I have some factory loads that I would like to swap the 70gn matchking with a 70gn ballistic tip.

Can I just pull the bullet out and re insert, or will the neck need re-sizing?

You shouldn't need to resize BUT, there may sufficient difference in the bullet bearing surface to change pressures. Let us know how this works out.

While swapping projectiles in factory ammo isn't really recommended, bullet weight for bullet weight probably won't make a difference IF the bearing surface is shorter or at least no longer than the original bullet.`If the bearing surface is longer, then excessive pressures are quite likely. Really is a risky business.

Resizing the case won't be necessary, but if the original bullet had any crimp applied, then the case mouths may need to be belled very slightly in order to seat the new bullets.

Regards DLM

The factory loads are Sako 6PPC with 70gn Matchkings(Sako call them raceheads)
There is no crimp.

I want to put in 70gn Ballistic tips.

EXPRESS,
Yes you can pull them out and simply replace projectiles without resizing. I've done it on two occassions for various reasons, but both times replaced the factory projectiles with lighter/shorter projectiles just in case. I've replaced Norinco 55gr FMJ's with 50gr Sierras looking for improved accuracy out of a Ruger 223 Varmint gun and replaced Winchester 510gr with 480gr Woodleighs in a 458WM to get more reliable feeding from a CZ550. I don't do it anymore as its too time consuming and expensive when you take all things into account. Good luck...
Con

it's not for the time or expense, it's for the load; the Sako factory stuff is very accurate, but the MatchKings are quite devastating on any game up the about 30 or 40kg (63 - 88lb), I wanted to see if the b-tips would be as accurate and not exit as the MatchKings often do.

EXPRESS,
To be on the safe side and accepting that changing any component in a known load makes it a new load, why not remove the Matchking, reduce the powder charge of the factory load and work back up to the full charge with your Ballistic Tips?
Cheers...
Con