jp8775 wrote:OAL:do you guys agree with this.
Initially, seat the bullet deliberatley too far out. Place in chamber and close and lock bolt.
Remove round. You will see some righteous rifling marks. This process will have seated
bullet farther into case. This a crude starting point.
Then, place this round into seater die. The Redding micrometer comes in real handy about
now. Spin micrometer down to make contact. Then spin down a little more,say, 0.010". At
this point it becomes a guessing game of sorts. Seat another, unmarked bullet in another
case at this setting. Chamber this rd. and check for rifling marks. If marks are still
pronounced ie. much longer than wide, then down another 0.010 or so on the micrometer.
This took me a few tries. Anyway, when the rifling marks are approx. 1/2 as long as they
are wide, I called that touching the lans. From that point, I could set the micrometer 2 or 3
thousandths lower and get no marks upon chambering. Then, whatever setting gave the
"touching lans" effect, I would double or triple check with another of same bullet type.
Then , make up a dummy rd. and record data on that case: mainly bullet type and
micrometer setting that yielded desired rifling marks. The "lans toucher dummy rd." if you
please. Every time I cha! nged the die setting for another bullet type, I would recheck the
"lans" setting to see if it still gave me the " just touching" effect. So far it has worked, it
just took some time.![]()
I havea forster bench rest Micrometer seater die for .338 Lapua, and a new Hornady concentricity tool.
That will work. If you are going to do this more than once or twice or with multiple rifles/chamberings, this is a very good investment and makes it very quick and easy to measure to the "lands":
http://www.midwayusa.com/product/570611 ... olt-action
I prefer this tool over some others available because it allows you to use the actual bullets that you will be loading for the rifle and Hornady makes the dummy cases for darn near every callable you can imagine.
Also, keep in mind that the throat will get longer as your round count increases, so the measurement is not a constant one and will need to be re-checked occasionally if you intend to maintain a particular amount of jump or jam...
I had a Surgeon Remedy in .338 LM a few years ago that was one of the most accurate rifles I have ever seen. It was responsible for some pretty astonishing 1000 yard groups with 300gr SMK's, even in heavy winds. I should have kept it, but felt the need for something bigger and better....
Good luck