Max bullet extension for 22-250

Anyone got any numbers?
Looking to deal with some minor throat erosion.

There are no numbers.
Especially since your barrel throat is eroded.
And you didn't say what bullet you intend to use.

The old rule of thumb for bullet seating is "one bullet diameter inside the case neck" for proper neck tension. That does not include the boat-tail on BT bullets, as they have no case neck contact.

rc

Oh, I was just wanting to get some ideas.
Weather here is so tee totally terrible it looks like it could be July before I can ever get out again anyway.

I too have throat erosion.

In my target rifle (YMMV), with a lower mid-range load developped specifically for my circumstances (again, YMMV), I am loading chronoed ammo whose COL is as much as 0.140" longer than book COL.

What matters more than COL (forgetting about rounds fitting a magazine), is determining and maintaining the ideal yet still safe distance from cartridge base to bullet ogive AND still have the bullet stable in the neck and not too far out there.

When seating that far out, you need to take chamber dimensions into account and resize/trim your cases accordingly. In my rifle, I can run cases as much as .006" longer than SAAMI, so I trim cases a bit on the long side: the longer neck gives more seating area around a bullet that's out there.

When seating, make sure to QC on the basis of base to ogive dimensions since projectile (i.e. actual bullet) length varies quite a bit and can mask a problem.

The danger in all this is that a guy who likes hot loads ends up not doing the homework and guesses his way to a solution. He loads rounds whose bullets are seated in necks that are way too long, and seats them way out there so that they crush into the lands. The end result is that the leade does not have enough room to allow the neck to release the bullet. Resistance to bullet movement is too high, and pressures spike beyond what the rifle can handle.

Don't experiment blindly without first gathering chamber data for YOUR rifle and components. If you are re-developping an existing load because your throat has eroded, work that bullet out incrementally as you chrono the results. Stay and keep others safe.

Remember, YMMV.