loads you plan to use. Normally Tula and Wolf steel are the lowest powered loads around.
Link Posted: 8/18/2017 11:18:20 PM EST
[Last Edit: 8/18/2017 11:23:53 PM EST by krdt]
Originally Posted By AZgun4runner:
.223 Tula is a weak load. Nato 5.56 is a lot hotter providing a higher port pressure and increasing the cycle rate. A heavier buffer will resolve the 5-6 oclock ejection of the hotter 5.56 but may cause issue with lower powered ammo like Tula, bolt might no lock back after last round and/or ejecting at 1-2 oclock. Ammo, buffer wieght, gas system length, gas port size all play a role on your rifles ejection pattern. Sounds like your rifle is a little over gassed, which is common, larger gas ports to ensure full function with low powered .223 loads. Uss the heaviest buffer that will lock your bolt back on last round with the lowest power loads you plan to use. Normally Tula and Wolf steel are the lowest powered loads around.
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That's backwards, actually. If it's ejecting at 5 o'clock, a heavier buffer is likely going to cause a short stroke, because that is already a symptom of being under gassed (or too heavy of buffer/spring). If it's ejecting at 1 or 2 o'clock, that's a sign of being over gassed and would then benefit from a heavier buffer.

While there are numerous factors that control ejection pattern (gas port size, ammo pressure, buffer weight and spring strength, etc.), the easiest way to tune it for a specific ammo is by changing buffer weights or using a stronger/weaker spring. If you have an adjustable gas block, that's even better. I would tune the rifle to the ammo you plan to shoot the most. If Tula is your main ammo, you will probably want to go with a lighter buffer weight and/or a reduced power spring. If you're wanting a cheap ammo, I would suggest switching to Wolf Polyformance 55gr, as that is higher pressure than Tula, and can generally be had for the same price. If the American Eagle is what you plan to shoot the most, add a heavier buffer weight and/or a stronger spring.

Sounds like the Tula is right at the edge of not being reliable already, so adding a heavier buffer is probably going to cause a short stroke or a failure to lock back on an empty magazine. If you switch to the higher pressure Wolf for your bulk ammo, you should be able to add a heavier buffer to tone down the over gassed American Eagle while still keeping it reliable with Wolf.

I like an ejection pattern around 3 o'clock to 4:30. I can't advise a buffer weight, because that's entirely dependent on your gas port size. On my DD 10.3" .070 barrel I use an H buffer, which ejects Wolf at about 4:30 and M193 at about 3 o'clock. On my Noveske 10.5" .078ish port I use an H3 to achieve roughly the same pattern. So, it's really a matter of deciding what ammo you want to tune the rifle for, and then just playing around with buffer weights. Just FYI, you can buy weights from Kak Industries to build you own custom buffer for a lot less than buying individual H/H2/H3s.
Link Posted: 8/19/2017 9:25:19 AM EST
[Last Edit: 8/19/2017 9:27:01 AM EST by savagemann]
OP, it sounds like your pistol is gassed perfectly.
As previously mentioned, the different loads will not eject to the same position.
I would only change to a heavier buffer if you plan on never using light loads, such as Tula.
If you will be using lots of ammo types, keep it as is.
Ejection pattern is all about port pressure, which relates to ammo pressure in the chamber.
Tula is a weak load, providing lower pressure.
Hot 5.56 loads will be the highest pressure your chamber will ever see, hopefully.
So, to surmise, you have proven your pistol will cycle the lightest and heaviest loads, so everything in between will be perfect.
I bet PMC Bronze would eject to around 4O'Clock and Wolf steel about the same.
Wolf Gold would probably be closer to 2:30....etc
Link Posted: 8/19/2017 11:22:27 AM EST
Thanks for the responses everyone! A lot of conflicting information though. My rifle ejected everything between 3:00 and 4:30 so it caught me off guard this one was so drastic between loads. I will try Pmc bronze, wolf, and some m855.
Link Posted: 8/19/2017 11:39:17 PM EST
[Last Edit: 8/19/2017 11:50:56 PM EST by krdt]
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Originally Posted By Macoffman:
Thanks for the responses everyone! A lot of conflicting information though. My rifle ejected everything between 3:00 and 4:30 so it caught me off guard this one was so drastic between loads. I will try Pmc bronze, wolf, and some m855.
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To summarize: 5 o'clock is a bit under gassed, 1 o'clock is a bit over gassed. Unfortunately, without an adjustable gas block, there isn't a single buffer/spring that is going to give you a perfect ejection pattern with both hot 5.56 and low pressure Tula. Just ain't gonna happen. That being said, all that really matters is that it cycles reliably with your chosen ammo type(s). The above poster is correct that some of the mid-range ammo like PMC Bronze and Wolf will probably be about perfect with your current setup.

The only reason I suggested switching from Tula to Wolf and adding a slightly heavier buffer is to tone down the 5.56mm a bit while still keeping it reliable with a cheap bulk ammo. If you're going to shoot mostly Tula, Wolf or PMC Bronze type ammo, I'd probably just leave it alone.

If you shoot mostly 5.56mm pressure ammo like M193, M855 or Wolf Gold, I'd put a heavier buffer in it to smooth out the recoil impulse and so you're not wearing your components faster than necessary. More than likely you'd still be able to cycle Wolf and PMC Bronze with a heavier buffer, but Tula probably wouldn't function reliably.
Link Posted: 8/20/2017 12:17:53 AM EST
What buffer is it and who made the barrel?
Link Posted: 8/20/2017 8:47:50 AM EST
Link Posted: 8/20/2017 9:54:21 AM EST
Link Posted: 8/20/2017 3:42:23 PM EST
Link Posted: 8/20/2017 4:00:00 PM EST
[Last Edit: 8/20/2017 4:01:04 PM EST by Marine6680]
Your issue is compounded by the fact that this is a pistol build.

The port is much closer to the chamber, and that will have a huge impact on how the action cycles. Being that close to the chamber makes variations of the load more pronounced. There is just less time for things to settle down and be a bit less dynamic.

Fired rounds have a pressure curve, the pressures do not stay the same through the whole cycle.

Wolf and Tula have a very odd pressure curve.

Two different brand 55gr 5.56 loads can behave differently due to using different powders, and that affects the pressure curve. Especially in the first several inches of bullet travel. Two loads may have similar pressures at the Port of a midlength, but be very different in a pistol length system.


All this means is that the pressure at the gas port will be significantly different between loads. Which leads to different ejection patterns.
Link Posted: 8/20/2017 4:30:51 PM EST
Buffer is phase 5 pistol assembly so wherever they source their buffers. Barrel is faxon.
Link Posted: 8/20/2017 5:33:35 PM EST
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According to this everything I'm describing is in the yellow, since the casings are bouncing off the deflector, right? Should I take it back to gunsmith to have checked out? I'm using standard buffer so how would I get more lightweight? Don't have adjustable gas block.
Link Posted: 8/20/2017 8:23:54 PM EST
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Originally Posted By Marine6680:
Your issue is compounded by the fact that this is a pistol build.

The port is much closer to the chamber, and that will have a huge impact on how the action cycles. Being that close to the chamber makes variations of the load more pronounced. There is just less time for things to settle down and be a bit less dynamic.

Fired rounds have a pressure curve, the pressures do not stay the same through the whole cycle.

Wolf and Tula have a very odd pressure curve.

Two different brand 55gr 5.56 loads can behave differently due to using different powders, and that affects the pressure curve. Especially in the first several inches of bullet travel. Two loads may have similar pressures at the Port of a midlength, but be very different in a pistol length system.


All this means is that the pressure at the gas port will be significantly different between loads. Which leads to different ejection patterns.
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He's using a carbine length system on a pistol build. Believe he said faxing barrel, which are definitely overgassed in most cases.
OP, I run an H2 in my only 10.5, currently a PSA CHF FN upper, eats everything perfectly. It sounds like you may be able to go a little heavier on the buffer, especially if you'll be shooting more 5.56
Link Posted: 8/20/2017 8:43:35 PM EST
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Originally Posted By di11igaf:
He's using a carbine length system on a pistol build. Believe he said faxing barrel, which are definitely overgassed in most cases.
OP, I run an H2 in my only 10.5, currently a PSA CHF FN upper, eats everything perfectly. It sounds like you may be able to go a little heavier on the buffer, especially if you'll be shooting more 5.56
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Thank you. I will try that
Link Posted: 8/20/2017 11:06:24 PM EST
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Originally Posted By Macoffman:
Buffer is phase 5 pistol assembly so wherever they source their buffers. Barrel is faxon.
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Found your problem.

Faxon couldn't properly gas a middy barrel to save their life. I reckon your barrel is insanely overgassed.
Link Posted: 8/20/2017 11:56:27 PM EST
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Originally Posted By joglee:


Found your problem.

Faxon couldn't properly gas a middy barrel to save their life. I reckon your barrel is insanely overgassed.
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It is carbine length gas though, not mid-length
Link Posted: 8/21/2017 12:14:44 AM EST
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Originally Posted By di11igaf:
He's using a carbine length system on a pistol build. Believe he said faxing barrel, which are definitely overgassed in most cases.
OP, I run an H2 in my only 10.5, currently a PSA CHF FN upper, eats everything perfectly. It sounds like you may be able to go a little heavier on the buffer, especially if you'll be shooting more 5.56
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Missed that part... Overall what I said still applies, and dwell time vs pressure will come into play as well with that gas system on a 10.5 barrel.
Link Posted: 8/21/2017 12:14:09 PM EST
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Truth.
Link Posted: 8/21/2017 12:55:04 PM EST
aliens
Link Posted: 8/21/2017 2:23:13 PM EST
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Originally Posted By Macoffman:


It is carbine length gas though, not mid-length
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That's my point. Middys are easier to gas, yet Faxon overgasses them to such a degree they dont run when pushed hard.

Their carbines appear to be just as overgassed.

If you're wondering here is a Crane built Mk18 on full auto.


perfect ejection pattern.
Link Posted: 8/21/2017 5:04:36 PM EST
While on the topic my Oracle ejects to 4 o'clock and is very consistent with box 55/62gr ammunition. I install my 16" PSA upper (complete with bcg and ch) and it consistently tosses them between 2:30-2:45; closer to 2:45.
Link Posted: 8/22/2017 8:14:10 AM EST
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