Tight freebore in Tikka factory barrel

[Tac-O]

It would be an interesting discussion on fat bullets vs skinny bullets, barrel inside dia, Harmonics, and throat dia.

Some gunsmiths have a set of reamer pilots for each caliber, they determine what the bore dia is with the reamer pilots that are graduated in .0001-.0002 sets, or they use Deltronic pins. It would be nice if the gunsmith were to stamp on the outside of the barrel the dia of the reamer pilot they used. There used to be a gunsmith in Tenn. that did this on every barrel, he has passed on now. Knowing the inside dia of the bore gives you a leg up on which bullets may work the best, as a best guess only.

As bullet making dies wear, bullets get fatter. Barrels will like what they like, no getting around it. Throat dia vs fat bullets is a must know situation. If the shank on a new lot# of the same bullet gets .0003 fatter than the same bullet you worked up a load with, your groups will go to pot.

As you get older, a Mechanical Digital Micrometer is much easier to read, and you are much less apt to make a mistake. Here is an example of an excellent Mechanical Digital Micrometer that some are probably not familiar with, this is not mine in the auction,to illustrate only.

Check ebay: Mitutoyo digital,vernier micrometer 0-1".0001".Machinist tool.

This pressure testing article is pretty interesting. Bore diameter, groove diameter, and freebore diameter were tested for pressure and speed.

 

[tobnpr]

For those that have a mic and know how to use them would disagree.

I have a Kennedy full of them, thank you.
And I know how to use them...

There is NOTHING in the realm of reloading that can be repeatable to a tenth- and even if it existed, wouldn't
make a damned bit of difference at the target.

I stand by what I said.

 

[mdmiller]

Boys lets be nice!!!
I like Kennedy, but I have Waterloo brand full of stuff!!

 

[shortgrass]

The only reloader who might need a mic that can measure 4 places to the right of the decimal point is the high end competitor shooting sanctioned BR or maybe F Class. They might sort bullets to the .0001". Even then, it would be for comparison, not for size, as true repeatability might only be achieved in a "clean, inspection room". We gotta' remember, this discussion is about a factory take-off barrel! If I thought I was in need of a 0-1" mic that could measure to .0001", I'd buy a Starrett or Mitutoyo off Ebay instead of buying one of the offerings by Horn/Speer/Red. In ending, you just can't expect "custom quality" in barrels when you buy "factory". Oh!, Ya' need to buy a 'standard' so you can check your mic for 'zero', also.

 

[VinceMule]

Measuring the bullet shank dia, comparing lot# is a very useful, especially when shooting hornady bullets.

 

[shortgrass]

Another 'hint' to those looking to by a dial caliper, get one with a dial that has only 1 "zero" on it, that only measures .100" per revolution of the needle on the dial. Some have 2 "zeros" and measure .200" per rev of the needle on the dial,,, makes them harder/more difficult to read.

 

[Tac-O]

I picked up a Hornady my krometer on sale at Scheels, and I'm going to have to take it back. The description made it sound like it measures accurately to 0.0001, but after I picked it up and got it home, noticed it says right on the package measures accurately to 0.001 and the ticks on barrel on the micrometer are only a small as 0.0005. I don't think it would be anymore useful than the calipers that I have. I'm able to get very repeatable measurements with my calipers to that accuracy.