If you're chasing accuracy, you'll want to try different powders. The Bullseye shooters often recommend Vit N330, N340, 231 and Power Pistol with the Hornady 115 grain bullets.
Other proven powders are A#7, True Blue, Silhouette.
I know you want to keep the volume up but I think single stage loading would reduce the variables in testing.
You are using same lot number brass fired the same number of times, right?
And you have a reason for loading to 1324 fps, I assume.
Unfortunately it is just a chamfer, that's why they only refer to them as comparators. They are not designed for direct measurement.Warpiece: I just thought of another possible explanation for a "chamfer" being present. IF the inserts are "chamfered", are they really merely "coned" internally, where the larger end of the cone is intended to face the comparator, NOT the cartridge? I can see that being done to ENSURE that it is only the actual EDGE of the insert that contacts the bullet ogive. The cone shaped hole in the insert would ensure that as it is widening in diameter as the bullet enters, whereas the bullet ogive is getting smaller.
Naturally such a setup would require the manufacturer to make it impossible to fit the insert to the comparator body "reversed" in direction, via flange or other means..
Jim G
I did not mean to imply there is anything "magical" about the .338" size other than that it happens to be the largest size that is still smaller than the .355" bullet diameter.
But I would not consider a hole of any size simply drilled at home by a drill as being precise enough in its diameter and surface quality to be a great substitute for a gage insert that I hope Hornady took greater pains to make correct!
The inserts they sell are not costly.
Really? They chamfered the edge?? Why on earth would they do that? A chamfer by definition will modify the results, unless it is perfectly matched to the specific ogive of the bullet being measured, and STILL maintains the correct gage reading at the outer edge of the gage. You would need a custom gage for each bulelt out there to make that work. Wouldn't you?
I can understand a chamfer on the OUTER diameter of the insert, to make it more comfortable to handle, nut never the measuring surface!
Are you SURE there is a chamfer??
Jim G
I really don’t see why that’s bad news. The BTO measurement won’t give you a consistent jump to the lands anyway. 9mm headspaces on the case mouth and that’s not reflected in BTO measurements, nor is the seating die adjusted for case mouth to ogive distance. The only way that I’m aware of to do that is to trim every case to the exact same length so that a consistent BTO will yield a consistent case mouth to ogive distance. That’s not easy to accomplish in itself. We won’t go into caliper/user accuracy nor trimmer/user repeatability. What you’re trying to do is what a lot of us do, i.e., get as consistent a jump to the lands as we can with what we have to work with. IMHO, you’re just overthinking it for a very small return, if any. But, I can sympathize. BTDT.Well the last 2 postings are certainly bad news for me. Looks like the best I can do is compare relative values, not determine absolute values.
Sigh . . .
Jim G
Have your optician grind the dominant eye lens to focus on the front sight and the other lens to focus at distance. Sounds freaky but the brain figures it out. Far easier and faster than doing the bobble head routine, trust me, I know.My first tests with this load show outstandingly good accuracy (compared to what I can normally do with 70 year old eyes looking through progressive bifocal eyeglasses, off a less than optimal sandbag)
Have your optician grind the dominant eye lens to focus on the front sight and the other lens to focus at distance. Sounds freaky but the brain figures it out. Far easier and faster than doing the bobble head routine, trust me, I know.
Still interested to read how much better these “seated to CBTO” are going to be. I still think it’d be wise to determine why you’re getting the seating variations you are. I just ran a batch of 500 147gr RN blue bullets in mixed range brass, and COL varied maybe +/- .002, most were +/- .001.
Have you measured your .338" insert. I'd bet it's not precisely .338". The point being, exact diameter doesn't matter. What does matter is that you use the same insert to compare BTO's from cartridge to cartridge.
My Hornady bullet comparator inserts average about .015" smaller than bullet diameter. It keeps the bullets from getting jammed I presume. You might want to redo the math on that .338 if the precise number is used in your process. Good luck.
Yes, I want 1300+ fps, because I believe that if you are going to compete, or just practice, you should compete, and practice, with a load and firearm that is representative of an effective stopper in the real world, not a low powered load that games the rules and depends upon using a pistol you could not conveniently carry in the real world. It's a personal standard thing