30BR Throat Angle vs Ogive

A

abintx

Guest
I 've read somewhere that if you're shooting a 30BR 1-18 twist barrel with a throat angle of 1 degree 30 [1.5 degrees] and Zero freebore, that a bullet with a 10 ogive is best.

And, if you're shooting a barrel with a throat angle of 1 degree 45 [1.75 degrees] and Zero freebore, that you're better off with 7 ogive bullets.

Is this the correct criteria for making bullet ogive selection for the 30BR?

Thanks for your response. Art :)
 
I thought it interesting

when I read somewhere the other day where Jeff Fowler said he liked 6 ogive bullets best but made 7's because that what "The People" wanted.
 
Pete ...

What were Mr. Fowler's thoughts on the best ogive for a given throat angle? Did he provide any insight on that subject? :)
 
1.5 degree is vary common among BR reamers, just ask what your reamer maker thinks?
 
Al ...

Big Al said:
1.5 degree is vary common among BR reamers, just ask what your reamer maker thinks?
Click to expand...

We've spoken at length. What I'm looking for now, is a consensus, if there's one, among shooters/competitors. Looking at the breath of responses so far, it doesn't seem to be a widely discussed subject. :(
 
Last edited by a moderator:
It's true that most shoot a 1.5 degree leade angle. However a lot of long range shooters use a 3 degree leade angle. For about a year and a half I shot a 3 degree leade on my 6ppc. I have now switched to a 1.5 leade angle and no freebore. The only difference I can tell is that I have now experienced having a bullet stick in the barrel with the 1.5. Never before in the 3 degree. That is the only difference I can tell.

Donald
 
Throat

What is the end of the lands becomes a ramp leading to the bore.
The s,urface of that is concave as the reamer cuts it. At the end of the ramp
is a small corner forming a point, where the top of the lands and throat
angle meet. This nice little point and the concave surface disappear
in very few rounds.That point rounds off slightly and what was concave
soon becomes flat , and not long after this becomes convex.When the
lands marks on a chambered round begin to narrow, that is what happened.
A friend asked that I break in a barrel, so I did , but monitored it with a
borescope and cleaned after each shot. I was very surprised to find that
all this changes in as little as 10 rounds. Depending on your bullet, its likely
that no advancement occurs yet, but as the corners are rounded , the
angle would seem to change with it.. Barrels and throats decline from
shot #1 on. Depending on how the reamer grinder sees things, changing
from 1 1/2 degrees to a steeper angle can give you some freebore. It
changes fast.
 
Pete ...

The math may be where you got lost. :D You'll find the conclusion in the Chart at the bottom of the article. ;)
 
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