Most big guns have a minimum strenght requierment for 6 and 7;
M60; 7 Strength
Minigun; 7 Strength
Avenger Minigun; 7 Strength
Vindicator Minigun; 7 Strength
Light Support Weapon; 6 Strength
H&K G11E; 6 Strength
Flamethrower; 6 Strength
Rocketlauncher; 6 Strength
(Gatling Laser; 6 Strength)
Powerarmor should give +3 strength and Advanced Powerarmor should give +4 strength.
I can't remember the excat Perception needed for the spear, but it is likely it is about 7. I always have high perception on my characters, so I couldn't tell the cut-off.
Hope this helps with your planning
