Before I start my discussion I would like to state a few things. If I ever build another single shot rifle it will not have a tapered round or tapered octogen barrel on it. If I do it will have a quarter rib at least. I always color case harden the actions of the rifles I build (I build most of the actions that are on my rifles) and the butt plate-grip cap and target bases and rings or scope bocks. Here is where the trouble started revious to these blocks and rings the only brand that I had color cased was; Leupold,Redfield & Browning.This time I used a pair of Ruger rings and target Blocks . The three previous brands are not a high carbon steel and they color beautifully and never break For some reason I figured Ruger would be the same, I guess I should have figured if Ruger used a different screw they would be different with my luck. Again they colored real pretty. While I was breaking the barrel in on the new rifle it started shooting everywhere. Guess what? One of the scope blocks had broken underneath the ring. Yes, I discovered that Ruger rings are high carbon steel. I was so aggravated that I set it up for several years and didn't touch it.. I started back a few weeks ago and as usual I like to make my own parts. So I started making a set of target blocks for a big round heavy tapered barrel..After several hours I had a set of barrel blocks made that were both level on top with the line of bore. But the problem was that the front block was a few thousands lower that the rear one. I started to make a shim that I could form to the shape of the outside barrel contour.
Now here is the gunsmith tip ,there may be plenty out there who have thought of this and I may just be a slow learner gunsmith type person. I had a straight edge and a feeler measuring how thick my shim needed to be. Hey my brain started working. I took that leaf off of the feeler guage set-annealed it-took a small ball peem hammer and some hastily constructed tooling and made a shim the same size of the target block and it fit the barrell perfectly and was precisely the correct thickness. I drilled two holes for the mounting screws to go through and I had a perfect target block. Let me know how many of you thought of using the feeler guage blade that you measured with. They anneal real quick with just air cooling also.
For all of you old timers who ever heard of Mashburn Arms & might be interested in the rest of this. I had three shop made chamber reamers that were built by Mr. Mashburn of Mashburn Arms formerly in Oklahoma City. I was going to build rifles using all of them. The calibers are: .17 Mashburn Bee-.218 Mashburn Bee-.219 Donaldson Wasp. This one is the .219 Donaldson Wasp .Now they are all done.
David a. Cogburn