02-02-2022, 02:54 AM
Dr,
The bullet will touch the throat before the bore.
SAAMI specs for a compound Grendel throat is .2644" narrowing to .2617 and then angled down to a .256" bore, with .264" grooves. As you know a barrel blank is rifled from one end to the other before the reamer cuts this throat so the rifling will start to appear fairly early in the throat. getting deeper as it goes.
The first part of the compound throat is 0.1547" long, while the tighter angle is 0.1088" long.
A 120NBT is exactly .263" diameter. The bullet touches the throat in the first section and .264" groove channels will have already started, but very shallow.
I seat my bullets to max magazine length which is a lot shorter than where bullets touch the barrel. If you have a bolt gun with mags longer than your throat then it's up to you.
Ref: https://saami.org/wp-content/uploads/201...g-Copy.pdf
The bullet will touch the throat before the bore.
SAAMI specs for a compound Grendel throat is .2644" narrowing to .2617 and then angled down to a .256" bore, with .264" grooves. As you know a barrel blank is rifled from one end to the other before the reamer cuts this throat so the rifling will start to appear fairly early in the throat. getting deeper as it goes.
The first part of the compound throat is 0.1547" long, while the tighter angle is 0.1088" long.
A 120NBT is exactly .263" diameter. The bullet touches the throat in the first section and .264" groove channels will have already started, but very shallow.
I seat my bullets to max magazine length which is a lot shorter than where bullets touch the barrel. If you have a bolt gun with mags longer than your throat then it's up to you.
Ref: https://saami.org/wp-content/uploads/201...g-Copy.pdf