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Which Recoil System? JP SCS Gen 2 vs MBX PCC Buffer System


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Sorry if this has been discussed before. With respect to setting up a PCC 9mm for USPSA matches, which recoil system do you prefer? Two that seem to have a following (successful?) are JP's Silent Capture GEN 2 (4 weights) with compatible BCG and MBX's PCC Buffer System. I'm new to this blow-back recoil challenge. I'm currently running a NFA upper/lower with JP trigger, Rock River BCG (I think, took from older carbine bought few years back and had milled for Glock mags), 16" Faxon barrel and have tried various buffer and spring combos and loads, which didn't really seem to have much of an effect. The gun runs excellent though, just a bit too much recoil for good doubles. Any advise is greatly appreciated.  I had a Faxon BCG on back order and canceled. Thinking of crying once and getting JP BCG and SCS system since I still need a BCG. Thanks!    

Edited by littlefish
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Hello: I like the tune ability of the JP buffer. You can change springs and weights to get the perfect setup for your reloads. I do use the JP bolt as well with their buffer tuned to my load. I also have a regular setup Matrix bolt with a 223 spring and a 4.6oz buffer that works pretty well also with 147 grain bullets. The JP is quieter and is less distracting since you don't feel and hear the spring. Thanks, Eric

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I ran my pcc for the first time today with the jp scs setup exactly as Eric's and I really like it. I was able to hit double taps within  2" groups at 40' many times over and over using 147gr bayou bullets loaded to 138pf. With the buffer in the stock form I couldn't get the doubles within 3 or probably even 4" at only 20' away. I'm anxious to see what I can do with my 130pf ammo (I didn't have it with me, I grabbed the wrong box)

 

Btw, Eric, thanks for all your tips and suggestions thus far. I think I'm ready for a match!

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On ‎6‎/‎29‎/‎2017 at 11:29 PM, nickbfishn said:

I ran my pcc for the first time today with the jp scs setup exactly as Eric's and I really like it. I was able to hit double taps within  2" groups at 40' many times over and over using 147gr bayou bullets loaded to 138pf. With the buffer in the stock form I couldn't get the doubles within 3 or probably even 4" at only 20' away. I'm anxious to see what I can do with my 130pf ammo (I didn't have it with me, I grabbed the wrong box)

 

Btw, Eric, thanks for all your tips and suggestions thus far. I think I'm ready for a match!

 

Is this the spring set you are using? There's appears to be a heaver 308 spring set available too.

  • JPSCS-SPRING15-80: 1 side white
  • JPSCS-SPRING15-85: 1 side black
  • JPSCS-SPRING15-90: 1 side green
  • JPSCS-SPRING15-95: 1 side yellow
  • JPSCS-SPRING15-100: no color
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Yes, I have the green 90% spring installed but you have to buy it as the kit that comes with all 5. I also have 3 stainless steel weights and 1  tungsten as opposed to the 3  tungsten and one stainless steel (stock form). 

 

When I get back to the range with my 130pf ammo I'm going to try the black and also the yellow for shits and giggles.

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15 minutes ago, nickbfishn said:

Yes, I have the green 90% spring installed but you have to buy it as the kit that comes with all 5. I also have 3 stainless steel weights and 1  tungsten as opposed to the 3  tungsten and one stainless steel (stock form). 

 

When I get back to the range with my 130pf ammo I'm going to try the black and also the yellow for shits and giggles.

 

Nick, did you buy the extra steel weights directly from JP or one of the retailers? Midwayusa lists the 5 spring kit but only shows the tungsten weighs (no steel). Brownells shows only Tungsten weights too, including a gen 2 version which might be for the 5 weight SCS.

Edited by littlefish
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I'm running the MBX buffer with a CMMG bolt, 16" barrel, no comp, regular 5.56mm buffer spring.  The buffer did not make much of a difference with my reduced 135pf loads, but made a very noticeable difference with my old Production loads which shot 155 pf out of the rifle.  Haven't tried the JP setup, but I can say the MBX does offer some tunability by adjusting the stroke of the buffer (full length vs shortened), as well as using a lighter spring internal spring.  For loads lighter than 145pf just take it out of the package, slap on a regular carbine buffer spring and you're GTG.

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Shooter connection has them in stock

i recently installed a MBX buffer with their yellow spring in my psa

and I had feeding issues that looked like the bolt was short stroking

i ended up putting the stock spring and adjusting the buffer to the short position, now the gun runs, soft shooting and I can manually lock back the bolt, which was damn near impossible with the yellow spring

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On 7/5/2017 at 2:56 AM, rishii said:

Shooter connection has them in stock

i recently installed a MBX buffer with their yellow spring in my psa

and I had feeding issues that looked like the bolt was short stroking

i ended up putting the stock spring and adjusting the buffer to the short position, now the gun runs, soft shooting and I can manually lock back the bolt, which was damn near impossible with the yellow spring

Edited by gnhowell1
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On ‎7‎/‎3‎/‎2017 at 9:38 AM, nickbfishn said:

I bought the extra weights and spring kit direct from jp. They don't send any additional parts with the buffer.

Do you know which spring comes with the 9mm SCS? Is it the no color 100 or maybe one of the 308 springs? 100 mean 100%, correct?  Just received a couple more steel weights and the 5 spring kit, so ready to try and tune a bit more (TBD).

 

I've change loads prior to the coming spring/weight testing, went from Longshot powder to WIN 231, which seemed to have a bit less bounce (doubles a little better). Thought the slower Longshot might do better with a 16" barrel, but it didn't. I have tried various projectiles from 115 JHP (.355 rem), 124 FMJ (.355 rem), 124 Berry THB (.356), 135 lead RN (Magnus .356). The 115 JHP with 231 seemed to be best so far bounce wise. Haven't tried anything heaver yet or chrono'd.       

 

Edited by littlefish
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I tried the JP SCS for 2 months modifying it in every configuration you could possibly think of. The best I ever got it was by running a light buffer spring with heaviest weights (all tungsten) and an additional 18lb wave spring UNDER the plastic cone piece at the bottom to reduce overall travel and add secondary buffering. You can see the results of that here:
 


But any configuration of the JP didn't even come CLOSE to the 9mm hydraulic buffer from blitzkrieg which I've been running for every major this year.

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I followed Aircooled6racer recommendation with my JP buffer system and swapped 1 tungsten weight for a steel weight and went with the lightest spring.  I'm running a 124 gr bullet @ about a 130 pf.  Seems O.K., more testing to follow.  

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Hello: Another thing to consider is how quick and how close your splits are on target at a fixed distance. I use 7 to 10 yards for testing. I have found that using my reloads in the 135-138PF with 147's works the best for me. My current setup is 3 steel weights, 1 tungsten and the green spring in one PCC. The other I am using 2 tungsten weights, 1 steel, 1 aluminum with the black spring. I am using a QC10 Colt lower since I feel it feeds a little softer than the Glock QC10 lower. Both are 100% with these setups. Going to test some 122 Acme bullets next. Thanks, Eric

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1 hour ago, nickbfishn said:

Are you shooting factory ammo or reloading? What is your power factor?

 

Not sure what you mean... when I tested the SCS? or currently?

I've tried an extremely large amount of bullet weights and pf combos

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1 minute ago, Gary H. said:

Max, are you using the spring that is recommended with the Blitzkrieg? I just put one together using a Spinta bolt and Blitzkrieg hydraulic buffer. 

 

Blitzkrieg recommends using JP 308 springs.

They sell a "carbine kit" which is the 9mm hydraulic buffer with a JP 308 RIFLE spring.

They also sell a "pistol kit" which is the buffer with a JP 308 CARBINE spring.

Kind of annoying but it makes sense why they label it like that.

I have the entire set of JP springs (.223 carbine/rifle, 308 carbine/rifle, as well as the TTI Lightspeed spring which is an underpowered .223 carbine spring) that I used to do all my tests.

I currently use the 308 Carbine spring with the hydraulic buffer since it simply gives me the smallest groups and lowest time when I test on 25 yard bill drills. 

 

EVERY GUN, AMMO TYPE, BARREL, MUZZLE DEVICE, SHOOTER'S STANCE, SHOOTER'S GRIP, ETC drastically affects how the gun will perform with different buffer systems. I'd recommend testing out different spring and travel length with your own setup and measure your times shooting small groups at distance.

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Back to the thread's original topic, my only experience with the MBX buffer system is testing them out at MBX's booth at Multigun Nationals back in april. I only shot the buffer system in their guns that they had set up so I can't directly compare it to the Blitzkrieg in my gun. But my initial impression of it was it is a good buffer system and I would definitely use it over the JP SCS.

But I wasn't blown away compared to the blitzkrieg which I run now so I won't be switching to one. IMO the blitzkrieg is still the best, but like I said I haven't directly compared the two in the same guns. 

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