Eject! Eject! Eject! Is anything other than 3:00-4:00 OK?

[TheHorta]

EXECUTIVE SUMMARY: “High-end” rifle works flawlessly, runs like a sewing machine, eats everything, but ejects rounds at 0130-0200 regardless of gas block setting. Is this a problem? Or who cares as long as it runs perfectly otherwise?

THE WHOLE NINE YARDS:

So… took an all-factory Noveske N4 G3 rifle and made it better, faster, stronger.

Put on Form-1 SBR.

Removed factory 13.7” with P/W Flaming Pig, replaced with 14.5” Proof CF “Wylde” coupled with the new JP D2 52-position (!!!) adjustable gas block.

Replaced 15” NSR3 rail with 13.5” NSR3 rail.

Replaced all lower parts with $400 in V7 Titanium bits — ‘cuz everyone needs an $80 safety selector and $100 ejection port cover.

Replaced buffer tube with V7 Lithium Aluminum tube, ‘cuz why not?

Replaced factory trigger with SSA-X.

Replaced Noveske BCG with JP Chromed LMOS.

Replaced Noveske buffer with JP SCS.

Cerakoted entire rifle in Gen2 HIR-265 (IR signature-reducing coating for NODs fun) — upper, lower, handrail, buffer tube, shiny bits like door cover and takedown pins, etc.

Added HUX flash hider and 7.62 Ti (pre-Flow) can.

Popped an FDE ATACR 1-8 with offset RMR-06 in C1 mount on top and called it a day.

Will take pics soon for posterity.

Anyhoo… with all that said, we finished the rifle on the Thursday before I took it to CR2’s Light Fighter course the very next day. First order of business was to get the gas system perfectly adjusted. The HUX can doesn’t have much backpressure at all, and the gun will never really be shot unsuppressed, but we did try it both with and without — zero difference.

JP’s new D2 AGBs have 52 positions for adjustment. Their instructions say to close it off entirely, then back-out 12 clicks, or roughly one full turn, and start there. They say the gun probably will NOT cycle at 12 clicks, and they were correct. They say to adjust in 3-click increments, which we did. After the first adjustment (15-clicks), the gun ejected, but just barely at about 0100. Went another 3 clicks and it was better, about 0130-0200. At this point I figured additional adjustment would push angle of eject toward the Orthodox Religious Dogma-Approved 0300-0400 angle, but no matter how may clicks we dialed-in, the pattern didn’t change — again, with or without the can.

Given this behavior, I figured the best position was at 18-21 clicks, since it cycled just fine with everything from cheap 223 Wolf Gold as well as 855A1 and 262 Mod 1C and the much maligned AAC 77g OTM 556.

Took it to the 3-day LF course the very next day and it never gave the slightest hiccup all weekend, nailing IPSC steel at >650 yards like a Rock Star.

Shoots like Chantilly Whipped Cream — soft and smooth.

But that eject angle…

Assume it’s more related to the LMOS/SCS than the gas system?

Aside from the angle, is there any reason to mess with it? It’s just absolute perfection otherwise and I hesitate to pfutz with it by playing Rifle Jenga.

 

[1911hombre]

I think it's that Gen 3 handguard; the Gen 4 would have it ejecting at 4:00 with all brass into a coffee can.

 

[TheHorta]

I think it's that Gen 3 handguard; the Gen 4 would have it ejecting at 4:00 with all brass into a coffee can.

Fak! I knew it!

 

[USK308]

EXECUTIVE SUMMARY: “High-end” rifle works flawlessly, runs like a sewing machine, eats everything, but ejects rounds at 0130-0200 regardless of gas block setting. Is this a problem? Or who cares as long as it runs perfectly otherwise?

THE WHOLE NINE YARDS:

So… took an all-factory Noveske N4 G3 rifle and made it better, faster, stronger.

Put on Form-1 SBR.

Removed factory 13.7” with P/W Flaming Pig, replaced with 14.5” Proof CF “Wylde” coupled with the new JP D2 52-position (!!!) adjustable gas block.

Replaced 15” NSR3 rail with 13.5” NSR3 rail.

Replaced all lower parts with $400 in V7 Titanium bits — ‘cuz everyone needs an $80 safety selector and $100 ejection port cover.

Replaced buffer tube with V7 Lithium Aluminum tube, ‘cuz why not?

Replaced factory trigger with SSA-X.

Replaced Noveske BCG with JP Chromed LMOS.

Replaced Noveske buffer with JP SCS.

Cerakoted entire rifle in Gen2 HIR-265 (IR signature-reducing coating for NODs fun) — upper, lower, handrail, buffer tube, shiny bits like door cover and takedown pins, etc.

Added HUX flash hider and 7.62 Ti (pre-Flow) can.

Popped an FDE ATACR 1-8 with offset RMR-06 in C1 mount on top and called it a day.

Will take pics soon for posterity.

Anyhoo… with all that said, we finished the rifle on the Thursday before I took it to CR2’s Light Fighter course the very next day. First order of business was to get the gas system perfectly adjusted. The HUX can doesn’t have much backpressure at all, and the gun will never really be shot unsuppressed, but we did try it both with and without — zero difference.

JP’s new D2 AGBs have 52 positions for adjustment. Their instructions say to close it off entirely, then back-out 12 clicks, or roughly one full turn, and start there. They say the gun probably will NOT cycle at 12 clicks, and they were correct. They say to adjust in 3-click increments, which we did. After the first adjustment (15-clicks), the gun ejected, but just barely at about 0100. Went another 3 clicks and it was better, about 0130-0200. At this point I figured additional adjustment would push angle of eject toward the Orthodox Religious Dogma-Approved 0300-0400 angle, but no matter how may clicks we dialed-in, the pattern didn’t change — again, with or without the can.

Given this behavior, I figured the best position was at 18-21 clicks, since it cycled just fine with everything from cheap 223 Wolf Gold as well as 855A1 and 262 Mod 1C and the much maligned AAC 77g OTM 556.

Took it to the 3-day LF course the very next day and it never gave the slightest hiccup all weekend, nailing IPSC steel at >650 yards like a Rock Star.

Shoots like Chantilly Whipped Cream — soft and smooth.

But that eject angle…

Assume it’s more related to the LMOS/SCS than the gas system?

Aside from the angle, is there any reason to mess with it? It’s just absolute perfection otherwise and I hesitate to pfutz with it by playing Rifle Jenga.

The downside to being overgassed is you will have a lot more 'crap' coming back towards the shooter. More backflow will likely mean more crap gumming up the BCG, trigger area, etc.

Have you cleaned the rifle after the course to see how dirty the rifle is?

Traditionally, 2:00 -> 2:45 is acceptable for hot ammo or running suppressed. Further north of 2:00 is overgassed and failures 'can' occur. But YMMV... :lol:

 

[TheHorta]

The downside to being overgassed is you will have a lot more 'crap' coming back towards the shooter. More backflow will likely mean more crap gumming up the BCG, trigger area, etc.

Have you cleaned the rifle after the course to see how dirty the rifle is?

Traditionally, 2:00 -> 2:45 is acceptable for hot ammo or running suppressed. Further north of 2:00 is overgassed and failures 'can' occur. But YMMV... :lol:

Same eject angle whether the can is on or not. Of course, the HUX can has little to no backpressure, so I wouldn’t expect there to be much of a difference. Same angle regardless of 223 or 556 pressure ammo. Same / similar angle under every variable I can think to throw at it.

No unusual fouling. Gun actually runs fairly clean. Love them HUX cans!

I’m thinking the LMOS BCG is cycling faster than a full-mass carrier and acting like it’s shooting hot ammo / overgassed. Easy test is to drop in a regular BC and confirm.

 

[roostercogburn98]

Maybe hitting your shell deflector and bouncing forward? How’s the brass look, do they have any dents in the body?

 

[USK308]

Same eject angle whether the can is on or not. Of course, the HUX can has little to no backpressure, so I wouldn’t expect there to be much of a difference. Same angle regardless of 223 or 556 pressure ammo. Same / similar angle under every variable I can think to throw at it.

No unusual fouling. Gun actually runs fairly clean. Love then HUX cans!

I’m thinking the LMOS BCG is cycling faster than a full-mass carrier and acting like it’s shooting hot ammo / overgassed. Easy test is to drop in a regular BC and confirm.

Given your level of knowledge...I would expect to see good results from any testing you do!

I had a hella time (initially) getting my 300BLK SBR going. The initial barrel selection was stupid on my part; went to a Rosco Mfg barrel (direct replacement for the Mk 18 Gen 2's) and now my 300BLK SBR sings, as you said, like a sewing machine!

Really love running the SBR with my OCL Hydrogen L can.

 

[Makinchips208]

If the gas system is good, then could a weak ejector spring contribute to this? Simply not doing its job fast enough?
I’m not sure if that’s possible or not.



I had an over gassed carbine that ran flawless but ejected at like 1-1:30. Finally, after several thousand rounds I decided to tuned it. Now it ejects at exactly 3:01 o’clock.
Yesterday I fired two rounds at a rock 400 yards away that needed killed, went to grab my brass and here is how i found it about 8’ away.

 

[TheHorta]

Maybe hitting your shell deflector and bouncing forward? How’s the brass look, do they have any dents in the body?

I’ll check that.

 

[hafejd30]

I had a bolt that would drop rounds in the chamber or eject forward. Seemed like the extractor wasn’t hanging onto the rim long enough. Turned out putting that little oring under the spring on the back of the extractor fixed it completely. Maybe yours has this already. My knowledge of AR stuff is limited. But this was the fix to my ejection headache

 

[Bigjake83]

It's your buffer weight, are you running the H2 or H1?

I bet if you installed the original full mass BCG you'd see a improvement with just increasing the reciprocating Mass.

 

[357Max]

I’d also suggest replacing the 1 pc gas ring with a good 3pc set. If your gass system is leaking or not efficient, then adjustment will be less responsive.

+1 to what Jake said. I have 1 AR with a fixed gas block that was ejecting 1:30 with Vltor A5. Swapped low mass carrier to std wt & ejection is now at 3:00

 

[MK20]

Sorry for the wall of text,, but this will explain how to understand what is happening.

Yeah. Light reciprocating mass will do that. Keep in mind, mass and velocity are inversely related when it comes to reciprocating parts. In order for your super light operating parts to cycle properly, i.e. reach maximum rearward travel before starting forward, they have to be moving faster. This is because they have less mass to retain inertia, and must therefore compensate for it with velocity.

The AR was designed around a certain weight of reciprocating parts and spring pressure which corresponds to gas port pressure coupled with the dwell time of the bullet. Many people use light weight bolt carriers because they think that it will reduce felt recoil. This is incorrect.

Let's look at the formula for kinetic energy. K= 1/2 × m × v2

Thus we can see that velocity is the element that is squared, and thus has the most impact on the outcome of the formula. If a person can only change one thing to reduce kinetic energy, velocity is the most beneficial to reduce.

Thus, all things being equal, a properly gassed, buffered, and sprung, full weight BCG will have LESS FELT RECOIL than a properly gassed , buffered, and sprung light weight BCG.

In your specific case @TheHorta , we can see that your light BCG has to have more velocity than a normal BCG to retain enough kinetic energy to continue cycling properly. Therefore, it has an ejection pattern similar to an overgassed normal BCG because it's rate of rearward travel is increased to maintain proper functioning.

If you want this resolved, put in a full weight BCG, swap in the heaviest buffer you can and still get it to cycle and lock open on empty with your weakest ammo. If you still need more resistance, up your spring weight as a last resort.

 

[Aftermath]

^^Thus is the way

 

[mtrmn]

If it works, and it obviously does, and doesn't tear up brass, leave it alone. JMO

 

[N_Turs]

Sorry for the wall of text,, but this will explain how to understand what is happening.

Yeah. Light reciprocating mass will do that. Keep in mind, mass and velocity are inversely related when it comes to reciprocating parts. In order for your super light operating parts to cycle properly, i.e. reach maximum rearward travel before starting forward, they have to be moving faster. This is because they have less mass to retain inertia, and must therefore compensate for it with velocity.

The AR was designed around a certain weight of reciprocating parts and spring pressure which corresponds to gas port pressure coupled with the dwell time of the bullet. Many people use light weight bolt carriers because they think that it will reduce felt recoil. This is incorrect.

Let's look at the formula for kinetic energy. K= 1/2 × m × v2

Thus we can see that velocity is the element that is squared, and thus has the most impact on the outcome of the formula. If a person can only change one thing to reduce kinetic energy, velocity is the most beneficial to reduce.

Thus, all things being equal, a properly gassed, buffered, and sprung, full weight BCG will have LESS FELT RECOIL than a properly gassed , buffered, and sprung light weight BCG.

In your specific case @TheHorta , we can see that your light BCG has to have more velocity than a normal BCG to retain enough kinetic energy to continue cycling properly. Therefore, it has an ejection pattern similar to an overgassed normal BCG because it's rate of rearward travel is increased to maintain proper functioning.

If you want this resolved, put in a full weight BCG, swap in the heaviest buffer you can and still get it to cycle and lock open on empty with your weakest ammo. If you still need more resistance, up your spring weight as a last resort.

This has always confused me a bit as well. Why does JP even offer low mass stuff if it doesn't reduce felt recoil. Is it purely to speed up cycling? I have a very similar set up as TheHorta does the same with the brass but always runs so I never worried about it.

 

[srt-4_uk]

This has always confused me a bit as well. Why does JP even offer low mass stuff if it doesn't reduce felt recoil. Is it purely to speed up cycling? I have a very similar set up as TheHorta does the same with the brass but always runs so I never worried about it.

Because in an AR, there's more than just felt recoil. Take a full mass setup and drop the bolt. Then do the same to low mass, which one dips the muzzle more? A good low mass setup will get faster and closer splits than a good full mass setup.

JP Low mass stuff has its uses but it's not the answer for all uses.

 

[supercorndogs]

This has always confused me a bit as well. Why does JP even offer low mass stuff if it doesn't reduce felt recoil. Is it purely to speed up cycling? I have a very similar set up as TheHorta does the same with the brass but always runs so I never worried about it.

Muzzle dip maybe? More forward recoil from the weight of everything going into battery?

 

[hafejd30]

This has always confused me a bit as well. Why does JP even offer low mass stuff if it doesn't reduce felt recoil. Is it purely to speed up cycling? I have a very similar set up as TheHorta does the same with the brass but always runs so I never worried about it.

JP is more geared towards race “game” guns. The less mass you have reciprocating the less the gun moves when fired. A AR vs a Tavor or a DI 9mm AR vs a cz scorpion have a noticeable difference. That’s extreme compared to just a BCG in an AR but same effect. Less weight moving. Gas vs inertia in those cases but you really notice the bolt weight

I had an AR set up with a Franklin binary trigger. I don’t remember the exact combo I used as it was a few years ago. But the BCG was skeletonized and very light weight. Just a standard 16” psa upper and psa lower. That guns recoil and muzzle flip was insanely low. Very easy to keep on target

 

[Cascade Hemi]

This has always confused me a bit as well. Why does JP even offer low mass stuff if it doesn't reduce felt recoil. Is it purely to speed up cycling? I have a very similar set up as TheHorta does the same with the brass but always runs so I never worried about it.

Because low mass does reduce felt recoil. That post speaks in absolutes when the reality isn't absolute. For example, I have a LFAR low mass BCG with a 1oz buffer ejecting at the 3 to 4 o'clock. According to that post, it must eject at 1 o'clock. The rifle shoots awesome and I can watch the hits which should be completely impossible based on posts in this thread.

I assume most commenters haven't actually done a weight and gas work up.

 

[MK20]

Because low mass does reduce felt recoil. That post speaks in absolutes when the reality isn't absolute. For example, I have a LFAR low mass BCG with a 1oz buffer ejecting at the 3 to 4 o'clock. According to that post, it must eject at 1 o'clock. The rifle shoots awesome and I can watch the hits which should be completely impossible based on posts in this thread.

I assume most commenters haven't actually done a weight and gas work up.

I do buffer weight work ups on every AR and a gas work up if applicable.

Your post does not give enough information.

Gas adjustment fixed or not?

Spring weight? Standard or other?

I spoke in absolutes because math is absolute. There are of course other factors, which is why in my example is stated that if all things are equal, thus and such will occur.

If your rifle has things like different spring rates and adjusted or reduced port size gas, then all things are not equal, are they?


It should say something when Jim Sullivan himself says that the best thing you can do for reliability is to increase the weight of your reciprocating parts in your AR.

 

[MK20]

Also,

If you go to 6:17 in this video, you will hear Jim Sullivan, head of the AR 15 dev team say that you are crazy if you lighten the weight of the bolt carrier.

 

[-H-]

Ejection pattern as a metric for sufficient gas for reliability in operation is garbage science. All that matters is reliability, I wouldn’t worry about ejection pattern.

 

[TheHorta]

Ejection pattern as a metric for sufficient gas for reliability in operation is garbage science. All that matters is reliability, I wouldn’t worry about ejection pattern.

Gonna stuff an unused Geissele REBCG I have just laying around in there just for kicks and see what that changes. I have zero issue keeping it as-is and not worrying about it. In fact, dudes on the firing line at classes will probably thank me.

 

[srt-4_uk]

It should say something when Jim Sullivan himself says that the best thing you can do for reliability is to increase the weight of your reciprocating parts in your AR.

Why is a full mass setup more reliable than a low mass?

 

[roostercogburn98]

H2 buffer and a Tubb flatwire would probably solve your dilemma.

 

[Cascade Hemi]

I do buffer weight work ups on every AR and a gas work up if applicable.

Your post does not give enough information.

Gas adjustment fixed or not?

Spring weight? Standard or other?

I spoke in absolutes because math is absolute. There are of course other factors, which is why in my example is stated that if all things are equal, thus and such will occur.

If your rifle has things like different spring rates and adjusted or reduced port size gas, then all things are not equal, are they?


It should say something when Jim Sullivan himself says that the best thing you can do for reliability is to increase the weight of your reciprocating parts in your AR.

Ironically Jim Sullivan isn't all that relevant anymore. It seems like you're back tracking with all of the sudden questions. Horta spelled out his conditions up front and you took that as your que to sound smart. There are cases to be made for FMOS and LMOS, you absolutely missed the mark. I'll leave you to the smart guy math.

 

[1911hombre]

 

[MK20]

Ironically Jim Sullivan isn't all that relevant anymore. It seems like you're back tracking with all of the sudden questions. Horta spelled out his conditions up front and you took that as your que to sound smart. There are cases to be made for FMOS and LMOS, you absolutely missed the mark. I'll leave you to the smart guy math.

I would merely point out that the advice of the gentleman in charge of scaling down and adapting Stoner's AR10 design into the AR15 would likely be relevant.

That is like saying that the owner's manual for your vehicle is not relevant because you have bought aftermarket parts, installed them, and are now experiencing altered performance.

 

[MK20]

Why is a full mass setup more reliable than a low mass?

Because if velocity is slowed artificially by carbon, grime, or thick lube due to cold weather, etc., then the mass of the reciprocating parts will be more likely to retain enough energy to properly cycle.

 

[srt-4_uk]

Because if velocity is slowed artificially by carbon, grime, or thick lube due to cold weather, etc., then the mass of the reciprocating parts will be more likely to retain enough energy to properly cycle.

But the opposite doesn't apply when the buffer spring acts on the low mass carrier slowing it down faster than the full mass carrier?

 

[chase723]

I ran into the same issue with a 16” 6.5 Creed. Didn’t matter what I did to the gas, can or no can, it ejects at 1:30-2:00. I’ve ran it at 0 deg F, no issues…so I’ve left well enough alone.

 

[st1650]

The only place I ever used a low mass BCG was on a dedicated subsonic 300 BLK with a tuned JP SCS weight and springs kit.
I’m sure they have their uses on comp guns but generally I prefer running H2 weights either in a A5, Armaspec or JP SCS and be a bit over sprung with the gas port turned down enough to reliably hold the last round bolt open.
Actually in my quest to find the quietest fastest burning powder for subsonic, I tried many light weight buffers and springs combo and always ended up on the edge of reliability when it would get cold or the gun dirty.

 

[Ernest 5.56]

EXECUTIVE SUMMARY: “High-end” rifle works flawlessly, runs like a sewing machine, eats everything, but ejects rounds at 0130-0200 regardless of gas block setting. Is this a problem? Or who cares as long as it runs perfectly otherwise?

THE WHOLE NINE YARDS:

So… took an all-factory Noveske N4 G3 rifle and made it better, faster, stronger.

Put on Form-1 SBR.

Removed factory 13.7” with P/W Flaming Pig, replaced with 14.5” Proof CF “Wylde” coupled with the new JP D2 52-position (!!!) adjustable gas block.

Replaced 15” NSR3 rail with 13.5” NSR3 rail.

Replaced all lower parts with $400 in V7 Titanium bits — ‘cuz everyone needs an $80 safety selector and $100 ejection port cover.

Replaced buffer tube with V7 Lithium Aluminum tube, ‘cuz why not?

Replaced factory trigger with SSA-X.

Replaced Noveske BCG with JP Chromed LMOS.

Replaced Noveske buffer with JP SCS.

Cerakoted entire rifle in Gen2 HIR-265 (IR signature-reducing coating for NODs fun) — upper, lower, handrail, buffer tube, shiny bits like door cover and takedown pins, etc.

Added HUX flash hider and 7.62 Ti (pre-Flow) can.

Popped an FDE ATACR 1-8 with offset RMR-06 in C1 mount on top and called it a day.

Will take pics soon for posterity.

Anyhoo… with all that said, we finished the rifle on the Thursday before I took it to CR2’s Light Fighter course the very next day. First order of business was to get the gas system perfectly adjusted. The HUX can doesn’t have much backpressure at all, and the gun will never really be shot unsuppressed, but we did try it both with and without — zero difference.

JP’s new D2 AGBs have 52 positions for adjustment. Their instructions say to close it off entirely, then back-out 12 clicks, or roughly one full turn, and start there. They say the gun probably will NOT cycle at 12 clicks, and they were correct. They say to adjust in 3-click increments, which we did. After the first adjustment (15-clicks), the gun ejected, but just barely at about 0100. Went another 3 clicks and it was better, about 0130-0200. At this point I figured additional adjustment would push angle of eject toward the Orthodox Religious Dogma-Approved 0300-0400 angle, but no matter how may clicks we dialed-in, the pattern didn’t change — again, with or without the can.

Given this behavior, I figured the best position was at 18-21 clicks, since it cycled just fine with everything from cheap 223 Wolf Gold as well as 855A1 and 262 Mod 1C and the much maligned AAC 77g OTM 556.

Took it to the 3-day LF course the very next day and it never gave the slightest hiccup all weekend, nailing IPSC steel at >650 yards like a Rock Star.

Shoots like Chantilly Whipped Cream — soft and smooth.

But that eject angle…

Assume it’s more related to the LMOS/SCS than the gas system?

Aside from the angle, is there any reason to mess with it? It’s just absolute perfection otherwise and I hesitate to pfutz with it by playing Rifle Jenga.

Pictures please!

I think you should try the jp light weight buffer.

Also here is another take on ejection pattern

AR-15 Ejection Pattern – Does it Matter as Much as the Internet...

While brass ejection CAN indicate something is wrong, it isn’t the end-all-be-all metric of determining an issue that people make it out to be. There are simply too many variables that can contribute to the ejection pattern for it to be a reason to trade out parts.

www.arbuildjunkie.com

 

[Cascade Hemi]

I really like JP's bolts and carriers. However, they seem to use sub optimal rings and springs. I would change the extractor spring and insert, the ejector spring, and the gas rings. I would (and do) use the sprinco springs and rings.

While you have the ejector out, run some Emory cloth around the edges. The rifle isn't over or under gassed which says it is ejector/extractor related. The SprinCo gas rings are a bonus since JP uses low tension one piece rings and they suck.

 

[BCP]

Different bolt carriers/bolts can have different ejection patterns. Swapping bolt carriers made one of my rifles go from 4 oclock to 2 oclock.

 

[308pirate]

EXECUTIVE SUMMARY: “High-end” rifle works flawlessly, runs like a sewing machine, eats everything, but ejects rounds at 0130-0200 regardless of gas block setting. Is this a problem? Or who cares as long as it runs perfectly otherwise?

THE WHOLE NINE YARDS:

So… took an all-factory Noveske N4 G3 rifle and made it better, faster, stronger.

Put on Form-1 SBR.

Removed factory 13.7” with P/W Flaming Pig, replaced with 14.5” Proof CF “Wylde” coupled with the new JP D2 52-position (!!!) adjustable gas block.

Replaced 15” NSR3 rail with 13.5” NSR3 rail.

Replaced all lower parts with $400 in V7 Titanium bits — ‘cuz everyone needs an $80 safety selector and $100 ejection port cover.

Replaced buffer tube with V7 Lithium Aluminum tube, ‘cuz why not?

Replaced factory trigger with SSA-X.

Replaced Noveske BCG with JP Chromed LMOS.

Replaced Noveske buffer with JP SCS.

Cerakoted entire rifle in Gen2 HIR-265 (IR signature-reducing coating for NODs fun) — upper, lower, handrail, buffer tube, shiny bits like door cover and takedown pins, etc.

Added HUX flash hider and 7.62 Ti (pre-Flow) can.

Popped an FDE ATACR 1-8 with offset RMR-06 in C1 mount on top and called it a day.

Will take pics soon for posterity.

Anyhoo… with all that said, we finished the rifle on the Thursday before I took it to CR2’s Light Fighter course the very next day. First order of business was to get the gas system perfectly adjusted. The HUX can doesn’t have much backpressure at all, and the gun will never really be shot unsuppressed, but we did try it both with and without — zero difference.

JP’s new D2 AGBs have 52 positions for adjustment. Their instructions say to close it off entirely, then back-out 12 clicks, or roughly one full turn, and start there. They say the gun probably will NOT cycle at 12 clicks, and they were correct. They say to adjust in 3-click increments, which we did. After the first adjustment (15-clicks), the gun ejected, but just barely at about 0100. Went another 3 clicks and it was better, about 0130-0200. At this point I figured additional adjustment would push angle of eject toward the Orthodox Religious Dogma-Approved 0300-0400 angle, but no matter how may clicks we dialed-in, the pattern didn’t change — again, with or without the can.

Given this behavior, I figured the best position was at 18-21 clicks, since it cycled just fine with everything from cheap 223 Wolf Gold as well as 855A1 and 262 Mod 1C and the much maligned AAC 77g OTM 556.

Took it to the 3-day LF course the very next day and it never gave the slightest hiccup all weekend, nailing IPSC steel at >650 yards like a Rock Star.

Shoots like Chantilly Whipped Cream — soft and smooth.

But that eject angle…

Assume it’s more related to the LMOS/SCS than the gas system?

Aside from the angle, is there any reason to mess with it? It’s just absolute perfection otherwise and I hesitate to pfutz with it by playing Rifle Jenga.

Quit worrying about trivial stuff. If it runs leave it alone.

 

[MO Fugga]

Almost have enough parts left over for another gun, what'll it be?

 

[sinister]

I am not sure you have a problem.

The weapon functions and cycles perfectly and it seems your gas system doesn't foul much.

Are you tuning for hits and to minimize stoppages or to save your brass? If you're just trying to solve an OCD geometry and brass collection problem I'd say save the calories. Just shoot.

 

[TheHorta]

I am not sure you have a problem.

The weapon functions and cycles perfectly and it seems your gas system doesn't foul much.

Are you tuning for hits and to minimize stoppages or to save your brass? If you're just trying to solve an OCD geometry and brass collection problem I'd say save the calories. Just shoot.

Pure OCD.

That said, if reciprocating mass is too light and higher speed than “normal” it may conceivably narrow the margin for error under varying shooting conditions. Maybe premature wear is a thing too, I dunno.

Maybe. Juss spitballin’

 

[sinister]

... if reciprocating mass is too light and higher speed than “normal” it may conceivably narrow the margin for error under varying shooting conditions. Maybe premature wear is a thing too, I dunno.

Maybe. Juss spitballin’

Unless you're going to do ridiculous military things (like shoot in sub-arctic conditions) I don't think it matters. If parts wear out, change them.

MIL-SPEC simply means it works under a known/specified set of conditions at a price point a bidder thinks he can meet while still making a profit. It is not perfection.

 

[Cascade Hemi]

Unless you're going to do ridiculous military things (like shoot in sub-arctic conditions) I don't think it matters. If parts wear out, change them.

MIL-SPEC simply means it works under a known/specified set of conditions at a price point a bidder thinks he can meet while still making a profit. It is not perfection.

Bro with the fancy math is gonna be big mad now.

 

[MK20]

Bro with the fancy math is gonna be big mad now.

Not really.

We were not talking about milspec.

And math is just math.

 

[MontanaMan]

Maybe I missed it but what length gas system are you using? Also, gas port size in the barrel?

I've set up lots of low mass systems on everything except carbine gas, with no real issue, so I'm thinking something is not quite right & sometimes you need to do some things differently with LMOS.

Also, not at all a fan of JP's spring system at all.

Also, JP doesn't make a chromed carrier...... the sliver colored ones are polished SS.

More comments after knowing what length gas system, but at a minimum, 3 PC gas rings, a different extractor / O-ring from Sprinco or BCM & a new ejector spring.

MM

 

[st1650]

Maybe I missed it but what length gas system are you using? Also, gas port size in the barrel?

I've set up lots of low mass systems on everything except carbine gas, with no real issue, so I'm thinking something is not quite right & sometimes you need to do some things differently with LMOS.

Also, not at all a fan of JP's spring system at all.

Also, JP doesn't make a chromed carrier...... the sliver colored ones are polished SS.

More comments after knowing what length gas system, but at a minimum, 3 PC gas rings, a different extractor / O-ring from Sprinco or BCM & a new ejector spring.

MM

What’s wrong with the JP spring system ?

 

[RUTGERS95]

2-3 isn't necessarily bad, will provide greater function over longer period and in more adverse conditions and is common on hotter ammo

downside is timing is fast and may lead to stovepipes and premature wear but that premature wear was found to be immaterial in testing by Crane

I like right at 3ish