If you really like the place, you're going about it a bit backwards. I guarantee he makes his living off accessories. Buy whatever ammo, gear, cleaning supplies, holsters, clothing, storage etc. you can off him (this stuff tends to be cheap at the big stores, but usually not-so-great brands, either.) Feel free to save a few bucks on the gun itself; if you ask him, and he knows he can trust you, he'll probably tell you he'd be fine with giving the big chain the business on the gun itself if you buy the holster, sling, cleaning, targets, case etc. from him.
Guns themselves are big investments for a small shop and the profit on them is slim to none for most of these guys anyway. They stock them because they're gunshops and you couldn't stay afloat on the accessories and ammo if you had no guns for customers to look at. If he knows his business, you're not going to be hurting him.
I do a "sort of" version of this. I'm just too broke to buy guns right now and have been for quite awhile, but every time I go in I buy something. Some cleaning stuff I need, a case, some reloading stuff I don't have. If I don't need anything, I buy powder, primers, bullets, cases or ammo; it's not going to go bad or anything.
Believe me, even though they don't see me often, they know me and my kids there now even though I have never, ever bought a single firearm from them!