Can you remove the a-2 sight on the sport model because the scope is really long and hits the sight?/

I believe you can. get a low profile gas block. Can't recommend brand, just bought one myself. I plan on a Vltor charging handle, so a vltor low profile gas block to go with it.....

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2nd Amendment!

I have the same gun.
Leave the front sight alone, a rail height gas block from Midwest weighs more. The front sight isn't visible in your optic anyway.
Take the rail off and put on a Magpul forend. Plastic is light.
Your vertical foregrip is WAY too big. Put the Nagpul MVG foregrip on, it mounts directly to the Magpul forend. No rail needed. The shorter Magpul grip looks too small but it isn't used like a broomhandle. Just put your fingers back against the foregrip and wrap your thumb over the top of the forend. Control is restored and you have Really chopped weight by implementing this paragraph. Who can shoot well enough to need freefloat with that fine Mossberg barrel anyway. Your forend should bring you enough cash to carry you far on this step.
As posted previously, get rid of the bipod. They look good, but a Caldwell Tack driver shooting bag does a much better job of improving your shooting, reducing firearm weight and can be paid for by selling the bipod. (Check Rifle Magazine from about August for shooting comparisons) Find it under Battenfeld Technologies and the beans to fill it at the grocery store.
Can't tell if that is a 3-9X40 NCStar on there; my personal use is their 1.5-6X40. The lenses are smaller and thinner and the power is perfect, glass very clear. TruGlo are also a good low budget optic, quality excellent. You don't need more than 6X with an AR. My vision with contacts is 20/35 and I do fine with 1.5-6 X. If you need a riser use a Tapco; very forgiving and very lightweight plastic. I prefer them to metal.
Buy EVERYTHING LOCAL. Save all packaging in as new condition. An internet dealer may not trade with you until you get your gun configured as you want but a local dealer will often take back resellable items at full credit towards something else you need.
My suggestions are just that, but I have travelled your road. The one thing I have done that added a lot of rear weight is add a PRS butt from Magpul. This would have been a MOE with no battery needs or an ACS with battery storage but my screwy eyes require a different eye relief day to day. Recomended only for people with crazy eyes.
Lose your focus on freefloat or a quad rail and a different, lighter world will open up; if only I haven't preached you to sleep. Thanks to anyone that read this.

What scope do you have on the rifle that it hits the front sight tower on a 16 inch barrel?

No kidding! Let's see this glass!

Yes, pics immediately please.

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Still carrying my S&W 642

Any pics on that scope? I am curious too. You might have it set up way too far forward, try backing it up closer to the charging handle. With your adjustable stock you should be ok.

If you have a scope long enough to reach the front gas block, then you have the wrong scope, or you are trying to do something with that rifle it is not designed to do.