Being forced into a situation of having to fire over "open sights" directly ahead definitely sounds way too scary for me! :shudder I guess that at point blank range even the blast effect of 105mm guns would have an effect on closing infantry. I'd certainly rather read about it than experience it first hand. The gunners did well to maintain discipline and stay with their weapons. Returned Vietnam vets I've talked to about the battles that raged around Coral from early May until early June 1968 always spoke with a degree of reverence towards the gunners as well as the APC and Centurian tank crews who I understand were involved in some of the later clashes.Obviously you've never read the history of the battle for Fire Support base Coral in Vietnam.
Suffice to say, towed 105mm artillery pieces firing over "open sights" in a direct fire role is very useful in certain situations. Obviously the persons involved would prefer NOT to have been in such a dire situation, but your enemy is not always that accomodating...
Here's an image of one of the Australian 105mm guns that was "over run" and recaptured intact, the next day.
http://www.diggerhistory.info/images/rar/coral01.jpg
edit: actually this is more likely the first time an AUSTRALIAN gun has been over run since the Boer war...
BTW, I'm certainly not putting forward the 105mm towed howitzer as an 'ideal' weapon against IFVs or infantry at close range but it does demonstrate that in an emergency all available assets can have a role to play.
Cheers