I started a game back in 98 called NEST-13 [NATO Emergency Strike Team]. It game was a return to my old Dark Conspiracy, Twilight: 2000. the basic premise was hunting down supernatural entities from the Millitary point of view and to play with all of the new toys that the military had.

I started using the Twilight: 2000 Rules, then after a short Shadowrun Game we decided to go to SR-2
Only months later SR-3 came out so we went to it. We ere having fun with it.
Then d20 Modern Came out and we all thought that some of the little problems we were having would go away.
Using Weird Wars and d20 modern we had an easier time with tanks and other large vehicles, then everyone made 10th level and .30 Machine Gun rounds were bouncing off the chest of unarmed PCs and NPCs. The Sniper was taking 3 shots to kill the Sentry with his Barrette Light .50.

We all decided to go back to the Shadowrun Mechanic and we went to SR4/4a
Most of the “Magic Items” were Easy to Convert.
-The Magic BAR that Ignored 10 Points of Damage Resistance, now was always loaded with APDS.
-The +2 Dagger became a Force-2 Weapon Focus
-The M60E3 that could fire underwater gained Extreme Environment Modification Water
-The Pearl of Power became a Force-4 Summoning Foci

Now here is the real problem
One of the Characters has gotten a Horn of Valhalla, which became a Boson’s Whistle that would summon an Undead SEAL Team.
-There are 8 of them

What do I do with them?

Crap yourself and run away.

We had discused using the "Master of the Hunt" as a basis, but we are still not sure
The other choices we came up with were
-Once a day
-Once a "Mission"

unless they all had some ungodly levels of CON, there is no way that should happen. In D20 modern, massive damage threshold is CON, not 50 like in D&D3.x. This result in even pistols being able to trigger said threshold on a (critical) damage roll. And critical damage automatically puts someone at -1 hp, no matter how much hp they had before the attack struck.

You would not beleve the levels of Toughness they were buying
[I thing it was toughness or watever that feet was the increased that threashold]
That ance they figured out how inmortiant it was evey 4 level "I put my point Into Con]