Bullet seating - what does this mean?

[FromSA]

Hi everyone,

I have what is probably a strange request. I need some help interpreting what I see in 4 pictures (attached - hope I did it correctly, never attached photos to a post before.

Yesterday I was playing around with my seating die and decided to try something I seen others do before - I coloured a bullet with a blue marker, fed it in my chamber, closed and opened the bolt, extracted the round and investigated the marks made in coloured area on the bullet. I took 4 photographs of what I saw from more or less four side of the bullet that are equally far apart (in other words I tried to quarter the bullet).

From side 1 it looks like the bullet is going into the rifling at this depth, but not touching all the way around.
On side 2 it looks like there is no contact with the rifling.
Side 3 three looks like it is touching again.
Side 4 also seems to touch but I don't know what to make of the long vertical area that seems to be making contact.

Can you please help me to interpret what I'm seeing?
Am I correct in saying that at this depth the bullet is into the rifling (not just touching).
Am I correct in saying that the contact with the rifling is not uniform?

Thanks

 

[trucraft]

I do the same test with marker pen or wirewool to find out where my bullets touch the lands.
I often see one side of the bullet showing mark like photo 4, caused by the side of the chamber when the round is extracted.
Not too sure about the other photos, sorry.

 

[AZShooter]

I think what you are seeing is just some scuff marks from feeding. Sharpies wear off too easily. Polish the bullet with fine steel wool then inspect bullet's jacket with some magnification for rifling marks. They will be evenly spaced small square or rectangular indentations.You will get better results if you drop the round into the chamber with rifle held muzzle down instead of feeding it.


Start by seating the bullet way out there and make some big rifling marks so you can easily identify rifling marks. Once you know what they look like you can proceed to tweak seating depth. Polish the jacket every time you make an adjustment and you will get this figured out easily.

 

[Punisher]

I'm not sure if your bullet had a little yaw and only touched one side of the lands or what.

Making your dummy round, the experts suggest that you take a fired case and do no. Resize it but insert a bullet and tighten the case mouth by pressing it tightly against a flat surface. The bullet needs to move fairly freely.

Then color and insert into your chamber. This part works best if you have the gun in a gun vise so you can be very still.

I repeat this on three cases and try to make sure I am getting the same measurement.

After you get a mark on your colored bullet, you have the distance to your lands. With most bullets I would start about .003 away from the lands and work back into the case.

 

[rcairflr]

Instead of using a marker, use a lit candle to mark your bullet. It turns it a flat black, works much better than a marker.