Mystery writers always try to get their facts straight and keep their plots as realistic as possible. Writers who like the technical side of things, such as Tom Clancy, go to great lengths (too great for me) to explain exactly how things work. Is all that really necessary?
In my new novel, due out in October, I wanted the bad guy to rig a bomb that would damage a car but not seriously injure the passengers. I consulted a certified arson investigator for how to do it. We discussed several options and chose the one most popular among terrorists: ANFO, ammonium nitrate and fuel oil.
Used in large enough portions, it can demolish a major building, such as the Murrah Federal Building in Oklahoma City. But the typical IED (Improvised Explosive Device) used in Iraq and Afghanistan is much smaller. And the strength of the resultant blast depends upon the mixture. Put together by an inexperienced bomber, my source said, the bomb can be as powerful (or lack thereof) as you wish.
I have found the same thing true in dealing with forensics. Dr. Doug Lyle, the medical forensic guru, makes that point frequently in answering writers' questions. Within limits, you can make a blow to the head or a shot through the midsection do as much or as little damage as you desire. The same thing goes for time of death. Medical examiners can bracket a time frame, but this is no exact science. Things like ambient temperature or how long a body has been in water can make a big difference.
I try to set up the situation and let my experts give comments that indicate what I want to happen is plausible. Some explosives pro or weapons expert may challenge your premise, but if you've done your due dilligence, most readers will readily go along with you. I think they're more interested in the action and the suspense than in details best left to a technical manual or a medical textbook.
My advice is to tailor the scenario to what you need plotwise. Show it to somebody knowledgable in the field and get their comments. If it sounds good to them, go with it. Otherwise, make adjustments as needed. Just like a recipe. Put in a little more sugar or leave off the salt.