I echo what Moses said; your rifle system's weight is what it is,... if you feel confident in its' capabilities and like the way it works, roll with it and invest your time in P90X to increase your strength and stamina. Also, try some "out of the box" thinking in regard to how you shoot/wrangle your rifle i.e. think about utilizing beanie bags, shooting bags/pillows to help support your shooting. Try tucking a beanie bag under your support arm to give it a little boost when shooting off-hand. Try placing a bag under your foot when shooting off a low barricade to raise your knee just enough to allow your elbow to rest on it,... whatever you can do to increase the support and stability of your rifle,... go crazy! I've seen guys running around the COF with pillows and bags strapped all over them for this purpose - it works!
That said, there are tons of options available to shooters that can both decrease weight and increase capabilities. I don't know what you're running for a stock, but from the fact that your rig is 17-lbs, it might be something to look at - there are a plethora of chassis systems and light-weight stocks available. While I love the feel of a McMillan A4, I'd never run with one in a practical match as the thing is just a beast to huff around the COF and its' "feel" just isn't that much better than anything else.
Also, do you REALLY NEED that 25+ magnification scope with the 56mm objective,...? I'd say, no,.. you don't. I just sold my Premier 5-25x56 as I found that it wasn't ever making its' way to my rifle. Yeah, it was a great scope, but it was just too much for practical matches,... it would go great on a serious long-range rig, but not for my 260 or 308 where the bulk of shooting is off-hand or cramming the barrel through tiny holes in barricades. Remember that you're not shooting groups in a Benchrest competition, you're shooting at targets that are typically at least a minute-of-angle within 800-yards. Sure there are those stages that are exceptions, but for the most part you could get by with something as 'measly' as a 10x optic.
While a bit drastic, but something to consider in the future is your barrel - the heaviest "accessory" on your rifle. Again, do you REALLY NEED the 26" heavy contour barrel on your rig? Again,... no,... not for 99.9% of the practical matches you're going to shoot. Yeah, there will always be those whack-a-doo stages the organizer comes up with where you're shooting out past 1K-yards, but for the most part, your shots will be under 800-yards. While it's great to eek out every bit of velocity you can out of your rifle system, the trade-off in weight and handling can make its' pursuit a waste of time. You might also consider a fluted barrel. Don't believe the myths that fluting will also increase rigidity and aid in cooling,... it does neither,... and in the case of rigidity, it actually decreases rigidity,... but oh well,... it definitely decreases weight and can transform a formerly front-heavy, off-balanced rig into a quick-handling, stable shooter,... something to consider. Again, this is a bit of a drastic measure to simply decrease weight, but eventually you're going to either shoot out your current barrel or want to change cartridges and you might consider these factors when spec'ing out a new barrel. In regard to rifle systems, the thing to remember is there are ALWAYS trade-offs,... there is NO panacea. You simply have to pick your 'must haves' and damn the consequences.
I'm currently running a 20" AIAE straight contour in 308 with an S&B 3-20x50, and atlas bipod,... not "dainty" by any means, but its' only 14.5lbs,... which is manageable for me,...
Ry