JP Enterprises Captured Spring System

[PJ65C]

All,

I could use your input. Close shooting buddy of mine runs the JP Enterprises captured spring buffer on a few of his gas guns (223 and 6.5 creedmoor, might have it in a 300 blk too, but not sure) with a standard BCG, not the JP BCG. I was skeptical of this system until i shot it. The spring bind and twang were gone from the traditional buffer system and the rifle seemed to shoot much smoother in the 223 setup of his that i shot. Follow up shots and/or reengaging targets also seemed to be smoother and faster (admittedly, i did not have a timer, just going by gut feeling on this aspect).

I only have a limited amount of experience with this system (few hundred rounds), so im looking for more real world data and im curious if any of you guys have run it, or do run it. Do you like it? Hate it? Give me the good bad and the ugly. Im thinking about putting this on one of my 223's and possibly my 6.5 creedmoors, but really would like more feedback before making the plunge, units certainly arent cheap for a buffer system.

Thanks for your time!

 

[ballisticdaddy]

I run the SCS in all my gas guns...even the pistols...without any issue

 

[eddie102870]

have em in all of mine too

 

[KZP]

I like it. I tried their spring kit and prefer the medium strength, which I believe is their standard spring (yellow). But you can swap springs to strong so it snaps back faster or weaker creating slower but soft impulse.

 

[PJ65C]

Awesome! thanks for the input!

Any of you guys put them in a SBR? more specifically with a 10.5" barrel??

 

[ballisticdaddy]

Awesome! thanks for the input!

Any of you guys put them in a SBR? more specifically with a 10.5" barrel??

Yup have a 556 pistol with 10.5" barrel and runs like a dream

 

[PJ65C]

never had any issues with any of mine

especially a fan in large framesView attachment 7576361

Nice! Looks similar to one of my rifles. Can i ask what JP spring and buffer weight combo youre running? Or are you running it "out of the box"???

 

[respiegel]

wrong thread...

 

[Johnny00K]

I run them in every gun that will ever wear a suppressor. They really make a noticeable difference in decibels. In short barrels I use either the 4 or 5 springs, the heaviest ones. That's more to prevent gas than for cycling. Never had to adjust weights. In 14.5" or 16 we use the standard spring.

 

[Smith1]

I though they were a waste of money until I actually got one. Between that and an adjustable gas block, everything is cycling smoothly and recoil drastically cut down

 

[PJ65C]

I though they were a waste of money until I actually got one. Between that and an adjustable gas block, everything is cycling smoothly and recoil drastically cut down

View attachment 7576506

Nice setup. How do you have your SCS setup, e.g. weights and springs? What is your rifle chambered in?

 

[Smith1]

Thank you. I just have the standard weight and spring on it now. I did have an additional weight when I was running a supressor and had a non adjustable gas block. It’s a .22 nosler

 

[S197]

I run them in every gun that will ever wear a suppressor. They really make a noticeable difference in decibels. In short barrels I use either the 4 or 5 springs, the heaviest ones. That's more to prevent gas than for cycling. Never had to adjust weights. In 14.5" or 16 we use the standard spring.

what do you mean by prevent gas?

 

[S197]

All,

I could use your input. Close shooting buddy of mine runs the JP Enterprises captured spring buffer on a few of his gas guns (223 and 6.5 creedmoor, might have it in a 300 blk too, but not sure) with a standard BCG, not the JP BCG. I was skeptical of this system until i shot it. The spring bind and twang were gone from the traditional buffer system and the rifle seemed to shoot much smoother in the 223 setup of his that i shot. Follow up shots and/or reengaging targets also seemed to be smoother and faster (admittedly, i did not have a timer, just going by gut feeling on this aspect).

I only have a limited amount of experience with this system (few hundred rounds), so im looking for more real world data and im curious if any of you guys have run it, or do run it. Do you like it? Hate it? Give me the good bad and the ugly. Im thinking about putting this on one of my 223's and possibly my 6.5 creedmoors, but really would like more feedback before making the plunge, units certainly arent cheap for a buffer system.

Thanks for your time!

Do any of his guns match your set up? was his a carbine, mid length or rifle?
what is your gas port size?
what muzzle device are you running?
What buffer setup is currently installed?

They do reduce that twang sound, but it might not change your rifle like you are hopping.

 

[PJ65C]

Do any of his guns match your set up? was his a carbine, mid length or rifle?
what is your gas port size?
what muzzle device are you running?
What buffer setup is currently installed?

They do reduce that twang sound, but it might not change your rifle like you are hopping.

S197,

Good questions. I'll tell you what i know for sure.

Im going to run a JP SCS in my AR pistol (Its a weird configuration to meet laws in CT - feel free to ask about specifics if that would help in some way) first to learn the system a bit more (I know this isnt ideal, however, if something bad happens, id rather learn about it on a cheap AR pistol than one of my Creedmoors), and then in a "test rifle" i have that is similar to his, and experiment a bit.

I bought the "H2 heavy builder kit" to start with and an additional steel and tungsten weight so i have some adjustibility, if needed. Regarding felt changes - his rifle was significantly smoother. The spring twang was gone, but its not the end of the world for me if its still somewhat present. However, with the JP SCS the mechanics of the rifle under cycling of a round both shooting and by running the BCG with the charging handle was very linear and smooth; follow up shots for me were noticeably faster, reacquiring targets was also faster. The sensation of "coil bind" (buffer spring compressing in the tube was also gone, obviously (liked this a lot). There are four rifles that i want to put this in - 12.5" 223 pistol. 16" and 20" 6.5 creedmoors, and 10.5" 300 Blk out SBR - im going to go slow with this process, this is a very new system to me, and i dont want to screw anything up, or damage my rifles in some way.

To answer your questions...

1. Somewhat (I know this isnt ideal for trying to match a feel). He has a JP SCS in his 308 w/ 16" barrel. I can get specifics this weekend about gas system etc.
2. I do not know what my gas port size is. I can totally see how this is important, i'll ask the builder of the rifle. I do have a 14 position adjustable gas block. Gas tube for the rifle(s) in question are roughly 14" - 14.5" long (measured without disassembling everything) for both rifles. One rifle is 16" barrel the other is a 20" barrel. Both chambered in 6.5 Creedmoor. The 12.5" AR pistol is approximately 8.5" non adjustable gas block.
3. Surefire Warcomp, three prong to go with my cans.
4. 16" 6.5 Creedmoor - 4oz buffer weight. Spring is 11.25" long. Buffer tube is 7.875" long. BCG total weight is 19 oz.
4a. 20" 6.5 Creedmoor - 3.75oz buffer weight. Spring is 13" long. Buffer tube 7.6875" long (Magpul PRS stock). BCG total weight is 18.125oz.
4b. 12.5" 223 AR Pistol - 2oz buffer weight. Spring is 11" long. Buffer tube is 7.25" long. Uses the SBA4 brace to abide by CT laws.
4c. 10.5" 300 Blk SBR is still in ATF jail, so its not built yet.

Hopefully that helps, let me know what other info would help or is needed and i'll do what i can to get it.

 

[Johnny00K]

what do you mean by prevent gas?

Back pressure from the suppressor. If your buffer spring is too light for your setup then you will get too much gas coming back toward your face and it will blast you. By swapping to the heavier spring it stops almost all the gas that was hitting you in the face. Something like the Radian Raptor SD charging handle will stop most of the blowback used with a correct weight spring.

 

[impactaddict]

I think JP's guide will help you on your quest for the proper setup. There is a selection tree toward the bottom. Long story short, its all going to depend on YOUR specific setup(s). I recently tuned my AR15 using the SCS. It's a night and day difference.

JP Rifles Spring Selection Guide

You can also call them.

 

[Longshot85]

I have 2 JP SCS setups up and running now

One is a SPR style build with a WOA 18 inch SPR barrel, SD Tactical AGB, factory DPMS bolt (for now) and the JP H2 with 2 tungsten weights. I also added a PRI gas buster. I only shoot suppressed. This rifle wears my 9x1.5 inch form 1 can and as far as trigger......SSA-E. I get ZERO gas in the face and boy does this rifle run SMOOTH.

Second is a 10.5 inch .300 BO Nordic components barrel. It has same SD Tactical AGB, palmetto nickel bolt and ruger msr trigger (good option for the price.) This rifle wears a 6x1.5 inch form 1 can. For this setup I am currently running a stock "regular" JP SCS with only steel weights for now. What makes this pistol so awesome is I got the Law Gen3 folder and actually ordered the whole "law ar15 kit" from JP. I cannot stress enough how awesome it is to have the JP AND the law folder.

Last build is in the works. I picked up an AR10 JP SCS second hand and it only has steel weights for now. This build is outside the norm......Aero M5 AR10 with Wilson Combat 16 inch 6.5CM barrel on order (uses their proprietary13.25 inch gas tube). I ordered an Anarchy Outdoors adapter for a Law Gen3 folder I'll be running on this setup. I ordered a JP AGB to try on this build.

I am a fan of the JP SCS

 

[S197]

Back pressure from the suppressor. If your buffer spring is too light for your setup then you will get too much gas coming back toward your face and it will blast you. By swapping to the heavier spring it stops almost all the gas that was hitting you in the face. Something like the Radian Raptor SD charging handle will stop most of the blowback used with a correct weight spring.

I’m going to be honest with you, I have never heard or seen that a buffer assembly could reduce gas flow. The buffer and spring only control the rate of the carrier. It dose not matter how fast or slow that carrier is moving, you will still have the same amount of gas exiting the gas tube. Now a charging handle can redirect gas from the end of the receiver.

 

[S197]

S197,

Good questions. I'll tell you what i know for sure.

Im going to run a JP SCS in my AR pistol (Its a weird configuration to meet laws in CT - feel free to ask about specifics if that would help in some way) first to learn the system a bit more (I know this isnt ideal, however, if something bad happens, id rather learn about it on a cheap AR pistol than one of my Creedmoors), and then in a "test rifle" i have that is similar to his, and experiment a bit.

I bought the "H2 heavy builder kit" to start with and an additional steel and tungsten weight so i have some adjustibility, if needed. Regarding felt changes - his rifle was significantly smoother. The spring twang was gone, but its not the end of the world for me if its still somewhat present. However, with the JP SCS the mechanics of the rifle under cycling of a round both shooting and by running the BCG with the charging handle was very linear and smooth; follow up shots for me were noticeably faster, reacquiring targets was also faster. The sensation of "coil bind" (buffer spring compressing in the tube was also gone, obviously (liked this a lot). There are four rifles that i want to put this in - 12.5" 223 pistol. 16" and 20" 6.5 creedmoors, and 10.5" 300 Blk out SBR - im going to go slow with this process, this is a very new system to me, and i dont want to screw anything up, or damage my rifles in some way.

To answer your questions...

1. Somewhat (I know this isnt ideal for trying to match a feel). He has a JP SCS in his 308 w/ 16" barrel. I can get specifics this weekend about gas system etc.
2. I do not know what my gas port size is. I can totally see how this is important, i'll ask the builder of the rifle. I do have a 14 position adjustable gas block. Gas tube for the rifle(s) in question are roughly 14" - 14.5" long (measured without disassembling everything) for both rifles. One rifle is 16" barrel the other is a 20" barrel. Both chambered in 6.5 Creedmoor. The 12.5" AR pistol is approximately 8.5" non adjustable gas block.
3. Surefire Warcomp, three prong to go with my cans.
4. 16" 6.5 Creedmoor - 4oz buffer weight. Spring is 11.25" long. Buffer tube is 7.875" long. BCG total weight is 19 oz.
4a. 20" 6.5 Creedmoor - 3.75oz buffer weight. Spring is 13" long. Buffer tube 7.6875" long (Magpul PRS stock). BCG total weight is 18.125oz.
4b. 12.5" 223 AR Pistol - 2oz buffer weight. Spring is 11" long. Buffer tube is 7.25" long. Uses the SBA4 brace to abide by CT laws.
4c. 10.5" 300 Blk SBR is still in ATF jail, so its not built yet.

Hopefully that helps, let me know what other info would help or is needed and i'll do what i can to get it.

Listen, they are nice and work well but it may not give you the results you want. Install the heavier weights and run it, at least this way you will know what spring setup to buy.

 

[Johnny00K]

I’m going to be honest with you, I have never heard or seen that a buffer assembly could reduce gas flow. The buffer and spring only control the rate of the carrier. It dose not matter how fast or slow that carrier is moving, you will still have the same amount of gas exiting the gas tube. Now a charging handle can redirect gas from the end of the receiver.

You are more than welcome to come shoot this pistol after I swap springs out. The only catch is you don't get to wear any glasses. I literally did this a week ago.

 

[MikeT]

I will soon have it in every lower.

 

[PJ65C]

First setup arrived today. I went with the H2 "heavy" builders kit so i have some variability.

Called JP and asked a few questions that i couldnt find answers too on their website, they werent as helpful as i thought they would be. Actually, guy was pretty rude - but, i got some information about where to start with everything etc so i guess i'll go from there. Even though ive shot a rifle with this before, hopefully the product runs significantly better than their customer service/tech/sales dept.

 

[TonyTheTiger]

I only have a limited amount of experience with this system (few hundred rounds), so im looking for more real world data and im curious if any of you guys have run it, or do run it. Do you like it? Hate it? Give me the good bad and the ugly.

Anytime someone has anything less than stellar to say about the SCS they get run off with pitchforks, so these threads always turn into echo chambers.

 

[S197]

‘S First setup arrived today. I went with the H2 "heavy" builders kit so i have some variability.

Called JP and asked a few questions that i couldnt find answers too on their website, they werent as helpful as i thought they would be. Actually, guy was pretty rude - but, i got some information about where to start with everything etc so i guess i'll go from there. Even though ive shot a rifle with this before, hopefully the product runs significantly better than their customer service/tech/sales dept.

I have one in my LMT and as we all know, LMT’s are over gassed. This is why I had asked about the gas port. On my LMT the SCS only gets ride of that twang.

Depending on who manufactured your buffer, it might not weigh what an H2 buffer should. I would install your H3 weights and test it out. Do you know anyone with a scale? If not, grocery stores have them.

 

[PJ65C]

I have one in my LMT and as we all know, LMT’s are over gassed. This is why I had asked about the gas port. On my LMT the SCS only gets ride of that twang.

Depending on who manufactured your buffer, it might not weigh what an H2 buffer should. I would install your H3 weights and test it out. Do you know anyone with a scale? If not, grocery stores have them.

No worries!

Ive been playing phone tag with the builder about the gas port size. Ironically enough, i got a little OCD with this and measured/weighed the BCG's, buffer springs, tubes etc. Still going back and forth with which platform will get the first SCS. I'll give you the weights once i figure that out for certain.

 

[Dryan910]

First setup arrived today. I went with the H2 "heavy" builders kit so i have some variability.

Called JP and asked a few questions that i couldnt find answers too on their website, they werent as helpful as i thought they would be. Actually, guy was pretty rude - but, i got some information about where to start with everything etc so i guess i'll go from there. Even though ive shot a rifle with this before, hopefully the product runs significantly better than their customer service/tech/sales dept.

Sounds like you had the pleasure of speaking to Andre. I’ve bought a couple rifles from them and never had a good experience talking to him.

 

[wyld3man]

Anytime someone has anything less than stellar to say about the SCS they get run off with pitchforks, so these threads always turn into echo chambers.

 

[Colorado S14]

I have one in my precision Valkyrie AR, running it with a Superlative gas block behind a TBAC Ultra 7. Pleasure to shoot.

I did buy an Armaspec sound mitigation buffer system for a 300 BLK SBR I just built. Interested to see how it does for a quarter of the price.

 

[Longshot85]

I have one in my precision Valkyrie AR, running it with a Superlative gas block behind a TBAC Ultra 7. Pleasure to shoot.

I did buy an Armaspec sound mitigation buffer system for a 300 BLK SBR I just built. Interested to see how it does for a quarter of the price.

Let us know how it goes

 

[Johnny00K]

Is it even considered a battle rifle if you don't weigh some of the parts on a grocery store scale???

 

[BurnOut]

Is it even considered a battle rifle if you don't weigh some of the parts on a grocery store scale???

That depends... has the grocery store been looted?

Anyhow, I have a gen 1 JP SCS in an 18"/mid-length gas RRA varmint gun chambered in 5.56 that also has an adjustable gas block. I'm fortunate that I was able to find a gas block setting that works both suppressed and unsuppressed (SiCo Omega) with my chosen ammo (Fiocchi 50 gr Vmax). In any event, the whole rifle feels, as others have said, very, very smooth, with less felt recoil than it had prior to the installation of the AGB and SCS. In an utter failing of the scientific method, I installed them both at the same time, so I cannot attribute the difference in the way it feels to either the SCS or the AGB; I can only say that the combination of them is absolutely fantastic.

As has been alluded to, I am trying the Armaspec SRS (Stealth Recoil Spring) in another build (16" Grendel) that I have not yet had a chance to take to the range, so I cannot offer any feedback on it.

Regarding the concern about damaging the rifle by installing the wrong combo of weights and springs on the SCS, I'd say it's effectively a non-issue; if you go too light and the carrier/SCS bottom out, you'll feel it and (hopefully) make adjustments. A few (hell, even a bunch) of rounds in that configuration won't do any harm (pretty much every factory gun is over gassed and runs like this anyhow). OTOH, if you go too heavy, the gun just won't cycle and/or lock back on an empty mag. As you zero in on the correct config for your gun/ammo, the rifle will start feeling smoother and smoother in its cycling, and when it either starts feeling less smooth or starts having function issues, back off a step or two... and Bob's your uncle.

 

[ReaperDriver]

I'm a big fan of the SCS system as well as the VMOS Bolt carriers for suppressed applications. I run them on both my JP rifles - a .223 and a newly built .260 large frame. Both work flawlessly when suppressed. However, when unsuppressed, neither will cycle well. I need to go play with the weights on my large frame, because even with the gas block fully open, it will not lock back on an empty mag when unsuppressed. So I'm pretty sure I'm just over-weighted on either the buffer spring or the carrier (or both). I'm hoping I can find a happy medium for both, because I shoot both suppressed and unsuppressed depending on what I'm doing. Suppressed for just fun at the range and can off for comps. Fortunately I have a standard Low mass carrier for the .223 to swap into if I want to shoot unsuppressed and it runs perfect with the SCS.

Getting rid of the twang of the buffer spring alone is worth the price to me. But it does definitely feel like the gun runs smoother.

 

[ReaperDriver]

Sounds like you had the pleasure of speaking to Andre. I’ve bought a couple rifles from them and never had a good experience talking to him.

I've not ever dealt with Andre. I have spoken to Ben Z. (in sales) on the phone several times and he's always been super helpful and always very polite. I do get the impression that they are crushed at the moment with orders and I'm sure the phone rings off the hook day and night from people wanting to know where their orders are - so I'd give them the benefit of the doubt if they seem rushed on the phone.

 

[PJ65C]

Sounds like you had the pleasure of speaking to Andre. I’ve bought a couple rifles from them and never had a good experience talking to him.

I wasnt going to name names - but you smacked that nail right on the head with a sledge hammer. I do my own leg work before calling any company, and only call when ive exploited the information that ive been able to obtain, so i called them - This guy was down right horrific!

 

[wyld3man]

Yeah, anyone who tunes up Hulk Hogan probably shouldn’t be answering the phone for JP during a busy time

 

[TurboTrout]

Got a few thousand rounds on mine, wouldn’t run anything else.

 

[rustyinbend]

Was having trouble with over-gassing on my LWRCI REPR MKII Elite in 6.5 Creedmoor ... it's an AR10 "beast" and even on the lowest gas setting, it would eject forward of the firing line. Long story short ... got the JP SCS (heaviest weights, tightest springs) and now it ejects perfectly (4 o'clock) on a medium gas setting. An unexpected benefit is how smooth and quiet it is compared to the normal spring/buffer combination. Haven't needed to go that "premium" on other AR's, but on this one, it absolutely solved this problem (over-gassed ejection).

 

[PJ65C]

Was having trouble with over-gassing on my LWRCI REPR MKII Elite in 6.5 Creedmoor ... it's an AR10 "beast" and even on the lowest gas setting, it would eject forward of the firing line. Long story short ... got the JP SCS (heaviest weights, tightest springs) and now it ejects perfectly (4 o'clock) on a medium gas setting. An unexpected benefit is how smooth and quiet it is compared to the normal spring/buffer combination. Haven't needed to go that "premium" on other AR's, but on this one, it absolutely solved this problem (over-gassed ejection).

I have an older REPR in 308, love it. Its on the list to receive a JP SCS. Glad it corrected things for you.

 

[rustyinbend]

I have an older REPR in 308, love it. Its on the list to receive a JP SCS. Glad it corrected things for you.

One thing I forgot to mention is that I shoot it suppressed ... one of the reasons it was over-gassed. Unsuppressed it was gassed OK using the adjustable gas settings. That said, the SCS is still a great addition even when I shoot unsuppressed.

 

[TurboTrout]

Was having trouble with over-gassing on my LWRCI REPR MKII Elite in 6.5 Creedmoor ... it's an AR10 "beast" and even on the lowest gas setting, it would eject forward of the firing line. Long story short ... got the JP SCS (heaviest weights, tightest springs) and now it ejects perfectly (4 o'clock) on a medium gas setting. An unexpected benefit is how smooth and quiet it is compared to the normal spring/buffer combination. Haven't needed to go that "premium" on other AR's, but on this one, it absolutely solved this problem (over-gassed ejection).

I have a JP upper on a custom lower with a JP spring and single stage trigger, the speed of it is crazy and no crappy twang after you shoot

 

[S197]

Is it even considered a battle rifle if you don't weigh some of the parts on a grocery store scale???

Us poors need to get creative sometimes

 

[S197]

Yeah, anyone who tunes up Hulk Hogan probably shouldn’t be answering the phone for JP during a busy timeView attachment 7583490

Andre The Giant = great guy. Andre The Giants ghost = CS Dic head

 

[nutation]

It's very smooth, like running a sewing machine. There are multiple other, less expensive ways to tune the cycling, but none feel quite as nice.

 

[englishguy3012]

I run two of them currently, with a third that didn't seem to work... more on that in a bit.

I run one on my 11.5 inch 5.56 with Superlative Bleed off gas block, law folder and have had no issues, especially just having the ability to throw on the suppressor and not worry about overgassing is a blessing. The second I run on my .300 SBR, which also has the same block, and folder, but I only run subs through it with suppressor on. This is where it really shines, as nothing accentuates the "twang" like running subsonics... really spices up that noise.

The one that didn't work for me was on my REC-10, as I didn't have a adjustable gas block, and I think that, twinned with the folder (both of which are no longer on the rifle) causes some FTF's some from bolt over magazine from moving too fast. and I wasn't holding the same group, not as tight, cause unknown.

 

[ReaperDriver]

The only downside I'm experiencing so far with the weighted SCS and the JP Variable mass carrier (with tungsten weights) is the recoil. Unsuppressed, it's a dream to shoot with the TBAC brake. As soon as I throw the can on, however, the mild .260 recoil feels more like a .308 or worse. All that weighted mass moving backwards can definitely be felt. I have an adjustable gas block and it's currently set for unsuppressed, but I'll need to play with it to find a suppressed setting that tones that recoil down. However, without a switchblock - it will be a PITA to go back and forth.

 

[JPaul]

The only downside I'm experiencing so far with the weighted SCS and the JP Variable mass carrier (with tungsten weights) is the recoil. Unsuppressed, it's a dream to shoot with the TBAC brake. As soon as I throw the can on, however, the mild .260 recoil feels more like a .308 or worse. All that weighted mass moving backwards can definitely be felt. I have an adjustable gas block and it's currently set for unsuppressed, but I'll need to play with it to find a suppressed setting that tones that recoil down. However, without a switchblock - it will be a PITA to go back and forth.

I have a rifle length gas .260 that had erratic ejection pattern with okay accuracy but was frustrated with infrequent wild random fliers always to the right with really beat up brass. I had tried the Tubbs flat wire spring with some improvement, then I tried the armaspec version of the SCS, i loaded as many spacers as I could in order to place more static pressure on the BCG. It cured my ejection but accuracy was only par. I don't like running suppressors on semis other than on a short 300BO but I took a chance with my old gem tech suppressor and it prints 1/3 MOA all day with any match ammo and brass in great condition. Recoil is a little more than what I think it should be but I can manage it just fine in The prone.

 

[englishguy3012]

Reaper - Superlative bleed off block might be right up your alley then.

 

[Sniperkid]

Hey all, I know this post is new but I could use yalls input. Im currently working on my first ever AR-10 build and need some advice on JP Enterprise buffer spring. I know the BCG inner diameter is recommended to be .530" for the buffer spring but is that just a recommendation or can my BCG inner diameter be any bigger? I have a Lantac EBCG on its way the and the inner diameter is approx .620". Im honestly just trying to find if this will be a problem or not. Any help works. Thanks

 

[kl3309]

Hey all, I know this post is new but I could use yalls input. Im currently working on my first ever AR-10 build and need some advice on JP Enterprise buffer spring. I know the BCG inner diameter is recommended to be .530" for the buffer spring but is that just a recommendation or can my BCG inner diameter be any bigger? I have a Lantac EBCG on its way the and the inner diameter is approx .620". Im honestly just trying to find if this will be a problem or not. Any help works. Thanks

That .530 is the minimum dimensioned BCG in which the captured spring will work. Your Lantac should be fine.
Get the special JP retainer pin too, it'll keep the captured spring from wanting to come out of the buffer tube with you have the receivers apart.