As the 6.5 PRC cartridge has wildly grown in popularity as a N. American hunting round, there are a few things that you need to know before you dive off into having one built or retrofitting your existing rifle. They're not really big things. But not taken into account will cost you a lot of time and a lot of money having to go back and forth between various parts.
As you can see in the picture above, there is an unusually wide "tolerance" for overall cartridge length. We've shown you that 0.200" looks like in reference to a penny. Two hundred thousandths might as well be a mile when it comes to making ammunition. Typically, we talk about that length being in the 0.010-0.020 inch range (ten thousandths to twenty thousandths), depending on the particular caliber and projectile in use. Historically, a 30cal cartridge likes to be about 0.010" off the lands for best performance. Berger bullets, on the other hand, are designed to be driven into the lands. The PRC, designed by George Gardner of GA Precision, in association with Hornady, was made with the idea of using Hornady's ELD projectiles. As with any ELD/VLD projectile, they have long, tapered "noses" and the ogive is set farther back (not really but it looks that way because of the long taper & for lack of a better description) compared to most other projectiles (reference bottom right picture above showing a factory Hornady 147gr PRC round). Suddenly, 0.200" doesn't mean a whole lot when it comes to cutting the chamber because most of that length is sitting inside the bore, untouched by rifling.
So, now you're asking, where does it matter? We'd be remissed to not mention that there is some consideration that needs to be given - or at least some due diligence - to the reamer that's going to be used. The print in the first picture does a pretty good job of detailing the specs for a reamer. But as with everything man-made, there are discrepancies. You, or your gunsmith, should ask the reamer's manufacturer where they fall into those tolerances. In our shop, we use Manson reamers because they have proven to be ultra consistent from one reamer to the next, virtually eliminating any possibility of error. Another brand, out of Oregon.....not so much.
Now, consider the method you're going to be using to feed ammo into your rifle. This is where it gets important. Are you going to be using a BDL design internal magazine, or external magazine like an AICS pattern or HS Precision box mag? Why does it matter? First, the PRC falls into that "mid-length" category of cartridge lengths. Companies like Defiance actually make a dedicated mid-length, short action receiver for stuff just like this (other examples are cartridges like the 6mm Remington). Your typical short action caliber usually has an overall length of somewhere in the 2.800-2.820" range. Any regular short-action receiver will feed those lengths just fine by any method you choose.
BDL style actions, with the internal magazine and follower, in that regular short action receiver based on the R700 footprint have a max length of 2.850" - give or take a couple thousandths. We've found that feeding the PRC in this type of action requires that a flat follower be used (like the ones from Wyatt Outdoors) with a box that has feed lips like an external magazine. Why? So that it will allow the rounds to self-center resulting in a "hey diddle diddle, right up the middle" feed into the chamber. The trouble here is making sure that the feed lips on the internal box are spaced correctly so that you can push the rounds into the magazine without damaging the cases. Please note that adjusting feed lips is a finesse operation and not one that you should grab some vice grips and go to pulling and tugging. The best solution that we've found for feeding BDL actions is using the detachable magazines from HS Precision. They're a drop-in feature that fits nicely into the BDL hinged floorplate inlet of your stock. They also center feed for flawless operation. All things considered, they're only about $40 more than buying the floorplate, box and follower for the standard BDL set-up. And the convenience of a detachable magazine system goes without saying. Plus, you don't have to your bolt rails machined for an AICS style DBM; nor, do you have to have your feed ramp adjusted for proper feeding. However, the max length of their magazine is 2.850" so using factory ammo is only possible if you have the capability of shortening the overall length.
If you're opting to go for the AICS style DBM, money is about the same as the HS Precision option but will vary depending on what brand components you choose to use. A word of caution to hunters though. This style DBM takes up more real estate and offers more opportunity for making noise - which, obviously, is highly unwanted - and makes the HS Precision DBM more appealing due to its lower profile. If you're making this rifle for competition use, then it's a moot point. You'll need a magazine made for a 300 WSM in order for the feed lips to be correct. However, please note that both Alpha and Accurate Mag brands are limited to a max internal length of 2.950" - the SAAMI spec says that rounds can be as long as 2.955" so there is a chance that you'll need the capability of reducing the length of your factory Hornady ammunition.
As a final note, we always strongly encourage everyone to roll their own ammunition. We hear from people all the time that it's an intimidating process to get started in. It can be. If you don't have someone to help guide you through the gauntlet of available options for equipment. If you're not reloading or maybe you're thinking about getting into it, please don't hesitate to contact us for help. We'll provide you with several options for every piece of equipment needed based on your needs. You're not alone in this. That said, making rifles chambered in 6.5 PRC, we've found that the 140-147gr ELD projectiles from Hornady, coupled with a chamber cut with our Manson reamer, perform best when set to a 2.835" overall length. Use that for reference as you go forward in this project.