I only now shoot mag loaded rifles. The point of loading near or into the landes is more to do with getting a more constant pressure spike/release pressure than relationship with the landes.

The OAL can be pushed back as well as forward and still get excellent groups, although they groups will be more down to the harmonics/load, with the release point being a factor.

Many military rifle shooters simply set to standard OAL (SAAMI etc, or copy a service round), then neck crimp (which serves a similar function to loading into the landes but does not need the bullet barely hanging on, this is not ideal when you are loading from a mag via a feed ramp as you may well end up with an eccentric bullet).

Firm crimping gives a more consistant group in all of my rifles which are all mag loaded fairly rapidly. You do not have to worry about the landes eroding and constantly pushing the OAL forward either.

You can often get great results simply by factory crimping and changing the load.