Been measuring some solid bullet diameters on a rainy afternoon here . Woodleigh steel jacketed solids and Barnes banded solids all seem slightly undersized. So do the PMP brass solids . I have shot hundreds of brass solids (PMP and Barnes)through my 375 and 9.3x62 with no signs of premature barrel wear.

But the niggling question is -----is a slightly undersized solid bad because it doesn't seal the barrel properly thereby resulting in more so called flame cutting or gas blow by or throat erosion? The hornady steel jacketed solids are not undersized.

Is the trade off of less pressure (created by under sizing) vs imperfect seal worth it?

Any experience or views on this?

In those slow velocity calibers its not a problem, doesn't seem to exist..Those barrels if maintained last damn near forever, the old big bores, mostly doubles, show cordite burning, but even when barrels look like hell those old guns seem to shoot just fine..Not so with high velocity calibers..

You will get less pressure with undersize bullets, and they may or may not shoot well in some guns..Its never been a problem in my 450-400 and bullets seem to come in all sizes with that caliber. most come in .408 or .411 but I have seen bores that slugged as much as .413??? I suppose the English felt like it made little difference at up to 50 yards, and that's probably right....

The Barnes banded solids are .002" undersized and I shot them safely in my vintage .600 Wikes. They are too long to load a full charge of 4831 but fine with a quicker RL 15. However, while safe, I still prefer Woodleighs due to their traditional look and they also preform very well.
Cal

If you produce a monometal bullet and you don't utilise pressure reducing features / technology how do you try to overcome the high hoop stress and challenges of high pressure?

Ja the issue is why those monolithic brass solids that do have rings or bands like the Barnes(which are easier for the barrel to smear) are still deliberately undersized

Undersized bullets may further reduce pressure but the disadvantage of the undersized solid is its damage to the barrel because it does not seal properly and the hot gasses that flow past the bullet down the barrel apparently cause more harm to the barrel than any friction from the bullet

Is it possible the manufacturer is sizing them slightly small to to account for bullet swelling/upset as it enters the rifling? I wonder if you fired some bullets into gel or wet paper and inspected them if they would show contact with the grooves?

quote:

Originally posted by phil ossifer:
Been measuring some solid bullet diameters on a rainy afternoon here . Woodleigh steel jacketed solids and Barnes banded solids all seem slightly undersized. So do the PMP brass solids . I have shot hundreds of brass solids (PMP and Barnes)through my 375 and 9.3x62 with no signs of premature barrel wear.

But the niggling question is -----is a slightly undersized solid bad because it doesn't seal the barrel properly thereby resulting in more so called flame cutting or gas blow by or throat erosion? The hornady steel jacketed solids are not undersized.

Is the trade off of less pressure (created by under sizing) vs imperfect seal worth it?

Any experience or views on this?

quote:

Originally posted by phil ossifer:
Ja the issue is why those monolithic brass solids that do have rings or bands like the Barnes(which are easier for the barrel to smear) are still deliberately undersized

Undersized bullets may further reduce pressure but the disadvantage of the undersized solid is its damage to the barrel because it does not seal properly and the hot gasses that flow past the bullet down the barrel apparently cause more harm to the barrel than any friction from the bullet

This theory of yours about the gas cutting is wrong. If it occurred at all, a barrel would be toast in no time. If it does happen, it's logical to assume the bullet is cut before the barrel steal cuz it is of a material that melts at a lower temp.
I have seen hundreds of fired solids, no evidence has ever been seen of gas cutting on the shank, also neither has it been seen in barrels I have scoped.

Cheers.

Check out the GS custom bullet website

quote:

Originally posted by phil ossifer:
Check out the GS custom bullet website

Yes, I have looked at that site, still do not see any evidence of gas cutting on ANY of those supposed undersize bullets.
Gas cutting has to perpendicular to the steel, not parallel with it. It doesn't happen in barrels shooting lead or bore riding designs.

Do not believe it to be a real thing, sorry.
Being a boilermaker, I know how the different techniques of cutting steel with oxy/acetylene works, without directly heating the steel, whether at 90 degrees or the maximum angle of 30 degrees, when 'gouging' steel plate, the flame simply runs across the surface without heating a generalised spot to get to 'burn temp'.

Doesn't happen in any rifle I've ever seen.

NO, NO, NO, and NO.

3 mechanisms causes barrel erosion.

1. Chemical: products of propellant combustion chemically reacting with barrel steel. Hydrogen is the worst offender. Carburization and Oxidation of bore surface.

2. Thermal: High heat is a normmal part of combustion however its when heat is concentrated that it becomes a problem. Leakage of gas leads to jetting which melts the bore barrel interface and actually washes the surface away with each shot ( Gas blow by) Investigations into barrel erosion has shown that gas leakage causes very high temperature spikes and erosion is increased by up to 300 %

The heat in combination with chemical reactions cause embrittling of the barrel and microscopic surface cracking

Gas blow by is bad !

3. Mechanical: The friction of the projectile itself but less obvious the Washing and scouring of solid products of combustion. When this leaks past the projectile the effect is amplified.