How far was he when you shot at him? If he was far enough that you missed him completely or even only put a scant few pellets in him I doubt seriously he's going to pack up and head elsewhere! 3-4 days is an eternity in a turkeys world and he'll likely forget about it if you leave him alone for a week.
When you said he was first 400yds away, is that general spot where he spends alot of time? If so I wouldn't hesitate to move down to that area. Turkeys are EXTREMELY habit minded creatures and generally do the same thing in the same places several days in a row. Prime breeding/strutting/feeding areas are even frequented year after year by not only the same turkey but new turkeys as well. What one old gobbler likes about one area another replacement will as well in the furture. I hunted the same ranch in southern MO for over 2 decades and by the last decade I could kill birds without even taking calls out of the truck. I just came to know several spots that gobblers would frequent time after time.
A big powerline like that is prime strutting zone, gobblers like to see and be seen. They know the ladies can see and hear them for a long way and the boys like to get out there and "advertise" their wares. Plus they know they can see trouble approach well before the danger level rises too high, a few steps into the brush and they are safe again. BUT that also makes it VERY difficult to call those birds in such places. They know when they don't see what they know they've heard then there might be "a flaw in the slaw" so they hang up or become wary in such open spots. So you've got to use terrain and situations to your advantage. Don't hunt near 100-200+yd long, perfectly straight sections. Move to a bend in the ROW or an area where maybe that line crosses a ditch or hollow, a slight depression (or an equally tall ridge/hill), anything that would require a bird to actually get closer to look around the corner or down/up a change in elevation. Even large brushpiles like dozer piles the size of a house can be put into play. Just something that could possibly hide a turkey that would force the gobbler to come looking for what he knows he heard! You just have to determine the ambush spot you need to be in to capitalize on such movements.
And something I learned along the way as well, when hunting open areas you REALLY must be concerned with over calling. You can get away with a little more of that in the woods but out in the open you just have to rely on the faith that you know the turkey has heard you and EVENTUALLY he's likely to act on your calling. That's why I said what I did about trying to get them to come looking for you. We are already behind the 8-ball by trying to call them too us vs natures way whereby the hens go too the gobblers. If he can see 400yds in either direction and he knows the hen making that noise is out there within that area he can see and yet he doesn't see her or she's not moving, then he smells a rat and that's why they seemingly "hang up" alot of times!
That's why I LOVE turkey hunting, it's such an awesome version of "natures chess". In a game of hearing and eyesight the turkeys will win EVERYTIME but the hunter has the brains, wits and in the case of hunting the same area for many years, you actually have MORE experience in that area than does a 4-5yr old bird. I know without a doubt I killed many a son, grandson, great grandson etc during those 2 decades on that ranch in MO. Just remember what I said, what gpaw likes about an area, his great grandsons will likewise! (Same goes for deer honestly!) That's how "trophy holes" come to be known...
Go get that joker!
HL