If you're buying a bare action, one of the first choices you'll make is which bolt face to get, and a lot of cartridge names don't make it obvious which one lines up with what you're shooting. If you're ordering one of our barreled actions instead, you don't need to worry about any of this, since we'll fit the right bolt head for your chambering when we put it together.

So here's a closer look at what the bolt face actually does, why some cartridges end up where they do, and how to figure it out yourself if your cartridge isn't covered here.

What the bolt face actually does

Firstly, the bolt face is the front end of the bolt that closes up against the back of the cartridge. It has a shallow recess cut into it that the rim of the case sits in, which keeps the case centred and supported when the rifle fires. The extractor clips over the edge of that rim, and that's what pulls the empty case back out of the chamber when you run the bolt.

Because the case sits right in that recess, the bolt face has to be sized to the rim of your cartridge. If the rim is too big for the recess, the bolt simply won't close on it. If the rim is too small, the case can sit off centre and the extractor won't get a solid grip on it, which is how you end up with extraction problems or cases getting left in the chamber.

So when it comes to picking a bolt face, the rim is the only thing that matters. That's how a 6mm and a 30 cal can share a bolt face, while two different 6.5s can need completely different ones.

Why the name doesn't help much

Cartridge names don't help much here, because they're based on the bullet and whoever designed the round, not the rim. What actually decides the bolt face is the case the cartridge was built from. Most cartridges are just an existing case necked up or down, shortened or blown out, so they fall into a few families that each share the same rim.

That's why a 22 Creedmoor, 243, 7mm-08, 6.5 Creedmoor and 30-06 all run the same bolt face even though they look pretty different side by side, and why a 6mm ARC and a 7.62x39 end up sharing one too. Once you know which family your cartridge belongs to, the bolt face is easy to figure out.

How our bolt faces line up

With those families in mind, here's how they line up with our bolt faces. Our two-lug actions run four bolt face sizes, and a fifth size, our .223, is available in our multi-lug actions. Our short actions are also Remington 700 short action aftermarket compatible, so whichever bolt face you end up with, you can still use the stocks, chassis and triggers built for a Remington 700 short action.

The ARC / PPC (.445) bolt face covers that whole 7.62x39 family, so 22 ARC, 6mm ARC, 6.5 Grendel, 6mm PPC, 22 PPC and 7.62x39 itself. These have really taken off for lightweight hunting rifles and efficient target builds, since they get a lot of performance out of a small case.

Standard (.480) is where most builds end up. It covers the 308 family and the Creedmoors (22 Creedmoor, 6mm Creedmoor, 6.5 Creedmoor, 25 creed, 308, 243, 7mm-08), along with the 30-06 and the benchrest-derived 6 Dasher, 6 GT and 6.5x47 Lapua. If you're building an all-round hunting rifle or a typical precision rifle, there's a good chance this is your bolt face.

Magnum (.540) takes care of the 6.5 PRC, 7 PRC, 300 PRC, 7mm Rem Mag, 300 Win Mag and 300 WSM. The 300 WSM is a bit of an odd one out since it's a short, fat case with its own lineage, but its rim is close enough to the others that it shares the same face. Above that, our Lapua (.585) bolt face is built for the big long range cartridges like the 338 Lapua Mag, 300 Norma Mag and 338 Norma Mag.

At the small end, the .223 (.380) bolt face runs 223 Rem, 223 Wylde, 204 Ruger and 300 BLK. That size is only available in our multi-lug actions, so if you're planning a small-bore build around one of those, that's the platform to look at.

The ones that throw people off

There are a handful of cartridges where the name points you one way and the bolt face goes the other. The 6.5x47 Lapua is the biggest one. It has "Lapua" right in the name, so a lot of people assume it needs our Lapua bolt face, but it actually runs a Standard. Our Lapua face is named after the 338 Lapua Mag, which is a much larger case, while the 6.5x47 shares its rim size with the 308 family.

The 6.5 PRC is kind of the opposite situation. It shoots the exact same bullets as a 6.5 Creedmoor, so it's easy to assume the two would share a bolt face. The PRC is built on a magnum case so it can push those bullets a lot harder though, and that bigger case means it needs a Magnum bolt face.

The 300 BLK catches people from the other direction. It's a 30 cal like the 308, so you'd expect it to run a Standard, but it was designed around the 223 case so it could run in an AR with just a barrel swap. That means it uses the same .223 bolt face as your 223 or 5.56.

You're not locked in

The good news is that the bolt face isn't a one-time decision on our two-lug actions. They run interchangeable bolt heads, so the bolt face isn't machined permanently into the bolt body. If you build a 6.5 Creedmoor now and decide a few years down the road that you want to step up to a 6.5 PRC, you can swap to a Magnum bolt head instead of buying a whole new action, since both run in a short action.

Keep in mind the bolt head only takes care of the rim. You'll still need a new barrel headspaced to the new bolt head and a magazine that works with the new case, and the action length has to suit the cartridge.

Even so, you get to keep the action that's already bedded in your stock, with your scope mount and trigger set up the way you like them.

Checking your own cartridge

If your cartridge isn't on the list, look up its rim diameter on the cartridge drawing (SAAMI and CIP both publish them) or measure a case with calipers, then find which of our bolt faces lines up with it. If it seems close between two, send us a message and we'll confirm it.

Wildcats and rebated rim cartridges, where the rim is smaller than the case body, can be trickier, so those are worth a quick conversation before you order.

If you're ordering a bare action and you're not sure where your cartridge lands, send it through the Rifle Builder on our site or reach out to us directly. And if you'd rather skip the guesswork altogether, our barreled actions come with the right bolt head already fitted. Let us know if you have any other questions!