Spring/buffer for premature ejection problem on suppressed AR10

[Squad51]

Bottom line up front: What’s the most cost effective spring/buffer combo to slow down premature ejection problems?

I’m having trouble with my suppressed AR10 308 unlocking while still under pressure. I‘m shooting mild loads and getting ejector smears, extractor damage on case rim, and super dirty brass. I do not have flattened primers and I am ejecting at 3:30-4:00. I have searched the Hide and found some good info - including this one that shows my exact problem: Ejector swipes on suppressed AR10

I have an AR-Stoner 5.3 oz buffer (actual weight 5oz on my scale) and a Superlative AGB (open 4 clicks). Buffer spring is from a local gun store but I don’t think it’s a heavy spring.

Which spring/buffer combo that I should try that will slow it down? I know the JP SCS H2 is highly recommended but I don’t want to spend $200 if it’s not going to solve the problem. Are there cheaper options? Better options?

Aero M5
BA 18” 308 bbl
unmarked bolt from LGS (maybe Toolcraft?)
AR-Stoner heavy buffer
SA AGB

Picture shows results from 168gr FMJ over 40.5 and 41.0 I4895

 

[mtrmn]

Measure the internal depth of the buffer tube. I THINK the M5 is supposed to be 7-5/8" deep inside and the buffer length will be 3-1/4".
The buffer should be a minimum of 5.4 oz which is equivalent to H3 carbine buffer.
The spring should have a relaxed length of 14-1/8" max and a minimum of 13-3/4"
You'll be much better off with the 7-5/8" deep tube than the 7" deep AR15 tube that many makers use. The 7" deep tube takes a buffer that's only 2.5" long in a 308.

The above should be your basic starting point and should run properly unsuppressed. A suppressor sends a lot more gas down the tube into the gun due to back pressure. Many say you can completely tune your gun with just an adjustable gas block whether suppressed or not. I say BS.
If you don't slow the reciprocal mass (when shooting suppressed) IN ADDITION to adjusting the gas, the system will be too overly sensitive to ammo variations and reliability will go to shit. The window of proper operation on the gas adjustment will be too narrow.

I bought an 8.5 oz buffer from heavybuffers.com with an Armalite rifle spring. I could mix/match the tungsten weights in my buffer with steel weights to get a few different total weights. (6.8 oz, 7.6 oz, and 8.5 0z) After much experimentation I finally settled on the full 8.5 oz and adjusted gas from there. My AGB is a Seekins suppressor gas block, adjustable without tools once you get the initial adjustment range figured out.

 

[USK308]

@Squad51 (old-school reference...love it), have you measured the gas port size?

When I was building my .308 AR10 (M5 Upper/Lower, AP 18" barrel, SupArms AGB, JPSCS2-10H2 with the A5 buffer tube spacer), the gas port was WAY too small (0.0835"). The gas port size should be between 0.090" - 0.095." My rife wasn't cycling for beans.

Also, @mtrmn is correct on buffer tube depth (see attached pic).

Once I drilled the gas port out (#42 machinists drill bit), I was at 0.0945." Put the rifle together, opened the AGB all the way up, shot 1 round...rifle cycled, but didn't lock back. Closed the AGB down to 18 clicks from closed and shot 1 more round. Nearly perfect. Opened up 1 click (19 clicks from closed) and it was dead-nutz perfect. Ejection at 3:30 and perfect cycling with every shot. Video with my smartphone was interesting to capture; wish I had my DJI Osmo Action 3 at that time...LOL.

FWIW, I shoot 168gr Fed Prem Sierra Match-King (after much research and shooting, that was what looked to be the best option. The rifle WILL shoot any .308 from 147gr to 178gr ammo, but really really likes the 168gr Fed Prem SMK's

 

[Clint H]

I had to end up with the JP SCS and an H3 equivalent weight (3 of their tungsten rings) to get my 18" Aero M5 in .308 to stop swiping brass.

I've heard good things about going A5 and running an H2 buffer, though. Forget if folks were doing rifle or carbine buffer with that setup, though.

 

[USK308]

I had to end up with the JP SCS and an H3 equivalent weight (3 of their tungsten rings) to get my 18" Aero M5 in .308 to stop swiping brass.

I've heard good things about going A5 and running an H2 buffer, though. Forget if folks were doing rifle or carbine buffer with that setup, though.

Mine is a rifle setup...

 

[TheOE800]

Usually take a little blue pill for premature ejection…

OH WRONG THREAD

 

[mettee]

Mtrmn gave you the solution. Suppressed this is the best and only solution in my opinion. The jp scs won't do the job.

 

[TheOE800]

Everybody’s guns are different, but I’ve choked a rifle with the Slash buffer. Whereas it was just violent before the buffer, with it I had malfunctions every few rounds.

 

[mettee]

Everybody’s guns are different, but I’ve choked a rifle with the Slash buffer. Whereas it was just violent before the buffer, with it I had malfunctions every few rounds.

Something else was wrong with that set up then. And it's not just a buffer, if the wrong spring is used with it in the wrong receiver extension it doesn't work because it's outside the designed parameters.

In a rifle with the gas set properly, with the proper spring for the reciprocating mass; the buffer will have very little effect on function. You could vary the buffer weight by 4-5-6 oz and typically all you experience is a reduction in felt recoil. Slash makes buffers up to 16 oz.

He's shooting suppressed, and he's showing a clear read on his brass.

 

[mtrmn]

Everybody’s guns are different, but I’ve choked a rifle with the Slash buffer. Whereas it was just violent before the buffer, with it I had malfunctions every few rounds.

Those buffers can be disassembled and weights changed out to suit your gun. Also the gas port could be a bit too small.

 

[mtrmn]

I had to end up with the JP SCS and an H3 equivalent weight (3 of their tungsten rings) to get my 18" Aero M5 in .308 to stop swiping brass.

I've heard good things about going A5 and running an H2 buffer, though. Forget if folks were doing rifle or carbine buffer with that setup, though.

The carbine 3.25" buffer

 

[bfoosh006]

I would certainly try a different recoil spring. The unknown aspect of a recoil spring would bother me.
You could swap over to the Armalite Pattern buffer tube ( longer by 3/4" ) and the 3.25" buffers... and try a Armalite EA1095 buffer spring, considering your suppressed use.

The Armalite EA1095 buffer spring, is a known , respected recoil spring for use in the Armalite / Vltor buffer tube length.

I do also want to mention, your Federal brass... might be softer than other brass. So consider trying another brand of brass.
Brass cases can differ greatly in "hardness".
This pic, and while not directly related to your brass issue pics, can show differences from repeated reloadings. .

 

[Squad51]

The depth of knowledge on the 'hide is awesome, and I truly appreciate you all taking time to help a brother out.

My buffer tube is the Aero M5 308 Enhanced carbine buffer, and it measures 7" deep. The heavybuffers.com buffer looks like a really good option. I will get the 7 5/8" tube if I go the heavybuffers.com route. I am going to start by ordering a known heavy spring.

Thanks!

 

[mtrmn]

So I was under the impression your buffer tube was already 7-5/8 deep. The "A5" in your first post led me in that direction. Since you have the 7" that takes a 2.5" buffer. You'd need the Sprinco ORANGE spring for that setup. You state your buffer is already ~ 5 oz. To go any heavier you'd have to get one from heavybuffers or similar and still you're limited with the 2.5"buffer to about 6.5 oz max.
If the spring doesn't work, (personally I doubt it) then it'd be best for to go ahead with the 7-5/8 tube and 3.25 buffers.

 

[Cascade Hemi]

What does the brass look like with the gas shut off? What does the brass fired from this gun look like when resized .003 and fired again?

Piling weight into the operating system isn't the solution when you have an AGB. More weight is the go-to for some members here and it defies logic.

I agree the SR25 length receiver extension is easier to work with because it uses standard AR-15 carbine length buffers and springs. I don't think you need to add a super heavy buffer. A Sprinco blue and/or red spring and an H1 buffer should be the starting point. Sometimes you have to take weight out to get lower gas settings to work. More weight just means more gas pressure and volume is needed to cycle the action. Consider a buffer weight kit from KAK, it'll allow you to start with lower weight and work your way up. I have a super heavy buffer, it super sucks.

 

[mettee]

What does the brass look like with the gas shut off? What does the brass fired from this gun look like when resized .003 and fired again?

Piling weight into the operating system isn't the solution when you have an AGB. More weight is the go-to for some members here and it defies logic.

I agree the SR25 length receiver extension is easier to work with because it uses standard AR-15 carbine length buffers and springs. I don't think you need to add a super heavy buffer. A Sprinco blue and/or red spring and an H1 buffer should be the starting point. Sometimes you have to take weight out to get lower gas settings to work. More weight just means more gas pressure and volume is needed to cycle the action. Consider a buffer weight kit from KAK, it'll allow you to start with lower weight and work your way up. I have a super heavy buffer, it super sucks.

I have never seen you talk about gas on/off troubleshooting where did you get that idea from?

Some members pay attention to the characteristics of the rifle in question and they provide suggestions based on known experience with the OPs rifle's given specs and the following corresponding results when fired. A suppressed 308 will not run optimally with a 7" receiver extension with a sprinco blue or red with an H1/H2/H3 buffer while suppressed... even if the rifle has adjustable gas. Adjustable gas works in two operating scenarios, 1.) To set gas for typical function, and 2.) To adjust gas down once a suppressor is added. If the gas port is too small or large it becomes the most prevalent factor.

Copied from my post above:

"In a rifle with the gas set properly, with the proper spring for the reciprocating mass; the buffer will have very little effect on function. You could vary the buffer weight by 4-5-6 oz and typically all you experience is a reduction in felt recoil. Slash makes buffers up to 16 oz."

"So piling weight" has little to no effect on a properly sprung and gassed rifle. Once we truly understand the parts and their individual function the logic makes more sense. Buffer weight is specific to the needs of the rifle. Without extra buffer weight in a suppressed rifle, your killing brass, extractors/ejectors, bolts, barrel extensions, and your just causing excessive wear in the weapon and likely causing premature failure of conponents.

"Super heavy buffers" don't suck they just need to be used correctly with the right combination of parts in a situation that calls for it. If your gun doesn't call for it you don't use it.

 

[supercorndogs]

Usually take a little blue pill for premature ejection…

OH WRONG THREAD

Dat's for ejectile dysfunction.

 

[Cascade Hemi]

Bottom line up front: What’s the most cost effective spring/buffer combo to slow down premature ejection problems?

I’m having trouble with my suppressed AR10 308 unlocking while still under pressure. I‘m shooting mild loads and getting ejector smears, extractor damage on case rim, and super dirty brass. I do not have flattened primers and I am ejecting at 3:30-4:00. I have searched the Hide and found some good info - including this one that shows my exact problem: Ejector swipes on suppressed AR10

I have an AR-Stoner 5.3 oz buffer (actual weight 5oz on my scale) and a Superlative AGB (open 4 clicks). Buffer spring is from a local gun store but I don’t think it’s a heavy spring.

Which spring/buffer combo that I should try that will slow it down? I know the JP SCS H2 is highly recommended but I don’t want to spend $200 if it’s not going to solve the problem. Are there cheaper options? Better options?

Aero M5
BA 18” 308 bbl
unmarked bolt from LGS (maybe Toolcraft?)
AR-Stoner heavy buffer
SA AGB

Picture shows results from 168gr FMJ over 40.5 and 41.0 I4895
View attachment 8308706

Mid length or rifle length gas system?

 

[mtrmn]

I have never seen you talk about gas on/off troubleshooting where did you get that idea from?

Some members pay attention to the characteristics of the rifle in question and they provide suggestions based on known experience with the OPs rifle's given specs and the following corresponding results when fired. A suppressed 308 will not run optimally with a 7" receiver extension with a sprinco blue or red with an H1/H2/H3 buffer while suppressed... even if the rifle has adjustable gas. Adjustable gas works in two operating scenarios, 1.) To set gas for typical function, and 2.) To adjust gas down once a suppressor is added. If the gas port is too small or large it becomes the most prevalent factor.

Copied from my post above:

"In a rifle with the gas set properly, with the proper spring for the reciprocating mass; the buffer will have very little effect on function. You could vary the buffer weight by 4-5-6 oz and typically all you experience is a reduction in felt recoil. Slash makes buffers up to 16 oz."

"So piling weight" has little to no effect on a properly sprung and gassed rifle. Once we truly understand the parts and their individual function the logic makes more sense. Buffer weight is specific to the needs of the rifle. Without extra buffer weight in a suppressed rifle, your killing brass, extractors/ejectors, bolts, barrel extensions, and your just causing excessive wear in the weapon and likely causing premature failure of conponents.

"Super heavy buffers" don't suck they just need to be used correctly with the right combination of parts in a situation that calls for it. If your gun doesn't call for it you don't use it.

Also I SUSPECT a lot of the makers who use the AR15 7" buffer tubes on their large frame guns also spec a smaller gas port in an effort to make the sub-standard (IMO for 308 etc) recoil system perform better. So finding out the gas port dia may be a good idea as well. If it's large, adjustable gas will deal with that. Too small, ain't nothin' gonna fix that properly until it's drilled out.
IME, neither heavy weight nor adjustable gas alone will make a suppressed large frame run properly. Rather, a combination of the 2 in the proper proportions will bring about decent reliability. I worked on a 16" PSA "mid-length" kit gun off and on for over 2 years as I had time. What a nightmare, but what a learning experience as well. I'm not here to argue all the pros and cons endlessly, just trying to help using the little experience and knowledge I have. The knowledge I have was gleaned from forums like this and a "let me try this no matter how dumb it sounds" outlook.

 

[mettee]

Cunnerman I believe it is...I think he is dealing with a small gas port in a Wilson barrel, he plans to try and use a sprinco blue to see if that works. His thread is around here some place.

 

[TheOE800]

Dat's for ejectile dysfunction.

I obviously have no experience either way, LOL.

 

[mtrmn]

So, would inability to pull out at the proper time or at all be called extractile dysfunction??

 

[TheOE800]

So, would inability to pull out at the proper time or at all be called extractile dysfunction??

No that's called child support.

 

[UpSideDown]

I’m going to provide my experience here with a large frame AR that has worked great. It does go against what I think has been shared here.

I have a Barrett REC-10 in .308. It has a mid length gas system and a standard AR-15 7” buffer tube. It is gassed to cycle when dirty with 147gr ammo and is absolutely gassed to the moon when shooting 180gr’s suppressed. I tried different buffer weights, Sprinco Orange and I think Blue or White, and a Superlative gas block. After going through all the iterations I ended up with the best solution being the factory spring and buffer with the gas block opened 14 clicks. It runs great suppressed, it runs well though a little slow unsuppressed.

In my opinion if you’re over gassed you should start with the gas block. Adding weight to the operating system of an AR is a bandaid that has the marginal effect of making the carrier move a little slower at the expense of recoil, but it doesn’t slow down the initial rotation of the bolt. It’s better to use higher spring rate - that is what is actually producing a force that counteracts the gas pressure’s force on the internal piston. The consequence of a stronger spring is that it makes the gun snappier, which is harsher on you and the gun. I much prefer just adjusting the gas down. It’s worked on all of my guns with my suppressors. It makes a nice shooting experience and reduces recoil instead of adding to it. Adjusting a gas block is the direct equivalent to having a smaller gas port drilled in your barrel.

I find it interesting your gun is doing that with the gas block open only 4 clicks. All of my guns for some reason like 14 clicks. Do you mean 4 rotations (16 clicks)? It’s hard to imagine you’d be way over gassed with an almost occluded gas port.

 

[Top O' Texas]

What does the brass look like with the gas shut off? What does the brass fired from this gun look like when resized .003 and fired again?

Piling weight into the operating system isn't the solution when you have an AGB. More weight is the go-to for some members here and it defies logic.

I agree the SR25 length receiver extension is easier to work with because it uses standard AR-15 carbine length buffers and springs. I don't think you need to add a super heavy buffer. A Sprinco blue and/or red spring and an H1 buffer should be the starting point. Sometimes you have to take weight out to get lower gas settings to work. More weight just means more gas pressure and volume is needed to cycle the action. Consider a buffer weight kit from KAK, it'll allow you to start with lower weight and work your way up. I have a super heavy buffer, it super sucks.

^^^guy has a point!

BUT........you're using an AR15 carbine spring in an AR10 A5 tube or is it rifle length? While I haven't checked compressed lengths of 15 carbine and rifle springs yet I'll add that I've had more trouble with superlative blocks than any other and add seekins and jp to that list.

What I will say is that if the gas port isn't a good operating size per system length it's a rat race on problem solving! In 308win chambered barrels from 12.5-26" and 3 different gas system lengths only 1 (faxon) gives me problems. 6 of 7 run great without an agb and only using standard weight springs and buffers. While I don't know the port size on any of them (wish I did without removing the handguard and gb) only 1 is from faxon. 2 are rock river production guns, 2 cbi m118 chambered, 1 apf complete upper (12'5"), 1 2A and 1 (?). More weight on the bcg needs more pressure (not volume) to move it. Adding spring pressure and buffer weight can delay unlocking and reduce bounce (only in battery position). Even at specific gas lengths (mid, interm, etc) not many companies will have the same port size per gas system length.

Here's another product I see in many "I have a problem" when it comes to AR's.............SA gas blocks.

Where did the OP find 168gr fmj 30cal bullets? All I can find is loaded ammo from wolf and barnaul.

How's the accuracy and function without the suppressor with the load info you provided?

 

[thehun]

The best buffer setup is a .308 rifle length buffer kit from Aero for a fixed stock setup or LMT MWS buffer kit for collapsible stock setup...

In my experience ... if you have to resort to super high tensioned springs and heavy buffers outside of what those two kits provide ... you have some other issues around your build ... for the record I absolutely hated how my previous AR10 felt after heavy springs and super heavy buffers (like what everyone recommends to solve "issues") ... yuck ... never again ... heavy springs/buffers are only band-aids anyways ...

My latest AR10 with the Criterion 22" M118LR Hybrid barrel with the Aero 308 rifle buffer kit and SLR gas block set for my can runs all ammo well including Russian steel (wanted to see what it would do with 10 rounds of that) and has the absolute most pleasant .308 semi auto shooting dynamics I have ever felt (this is compared to other .308 semis I've owned like tuned SCAR17/20, tuned MWS, 716, Tavor 7 and M14 EBR Mod 0 clone) ...

 

[mtrmn]

Screw a high-backpressure suppressor on them and let's see if they'll run with/without the suppressor with most any full power ammo you can get your hands on...
As with everything that we think we've got figured out--YMMV. What works on one, ain't gonna work on the next 3. My advice included.

 

[mettee]

The best buffer setup is a .308 rifle length buffer kit from Aero for a fixed stock setup or LMT MWS buffer kit for collapsible stock setup...

In my experience ... if you have to resort to super high tensioned springs and heavy buffers outside of what those two kits provide ... you have some other issues around your build ... for the record I absolutely hated how my previous AR10 felt after heavy springs and super heavy buffers (like what everyone recommends to solve "issues") ... yuck ... never again ... heavy springs/buffers are only band-aids anyways ...

My latest AR10 with the Criterion 22" M118LR Hybrid barrel with the Aero 308 rifle buffer kit and SLR gas block set for my can runs all ammo well including Russian steel (wanted to see what it would do with 10 rounds of that) and has the absolute most pleasant .308 semi auto shooting dynamics I have ever felt (this is compared to other .308 semis I've owned like tuned SCAR17/20, tuned MWS, 716, Tavor 7 and M14 EBR Mod 0 clone) ...

Heavy springs and heavy buffers do not go together. I think everyone is missing that fact, and then people still keep saying the same thing, that heavy buffers "suck". Well again, if you use the parts wrong, and don't know how to use them or set them up, while not understanding what the parts are actually doing, you get bad results.

A heavy buffer is in no way a bandaid, but they have a very specific function they serve.

No two cans have the same back pressure, and flow through cans have very little back pressure. You can get away with light springs and lighter buffers with flow through cans. If a gun runs fine with a high back pressure can with light springs and buffers it's gas can be assumed to be "lower." Again, these are parameters that don't match the OPs experiences.

No two rifles are the same.

It's best to consider the total sum of parts and accessories before we offer opinions, especially if we don't understand specifics.

 

[Squad51]

The bbl is an 18" Ballistic Advantage with Mid-Length gas system. I measured the gas port on a different BA barrel and it was 0.073".

I'm not sure how the brass marks look without the suppressor. I fired without the suppressor when I was breaking in the barrel but I was not focused on accuracy. I don't recall seeing ejector marks but can't say for sure. Will check the next time I go to the range.

The AGB is open 4 CLICKs (1 complete revolution). When breaking in the bbl without the suppressor, it needed to be open 8 clicks to lock back on an empty magazine.

I really don't want to chase heavier springs and buffers, but I really want to be able to shoot this with a suppressor.

 

[UpSideDown]

The bbl is an 18" Ballistic Advantage with Mid-Length gas system. I measured the gas port on a different BA barrel and it was 0.073".

I'm not sure how the brass marks look without the suppressor. I fired without the suppressor when I was breaking in the barrel but I was not focused on accuracy. I don't recall seeing ejector marks but can't say for sure. Will check the next time I go to the range.

The AGB is open 4 CLICKs (1 complete revolution). When breaking in the bbl without the suppressor, it needed to be open 8 clicks to lock back on an empty magazine.

I really don't want to chase heavier springs and buffers, but I really want to be able to shoot this with a suppressor.

Im surprised that 4 clicks is allowing it to be overgassed. All of my large and small frames are right at 14 clicks. You should be able to tune it by turning the gas down and trying again.

 

[USK308]

The bbl is an 18" Ballistic Advantage with Mid-Length gas system. I measured the gas port on a different BA barrel and it was 0.073".

I'm not sure how the brass marks look without the suppressor. I fired without the suppressor when I was breaking in the barrel but I was not focused on accuracy. I don't recall seeing ejector marks but can't say for sure. Will check the next time I go to the range.

The AGB is open 4 CLICKs (1 complete revolution). When breaking in the bbl without the suppressor, it needed to be open 8 clicks to lock back on an empty magazine.

I really don't want to chase heavier springs and buffers, but I really want to be able to shoot this with a suppressor.

I don't think you are adjusting your Superlative Arms AGB correctly (based on what you have stated. 4 clicks (1 revolution) is still in restrictive mode, per their guidance shown below...

 

[msgriff]

The bbl is an 18" Ballistic Advantage with Mid-Length gas system. I measured the gas port on a different BA barrel and it was 0.073".

I'm not sure how the brass marks look without the suppressor. I fired without the suppressor when I was breaking in the barrel but I was not focused on accuracy. I don't recall seeing ejector marks but can't say for sure. Will check the next time I go to the range.

The AGB is open 4 CLICKs (1 complete revolution). When breaking in the bbl without the suppressor, it needed to be open 8 clicks to lock back on an empty magazine.

I really don't want to chase heavier springs and buffers, but I really want to be able to shoot this with a suppressor.

18" with MLGS is going to be a challenge running suppressed. Very long effective dwell, with a higher port pressure compared to rifle length gas. I might have missed it, but what specific suppressor are you running?

 

[wade2big]

18" with MLGS is going to be a challenge running suppressed. Very long effective dwell, with a higher port pressure compared to rifle length gas. I might have missed it, but what specific suppressor are you running?

I was just going to say this. The correct gas port location for an 18” barrel is rifle length. You cannot fix an incorrectly placed gas port with any combination of adjustable gas block, spring, or buffer. Adding a suppressor only compounds the issue. @Squad51, you need a different barrel that has a correctly placed gas port. This is your fix.

 

[sinister]

18" with MLGS is going to be a challenge running suppressed. Very long effective dwell, with a higher port pressure compared to rifle length gas.

I was just going to say this. The correct gas port location for an 18” barrel is rifle length. You cannot fix an incorrectly placed gas port with any combination of adjustable gas block, spring, or buffer. Adding a suppressor only compounds the issue. @Squad51, you need a different barrel that has a correctly placed gas port. This is your fix.

Nailed it.

 

[Squad51]

I was just going to say this. The correct gas port location for an 18” barrel is rifle length. You cannot fix an incorrectly placed gas port with any combination of adjustable gas block, spring, or buffer. Adding a suppressor only compounds the issue. @Squad51, you need a different barrel that has a correctly placed gas port. This is your fix.

I have a 16" bbl (same BA mid-lenght, but in 16"). Would 2" less dwell time help my situation?

 

[Squad51]

18" with MLGS is going to be a challenge running suppressed. Very long effective dwell, with a higher port pressure compared to rifle length gas. I might have missed it, but what specific suppressor are you running?

The suppressor is a YHM Resonator R2

 

[Top O' Texas]

I have a 16" bbl (same BA mid-lenght, but in 16"). Would 2" less dwell time help my situation?

Carbine (7.3") and mid (9.3"), so 16 - 7.3= 8.7" and 18 - 9.3=8.7". That makes dwell time the same, but pressure will be less with the same ammo. Dwell time before the port is unimportant, only lessens pressure at distances.

 

[Squad51]

Carbine (7.3") and mid (9.3"), so 16 - 7.3= 8.7" and 18 - 9.3=8.7". That makes dwell time the same, but pressure will be less with the same ammo. Dwell time before the port is unimportant, only lessens pressure at distances.

Both are mid length gas systems, so it is 16-9.3=6.7 vs 18-9.3=8.7.

 

[Squad51]

I don't think you are adjusting your Superlative Arms AGB correctly (based on what you have stated. 4 clicks (1 revolution) is still in restrictive mode, per their guidance shown below...

You are correct - I am using in the Restrictive mode instead of the Bypass mode. A number of people have posted that .308 is too much for Bypass so I did not try it. I will do so next time I go to the range.

 

[mettee]

Just an FYI, the bypass mode will cover the front end of the barrel and inside of HG with carbon.

Id give the 16" barrel a try if you can swap it easily, if its not easy then ignore The YHM Res is fairly high back pressure, as Im guessing you already know.

 

[USK308]

You are correct - I am using in the Restrictive mode instead of the Bypass mode. A number of people have posted that .308 is too much for Bypass so I did not try it. I will do so next time I go to the range.

Hopefully you get the rifle dialed in at some point soon...

 

[Top O' Texas]

Both are mid length gas systems, so it is 16-9.3=6.7 vs 18-9.3=8.7.

I need to stop reading from my phone.........................

 

[wade2big]

I have a 16" bbl (same BA mid-lenght, but in 16"). Would 2" less dwell time help my situation?

It will help and you may be satisfied. Companies like Daniel Defense use an intermediate length gas systems in their 16” .308 gassers. Basically the gas port is drilled in between rifle and mid-length.

 

[thehun]

The suppressor is a YHM Resonator R2

I run the same can ... nice choice ... you shouldn't need super heavy buffers/stiff springs ... but I would say you do need a matched buffer kit to set your baseline vs the mismatch stuff you got going on.

If you do run your gas block in bypass mode ... you will lose some velocity ... I ditched my Superlative for a SLR ... couldn't be happier.

Have you headspace your barrel to your bolt?

 

[Squad51]

Have you headspace your barrel to your bolt?

I have not headspaced it. I have only used a comparator to check brass before and after firing, which showed the shoulder grew by 0.002-0.003".

 

[Top O' Texas]

I have not headspaced it. I have only used a comparator to check brass before and after firing, which showed the shoulder grew by 0.002-0.003".

That's 1 way to do it and way cheaper is by shoulder bump.

 

[Top O' Texas]

It will help and you may be satisfied. Companies like Daniel Defense use an intermediate length gas systems in their 16” .308 gassers. Basically the gas port is drilled in between rifle and mid-length.

Interm gas is .45" longer than mid.

Pistol 4.1
carbine 7.3
Med 9.3
Interm 9.45
Rifle 12.7

These exclude Armalite and a few other companies.

 

[mettee]

Using peak carrier velocity and two buffer weights, excluding and ignoring all other frictional forces(drag/hammer, etc.), you obtain the same or very similar KE between a +5.3 oz buffer and an 8.5 oz buffer(plus bcg @20 oz) with only a 6.5% reduction in peak carrier velocity alone. Carrier velocity is not constant in the cycle, the contributing factors are spring(weight) and buffer(weight) differences, if you add buffer and it slows the peak carrier speed down the release of the PE and the creation of KE is less(less felt recoil). There are also naturally occurring speed changes in the cycle of the reciprocating mass when the gun fires(to keep this simple just ignore that). The buffers job is to buffer the initial force on the reciprocating mass, and to slow it and give the spring a chance to absorb and control, then return. The full weight of the reciprocating mass should be considered(bcg & buffer). Full mass ar10 BCG's can vary 2-3 oz from brand to brand(5.3oz could quickly become 8.5 oz and really at that point its not a heavy buffer as its making up for a light carrier possibly).

The other acting force is PE and that relates to the spring, but for this lets say the spring stays the same in both comparisons with two buffer weights. If the carrier is moving faster it has more energy and carries that further rearward where the spring is storing more energy; going slower it travels less and stores less. Hooks law, force needed to compress scales linearly.

If you throw a racket ball against a wall at 50 mph its return force will be X, if you throw it at 75 mph it will be more than X.

With 20 oz carrier figured in:

 

[wade2big]

Using peak carrier velocity and two buffer weights, excluding and ignoring all other frictional forces(drag/hammer, etc.), you obtain the same or very similar KE between a +5.3 oz buffer and an 8.5 oz buffer(plus bcg @20 oz) with only a 6.5% reduction in peak carrier velocity alone. Carrier velocity is not constant in the cycle, the contributing factors are spring(weight) and buffer(weight) differences, if you add buffer and it slows the peak carrier speed down the release of the PE and the creation of KE is less(less felt recoil). There are also naturally occurring speed changes in the cycle of the reciprocating mass when the gun fires(to keep this simple just ignore that). The buffers job is to buffer the initial force on the reciprocating mass, and to slow it and give the spring a chance to absorb and control, then return. The full weight of the reciprocating mass should be considered(bcg & buffer). Full mass ar10 BCG's can vary 2-3 oz from brand to brand(5.3oz could quickly become 8.5 oz and really at that point its not a heavy buffer as its making up for a light carrier possibly).

The other acting force is PE and that relates to the spring, but for this lets say the spring stays the same in both comparisons with two buffer weights. If the carrier is moving faster it has more energy and carries that further rearward where the spring is storing more energy; going slower it travels less and stores less. Hooks law, force needed to compress scales linearly.

If you throw a racket ball against a wall at 50 mph its return force will be X, if you throw it at 75 mph it will be more than X.

With 20 oz carrier figured in:


View attachment 8312507

View attachment 8312508

Nobody is going to read that. I didn’t.

 

[UpSideDown]

Using peak carrier velocity and two buffer weights, excluding and ignoring all other frictional forces(drag/hammer, etc.), you obtain the same or very similar KE between a +5.3 oz buffer and an 8.5 oz buffer(plus bcg @20 oz) with only a 6.5% reduction in peak carrier velocity alone. Carrier velocity is not constant in the cycle, the contributing factors are spring(weight) and buffer(weight) differences, if you add buffer and it slows the peak carrier speed down the release of the PE and the creation of KE is less(less felt recoil). There are also naturally occurring speed changes in the cycle of the reciprocating mass when the gun fires(to keep this simple just ignore that). The buffers job is to buffer the initial force on the reciprocating mass, and to slow it and give the spring a chance to absorb and control, then return. The full weight of the reciprocating mass should be considered(bcg & buffer). Full mass ar10 BCG's can vary 2-3 oz from brand to brand(5.3oz could quickly become 8.5 oz and really at that point its not a heavy buffer as its making up for a light carrier possibly).

The other acting force is PE and that relates to the spring, but for this lets say the spring stays the same in both comparisons with two buffer weights. If the carrier is moving faster it has more energy and carries that further rearward where the spring is storing more energy; going slower it travels less and stores less. Hooks law, force needed to compress scales linearly.

If you throw a racket ball against a wall at 50 mph its return force will be X, if you throw it at 75 mph it will be more than X.

With 20 oz carrier figured in:


View attachment 8312507

View attachment 8312508

Recoil isn’t a measure of force. It is an Impulse. We also have no idea what carrier velocity is as play here. These numbers have no meaning. It is the de facto experience that having a lighter operating system equates to less recoil than a heavier system, if both are adjusted to cycle correctly.