RE: Any ways to make for a flatter shooting bow?
I agree with the last two posters on one thing. Whoever is only getting 1" drop between 20 and 40 yards has no idea of what he is talking about. The bow hasn't been made that can do that. Look at Quicksilver's setup. Nearly 80 fps faster than what's probably average and still getting 10" drop. At least he's honest about it.
As for your bow? There is something seriously flawed here. Not even the slowest bow has 4-5" of drop between 15 & 20 yards. Even with a heavy arrow with your setip there should probably be only about 1 1/2" difference at these distances. Maybe 2" from 20 to 25 yards. This would be fairly normal for a bow shooting 230 fps or so, slow by today's standards.
There are ways to get more speed, but you have to willing to spend a few dollars and the time to play around and find what works. It also helps to have your own chronograph or access to one.
Look, I shoot a 27" draw and used to shoot 60# so I know what can be had. You have to buy and set up arrows for a minimum of 5 gr/lb (sorry Quicksilver) because your limb design isn't going to hold up if you go lighter. Trust me on this one. I've replaced a lot of this style of limb on PSE's.
Next, what all is on the string. Heck, just for starters get rid of the factory strings and get a good set of aftermarket ones (Gibblet comes to mind). Order them BCY 8215. This may gain you as much as 10 fps right there. Not guaranteed, but it doesn't matter. You'll have good strings.
OK, back to what's on the string. Brass nock sets? Each ones slows the bow down 4 fps. If you have a peep and kisser get rid of one of them. You don't need both. If you keep the peep then use one without a rubber tube aligner. These two combined can give you another 10 fps.
What kind of string silencers? Some rob you of less speed than others. Try the Simms Super Leeches. Then try to keep them as close to the cam as possible while balancing out speed and quiet. If you err go for more quiet. This is a hunting rig.
If all else fails and you feel a real need for speed then next time don't buy a bow based on price or shortness of A2A. Look for bows with the highest IBO rating right off the shelf.
Giving you an idea of what's possible, I have set up a few Martin bows with Nitrous cams. All were set at a measured 27" AMO draw and 53#. All shooting at 5 gr/lb. Here's some results:
2004 Martin SlayR---299 fps
2005 ShadowCat SE (9 3/8" brace)---272 fps
2007 Pantera (7" brace)---287 fps.
These were all set as 3D rigs. They typically drop about 12 fps when I have them set in hunting trim with a slightly heavier arrow. And all produce enough of that often over rated KE for deer sized game.
What was neat about the SlayR in particular was that I could sight it in for 25 yards and only have a vertical spread of 2 1/2" between 20 and 30 yards.