I was previously using the JP captured setups in several configurations (9mm straight blowback and 5.56).  I have the spring tuning kits, standard version in Gen1 and Gen2, Gen2 H2 version for full auto as well as the 9mm version (straight blowback).  Initially tried the H2 version and it was too heavy and was getting malfunctions.  Tried the standard weight and was getting light primer hits and cycled way too fast.   I decided to ditch the JP system since that system wouldn’t allow me to add weight to the carrier.

Did some preliminary testing on smoothness with the Tubbs flat wire comparing to the Sprinco Green and no-name AR rifle spring and think the Tubbs flat wire was the smoothest.  After that did all testing with the Tubb’s flat wire.

Testing below was with custom 5.1 oz tungsten carrier weight.
H2 RoF too fast and couldn’t get singles
H3 As seen on timer only got 7 rounds tried another time and got to around 8 rounds before malfunction again.  Was also bouncy
The Enidine Hydraulic was noticeably stiffer to compress than the Blitzkrieg/Kynshot
Blitzkrieg/Kynshot seemed to be the smoothest but did encounter some malfunctions which I think was due to just too much weight.
AAC tungsten was kind of bouncy and didnt’ lock the bolt back.
MGI was also bouncy and didn’t lock the bolt back.
The Griffin Armament AR SOB was surprisingly quite good and I’d say the best choice behind the hydraulics….Enidine and Blitzkrieg/Kynshot.
Did a little bit of testing with no weight and it was just too fast although quite smooth.
Finally switched to the 3.5 oz Colt Steel carrier weight.
Didn’t encounter anymore malfunctions with the Blitzkrieg/Kynshot, singles were quite easy to get.
Enidine was noticeably more bouncy than the Blitzkrieg/Kynshot.  Wonder how an carbine Kynshot would do compared to the Enidine since the Blitzkrieg/Kynshot is not as stiff.
** Update – ended up getting a Kynshot carbine buffer and the stiffness seems identical to the old Enidine.  Interesting that they both feel stiffer than the 9mm ‘Blitzkrieg’ version. **
Again, Griffin Armament AR SOB was pretty good and would probably use that if was not able to use the Blitzkrieg/Kynshot.
All pictured RoF results below were with a standard steel Colt 9mm bolt weight (3.5 oz) except for the AAC 7.4 oz buffer was done with 5.1 oz tungsten carrier weight.

Enidine Hydraulic buffer – 4.3 oz

H3 buffer 5.3 oz

Slowest ROF AAC 7.4oz buffer w/ 5.1 Tungsten carrier weight – bouncy and didn’t lock bolt back.

Griffin Armament AR-SOB buffer – 4.8 oz

Blitzkrieg / Kynshot 9mm Hydraulic buffer – 5.9 oz

A5 Buffer Length – HeavyBuffers.com

Blitzkrieg/Kynshot 9mm buffer (RB5007) – compressed

Blitzkrieg/Kynshot 9mm buffer (RB5007) – extended

Blitzkrieg/Kynshot 9mm buffer (RB5007) – weight