Reloads/Headspace Issue

[LRRPF52]

When I was young, many decades ago, the guy who taught me to reload warned me to never, under any circumstances, shoot someone else's handloads. Any idea what happens when the too long neck becomes impinged by the rifling? Catastrophic failure.
Reload or don't, but don't shoot someone else's handloads. JMHO~ Riuma

Normally if your case mouth has grown past its limit into the cone that transitions from the mouth to the freebore in the chamber, that cone will basically crimp the mouth around the projectile if it is forced into battery.

That can spike pressures significantly, depending on how excessively long the mouth is (neck not trimmed), and where the charge weight is.

With Lapua and Hornady brass, I’ve never seen them grow to 1.530” length, which is where the max case length is for 6.5 Grendel to the mouth.

The lower chamber pressure precludes excessive case growth.

Now on my .260 Rem brass or .308 brass, it’s a totally different story. Brass has to be trimmed often.