KAK Industry AR15 9MM Carbine Buffer Extended, Heavy 10 oz

I was running a Stern Defense bolt (13.77 oz) with a standard length H3 buffer & spacer (totaling about 18 oz); it worked reliably, but I was getting quite a bit of felt recoil with the buffer slamming into the spacer. I picked up a Foxtrot Mike bolt to build a second 9mm AR with my son. The FM bolt weighs only 12.5 oz, so I started looking for heavier buffers over concerns that the FM bolt/H3 combo would be too light. Found this buffer and purchased two; swapping out a couple of tungsten buffers for steel on one of them, we were able to get both bolt/buffer combos to about 22.5 oz. The difference in felt recoil with the heavier buffer slowing the bolt is stark; not having to run a spacer is a nice bonus. I won't build another 9mm AR without this buffer.

Have run a smaller 5.4 oz buffer and spacer set up for a long time in an AR9 pistol with a brace. Discovered "Demonstrated Concepts" and cheek pistol use on youtube. Ditched my SBA3 brace, switched out the adjustable tube for a pistol tube, and used my cheek as the third point of contact along with the lighter buffer. This was not pleasant. It worked however the recoil was too much for long term use and good quick followup shots were almost impossible. Talked to the people at KAK about this, the customer service was excellent, and I decided to try the big 10 oz buffer. This solved everything. The heavier buffer made the cycling better, reduced felt recoil significantly, provided the ability for rapid accurate followup shots, and eliminated the need for aspirin afterwards. Looking back to regular brace use, I'm sure it would have made that much easier as well. I have a 16" AR9 rifle also and as soon as I can, I'm replacing the little 5.4 oz buffer in it with another 10 oz heavy buffer.

Installed this buffer on an Aero Precision build using their 11" upper, BCG, LPK, and EPC-9 lower. I wanted to avoid the solid buffers to prevent a chance of bolt bounce, so KAK is the way. This KAK buffer did weigh 11.05 ounces on my scale; combined with the Aero Precision BCG at 14.5 ounces using a 5.56 standard carbine spring she ran a flawless 132 rounds on the first range outing using rather low powered Fiocchi 'range dynamics' 115 grain ammunition. The recoil impulse was smooth and mild. This KAK buffer is very well made and a must have for a 9mm build.

AR15 9mm extended heavy buffer resolved all my feeding and ejection issues with FM9 16 inch upper. Standard spring worked great. This item made a troublesome rifle fun to shoot again.

It was counter-intuitive to me, but switching to a super heavy 10 oz buffer reduced felt recoil and doubled my rate of fire. I bought the 8" gen 4 PSA 9mm kit (everything minus the receiver), shot it about a 150 times and was kinda bummed. It was a slow pig with a lot of recoil. More than a 5.56 for sure, but no concussive blast of course. I felt like I could shoot way faster on target with my PF940V2 (Glock 17). Swapped out the buffer and now my AR9 shoots very nice.

Have one in my ar9 build and it works great...just purchased another for a new ar45 build...

Perfect weight on my PCC rifle with KAK 16" barrel and BCG. Installed with BCM intermediate receiver extension (A5), 308 AR rifle spring, and a buffer spacer. Shot 115 gr and 124 JHP without any issues.

Buffer seems well made. Smooth recoil and absolutely no gas to the face with the suppressor attached after switching to this weight buffer. The deadblow weights seem like the only way to go on a blowback platform.

Great quality as always.