Suppressor host reviews · editorial reference

FN 545 Tactical .45 ACP: The Big-Bore Host on Its Own

Most suppressor hosts need subsonic ammunition to be quiet. The .45 ACP starts out there, which changes the calculation.

Short answer

The FN 545 Tactical pairs an 18-round .45 ACP magazine with a threaded barrel, and ordinary .45 ACP ball loads are typically subsonic to begin with. Check the thread spec and the can maker's guidance on booster use, and expect a bigger, heavier setup than a 9mm.

Why .45 ACP and suppressors fit together

A lot of this site is about getting rifle and pistol rounds below the speed of sound. Subsonic ammunition keeps the sharp crack of a bullet out of the noise signature, and that is why subsonic loads get so much attention. Many standard 230-grain .45 ACP loads are subsonic as sold. The cartridge was designed around a heavy, slow bullet, long before anyone worried about suppressors, and that heritage is exactly why people who suppress pistols often gravitate to it.

The FN 545 Tactical .45 ACP is FN's big-bore answer to the 509 Tactical. The listing we link is the black model with an 18+1 capacity, and retailer descriptions of the 545 Tactical line commonly list a 4.71-inch threaded barrel and magazines in 15- and 18-round sizes. It comes in the same "ready for a suppressor" mold that made the 509 Tactical a reference host. If you want the pair view, our big-bore hosts post covering the 545 and the 10mm FN 510 sets them side by side. This article is the standalone version.

What "subsonic by default" does and does not give you

It does mean you can start with ordinary .45 ACP ball ammunition without hunting for a special load. It does not mean your pistol is quiet.

A few reasons:

The action is still audible. A suppressor quiets muzzle blast, not the slide. A heavy .45 slide moving through its stroke makes noise of its own.
Velocity varies by load. Some .45 ACP products are loaded hotter, including +P and certain defensive loads, and can approach or exceed the speed of sound depending on conditions. If you want to be sure, check the manufacturer's published velocity and, if it matters to you, measure.
A suppressed gun is not hearing-safe. Keep hearing protection on. Our post on why a suppressor is not hearing protection explains why a quieter gun is not a quiet one.

For a broader look at which calibers sit on which side of the speed of sound, see subsonic ammo by caliber, and BuyMoreAmmo has a plain-language explainer on subsonic versus supersonic.

The threads and the mount

Confirm three things before ordering a can for a .45 pistol:

Thread spec. The listing should say threaded, and the maker's documentation should give the pitch. Pitch conventions for .45 are different from 9mm and .22, so do not borrow a number from another caliber. Our thread pitch cheat sheet covers the common ones.
Can rating. A .45 ACP suppressor needs to be rated for the cartridge. A can built for a different caliber, or for a smaller bore, is not an option.
Mount and booster. Many centerfire pistol cans use a mount with a booster, sometimes called a Nielsen device, to help a tilting-barrel pistol cycle with the added weight. Whether your can needs one is something the can maker tells you. Read our pistol booster explainer for the idea, then follow the manufacturer's instructions for the actual hardware. We do not provide installation or modification steps here.

Size and weight: the cost of going big

A .45 suppressor is typically larger than a 9mm one, because the bore is bigger and the can has to deal with a larger volume of gas. A .45 pistol with a can on it will be longer and heavier than the same pistol in 9mm. That is a worthwhile trade for some owners and a deal-breaker for others. A few things to keep in mind:

Holster fit for a suppressor-equipped pistol is its own project.
Magazine capacity is generous at 18 rounds, but a loaded 18-round .45 magazine adds weight on its own.
Sights matter. Taller sights are common on suppressor-ready pistols so that the sight line clears the can. Check that the sights listed on the pistol you choose clear the can you intend to use.

545 or 509?

Choose the 545 if...	Choose a 509 if...
You want a cartridge that is typically subsonic out of the box	You want lighter recoil and the widest choice of practice ammunition
You like the idea of a larger bullet	You want broader ammo and accessory choices
You are comfortable with a larger, heavier suppressed pistol	You want the smallest, lightest suppressed setup
You do not mind paying attention to booster compatibility	You want fewer variables

Our FN 509 Tactical host post covers the 9mm reference, and the right answer depends on what you value more: a built-in subsonic bullet or a simpler, lighter package.

A reason not to buy

If you do not already own, or plan to own, a .45 ACP suppressor, the pistol alone is just a good .45. A big-bore pistol with a threaded barrel can be a fine gun in its own right, but you will not be getting a suppressor benefit unless you buy and register a can, and in some states that is not possible at all. Settle the can question before you decide the host.

Legal reminder

Suppressor ownership is regulated federally and by individual states, and several states prohibit it outright. Federal procedures changed in 2026 and the picture keeps moving. Start with our buying a suppressor in 2026 walkthrough and check your state's rules.

Bottom line

The FN 545 Tactical is a logical big-bore host: a threaded barrel, a high-capacity magazine and a cartridge that is subsonic in most common loads. The cost is size and weight, and the tasks are the usual ones: verify threads, choose a can rated for .45 ACP, and follow the maker on boosters.

Editorial note: This is an independent editorial overview built from manufacturer specifications and publicly available information. We have not performed hands-on testing of the products discussed, and nothing here is a performance guarantee. Verify specifications, compatibility and legality for your own situation.

Frequently asked questions

Is .45 ACP naturally subsonic?

Common 230-grain .45 ACP loads travel well below the speed of sound, which is why the caliber is often described as a natural fit for suppressors. Individual loads vary, so check the manufacturer's published velocity.

Does the FN 545 Tactical need a booster?

It is a tilting-barrel style pistol, and whether a suppressor needs a booster depends on the can and mount. Follow the suppressor maker's instructions. Our pistol booster explainer covers the concept.

What are the listed specs for this FN 545 Tactical?

The listing we link is the black model in .45 ACP with an 18+1 capacity, and other retailers describe a 4.71-inch threaded barrel. Check the product page for the full details.

Is the FN 545 a better suppressor host than the FN 509?

They fill different roles. The 509 is the 9mm reference; the 545 is the larger-caliber option. Our existing big-bore post covers the pair, and the 509 host post covers the 9mm.