.357 maximum contender lapping

[BHill]

The throat on a recently acquired contender looks as though I had reamed it with a stick of rebar and it's a straight taper for .4". I was planning on lapping it with some .367" diameter soft boolits to knock out some of the horrible tooling marks and then use a stepped boolit (large ring just in front of the base) with a gas check to preserve integrity of the base. If any body has fought this battle and won would you be so kind as to let me know how you did it and what were the results. Thanks.

[LAGS]

Can you make a Brass Lap the exact shape and size you want and then put Dyekem in the chamber and lap lightly to see how far it is off plus where the low and high points are.
You can probably make a Lap using a Poor Man's Lathe, if you do not have access to a real lathe

[BHill]

That may be an option. The throat has circular rings as it gets smaller and I was wanting to not only smooth them out but eliminate the circular pattern to some extent. I like the idea of a brass lap and may have to borrow some lathe time in the future. Still leaning towards the oversized boolit with lapping compound to start with. Worst case scenario is I have a buddy that would buy the barrel and change the chambering. (probably the best idea but I'm hard headed)

I appreciate you taking the time to respond.

[runfiverun]

maybe it could be re-cut with just a throating reamer.
the 357 max likes the rcbs 200 meant for the 35 Remington anyway.

[BHill]

I'll look into that as well. That would certainly clean it up a bit. How would you compensate for the long taper? Would a .08 or so band at .368 dia just ahead of the crimp work to keep gasses and bullet alignment in check if the boolit is seated shallow? Probably have to make sure the grove is just large enough to accommodate the flow from the oversized area.

Thanks for your thoughts.