AR-Stoner 6.5 Grendel barrel short chambered.

[BluntForceTrauma]

The lands look like they are shallow from the start because of the compound throat. Seems like the slight gradual engraving of the bullet won't have much of an effect on pressure. If factory loads will extract without being sticky and too much engraving into the bullet it doesn't seem like a big deal to me. If the bullet is close or kisses the lands slightly isn't that what the chamber is designed to do.

It seems to me that this is actually the correct technical answer. I'm assuming the compound throat was designed around Bill A's original favorite load, the 123 Lapua Scenar. The challege was to then shoot with reasonable accuracy the VERY wide range of 6.5mm projectiles available (part of the beauty of a 6.5).

You could even say the 6.5 Grendel SAAMI chamber is DESIGNED to headspace on the very shallow first angle of the compound throat. Understandably, this is CONFUSING to those who have heard all their shooting lives: "Don't jam into the lands! Don't jam into the lands!" In standard throats this is prudent advice. A compound chamber upends the conventional wisdom.

I think the concerns of those trying to learn are valid. But both Satern and AA know and knew what they are doing. Satern, for example, takes pride in very precise measurements, in having a "line-to-line" fit of bullet to barrel, so I'm guessing they will seem a hair tighter (and shoot a bit faster).

Let the newer shooters simply understand that a slight kiss into the lands of the shallow first angle of the compound throat is both per spec and is OK with the SAAMI 65G chamber.

John

P.S. Knowing the various personalities and agendas involved in this thread, there JUST might also be a titch of pot stirring, as well.