OK, the dilemma is a pretty simple one that I'm fairly certain a large amount of people have come across in their New Vegas travels. My weapons simply aren't getting the job done. My character is currently using the following weapons:

• Sniper Rifle+ (Fully modified)
  
• A Light Shining in Darkness (.45 Auto Unique Pistol)
  
• Broad Machete (For when I'm out of ammo or need to conserve it)

My character is typically a sniper that uses pistols or other one-handed conventional firearms as a sidearm. However, I'm level 45, and my weapons simply aren't performing to the standards that my travels demand. I'm playing on hardcoe, Very Hard, idolized by the NCR. I can't withstand the two to three Legionary Assassin ambushes that occur every time I travel long distances. I'm basically looking for a new long-ranged weapon more powerful than the Sniper Rifle+ that is still able to get effortless sneak attack criticals like the Sniper. The .45 is fine, but if there is anything more powerful I'd like to know.

Thanks for the help ahead of time guys!

Christine's COS Silencer Rifle
A Light bla bla bla
Saturnite Fist Superheated

Yeah I'd go with either the COS Rifle or the AM Rifle. Both can make short work of the assassins, and the weapons dropped can be used to repair the COS with jury rigging.

I have personally been booby trapping assassin spawn points with bottlecap and plasma mines (which the assassins often drop) which really helps out. I've also been reverse pick pocketing combat armors and heavy weaponry onto the travelling merchants/mercenaries and anyone else I think might bump into assassins. Its a great sight to see at the grab and gulp; Lupe and Fitz, a travelling merchant and his/her mercenary, armed to the teeth and covered in high DT armor helping me wipe out the legion assassins.

Sniping is impractical, citizen! Invest in assault rifles. That or the COS sniper

Shame on you PRIVATE! Any self-respecting soldier would love to have your arsenal. A good soldier knows how to survive in the tightest of situations. Listen you Godamn PUKE! Your enemies have weapons right? Use what those Caesar legion fruit cakes use against them! You mean to tell me that a bunch of grown men in dresses are whipping the floor with you? You sully the name of the New California Republic Stealth Division. Now go out there and rip them a new one, my grandmother is tougher than you and she has arthritis and weak bladder. Shame on you!!!

(Guess who im immitating, XD Also just get yourself one of the marksman carbine they use or the 12.7 SMG they carry or a brush gun. Doesnt take much to kill them. I use a marksman carbine with 223. ammo and I use Light in the Darkness with .45 standard, as my melee weapon I use a combat knife so dont worry so much. Just stay in the shadow's, dont make much noise when you spot them and take em out 1 by 1. I usually face 4, 1 comes running up front he you dispatch swiftly, watch out for the melee guy he carries either a Super Sledge or a Thermal Lance, and a Brush Gun, the Vexilla carries a 5.56 Assault Rifle a Ripper and some explosives the Praetorian carries 12.7 SMG and some Plasma Granades. Basically take out the first guy, then execute the melee from afar, and finally the last 2. All doable quite easily with your weapon's at your level.)