I Have both Axis and FMJ's in 400 cut to 27" and I shoot pretty well with them. (07 Alligence #70 29"draw) They are quiet with Blazers but make excessive noise with feathers. Last week I tried some 340 FMJ's cut to 28" with feathers....no noise and they also shoot very well. I haven't had a chance to chrono the different arrows. Do you think it's speed causing the noise or am I close to the spine limit for my set up? BTW I currently shoot 100 grn heads. Thanks.