How important is bullet run out?

[Oldbloke]

I always thought bullet run out was critical. Seems not so for the average hunter.
This is for me a very surprising result.
Certainly puts my mind at rest.

https://youtu.be/6m8Y6ZmSBiU

[deye243]

Depends on your chamber I can deliberately cause run out in a seated bullet then chamber and it comes out with around 0.002" of run out

[straightshooter]

deye243 is on the right track.
This 1000 yard F class shooter is unlikely to have a factory barrel with a factory chamber. More likely he will have a good concentric chamber perfectly in line with the bore, with fitted necks, a minimum clearance throat and zero jump.
The net result is that with that setup and an action with an adequate amount of 'cam forward' much if not all of the run out of the round will be corrected on chambering and the projectile will be presented square and concentric to the lands.
That should not be interpreted to mean that poor quality projectiles can be magically made accurate.
Things will be different in a typical commercial sporter.

[JohnV]

I agree with " straightshooter " . We should all strive for precise loaded ammo but a few thou run out is not such a big deal in hunting ammo even when seated off the lands . A lot depends on how small your groups are and if you can even see the difference in your average group accuracy anyway . Some longer Tangent ogive bullets and Secant ogive bullets are a bit more susceptible to entering the bore out of alignment ( in bore yaw ) especially with a big jump to the lands . So on average it is better to get good bullet seating concentricity rather than bad and case neck fit is also a compounding factor . A lot of the small things that do improve accuracy slightly are not easily noticeable until average group accuracy gets down to say sub I inch anyway . You got to get the gun tuned up right and your shooting techniques right before you can really test some of the finer accuracy improvements . You will never see the effects of bad seating concentricity in the average gun if the gun shoots 2 inch groups . Projectiles that have too much run out will not straighten up much if the projectile is seated off the lands which is the case in most hunting ammo as it's not safe or practical to seat hard into the lands in a stalking type rifle . This is why I developed ( for myself ) skim neck turning for the factory chamber , partial neck sizing and the separate body die back in about 1967 . Redding manufactured the body die in secrecy for US target shooters for 20 odd years because they stole the idea .

[Oldbloke]

I agree with " straightshooter " . We should all strive for precise loaded ammo but a few thou run out is not such a big deal in hunting ammo even when seated off the lands . A lot depends on how small your groups are and if you can even see the difference in your average group accuracy anyway . Some longer Tangent ogive bullets and Secant ogive bullets are a bit more susceptible to entering the bore out of alignment ( in bore yaw ) especially with a big jump to the lands . So on average it is better to get good bullet seating concentricity rather than bad and case neck fit is also a compounding factor . A lot of the small things that do improve accuracy slightly are not easily noticeable until average group accuracy gets down to say sub I inch anyway . You got to get the gun tuned up right and your shooting techniques right before you can really test some of the finer accuracy improvements . You will never see the effects of bad seating concentricity in the average gun if the gun shoots 2 inch groups . Projectiles that have too much run out will not straighten up much if the projectile is seated off the lands which is the case in most hunting ammo as it's not safe or practical to seat hard into the lands in a stalking type rifle . This is why I developed ( for myself ) skim neck turning for the factory chamber , partial neck sizing and the separate body die back in about 1967 . Redding manufactured the body die in secrecy for US target shooters for 20 odd years because they stole the idea .

That was my main point. For hunting a few thou won't matter. Target comp is a different matter.

Especially when you consider blokes get good accuracy with a Lee Classic loader, sort of proves the point.

Like a lot of things relating to quality. You need a lot of effort to achieve the very finest quality. But pretty darn good is easy to achieve. If you get my meaning.

[JohnV]

I agree with " straightshooter " . We should all strive for precise loaded ammo but a few thou run out is not such a big deal in hunting ammo even when seated off the lands . A lot depends on how small your groups are and if you can even see the difference in your average group accuracy anyway . Some longer Tangent ogive bullets and Secant ogive bullets are a bit more susceptible to entering the bore out of alignment ( in bore yaw ) especially with a big jump to the lands . So on average it is better to get good bullet seating concentricity rather than bad and case neck fit is also a compounding factor . A lot of the small things that do improve accuracy slightly are not easily noticeable until average group accuracy gets down to say sub I inch anyway . You got to get the gun tuned up right and your shooting techniques right before you can really test some of the finer accuracy improvements . You will never see the effects of bad seating concentricity in the average gun if the gun shoots 2 inch groups . Projectiles that have too much run out will not straighten up much if the projectile is seated off the lands which is the case in most hunting ammo as it's not safe or practical to seat hard into the lands in a stalking type rifle . This is why I developed ( for myself ) skim neck turning for the factory chamber , partial neck sizing and the separate body die back in about 1967 . Redding manufactured the body die in secrecy for US target shooters for 20 odd years because they stole the idea .

That was my main point. For hunting a few thou won't matter. Target comp is a different matter.

Especially when you consider blokes get good accuracy with a Lee Classic loader, sort of proves the point.

Like a lot of things relating to quality. You need a lot of effort to achieve the very finest quality. But pretty darn good is easy to achieve. If you get my meaning.

I agree . Good results can be achieved with basic equipment and using some good case prep and seating techniques .
Like don't just ram the bullet into the case in one massive thrust . Start the bullet first then twist the case approx. 180 degrees and then gently seat it home .

[Oldbloke]

"Start the bullet first then twist the case approx. 180 degrees and then gently seat it home"

That's how I do it.

[JohnV]

A lot of us old timers do it that way using standard dies .

[GQshayne]

I reckon it's pretty important.

Can't go shootin' if ya run out.

[Oldbloke]

I reckon it's pretty important.

Can't go shootin' if ya run out.

[Billo]

"Start the bullet first then twist the case approx. 180 degrees and then gently seat it home"

That's how I do it.

I use a Lee hand press and if Im feeling lucky and really chasing a load I twist the bullet 120 degree twice and seat down 3 times

[northdude]

https://youtu.be/LoLDGeK6_6M

[JohnV]

The projectiles are probably seated against the lands and the bullets are just straitening up in the chamber . That is not always the case when seated off the lands . Some bullets like solid base , thicker jackets and core bonded tend to resist in bore yaw better . Others with thinner jackets and bases and loose core design tend to suffer more . Ballistic science in firearms is an incredibly complicated thing and there is no single answers that cover everything . There is many variables . Generally speaking a few thou run out is no big deal in hunting ammo .

[JohnV]

site is playing up.

[bigpete]

Never checked it. Still kill plenty of stuff.