I have a companion who likes to use hand to hand. My personal combat strategy however is ranged, very ranged. I took out 8 Deathclaws with eight head shots, using the 50mm, and high points. So I talk to my companion and set her to use ranged weapon. I give her a sniper rifle, plenty of ammo, also a missile launcher, grenade launcher, a varmint rifle w/scope ammo for all. what does she use? a 10mm pistol that as far as I can tell is not even equipped. My question is how do I get her to use one of the weapons I gave her. She runs ahead and gets knocked out everywhere we go. Does she not realize that a 10mm pistol is no match for a Deathclaw? I gave her some stimpacs and I make her use them every-time she wakes up, but she really is getting in the way more then she helps. I really do need her to use a stronger weapon. Any help will be appreciated.

I would use Boone if I were you, sounds like he's much more suited for your play style than Veronica is.

Okay, here is what you do.

Get the Gobi Campaign Scout Rifle, a ton of .308 ammo, then give them to Boone. With that combo, Boone is an absolute beast. I did this and Boone was able to bring down Deathclaws like they were nothing.

This.

Veronica is melee first and her tagged skillset is for energy weapons, meaning her potential dmg output for bullet guns won't be as high. You can set her to be ranged, but she'll constantly go back to her glove, especially if enemies start to get close. All companions have a distressing tendency to switch weapon modes now and then w/out so much as a by your leave, but Veronica (in my game at least) is one of the worst.

The 10mm pistol actually has a fair dps (60ish) and this could be part of why she's not equipping some stuff. The varmint rifle, for example, is not considered "more powerful" than their default weapon by companions & they won't ever use it. Even the grenade launcher is only 40dps.

Also, the more weapons/ammo you dump into their inventory, the more confused they seem to become about which one to use, causing a lot of switching around as their stats or items cause all those weapons dmg/dps to alter a fraction (alter for the companion - remember that the numbers you see on weapons are based on YOUR skills, not companions...if you could see them, companions would have different numbers).

If you don't like Boone, Raul works well with snipers/rifles as well.

When I use Veronica, I just leave her set to Melee. She is useless at range. I just equip her with a balistic fist and turn her lose, while I hang back and snipe and have E-DE for ranged backup.

E-DE is great, especially if you upgrade its weapon during the quest E-DE My Love. It becomes a very powerful ally in combat, able to deal some serious hurt on even the toughest opponents.

As for allies switching weapons, when I equiped Boone with the Gobi Rifle and a ton of the .308 ammo, he never switches out to anything else. He stays with that gun, and is dominant with it. He brought downt a Deathclaw mother in less than 5 shots with it before it could reach him. I dont know what the stats are for him with that gun, but whatever they are, they rule!

Also, since I usually have high rep with the NCR, I always have a Ranger with me. Their damage is acceptable, but they are mostly there as cannon fodder to keep the baddies off of me. And when they die, I get a nice suit of Ranger Patrol Armor.

Yes, if the weapon is strong enough, that's true. The All-American is another one that gets similar results like that - altho for me he'll still occasionally switch to melee sometimes, if you've given him a strong melee weapon.
I mentioned the weapon switching because the OP mentioned trying lots of different weapons/ammo & I wasn't sure if that was one at a time or dumping them all in her pack at once.

Edit: Boone has Guns tagged, nothing else is special...he'll do max dmg. with any bullet gun at high lvls because of that, just like you do (except he doesn't have Perks to add to it).

Very true. You have to be careful how many weapons you give to your followers. Thats why find out what weapons they prefer, then find the strongest one I can and give that one weapon to them and a ton of ammo for it if it needs it.

I assume you're talking about Veronica. I give her a good energy weapon (either the Q-35 Matter Modulator or a Laser RCW) and plenty of ammo for it, and she does just fine with it. She's better with energy weapons than with conventional guns, so you should give her one of those for a ranged weapon. I'm thinking about trying her out with my Holorifle to see how she does.

Generally, I've found it to be a very bad idea to give any companion explosives or any weapon that fires explosives. They have a tendency to not care who or what may be near a target they decide to use them on.