since the buffer tube is most likely the same length (rifle length i'm guessing based on buffer length?) there are other recoil parts that will be able to be used/swapped out. i say this as i've used ar15 carbine buffers in ar10 rifle length buffer tubes. i need spring dimensions (including coil diameters) to know compressed length. trying to go from memory there's about 1/2" difference in bcg lengths between ar15 and ar10 length. if that's correct is the 300wm bcg about 1/2" longer than your ar10 (if you have 1) bcg? this is how i can help regardless of gas port size.