G'Day Fella's,
No shortage of reloaders, seem to be a bit in the dark about what's on the inside of a Rifle and Pistol barrel.
So I set up a used .308 Win barrel in my milling machine, and removed a bit of the exterior of it, to give you an inside look.
Here's a view of the chamber area (empty) and the first inch of the bore.
Here I have a .308 case in the chamber but not seated all the way to the shoulder (arrow 1).
Ditto but with the case seated all the way.
You can also see, a small amount of clearance in front of the case mouth here (arrow 2), this is to give you case length clearance.
Thats why you need to trim your cases, to the recommended OAL.
If you don't do this, when the case length grows (after repeated firing and reloading), it will eventually bottom out into this area and stop you from being able to close the bolt etc!
This time, I have a Remington 180grn (sorry Mr Nosler), seated base first, to show how the lead (arrow 3) area of the chamber, is slightly larger in diameter than bullet diameter (of 0.308").
Now I have a case with the same 180grn bullet seated in the case and in this position, the ogive of the bullet is touching the lead (arrow 3) but the case is not yet chambered up to the shoulder.
Ditto but with the case fully chambered.
FYI, arrow 4 shows the position of the meplat (tip) of the bullet, when it is in contact with the lead (arrow 3), of the bore.
Hope that helps
Doh!
Homer
No shortage of reloaders, seem to be a bit in the dark about what's on the inside of a Rifle and Pistol barrel.
So I set up a used .308 Win barrel in my milling machine, and removed a bit of the exterior of it, to give you an inside look.
Here's a view of the chamber area (empty) and the first inch of the bore.
Here I have a .308 case in the chamber but not seated all the way to the shoulder (arrow 1).
Ditto but with the case seated all the way.
You can also see, a small amount of clearance in front of the case mouth here (arrow 2), this is to give you case length clearance.
Thats why you need to trim your cases, to the recommended OAL.
If you don't do this, when the case length grows (after repeated firing and reloading), it will eventually bottom out into this area and stop you from being able to close the bolt etc!
This time, I have a Remington 180grn (sorry Mr Nosler), seated base first, to show how the lead (arrow 3) area of the chamber, is slightly larger in diameter than bullet diameter (of 0.308").
Now I have a case with the same 180grn bullet seated in the case and in this position, the ogive of the bullet is touching the lead (arrow 3) but the case is not yet chambered up to the shoulder.
Ditto but with the case fully chambered.
FYI, arrow 4 shows the position of the meplat (tip) of the bullet, when it is in contact with the lead (arrow 3), of the bore.
Hope that helps
Doh!
Homer