I just put the B&T hydraulic buffer with a Neverwear flat spring in a AR 9 that I built.  It transformed the gun.  Less recoil and smooth firing action
It is a good product.  I wished they made one for a 308.  

Tag for comments.

In my comparisons so far, the B&T hydraulic buffer and the KynSHOT RB5007 hydraulic buffer are both very good in semi auto 9mm shooting; and with the B&T yielding lower ROF in full auto, I have the RB007 in a dedicated AR9, and use the B & T in an M16.

Disclaimer:  I have no affiliation with or financial interest in any vendor or manufacturer; and I am not a competitive shooter or a blogger who receives any form of compensation for endorsements or favorable public or private comments.  Use of vendor and/or product brand names, if any, is for informational purposes only.

Best of luck.
MHO, YMMV, etc.  Be well.

I repurposed an Enidine hydraulic from my 5.56 3 gun rifle to my AR9, currently with a CMMG radial delayed bolt... coupled with a modified Miculek comp, dot movement is greatly reduced

I didn't know about these hydraulic buffer and the different manufacturers but they sure make shooting nice.  I just looked at the Kyn shot and they make one for 308.  Im going to try that one next

Hydraulic buffers have been used in connection with firearms since the late 1800's, and in the AR-15/M16 platform since the mid-1970's when Colt came out with their version that I believe has been discontinued for some time.  Enidine AR pattern hydraulic buffers date from around 2005 or so; and while Enidine still appears to sell to the military, they discontinued commercial sales quite a while ago.  Crosshair brand AR hydraulic buffers appear to be a now discontinued product that looks to be a re-branded or made under license version of the Enidine buffer.  KynSHOT appears to have brought out their version (which has a number of specific application varieties) around 2015 or so.
I now have a KynSHOT RB5015HD that I'll be comparing with the RB5007 and the B & T buffers when the weather improves.

MHO, YMMV, etc.  Be well.