I'm going to answer the title question with a qualified "yes." If I were living in a local community that struggled with a high level of gun violence, that answer would undoubtedly have to change. If I actually had guns in my house, I would probably change the answer. But, in the context I find myself in right now, I think it's OK to let my boys pretend they're shooting guns. Why? Because the main objections against this sort of thing fail to address what my boys are actually engaged in. They have no access to real guns, so there's no danger they would use one. We have talks with them to help them understand that actual violence against other people is not acceptable. In most of their games, there's an implicit understanding that no one really dies when being shot by a pretend gun; at most, the shooter has the pleasure of watching a theatricalized faceplant before his opponent pops right back up again. I have almost no worries that either of them is going to turn out to be a homicidal psychopath; if I did, I would probably not let them "play guns." In fact, they both seem to have an early sense that the very best outcome of all is not merely for the forces of good to beat down evil into a hopeless wreck, but for evil people to be redeemed. My oldest son has recently gotten into Star Wars, and as we watched the movies of the original trilogy for the first time, I was surprised to see that his immediate expectation for Darth Vader, upon learning of his connection with Luke, was for their reconciliation and for Vader's redemption. So, with Spirit-infused instincts like that, I'm not too concerned when he wants to play at lightsabers and blasters.
Part of this leniency also comes from my own upbringing--I have memories of using pretend guns when playing at cowboys or cops and robbers; and if my brother's way of telling it is right, there was probably not a child in the world with a fiercer violent streak than me. And yet I turned out all right, I think. Violence is so far removed from my way of life as an adult that I would almost always prefer to accept grievous bodily harm on myself than to wield a gun against another person. Frankly, I think Christian arguments for using guns as a means of self-defense are theologically ridiculous.
The reason for allowing my kids to play guns that I've given so far--that it really won't do any harm--is not the main reason, though. The main reason is that I don't want to smother the beautiful, big-hearted view of the heroism of life's battle that my boys act out each and every day. Boys are growing up today in a culture that is going to question every fundamental assumption of what it means to be a man (indeed, what it means to be any gender at all), and I don't want to be the one to start that process by telling them to give up their battles. They fight and wield swords and shoot guns because they understand instinctively that this life is a battle, and they dream of being the heroes through which justice will triumph. (Here's a wonderful blog post my wife shared with me a few days ago on this topic.) I'm not going to take that martial sensibility away from my boys, because the truth is, life is a battle. The pages of the New Testament use warlike imagery and metaphors of armor and weapons to describe the story of the Christian life. I want my boys to see their lives as they really are--a grand but dangerous adventure, where every step will bring them up against temptations and systems of injustice against which they will have to fight with everything they've got. I want them to believe that they can win that battle, that through them God can do great and mighty things.
I hope that, one day, their pretend guns will be transformed into prayers and earth-shaking acts of love, and that the God of all nations will shatter many strongholds of the Enemy through the courage of my sons. I love their fire, their boldness, their exultation at the way that good can triumph over evil. The dream of a triumphant life of true spiritual warfare is already alive in their hearts. And if the foundation for that dream is played out for a few of their early years with an imaginary gun in hand, I think I'm OK with that.
(Images--Top left, painting: "Boy with Gun," by Slobeslav Pinkas, late 19th cent.; Middle right, photo: My boys, trying to look like their Dad; Middle left, photo: Me and my bro, back in the day; Bottom two images, drawings: illustrations from the 1890 Henry Altemus edition of The Pilgrim's Progress)