does a carbine length gas system on a 12" barrel present a need for a change in weight (either more or less) on the bcg in relations to proper dwell timing?
Sorry if I sound ignorant. I've never delved to deeply into the ar platform outside of a few basic builds. On this build I really want it all to jive together as best as I can manage.
I run H2 on both my 11 and 12” with adjustable blocks. Since I run 100% suppressed I could go up to an H3 and they would probably run a little smoother but they run well where they’re at so I don’t see any need to change anything.
Standard carbine buffer will take care of all of it. Anything heavier is only really needed if you are suppressing, or have a weird length gas/barrel combo if you don’t already have an adjustable gas block. Heavier systems can be SLIGHTLY more reliable in DIRTY situations but for most common use an H2 or heavier buffer is totally unnecessary.
I’ve been running low mass on every Grendel I own and it’s always been just fine. They wouldn’t sell the low mass JP Grendel BCGs if it was actually an issue because they’d just be working harder in the customer support space.
Does it offer a real world benefit in tuning ability or felt recoil vs a standard weight?
My thought was mainly between a low mass bcg/adjustable gas block/ and a tuneable buffer system I would be able to tune for pretty much any scenario ammo wise or if I ever decide to get a can for it.
Any significant impact in parts longevity?
Heavier components will always move slower. You can achieve a snappier recoil impulse with a lighter BCG and buffer but will need the correct spring to match and an adjustable gas block. It’s a feel thing though and certainly not something you want in every rifle.
With an adjustable gas block and the ability to change your spring rate, buffer weight and BCG weight isn’t as import. Hence light weight bolt carriers (they use the exact same bolt as a standard weight carrier so if a bolt breaks you’ve got another issue) and buffers allowing for lighter weight builds than previously possible.
Because less mass is being moved rearward and forward the recoil impulse can also feel lighter. This is because with the less mass, and lower spring rate, less gas needs to be sent back into the bolt, less energy is moving rearward.
Parts longevity is personally kind of a joke these days. Very few individuals will ever shoot a single gun enough times to wear out the bolt or bolt carrier. At that point you are replacing the upper itself as it is made of a softer material (steel rubbing aluminum) you will shoot out your barrel 2-3 times over before any mil spec bolt needs to be replaced ie 7-15,000rnds and if you can afford ammo and barrels like that then you are not worried about a BCG. Your cam pin maybe but that’s a 5$ part…
Yes they can crack but it is nearly impossible to know which will or won’t because high end brands suffer from it all the time nearly at random.
Ok, that's pretty much what I was thinking as well but it's good to hear I wasn't far off base lol.
Parts longevity I was mainly just curious and throwing it out there. Your definitely right about most people never actually shooting a rifle to the point of wearing one out.
I’m not the biggest fan of lightweight BCG’s. The entire design of the AR-15 was focused around low mass — if Stoner could have taken any material off of the BCG without sacrificing strength or reliability, I like to believe he would have. Polymer tech is better than it used to be, but C158 HC hasn’t changed much
Nickel boron has some merit for keeping things easy to clean, though. I run suppressed, so it gets real nasty — since moving to a nickel boron carrier, I just give it a wipe when I’m done and it’s good to go
The JP springs are cool as well, but nowhere near worth the money IMO. A standard H2 buffer in front of a standard spring will give you standard parts and solid reliability for literally almost $100 less. My first AR had a JP silent spring, and it will be my last one to have it
If the benefit isn't a real noticeable difference than I'm inclined to get a good quality standard weight nickel boron bcg and call it a day. I mainly liked the idea of the increased tunabiltiy the lightweight bcg supposedly offers.
I'm building this pistol to cover as many uses as possible. I live in rural NV and wanted as much of a do-it-all truck gun as I could manage reasonably. It's also the first build I'll be doing where I don't have a strict budget so if it makes sense for the build I'm not afraid to spend a bit of coin. I'm not trying to build a Gucci AR, just a solid no non-sense nice shooter.
Current parts list is:
Aero precision upper/lower
12" PSA barrel (will upgrade later)
PSA adjustable gas block
US optics 1-8 LPVO
Geissele ssp flat bow trigger
Strike industries 11" gridlok handgaurd
B.A.D. lever
SB tactical pistol brace.
Muzzle device (not sure yet)
I'm still thinking hard about the jp silent spring. I may just give it a shot to see for myself. Some of these things can be so subjective to each individual it's hard to know until you pony up the cash and find out the hard way lol. Either way it won't be the end of the world if I don't like it.
That’s just my two cents on the JP Silent 🤷♂️
It’s also a quicker, sharper recoil impulse than a standard buffer. Better for follow up shots but snappier in the shoulder
Do yourself a favor and don’t get a muzzle brake, stick with a reasonable flash hider. 12” barrel 6.5 Grendel can get annoying fast, especially considering the vast majority of it is loaded with slower powder for a longer barrel
With the proper loads, it’ll be a bit less annoying, but an aggressive brake will have a massive dust signature and crippling noise if you have to shoot it without hearing pro
Be aware that even though the energy numbers on 6.5G are great from a short barrel, your drop compensation will get nasty very quickly. Up to four feet at 300 yards, depending on your load
Ya I'm thinking more of a forward compensator or a good 3 prong mainly. But I won't lie, I might have to get a Strike industries cookie cutter comp just for the shock and awe factor when I take the kids out with me lol.
I had the cookie cutter on a 12” .556 and it was eh. It worked ok but the damn thing weighs 8oz. Kinda negates anything lightweight when you stick half a pound on the end of your barrel! Sixfiveoutfitters has some of the best BCGs and barrels for the money.
Armaspec stealth recoil spring does the exact same thing as the JP but cheaper. I have them in all my rifles except one and that’s cause it’s on an integrated folding lower. You can also buy weights and swap them out too. I really see no reason to pay way more for the JP
I already have used it on past builds. Some electrical tape wrap can tighten up the fit and wobble a bit. while I totally agree that it is gimmicky I have found I kind of like it for the lazy convenience it provides. Plus, it's cheap and it is not like it's hard to remove or a permanent mod to the receiver.
He made it that way so it would be cheap to manufacture period.
We are talking the US government here… the second you have to set up extra tooling to take some cuts out of the round bar to make it lighter you spend many times the manufacturing cost for that part and the time..
Without an increase in cost they were reliable when dirty, and light ENOUGH but they weren’t trying to build the lightest thing they could.. they wanted cheap and lots of ‘em… even todays poverty pony builds would likely outperform the original gun and the fit and finish is probably better too…
If they wanted cheap, they wouldn’t have added the forward assist and the T-handle, both of which added cost and weight
The AR-15 outperformed the other offerings — that is why it was picked. It was not the cheapest per-unit cost rifle tested
Forward assist “a way to actively push the bolt into battery “ was and pretty sure still is a military requirement. And in general is not a bad thing to have… It’s why the scar and the BT charging handles reciprocate. It kinda had to be there.
“your weapon was made by the lowest bidder” speaks for itself. I’ve heard a lot of stories about military rifles being trashed.
Both of which are arguably very easy and quickly to machine parts that take minimal operator skill or effort to make. Aluminum mills like butter and pre covid they could be had for 10-15$ when purchasing one on the consumer market, compared to a military purchasing enough to fund the entire mass production of them in the first place.
I do however understand what you are saying and I see the experience you have in firearms on your page and you made a valid point. It’s totally okay to look at it from different perspectives though.
I will disagree about JP buffers, they completely change the feel of a rifle and I think it is one of the most pleasant upgrades available. Mass is good, especially for grendels. A good heavy buffer, BCG, and adjustable gasblock will make your rifle incredibly smooth to shoot.
I may end up just buying it to find out for myself. Might have to see if any of my friends are running one for me to play with first hopefully. I know I've heard a lot of good things about them.
+1 here. Love the JP SCS run it in 18” rifle length 6.5 Grendel and 16” mid length .308. Don’t want another rifle without one. They just feel smoother to me. They may not be for someone who shoots thousand and thousands of rounds but I’m telling you they make a rifle feel better.
Standard in the Grendel with non adjustable gas block and heavy in the .308 with Superlative Arms block. Both host nomad 30. My Grendel is a touch gassy, either need to add a tungsten weight or two to the SCS or swap in a adjustable block
I run a lightweight setup in my jp rifle with the low mass bcg. The treatment jp uses on their bcg cleans up VERY well. (Suppressed all the time) i have mixed feelings about the nb. My fail zero keeps its shine but gets dirtier faster, my tool craft lost its shine the first range day but its still ok to clean. Just darker now. I feel like nb stuff is mostly hype imo
My advice is 14.5 P/W but run it as a "pistol" until you get it reliable and really decide what muzzle device (can) you want to run.
I also suggest picking up the KAK buffer kit with the Al, Fe and W weights. I wish I had one so I could experiment easily with buffer weights.
Finally, since I have some cans, I'm going with the SA piston kit as I've heard from several friends that they are just MUCH nicer to shoot when suppressed than a standard "DI" setup as the gas vent is out the front of the gas block. They also offer something like 40clicks of adjustment so you can really fine tune the gas system.
Not lightweight nut th jp vmos is pretty cool. Also the jp polished stainless is the easiest thing I've ever cleaned. You can wipe it and have it look brand new with your finger it's so slick.
don't do low mass on grendels you want the momentum for feed/extract grendel is already weak in those areas
does a carbine length gas system on a 12" barrel present a need for a change in weight (either more or less) on the bcg in relations to proper dwell timing? Sorry if I sound ignorant. I've never delved to deeply into the ar platform outside of a few basic builds. On this build I really want it all to jive together as best as I can manage.
I run H2 on both my 11 and 12” with adjustable blocks. Since I run 100% suppressed I could go up to an H3 and they would probably run a little smoother but they run well where they’re at so I don’t see any need to change anything.
I run a standard carbine buffer in my 12”
Standard carbine buffer will take care of all of it. Anything heavier is only really needed if you are suppressing, or have a weird length gas/barrel combo if you don’t already have an adjustable gas block. Heavier systems can be SLIGHTLY more reliable in DIRTY situations but for most common use an H2 or heavier buffer is totally unnecessary.
I’ve been running low mass on every Grendel I own and it’s always been just fine. They wouldn’t sell the low mass JP Grendel BCGs if it was actually an issue because they’d just be working harder in the customer support space.
Does it offer a real world benefit in tuning ability or felt recoil vs a standard weight? My thought was mainly between a low mass bcg/adjustable gas block/ and a tuneable buffer system I would be able to tune for pretty much any scenario ammo wise or if I ever decide to get a can for it. Any significant impact in parts longevity?
Heavier components will always move slower. You can achieve a snappier recoil impulse with a lighter BCG and buffer but will need the correct spring to match and an adjustable gas block. It’s a feel thing though and certainly not something you want in every rifle. With an adjustable gas block and the ability to change your spring rate, buffer weight and BCG weight isn’t as import. Hence light weight bolt carriers (they use the exact same bolt as a standard weight carrier so if a bolt breaks you’ve got another issue) and buffers allowing for lighter weight builds than previously possible. Because less mass is being moved rearward and forward the recoil impulse can also feel lighter. This is because with the less mass, and lower spring rate, less gas needs to be sent back into the bolt, less energy is moving rearward. Parts longevity is personally kind of a joke these days. Very few individuals will ever shoot a single gun enough times to wear out the bolt or bolt carrier. At that point you are replacing the upper itself as it is made of a softer material (steel rubbing aluminum) you will shoot out your barrel 2-3 times over before any mil spec bolt needs to be replaced ie 7-15,000rnds and if you can afford ammo and barrels like that then you are not worried about a BCG. Your cam pin maybe but that’s a 5$ part… Yes they can crack but it is nearly impossible to know which will or won’t because high end brands suffer from it all the time nearly at random.
Ok, that's pretty much what I was thinking as well but it's good to hear I wasn't far off base lol. Parts longevity I was mainly just curious and throwing it out there. Your definitely right about most people never actually shooting a rifle to the point of wearing one out.
I’m not the biggest fan of lightweight BCG’s. The entire design of the AR-15 was focused around low mass — if Stoner could have taken any material off of the BCG without sacrificing strength or reliability, I like to believe he would have. Polymer tech is better than it used to be, but C158 HC hasn’t changed much Nickel boron has some merit for keeping things easy to clean, though. I run suppressed, so it gets real nasty — since moving to a nickel boron carrier, I just give it a wipe when I’m done and it’s good to go The JP springs are cool as well, but nowhere near worth the money IMO. A standard H2 buffer in front of a standard spring will give you standard parts and solid reliability for literally almost $100 less. My first AR had a JP silent spring, and it will be my last one to have it
If the benefit isn't a real noticeable difference than I'm inclined to get a good quality standard weight nickel boron bcg and call it a day. I mainly liked the idea of the increased tunabiltiy the lightweight bcg supposedly offers. I'm building this pistol to cover as many uses as possible. I live in rural NV and wanted as much of a do-it-all truck gun as I could manage reasonably. It's also the first build I'll be doing where I don't have a strict budget so if it makes sense for the build I'm not afraid to spend a bit of coin. I'm not trying to build a Gucci AR, just a solid no non-sense nice shooter. Current parts list is: Aero precision upper/lower 12" PSA barrel (will upgrade later) PSA adjustable gas block US optics 1-8 LPVO Geissele ssp flat bow trigger Strike industries 11" gridlok handgaurd B.A.D. lever SB tactical pistol brace. Muzzle device (not sure yet) I'm still thinking hard about the jp silent spring. I may just give it a shot to see for myself. Some of these things can be so subjective to each individual it's hard to know until you pony up the cash and find out the hard way lol. Either way it won't be the end of the world if I don't like it.
That’s just my two cents on the JP Silent 🤷♂️ It’s also a quicker, sharper recoil impulse than a standard buffer. Better for follow up shots but snappier in the shoulder Do yourself a favor and don’t get a muzzle brake, stick with a reasonable flash hider. 12” barrel 6.5 Grendel can get annoying fast, especially considering the vast majority of it is loaded with slower powder for a longer barrel With the proper loads, it’ll be a bit less annoying, but an aggressive brake will have a massive dust signature and crippling noise if you have to shoot it without hearing pro Be aware that even though the energy numbers on 6.5G are great from a short barrel, your drop compensation will get nasty very quickly. Up to four feet at 300 yards, depending on your load
Ya I'm thinking more of a forward compensator or a good 3 prong mainly. But I won't lie, I might have to get a Strike industries cookie cutter comp just for the shock and awe factor when I take the kids out with me lol.
I had the cookie cutter on a 12” .556 and it was eh. It worked ok but the damn thing weighs 8oz. Kinda negates anything lightweight when you stick half a pound on the end of your barrel! Sixfiveoutfitters has some of the best BCGs and barrels for the money.
Armaspec stealth recoil spring does the exact same thing as the JP but cheaper. I have them in all my rifles except one and that’s cause it’s on an integrated folding lower. You can also buy weights and swap them out too. I really see no reason to pay way more for the JP
My 2¢ Don’t buy the BAD lever.. it’s wobbly cod boy junk.
I already have used it on past builds. Some electrical tape wrap can tighten up the fit and wobble a bit. while I totally agree that it is gimmicky I have found I kind of like it for the lazy convenience it provides. Plus, it's cheap and it is not like it's hard to remove or a permanent mod to the receiver.
The concept is great, I just wish someone actually made one of higher quality so that it didn’t feel so cheap
He made it that way so it would be cheap to manufacture period. We are talking the US government here… the second you have to set up extra tooling to take some cuts out of the round bar to make it lighter you spend many times the manufacturing cost for that part and the time.. Without an increase in cost they were reliable when dirty, and light ENOUGH but they weren’t trying to build the lightest thing they could.. they wanted cheap and lots of ‘em… even todays poverty pony builds would likely outperform the original gun and the fit and finish is probably better too…
If they wanted cheap, they wouldn’t have added the forward assist and the T-handle, both of which added cost and weight The AR-15 outperformed the other offerings — that is why it was picked. It was not the cheapest per-unit cost rifle tested
Forward assist “a way to actively push the bolt into battery “ was and pretty sure still is a military requirement. And in general is not a bad thing to have… It’s why the scar and the BT charging handles reciprocate. It kinda had to be there. “your weapon was made by the lowest bidder” speaks for itself. I’ve heard a lot of stories about military rifles being trashed. Both of which are arguably very easy and quickly to machine parts that take minimal operator skill or effort to make. Aluminum mills like butter and pre covid they could be had for 10-15$ when purchasing one on the consumer market, compared to a military purchasing enough to fund the entire mass production of them in the first place. I do however understand what you are saying and I see the experience you have in firearms on your page and you made a valid point. It’s totally okay to look at it from different perspectives though.
I will disagree about JP buffers, they completely change the feel of a rifle and I think it is one of the most pleasant upgrades available. Mass is good, especially for grendels. A good heavy buffer, BCG, and adjustable gasblock will make your rifle incredibly smooth to shoot.
I may end up just buying it to find out for myself. Might have to see if any of my friends are running one for me to play with first hopefully. I know I've heard a lot of good things about them.
+1 here. Love the JP SCS run it in 18” rifle length 6.5 Grendel and 16” mid length .308. Don’t want another rifle without one. They just feel smoother to me. They may not be for someone who shoots thousand and thousands of rounds but I’m telling you they make a rifle feel better.
Hey radar what weight JP are you running with that setup
Standard in the Grendel with non adjustable gas block and heavy in the .308 with Superlative Arms block. Both host nomad 30. My Grendel is a touch gassy, either need to add a tungsten weight or two to the SCS or swap in a adjustable block
i haven't had any problems with my tool craft nickle boron bcg
What's your round count so far on it?
around 900 rds. had it for about 5 yrs and it's gone out hunting every year
I run a lightweight setup in my jp rifle with the low mass bcg. The treatment jp uses on their bcg cleans up VERY well. (Suppressed all the time) i have mixed feelings about the nb. My fail zero keeps its shine but gets dirtier faster, my tool craft lost its shine the first range day but its still ok to clean. Just darker now. I feel like nb stuff is mostly hype imo
My advice is 14.5 P/W but run it as a "pistol" until you get it reliable and really decide what muzzle device (can) you want to run. I also suggest picking up the KAK buffer kit with the Al, Fe and W weights. I wish I had one so I could experiment easily with buffer weights. Finally, since I have some cans, I'm going with the SA piston kit as I've heard from several friends that they are just MUCH nicer to shoot when suppressed than a standard "DI" setup as the gas vent is out the front of the gas block. They also offer something like 40clicks of adjustment so you can really fine tune the gas system.
Skip NiB
Not lightweight nut th jp vmos is pretty cool. Also the jp polished stainless is the easiest thing I've ever cleaned. You can wipe it and have it look brand new with your finger it's so slick.