Using the Hornady OAL Gauge AKA the Stoney Point Gauge and a Special Cartridge, there are two points of contact that the projectile makes. There is an initial resistance which I assume to be the throat. If I push harder -- in some rifles, much harder -- on the plastic rod that extends the projectile further I encounter a hard stop which I assume to be the lands.
Are those assumptions correct?
If I want to load to the lands or slightly into the lands, then I load to or slightly further than the hard stop correct?
Just want to make sure I am doing this right.
|I have not yet begun |
The "throat" in my parlance is freebore which shouldn't have any resistance.
I may be wrong but I think the first resistance you feel is the leade - that initial gradual lead up to land height.
Pushing harder just puts the projectile into the lands harder.
What's the difference in your measurements between the two points?
(I'm going off memory and I haven't had my full caffeine ration yet)
After the game, the King and the pawn go into the same box.
I am going to answer my own question.
It seems that if you want to measure to the lands then you stop at the initial contact to resistance.
If you continue to push through the resistance what you are feeling is the bullet jacket material allowing some engraving to occur and that measurement would be "into the lands."
That said from an accuracy perspective, either method is okay as long as you are consistent but if your goal is to measure to the lands then stop at first resistance.
Hope that helps someone.
I measure to the lands/rifling with all of my loads, taking into account magazine & book COL.
As mostly a hunter, I don't want a bullet pulled out of the case by the rifling when unloading a round. This could render a gun unusable, if in the field with no tools or cleaning rod.
I have a rod with twin collars where I can measure the distance to the lands with any rifle bullet. I realize there are other ways to measure, pick one. Just listing the methods I use.
I made sure the shoulder was pushed back, put bullet in long, took ejector off bolt, markered area on bullet, put it in, took it out, looked for dots made by rifling. Pushed bullet in father.
Kept doing this till no dots.
You tube has a video.This message has been edited. Last edited by: Haveme1or2,
I use a couple of methods depending on the bullet and it’s probable seating depth requirements. For bullets that will handle jump, I will use the Hornady tool in the manner you describe. All I need is a relative measurement that’s close to the lands.
For bullets that require more exacting numbers because of needing to be at or in the lands, I first remove the firing pin assembly and EJECTOR from my bolt and then using a sized case, hook it under the extractor, guide it into the chamber while closing the bolt and then camming down the bolt handle. It should drop without resistance. If the bolt closes hard or there is resistance in the camming of the handle, size the case again with an increase in the bump. Once you have verified the case is sized correctly, take and seat a bullet long. Now, with this dummy round made with a bullet seated long, hook the case under the extractor and guide the case into the chamber while closing the bolt. The bolt may not close or the bolt handle should not cam down. This is expected because the dummy round is too long creating an incorrect headspace while the bullet is in the lands. Remove the dummy round and seat the bullet a little deeper and repeat the process of chambering the round. Seating the bullet in small increments will eventually get you to where the bolt will just close and the handle will cam down with just the slightest pressure. At this point, you are seated just slightly into the lands.
I usually measure, base to ogive, at this point before seating the bullet any deeper. After measuring, you can continue seating the bullet .001 deeper until the bolt handle falls as if there were no round in the chamber. At this point you are just outside the lands. This method will get you a measurement within .001 of what you need.
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