Alex Wheeler
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This gets me on the topic of bushings. They are not to size or square. I think we may have a solution in the future but try different ones regardless of the stamping.
300 Norma Improved 35 degree
- Thread starter Alex Wheeler
- Start date
Could you elaborate on this. This is my first time using a bushing die. I understand that mandrels are normally used to make the necks round again after they become dented. How do you recommend sizing the neck?
Ledd Slinger
Silver $$ Contributor
I found the same thing as Alex with the graduated expander ball set I use. They are all make for a very round neck ID so that’s a plus, but the labeled diameters were not exact. A couple of them are a thou off. So instead of having a full set of expander balls that can change my neck tension in exact increments of .001”, I have a couple gaps that I can’t test where the two balls actually measured the same as the one above or below them in the set.
I never buy one specific recommended bushing size for a rifle. I start with a bushing that is “labeled” .002” smaller than the neck diameters of my loaded rounds. Then down to about .004” below that so I can test from .002” all the way up to .006” neck tension. Only one bushing will work the best and that’s what you’ll use on that particular load in that rifle. But it’s nice having the others because if you ever change powder, primers, brass, bullets, barrels, or build a completely new rifle, it may prefer a different neck tension.
I use the expander balls in conjunction with neck bushings to set neck tension as a sort of “checksum” on the sizing process to ensure the ID of the neck sized with a bushing is nice and round. They also give me a good “feel” to know whether or not my necks are being sized correctly. If I’m getting bounce back on the neck walls from work hardening I won’t feel the expander ball opening the neck as it passes thru. Then I know it’s time to either go down .001” in neck bushing size or re-anneal the cases.
When using the expander balls, I will usually use a neck bushing that is .001” or .002” smaller than the ball so I can feel the ball ironing out the neck to proper tension. One thou smaller doesn’t sound like much, but as Alex said, you can’t always trust the size stamp on the bushing. So I step down until I get the light feel I like with the expander passing thru.
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Alex Wheeler
Site $$ Sponsor
Wouldn’t run out be decided by your freebore diameter once round is chambered? Unless you have 0 run out to begin with...
Alex Wheeler
Site $$ Sponsor
Yes, for the most part. I typically do not worry about runout. But we do try to improve everything anyhow.
Ledd Slinger
Silver $$ Contributor
Yeah I got some good groups with the 245s in my 9” twist but never did get them to ladder test very well. Was hoping maybe your 8” barrel would do better. I ended up giving up on the 245s because I could tell they were going to be touchy. Not nearly as forgiving in ladder tests as the smaller 215, 230, and 220 Bergers.
Don’t forget that you had a node with the 245s @ 3100 fps. Probably worth testing the lower node before closing the door on them.
Also wonder how they would shoot testing around the -.020” seat depth? That’s where I have had the best luck in the NMI. Maybe start at -.025” or -.030” and work in to around -.015” or -.020”. That’s the range where I have had the best accuracy with 215, 220, 230, and 245. Don’t know why, but in contrast to Berger bullets in other calibers, they all seem to like a little extra ramming speed before hitting the lands in the 300 NMI.
Don’t forget that you had a node with the 245s @ 3100 fps. Probably worth testing the lower node before closing the door on them.
Also wonder how they would shoot testing around the -.020” seat depth? That’s where I have had the best luck in the NMI. Maybe start at -.025” or -.030” and work in to around -.015” or -.020”. That’s the range where I have had the best accuracy with 215, 220, 230, and 245. Don’t know why, but in contrast to Berger bullets in other calibers, they all seem to like a little extra ramming speed before hitting the lands in the 300 NMI.
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tom
Gold $$ Contributor
At first here, until forced otherwise, I'm trying to tune around sufficient ballistics to arrive at 2,000 above 1,340 fps. This, depending on the day, but safe estimates are 245s above 3140, 250s above 3040. The 230 A tip can get there probably around 3140 like the big Berger, and the 230 Berger i thought we had to run 3240+....but we know that bullet shoots good at "normal" speeds.
Big Red to the rescue for tomorrow maybe?
It's a big mother!
Tom
LA50SHOOTER
Sworn To Protect The Constitution.
Alex Wheeler
Site $$ Sponsor
Ledd Slinger
Silver $$ Contributor
LA50SHOOTER
Sworn To Protect The Constitution.
It looks it, my guess was 0.320 - 0.350.
- I'm running a 0.300 (in my 300 NMI 40 degree) and I know that I can't get the 250 gr. A-Tip out as far as what he's shown in the photo.
Thanks -
Good question. I have been researching both and was pondering asking the same exact question.
tom
Gold $$ Contributor
Nope, I don't sort bullets anymore lol. Not for this initial pressure/ladder, if it looks like it might go somewhere I'll check them out a bit.
To answer which 230 Berger, I've only used the target hybrid myself.
Tom
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