I would like to get a little advise about what action one should use to build a 6.5 PRC. Thanks

Depends on your intended use but I'd build on a medium action. A budget friendly action would be the Zermatt Origin (medium action) as plenty of prefits available for the Origin.

SD

Actions are personal preference but anything but a SA and save yourself some grief and have it chambered with a AW2 reamer.
My top 3 right now would be without breaking the bank
Kauger SST, Kelbys and Mac Bros EVO

If you build on a magnum SA, you will have limited choices that actually take advantage of the 6.5 PRC 2.955” length. When the Remington SAUM was introduced the Remington magnum SA was designed for a 2.825” COAL in the SAUM. Essentially making it worthless for today’s SA COAL as the design allowed for approximately a 2.86”. When Winchester devised its WSM it and others abandoned the SAUM theme and designed for the SAAMI length of a WSM cartridge at 2.860”. Both Howa and Ruger designed their WSM actions at approximately 2.920” and 2.940” while Winchester used a 3.050” magnum WSM SA. If building from an OEM platform then Winchester is the answer or there are many custom aftermarket actions that are 3.00”+ on a 0.532” bolt. Obviously you could use a std long action magnum that easily accommodates a 3.400” COAL and never worry about any bullet or COAL within your preferred/selected throat dimension/chambering.

One of the mediums or a Tikka

I’m considering putting together a Howa 1500 LA in 6.5 PRC with a lightweight stock. Think it would be a winner for not a ton of dough!

https://www.brownells.com/gun-parts...00-6.5-prc-carbon-fiber-barreled-action/
$750 for the CF barrel

https://www.brownells.com/gun-parts...500-la-barreled-action-6.5-prc-threaded/
$430-520 for the steel barrel

In factory actions, Remington 700 SA magnum will work if you run AICS-type mags and relieve the front of the feed ramp, though it won't give you room to run any longer coals than factory. Hornady 147 ELDM factory 6.5PRC ammo runs fine through a 700 WSM I have set up that way. Though it gives no room to grow COALs.

A Winchester WSM mag action will also work and is a better choice as long as you like the stocks you can get for that platform. The mag box is 3.05 but in my experience the practical max length for feeding is maybe 2.98, possibly 2.99. Neither of my M70 WSMs like feeding at 3.00 COAL...both feed perfectly at 2.98 though. Maybe someone else has gotten it to work.

Defiance XM length with their XM bottom metal,
I have a 6.5 Gap built with these components and they compliment the Saum and PRC well!

ive got one built on a Zermatt / Bighorn short action origin.

Alamo Precision did the build.

id have to look at the build sheet, but they used the longer Wyatts mag box?

If its a SA Wyatts its a 3.0 outside and about .295 internal

IMO, the 6.5 PRC isn't worth it. It is a step up from 6.5 CM, but can't hang with the larger 7 and 7.62 rounds. I went with 300PRC and have been really happy with it.

I run a 6.5 prc in a short action with the EOL projectiles. I treat mag length as jam length and its been fine for competition use.