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I am building my first 6.8 as we speak. The buffer system is the last part I need. I have a Daniel defense 16 inch barrel, larue upper receiver, larue lower, larue trigger, larue lower receiver extender, magpul stock, aero precision bcg, Troy magazine release, bad ass pro safety lever, and curious what buffer system I should get. Should I get the vltor a5 or jp enterprises silent captured spring builder kit? Can I use the vltor a5 in my larue lower receiver extender and if the jp enterprises should it be heavy h2 or standard? Thanks for all of the help.
 

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I’m running the JP H3 in my 16” with a Dead Air can and an adjustable gas block. If I was running the gun without a silencer I would have gone with the JP H2


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There is no reason I can think of to use a heavier than standard buffer when using an adjustable gas block. My set up is JP silent captured spring with the lightest spring in the kit with adjustable gas. Suppressed or non suppressed, adjust the gas. Leave the buffer alone.
 

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There is no reason I can think of to use a heavier than standard buffer when using an adjustable gas block. My set up is JP silent captured spring with the lightest spring in the kit with adjustable gas. Suppressed or non suppressed, adjust the gas. Leave the buffer alone.
I went with the H3 out of precaution when I built the rifle, just in case the heavier buffer was needed. I figured I could use it in my 10.5” suppressed 5.56 if it was too much. Whether it’s an H2 or an H3, I really like the JP silent capture buffer system over the traditional system


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I went with the H3 out of precaution when I built the rifle, just in case the heavier buffer was needed. I figured I could use it in my 10.5” suppressed 5.56 if it was too much. Whether it’s an H2 or an H3, I really like the JP silent capture buffer system over the traditional system


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So the only reason for the existence of a heavy buffer or H2 or H3 (at least to my knowledge) is to tame an over-gassed system. If it has adjustable gas block then instead of using the heavier buffer to tame it down, you just turn down the gas. That was my point as to it not being needed with an adjustable gas block. If you go with the lighter spring (or buffer) then turn down the gas till it has just enough to lock back on empty mag I think you will notice a much smoother cycling system.
 

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H2 is the lighter weight system, whether it’s a JP silent capture or a tradition buffer system. The JP system is not a weight inside of a spring, rather it’s a weight on the back of a rod, which is incapsulated inside a spring. It’s much quieter than a traditional buffer system and there is much less buffer spring ware. In the absence of an adjustable gas block the H3 will also reduce bolt ware in an AR rifle chambered for larger, heavier projectiles.

But yes, the adjustable gas block serves the purpose you are trying to achieve


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H2 is the lighter weight system, whether it’s a JP silent capture or a tradition buffer system. The JP system is not a weight inside of a spring, rather it’s a weight on the back of a rod, which is incapsulated inside a spring. It’s much quieter than a traditional buffer system and there is much less buffer spring ware. In the absence of an adjustable gas block the H3 will also reduce bolt ware in an AR rifle chambered for larger, heavier projectiles.

But yes, the adjustable gas block serves the purpose you are trying to achieve


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I know what the JP system is. I use it as stated earlier. Generally speaking there is standard weight, H (sometimes called H1) which is heavier than standard. H2 which is heavier than H and H3 which is the heaviest of all. If you have an adjustable gas block there is pretty much never any need for anything heavier than a standard carbine weight buffer.
 
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I know what the JP system is. I use it as stated earlier. Generally speaking there is standard weight, H (sometimes called H1) which is heavier than standard. H2 which is heavier than H and H3 which is the heaviest of all.



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If you're interested in a lighter weight system than the JP SCS and the A5, try a Tubb flat spring with a standard weight buffer. Lightest weight and softest recoil impulse that I've found.
 

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For reference, JP specify's their SCS springs for a service life of 15k rounds vs. a GI buffer spring at only 5k. As mentioned, there's a lot less friction and you don't get spring oscillations. I have tried hydraulic buffers as well and I do think they have application in over gassed systems as a band aid, but they don't work on tuned systems because then you have two masses moving at different speeds during unlocking and it causes erratic cycling issues.

I have found NOTHING I like better than the JP SCS. You can go from Carbine all the way up to H3 weight. You can use five different spring weights from reduced power (white 80%) up to (extra power 100% uncolored). And, if you have the cash, you can buy two and swap out different setups for different uppers on the same lower. It's HIGHLY modular. You still get the dead blow effect of a additional buffer but with a little smoother impulse due to the viton o-rings damping out the movement of the weights.
 

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If you're interested in a lighter weight system than the JP SCS and the A5, try a Tubb flat spring with a standard weight buffer. Lightest weight and softest recoil impulse that I've found.
I tried that (had five different flat wire springs, cut to different lengths) and actually came to prefer a low mass carrier paired with a JP SCS. Using an 8.5oz low mass carrier and the SCS, I can go from 11.5oz combined weight up to 13.9 (standard carrier and carbine buffer are 14oz total). Tuning the gas flow and it's extremely smooth, low and short impulse.

This is why ALL race guns at the top level are using low mass buffers instead of hydraulic or full mass carriers with light buffers. Also, running more of the Wight in the buffer increases the dead blow, maximizing the available energy so you can tune to the limit more adequately. The dead blow effect maximizes total energy transfer, which is important for stripping the next round from the magazine when going back into battery.

Another tuning trick to minimize BCG energy is using one piece gas rings. Due to the lower friction, you don't need as much mass and energy to reliably go back into battery. Then we have NiB or Nitrided BCG's, which also lower friction vs. traditional phosphate which is highly prone to fouling and corrosion if not frequently oiled and requires higher average energy for adequate cycling.

Just like with car engines or computing power in a PC, the sum total of small changes through various areas of the system are what result in both a reliable and high performance system vs. just one big change. All of these optimizations I've implemented slowly and that' is what has allowed me to have BOTH a low recoil impulse AND high reliability while still having a low loss gas system to maximize muzzle velocity. It's all about balance and optamization.
 

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I tried that (had five different flat wire springs, cut to different lengths) and actually came to prefer a low mass carrier paired with a JP SCS. Using an 8.5oz low mass carrier and the SCS, I can go from 11.5oz combined weight up to 13.9 (standard carrier and carbine buffer are 14oz total). Tuning the gas flow and it's extremely smooth, low and short impulse.

This is why ALL race guns at the top level are using low mass buffers instead of hydraulic or full mass carriers with light buffers. Also, running more of the Wight in the buffer increases the dead blow, maximizing the available energy so you can tune to the limit more adequately. The dead blow effect maximizes total energy transfer, which is important for stripping the next round from the magazine when going back into battery.

Another tuning trick to minimize BCG energy is using one piece gas rings. Due to the lower friction, you don't need as much mass and energy to reliably go back into battery. Then we have NiB or Nitrided BCG's, which also lower friction vs. traditional phosphate which is highly prone to fouling and corrosion if not frequently oiled and requires higher average energy for adequate cycling.

Just like with car engines or computing power in a PC, the sum total of small changes through various areas of the system are what result in both a reliable and high performance system vs. just one big change. All of these optimizations I've implemented slowly and that' is what has allowed me to have BOTH a low recoil impulse AND high reliability while still having a low loss gas system to maximize muzzle velocity. It's all about balance and optamization.
Good stuff. Thanks for sharing
 

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I've literally tried every combination.

Tubbs flat wire + AKTIVE buffers (even had one custom made at 3oz as their standard is 4.4izh)

Spring Co. Chrome Silicon with Kynshot Hydraulic (light version for softer cycling rifles)

Standard GI setup with 3oz carbine buffer

JP SCS + Low Mass Carrier - I keep going back to this every time. I like a short but smooth recoil impulse the best of all and this delivers that. This would probably be why all the top competition rifles to my knowledge run low mass carriers and light buffer setups for 5.56. Works equally well with 6.8 SPC, but keeping mass a little closer to standard than super lightweight.

I have standardized on using a low mass NiB carrier, 2 tungsten / 1 steel weights and the stock 85% black buffer spring for the SCS. Ejection is around 3 with the gas setting on 9 from fully closed (there are a total of 15 positions). I've stuck with mid-legnth gas systems weather it was back when I was running 5.45x39mm 7N6 Russian, my first 6.8 SPC upper using the AA piston gas system (still mid-length) and ARP 3R 1:11 Scout barrel or this final setup using a Daniels 5R 1:11 S2W (heavy) barrel also in 6.8 SPC.

And I now run the same setup in my 5.56 upper, also mid-length, that has a 16" Daniels 6R 1:7 lightweight barrel. Both of my Daniels uppers are Internal Gas Piston (what you call DI), where the 5.45 and my first 6.8 supper were AA's free floating short stroke piston (external gas piston). The reason for the switch from external gas piston to internal gas piston was weight and trying to gain a tad more accuracy.

The AA piston system is pretty good on accuracy, but there is still a drive rod applying pressure to the barrel when it's moving the carrier. With a IGP (aka DI) system that is the standard, the bolt pushes against the barrel extension to drive the carrier back, so everything is directly inline with the bore. I would say precision DI AR's are fairly close to bolt action in terms of practical accuracy. It's a really good system for a precision semi-automatic tactical rifle.

It's NOT so great for heavy full auto as the extreme heat of constant auto can become problematic. For short bursts or a mag or two of full auto it's still highly reliable. Most reliability issues with the AR's gas system have been primarily from magazine feed issues, the US military figured that out some time in the 2010's after firing hundreds of thousands of rounds through a batch of service M4's, I think the cause was something like 80% or more of stoppages were magazine related.

The majority of the remaining stoppages were inadequate lubrication, even on dirty rifles, if they kept the BCG wet with lube, it worked just fine. DI gas systems work good for some applications, but not so great for others and I think light machine guns are an application better suited for short stroke pistons, but there's not as much of a premium placed on accuracy and lightweight handling for such uses. Certainly for any civilian, LE or typical infantry rifle use, there's no need for short stroke pistons, not even the justification of less cleaning. I only clean the DI BCG every couple thousand rounds, just keep it lubed periodically. I do clean the barrel after every session, but only with a jag to minimize wear as much as possible, this removes any corrosives without being abrasive or harsh.

Chrome lining may be highly corrosion resistance, but it's not corrosion immune. A little wipe down and oil can go a long way for reducing pitting from storage intervals that can start to damage the chrome lining over years of use, I did the same thing with my nitrided barrels and they always looked pristine inside (mirror finish).

I only do copper brush and Pro-Shot copper solvent every few thousand to avoid excessive wear, but remove minor copper fouling that builds up to a small degree (I mostly shoot copper jacked lead core, not SCHP so it's not much of an issue). Too much or too little is bad of anything. Some things need to be done frequently (every range trip) while other things less frequently (once every few months or even once a year).
 
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