Been meaning to do some testing on rate of fire using various buffers, but events always conspired against me on getting time to do tests.

Rifle is a registered receiver Colt M16a1 with factory FCG and factory A1 stock, 20" Brownell's chrome lined 1/7 twist A1 pencil barrel. (no idea of gas port size) installed to a A2 upper receiver.
Recoil spring is the factory M16a1 Colt rifle spring.
Bolt carrier used was a Fail Zero NiB coated M16 bolt.
Magazines used were surplus '94-'04 ban era restricted marked Center Industries 30 round magazines fit with latest gen anti tilt followers.
Ammunition used was PMC 55 gr. M193 spec FMJ.
Shot timer is a Competition Electronics Pro Timer BT.
20 rounds per string with averages of 3 strings each, I rounded down to the nearest whole number.

Here are the buffers I used.

Left: Colt standard rifle buffer that came with M16a1.
Center: MGI Rate and Recoil Reducing Buffer (buffer is a carbine buffer with drop in spacer for use with rifle extension).
Right: KynSHOT RB 5001 fixed stock hydraulic buffer.











Rate of fire results:

Colt standard buffer = 765 rounds per minute.
MGI Rate and Recoil Reducing Buffer = 688 rounds per minute.
KynSHOT RB 5001 fixed stock hydraulic buffer = 603 rounds per minute.

I have been running the KynSHOT for some time and knew it had very noticeably reduced the rate of fire, but never quantified it.
Had also read about the MGI Rate and Recoil Reducing Buffer, so decided to to buy one for testing purposes.

The KynShot will be staying in my M16a1.
The MGI will likely be sold on the EE.


RCA

I love my Kynshots, but the ROF seemed a little too low for me. I like mine running at about 650 rpms. I took my Colt rifle buffer and replaced two steel weights with tungsten weights, and now the ROF is about 625.   Perfect for my tastes.

FWIW, the data I have indicates the following weights for the buffers tested -

Standard AR Rifle length: 5.2 oz.
MGI/Hydra Weaponry Rate Reducer: 7.1 oz.
KynSHOT RB5001: 8.3 oz.

MHO, YMMV, etc.

@Amphibian

When I get the chance, I'll redo the test with 62gr. M855.

RCA

NVM