03-03-2022, 10:47 PM
Gents,
Here are the diameters of a range of 6.5mm bullets. They have been measured with a micrometer (not calipers) and a few of each for precision.
Lapua is a relatively thick case at 0.0130" at the neck, sometimes 0.0135". If the outside diameter of the neck is sized down to 0.286" then when the bullet is seated they expand about 0.004" which is a serious grip. To do this the expander ball has been removed from the Forster depriming stem (you don't need it), otherwise it would grip a bit less.
[ATTACH=CONFIG]18706[/ATTACH]
All 14 different bullets are close to 0.264" so your 0.262" is an issue.
Yes, you can shoot a smaller diameter bullet but it might not obdurate and spin properly. I have heard 6MOA groups for a 3MOA rifle is typical when using 30cal bullets - never seen or done it however. Lee Enfield .303 shooters sometimes use 308 bullets at a pinch. A 303 is .311 calibre and in this case would be shooting 30cal bullets. Same with the Mosin Nagant. Those old rifles, especially ones made during wartime can have bores that were out of spec but shooters try what they have on hand, as long as it's not the reverse.
Here are the diameters of a range of 6.5mm bullets. They have been measured with a micrometer (not calipers) and a few of each for precision.
Lapua is a relatively thick case at 0.0130" at the neck, sometimes 0.0135". If the outside diameter of the neck is sized down to 0.286" then when the bullet is seated they expand about 0.004" which is a serious grip. To do this the expander ball has been removed from the Forster depriming stem (you don't need it), otherwise it would grip a bit less.
[ATTACH=CONFIG]18706[/ATTACH]
All 14 different bullets are close to 0.264" so your 0.262" is an issue.
Yes, you can shoot a smaller diameter bullet but it might not obdurate and spin properly. I have heard 6MOA groups for a 3MOA rifle is typical when using 30cal bullets - never seen or done it however. Lee Enfield .303 shooters sometimes use 308 bullets at a pinch. A 303 is .311 calibre and in this case would be shooting 30cal bullets. Same with the Mosin Nagant. Those old rifles, especially ones made during wartime can have bores that were out of spec but shooters try what they have on hand, as long as it's not the reverse.