Optimum nose size?

[Char-Gar]

First of all, I am talking bullets with long noses to ride on the lands. What is your opinion of the optimum ranges of sizes for the nose of, let's say, a 30 caliber bullet. Assume a diameter of .300 across the lands.

1. What is the smallest nose that can be expected to perform well.
2. What is the largest nose that can be expected to perform well.
3. What would be your choice of the perfect nose size.

What would be your answers if we are talking about an 8mm with a diameter across the lands of .311?



Thanks for any light you can shine into my darkness.

[Shiloh]

In my opinion, and in my experience, the .298+ nose of my Lyman 311299 was two small for my .30-06 I had to go with the 314299 with the .3026 nose. I'd love to try a 311299 with That dropped at .311 with a .301-.302 nose.

Shiloh

[runfiverun]

1-301
2-301
3-301
for the 8mm id go with 312
you might have to take the boolit and cartridge back from the gun.
i like the shortest bore riding section i can find but keep the base of the boolit out of the case.

[trk]

What do you mean 'perform well'?

Velocity (lowest drag) will be the smallest.
Effect on game will need to be bigger for effect/expansion.

There's a very good discussion on this a few years back on Graybeard Outdoors under the Swaging forum when we were designing the HBC (high ballistic coefficeint) bullet.

[Buckshot]

.............For a .300" bore I'd for sure have to see some engraving so .301" minimum.

http://www.fototime.com/265014FCCB26D95/standard.jpghttp://www.fototime.com/320564FA7E910BB/standard.jpg
http://www.fototime.com/AF64316B2953327/standard.jpg

For any caliber with a bore rider I want to see definative evidence of the lands on the nose.

..............Buckshot

[grumpy one]

Buckshot is right of course, but you need to watch the amount of land engagement (which depends on how you want to seat the bullet). I really hate it when you've got a round chambered and 'cease fire' is called, and the bullet stays behind when you eject the round. That spilled powder really gets in all the wrong places inside the action, and leaves you feeling like an idiot.

Ideally I like about .002" of interference fit, but with 12-15 BHN bullets, you won't be able to engage it very far and have any hope of extracting a chambered round successfully. You also need a mighty crimp to be able to chamber those rounds without pushing the bullets back into the cases. So, for me it all begins with how the lede is configured. Maximum .002" interference, and minimum just a push fit if you want a long nose engagement on chambering.

[Bret4207]

What Buck and Grump said. In a .300 bore I want at least .301 but not much more than .302 if I expect to be able to withdraw a loaded round, but that depends on leade angle. In theory you could go a fat as maybe .304-.305 as long as things are centered and there's some room for the dispalced material to move. I would think rifling form might have an effect on that.