120 SMK Vs 123 SMK....what is the difference?

[LRRPF52]

LRRPF52, what kind of change in accuracy do you see as the throats wear in high round-count rifles? I have wondered if the compound-throat chamber wears evenly or whether its shape changes to be, for example, less accurate with secant-ogive vs tangent-ogive bullets after some point. With the precisely made barrels that you use, I don't have an idea of the number of rounds fired before you would consider the accuracy unacceptable.
Thanks

I haven't seen accuracy fall off yet with any of my Liljas. With the high-end barrels, you often won't see accuracy fall, but velocity will drop with throat erosion.

6.5 Grendel doesn't suffer from this really since the chamber pressure is so low compared to any of the 6.5-08 class of cartridges, and especially the 6mm Dashers, 6 Creedmoor, or 6x47 Lapua.

The Bartlein and Krieger barrels have been known for using harder stainless steel, whereas your Liljas and Shilens typically use softer stainless to get that straight bore reamed through the stock before rifling. Stainless is preferred by accurate barrel makers because it is softer than 4140 and higher chromoly steels, which do better for machine-guns and assault rifles that will have high round counts blasted through them, especially on automatic.

Throat erosion is more an issue above 55,000psi, especially with more "over-bore" cartridges like the 6mms and fat cases with smaller neck diameters.

Since Grendel is neither over-bore nor anywhere near 55ksi working pressure, throat life will exceed .308 Winchester, which is the gold standard for barrel life among accurate rifle shooters.

.300 Win Mag is notorious for throat erosion and velocity loss, to the extent that guys have experienced significant POI shift in courses.