If the OP has a draw weight of 60 lbs and draw length of 28" (as said in his post) I'd say his speed is pretty close to what should be expected. My lighter weight arrows are also 450 grains and with my DW being 63 lbs and DL being 29" these are shooting (measured through a chronograph) at 280 fps. My additional 3 lbs DW and 1" DL making the difference, in my estimation.
One thing the OP might also want to consider is that shooting heavier arrows will make for a quieter shooting setup AND his arrows will retail more down-range energy for increased penetration potential. If he's truly going after BIG game, such as elk and similar size critters, his 450 grain arrows would be a better choice than something lighter, just for the sake of getting a little faster initial out of the bow velocity, IMO. Faster, lighter arrows lose more speed over distance than do heavier arrows. That's just a fact that follows the laws of physics.
There are several online articles as well as in hard print, about the pros and cons of light vs heavy arrows. He might benefit from checking into this before buying light arrows - he just might determine what he has are a good choice and save some money too.
08/12 Martin Firecat Pro-X (29" DL, 66# DW), Nitro 3 cams, home-made torque reducing cable guard rod, new VEMs, DS Advantage/HHA Pro-5519 front sight, No-Peep Sight Eliminator, Limb-Driver arrow rest, B-Stinger stabilizer, custom lower & upper STS with offset stops, G5 Head-Loc quiver on custom mounting bracket. Gold Tip Velocity XT300 arrows with Bi-Delta 2.5" Sharkstooth vanes and Grizzly single-bevel broadheads, 498 grains at 262 fps (22% FOC)
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin Gold Plus Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver
I figured you might have been thinking it was a Ridge Hunter or other single cam bow Barry. True, that 450 grn arrow is heavy for speed. However, I hear bows are more efficient and quiet with heavier arrows. Beats me?
270 FPS seems to be moving along pretty good for that weight.
I didn't see this was all covered already on page two!
Run it through the calculator mentioned previously, and pay attention to the Kinetic Energy figures. 65# KE will kill just about anything in North America if hit well. You are shooting 54gr. more than I am, and I'm getting 296 fps, 28.5 in. draw, and 68#. I'd say 270 with your set-up is about right, and a good speed.
2006 Rytera Bullet X 60#---2008 Moab 70#
2008/12 Firecat 60#--- 2010 Warthog 70#
2009 Warthog 70#---2009-10-12? Warthog Frankenbow with Nitrous B
2010 Strother SR-71 65# & 2012 Strother Rush 65#
2012 Strother SX Rush 60# & 2011 Strother Infinity 70#
BSD strings and cables
Yeah, I know I'm grumpy and opinionated.