Good post. It does seem that I am hearing more instances of injuries lately. I can tell you this. I WILL NOT BORROW ANY WEAPON FROM ANYONE IN DAG! I am fully aware of how hard I "can" hit, and have spent an enormous amount of time and effort into making my weapons safe when in my hands. This includes the efforts of Axe & Arrow to make sure I do not hurt you. The construction of my 12oz blue sword is VERY different than the 42oz blue sword designed specifically for me by Axe & Arrow. But I think the differences in their construction fully demonstrates what Olaf is saying.
The 12oz sword is made of stiffer foam, no matter how hard I swing, the foam will only squish so far. This results in a sting feeling when struck. The lack of mass allows for this to be safe, but at the top end of swing strength, will hurt but not injure you. This construction would not be safe for a heavier weapon as the lack of squish and the added mass would result in injury.
The 42oz is made with 2 types of foam providing progressive resistance or what feels like more squish but the max squish is reached before the core is felt. This is vitally important due to the overall mass of the weapon. At full swing, this is actually the safer weapon under one circumstance, and more dangerous in another.
If you punch block, you want me using the heavy, your fingers are safe due to progressive resistance. The lack of squish in the 12oz weapon will hurt more, but the lack of mass will save you from injury. Both are safe, but for different reasons.
If (as Olaf points out)
Do not block shots with your open hands. If you try to grab a swinging weapon non striking surface. If you are not fast enough the striking surface could jamb or break your finger. You take that risk
The risk from the heavy is greater than the light. Simply due to its mass.
The net result of having both weapons is that a light hit from the light weapon will feel more solid than the same shot with the heavy. This would allow me to (if I was so inclined) develop a style of fighting that would have me hitting lighter yet having my opponent think I am hitting harder with the light weapon. The trend in Dag is to use the light weight (not so squishy) foam to cover the cores of heavier weapons. And when I say heavier, I mean just a few ounces. The best fighters have discovered that the added mass of a 16-22 oz weapon will give them abundantly better parrying ability while not slowing their attack.
It is this trend that IMHO is causing the increased injuries we are experiencing. The foam is (even though the core is not coming through) not squishing enough to protect the opponent from injury due to the increased mass. A weapons checker might pick up 2 identical swords, constructed with the same foam and not notice that they have different masses (due to counter-weighting) resulting in one safe weapon on the field, and one dangerous weapon on the field.
We (weapons checkers) need to be vigilant in spotting this, or more people will be injured.
You (fighters) need to stop punch blocking or open hand blocking, or you will be injured. Even with good gloves.