Semi

I am concerned about the lack of a crown in the field of accuracy...

I'm sure no expert on that Sabotloader. I've always thought the primary purpose of a crown was to protect the edge of the rifling. Does a particular angle and/or depth tend to improve accuracy? I know I've seen target rifles that looked pretty much like my final product with a plain flat face.

Here take a look at this - you already know Larry I am sure this will help...

http://www.youtube.com/watch?v=OorpZlG28fI

Some additional reading....

http://www.ehow.com/how_8430497_diy-...-crowning.html

In my little world - crowning is a key to good consistent accuracy... Also maybe check with Lee - he is an retired gun smith...

I looked at the Potterfield video. I don't see that the final result is much different than what I got using fine emery paper and the ball of my thumb. But it sure won't hurt to pick up a large brass screw and dress it a little more the Potterfield way.

What say you Lee? Does it need more?

As I understand it... all of the crown must be equal all the way around to keep the pressure from pushing more in one direction than the other...

Are you saying the ball of my thumb is not perfectly symmetrical or that I could possibly have applied uneven pressure? I'm hurt!

Ya but... if you get it crowned correctly and the groups tighten will not the hurt go away?

Nice job Semi! Great patience to get it done right. I tend to fall in the camp that would put a bit of a crown on there.
Art

Here is my unprofessional opinion on muzzle crowns. Take it or leave it, but I also think the crown is there to recess the rifling a little into the bore in order to protect it from damage. I would certainly crown the barrel if I could. If unable to do it I think I would be fine without it crowned but I would be very careful not to bump the end of the barrel for fear of damaging the rifling. And I'm sure we all are careful not to do that anyway, yet it still happens. Once again, just an opinion that's not based on any known fact.
On a second note, why didn't you, Semi, contact Thompson Center and discuss your accuracy problems with them? Now that you have cut the barrel you may have voided the warranty.

Based on the range report, It looks plenty accurate to me. Sub 2", 5 shot groups at 100 yards is pretty good in my book.

How many of us can beat that on a consistent basis? I may get lucky and line'em now and again but always. Human error on my part is too great. Perhaps, if I had better glass but the cross hairs cover the the bull at 100 yards and even with bags I know I'm off a little from shot to shot.