Let me preface my query by stating that I realize ejection patterns are not the end-all, be-all when it comes rifle function, and that unless my rifle is not functioning properly, then I shouldn’t worry about ejection patterns. That being said, the rifle in question has functioned reliably thus far.
Today I brought my KAC SR-15 14.5" w/ KAC buffer and BCM Mid-length 14.5" w/ H buffer to the range, and ran 55gr 5.56 PPU through both.
I noticed that the BCM ejected brass strongly and consistently at 4:00-4:30, while the KAC seemed to have a weaker and more erratic ejection pattern.
I’m sure this boils down to gas length differences (not sure if KAC still uses intermediate gas) and buffer weights (don’t know the weight of a KAC buffer), but I’m looking for more insight…
My first upper from KAC ejected all over the place. So much so that it left brass marks on the rail.
It also would fail to eject sometimes. Turns out the gas port was to big and the buffer spring was to short from the factory.
Wow, I didn’t realize that the Carbine upper came with an H2 buffer. I figured they were ported the same as the 16" and would run on a carbine or H buffer.
Yea. The 3 that have come to me have come with HH buffers. One even came with 2 HH buffers!
I had a complete factory KAC 14.5 carbine join the family recently. Just checked and it comes with a buffer with the KAC insignia PN 21057 which apparently is a 4.5 oz buffer (H2).
Other than the marking of HH buffers that comes with the upper they appear to be the same buffer.
They do come with different buffers. The one in your mod 1 lower should just be an H buffer w/ KAC insignia whereas the buffer that came with your factory 14.5 upper should have an HH engraved on it.
Just so we’re clear, is this a 100% factory 14.5" upper? Or did you go through with cutting your 16" down to 14.5" like you asked about in the other thread?