Looking at 6.5CM Lapua brass. Do I want small or large primers?

What are the experts using for powder charge with 140ish gr bullets? Would prefer to use H4350 with berger, or other match bullets.

I have thousands of Federal Match primers 😎 In all sizes.

Thanks for the guidance!

The grain recommendations are spot on. For good results, get ahold of some factor 140 ELDM rounds and copy their physical dimensions. From there refine your CBTO to your rifle and squeeze the last little bit of accuracy you can out of your loads.

Brownells has small primer Lapua 6.5 CM brass in stock.

I prefer small primer Lapua brass.

I use small primer pocket Lapua for what I hope will be longer brass life.
These days It’s more about what primers are you stocked up on

I have been having excellent result with 41.5 grains of H4350 behind the sierra 142 matchking in lapua large primer brass. I haven't had good luck with the berger 140 VLD.  The Berger 140 hybrid was the best of all, same load. I haven't seen a box of those in over a year so the Sierra it is.

Small primer brass may have a tiny theoretical advantage in SD but both should hit single digits fairly easily. The bigger advantage is if you only load small primer ammo on your press. Like 9mm, 5.56mm, 300 BLK, and 6.5 Creedmoor all with small primers and never have to swap out to load large primers.

For me, all match primers are harder to come by now and I had several thousand Federal large rifle match primers from when I started shooting 6.5 Creedmoor with Hornady brass. So I bought Lapua large rifle primer brass to upgrade from my Hornady brass and use my existing large rifle primers.
If I started new now, I might go small rifle primer and consolidate my primers. To avoid swapping priming systems on the press, I hand prime large primers. I obviously don't shoot .45 ACP.

I use ~42.0 grains of H4350 with 140-143 grain Hornady and Berger bullets. 41.7-42.1 grains specifically. That is over book like almost everyone's 6.5 Creedmoor bolt gun load, so start low and work up.