I have notched the front bolt in this case in the past. I figured it was better to notch the bolt instead of turn the whole diameter down, which would have compromised it's strength. Of course, this means you must have the bolt indexed. But I hate doing it, as some dolt may not remove his ramrod before trying to take out his lock bolts. Another thing I have done is used a dowel to fill the miss-drilled hole, and was careful to get it right the second time.
Neither of these solutions has been satisfactory for me, but they are the only ones I have. One way to do it though is to fake it, and make your front bolt just an artifice that just threads into the wood, but the dishonesty in that to me that is almost sacrilege. I filled a hole with a dowel twice once, since it wander both times, no matter how careful I was, or how slowly I progressed.
Having had a failure or two when doing this, I decided I would shoot for a front lock screw that was a little on the high side. This seems to work well. I would like to be able to see the front lock bolt when the barrel is out of the stock, so I know it is about as high as I can get it. But this doesn't help with your problem.
I suppose another solution could be to re- drill the front lock bolt hole. This would require filling the hole in the wood and the lock, and using a different angle when drilling through the original hole in the side plate. This is a viable solution, but only in a situation where you have the latitude to be able to pull it off.
In my opinion, drilling the ramrod hole is probably the hardest task in building a proper rifle. Even the ancient builders had this problem, as is evidenced by so many repairs where a hole came through the bottom of the stock and was covered with an inlay by those gunsmiths. I don't care how often you clear chips or how slow you might progress... The bit can still wander, depending on how the wood wants you to go. It is the task I fear most when building a rifle.
Matt