I have the JP spring in one of my ARs (16") and noticed no difference anywhere as compared to the original.

For grins, I have tested a carbine buffer, H buffer, and H2 in my 8.5" pistol using basic 55 gr ammunition (PMC X-TAC 55gr FMJ-BT).

Surprisingly, I find no difference to include felt recoil or ejection pattern.

It runs fine with all 3. My brass is tossed to approximately 4 o' clock. The H2 might have tossed to about 3:45 but that's about it.