Just reading and if it's true that you can get two power fist and a large backpack, is therre any of you trying to fight with a real sword more than 15 minutes? What to say about heavy medieval weapon  from 10 to 15 kg?

Carriyng object is something, fight with them is not the same.

After 10 minutes of swordmanship even with light blade as katana or cavalery saber your arm is going to hurt, with 12kg on each of your fist you would not be even capable to touch your nose after 10 minutes of fight.

You are a killing machine close to Broke Lesnar, HHH, batista, Kane, Undertaker, André or big show maybe you could fight for 30 minutes with those 44kg (more or less 90 lbs) attach to you but no more.

Have a try, take sand bags 5 kg each and attach them to your arm, them punch in the void for 2 minutes, how are your arms? If you are a martial artist or a sport practionner do it 5 minutes.

Shadowboxing is quite taxing even bare hand, I will never be able to do it with two powerfist and a large backpack. And for the numbers I'm 6'7" and 210lbs or 1m95 and 100kg, and i'm also a martial art practionner.

From the dawn of tabletop RPGs, weapon weights have been grossly distorted, with the few exceptions often being portrayed as "exotic" or somehow special. You can usually just halve everything across the board, except for the "exotics" like katanas which, while they oughta be a few grams heavier, are usually listed about right due to, again, distorted views on all of this.

In this case, I'm relatively certain that FFG has used the standard basic weapon weight ranges found in all sorts of games, but did so without considering that they're usually expressed in pounds due to americans writing it. They put Kg at the top of the table instead and that was that. It does, however, appear that this is just a melee issue: A Lasgun, at 4kg, is just a little heavier [and a whole lot more resilient] than, modern Assault Rifles, and about on par with older ones like the AK-47 [

Problem as you've seen is: A kilogram is just a few grams over 2.2 pounds. A Lasgun is over nine pounds once its got a power-pack in there.

Now, granted, Warhammer, particularly imperial tech, is rather big on "we are archaic and huge and you can run a tank over this gun", but that would explain the weights if they were in pounds… not really more than that. Backpack's not on your arms and you' re probably having most of the mass driven by your power-armor though, which at least helps a bit.

If you are wearing an energetic armour then dual wierlding of powerfist will not be a problem, firstly because the power is given by the armour and then you don't any power source, secondly because the artificial muscle incorporated in the armour balancing the weight of the weapon.

But as far as I was reading that was not the case.

And even if the power source isn't on your arms let me tell you that 20 kg (45 lbs) on your back will make you life in combat real difficult.

With range weapon the problem isn't that important, but in cllose combat it will be much harder to endure.

 Another option is creating a single stat bar for the combined weapon.

Normal Power fist would be 2d10 E, Pen 9, Unwieldy if I'm correct with double SB, with the added boltpistol discharge it could be something like.

2d10+5 X, Pen 9, Unwieldy, Tearing, just add a serious mishap when the character fumbles like with the eviscerator.