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CMMG Resolute .300 BLK 16-Inch: A Rifle-Length Suppressed Setup

Sixteen inches is the unglamorous barrel length in .300 Blackout. It is also the one with the fewest legal headaches.

Short answer

The CMMG Resolute Mk4 in .300 BLK has a 16.1-inch barrel and a 30-round magazine, which puts it in standard rifle territory. That sidesteps short-barreled-rifle questions and gives supersonic loads a bit more barrel, at the cost of a longer suppressed setup.

The case for the boring barrel length

Short .300 Blackout guns get all the attention. The CMMG Resolute Mk4 in .300 BLK is the sensible sibling. The listing describes a 16.1-inch barrel and a 30+1 capacity, which puts it above the 16-inch line that separates a rifle from a short-barreled rifle in the usual federal sense. That has practical consequences:

It is an ordinary rifle for most legal purposes, with the exception of whatever your state does with semi-auto rifles and magazines.
It does not carry the stock and brace complications of a short-barreled gun.
It gives supersonic loads a few more inches of barrel to work with.

The trade-off is size. A 16-inch barrel with a suppressor on it is a longer gun than a pistol-format compact, and you give up some of the portability that draws people to .300 BLK in the first place.

Why 16 inches still makes sense suppressed

Many people assume that suppressing a .300 BLK demands a short barrel. It does not. A suppressor is rated for a caliber and a cartridge class, not for an overall length. What a longer barrel changes:

It tends to make supersonic ammunition faster. Longer barrels give a bullet more time to accelerate. That matters if you plan to shoot supersonic .300 BLK as well as subsonic. Look at the ammunition maker's published velocities and remember that real results depend on the individual rifle.

It can make subsonic cycling a little different. A longer barrel places the gas port farther from the muzzle and leaves more of the barrel behind it. Subsonic .300 BLK generates less gas to work the action. Whether it will run reliably in your gun with your can is something you establish by trying it. We have not tested this rifle.

It can mean steadier handling. Many shooters find a longer barrel easier to hold on target than a very short one, which can matter for accuracy at the distances people actually shoot .300 BLK. A suppressor adds weight at the muzzle either way.

It reduces the legal clutter. If you want a suppressed .300 BLK and do not want to think about braces or short-barreled-rifle registration, a 16-inch rifle is the straightforward answer. The suppressor is still its own matter, and our buying walkthrough lays out the order of questions.

Hunting: legality first

Suppressed hunting comes up often enough that it deserves its own warning. Hunting law is state law, and it is not uniform.

Suppressor use while hunting. Some states permit suppressors for hunting, some restrict them to certain species or seasons, and some prohibit them. Check your state wildlife agency's current regulations.
Caliber and cartridge rules. States set minimum requirements for big game, and .300 BLK may or may not be permitted for a given species. Rules can reference bullet type, energy or caliber.
Bullet construction. Full metal jacket bullets, which are the common construction for subsonic range ammunition, are restricted for big game in some places. Expanding bullets are designed for the purpose. Do not assume a range load is legal or humane for hunting.
Published ballistics. If you plan to hunt, rely on the ammunition maker's data and your state rules, not on a forum thread.

This site is not a hunting-regulation guide and cannot tell you what is lawful where you live. Treat the paragraph above as a prompt to go read the rules.

Ammunition: a quick map

Goal	Typical choice	Note
Quiet range work	Subsonic, heavy bullet	Check cycling in your gun
Range work with louder crack	Supersonic .300 BLK	Suppressor reduces blast, not bullet crack
Hunting	Expanding bullet appropriate to your state's rules	Read the regulations first

For a spec-based look at one specific subsonic load, see our Magtech 200-grain subsonic article. BuyMoreAmmo's best .300 Blackout ammo piece compares subsonic and supersonic options in more detail.

A safety note you will see again: .300 BLK cartridges fit magazines for 5.56 but must never be fired from a 5.56 rifle. Mark your magazines and keep your ammunition labelled.

Thread pitch and mounts

We are not going to guess the Resolute's muzzle details. Check the listing and CMMG's documentation for the thread pitch and the muzzle device it ships with, then match the suppressor's mounting system to it. If you are unsure how mount systems differ, read our guide to choosing your first suppressor mount and the thread pitch cheat sheet. We do not provide steps for modifying firearms or suppressors.

Who should look at it, and who should skip it

The Resolute makes sense if...	Skip it if...
You want a standard-length .300 BLK rifle	You want the most compact suppressed setup possible
You do not want to deal with short-barrel rules	You like pistol-format guns
You may shoot both subsonic and supersonic loads	You will only ever shoot subsonic and want to shave length
You want to keep options open for hunting where it is legal	You have no interest in anything beyond range use

If compactness is the priority, compare the CMMG Dissent compact and the Banshee 8-inch versus 12.5-inch. If you want a bigger roundup of premium .300 BLK hosts, read our premium .300 BLK hosts post.

Hearing protection

A suppressed rifle in .300 BLK is not quiet enough to skip hearing protection, particularly with supersonic loads where the bullet itself is loud. Our quieter does not mean quiet post explains the thinking.

Bottom line

The Resolute is the straightforward answer to a suppressed .300 BLK rifle. It trades some portability for fewer legal complications and more barrel, which is a good deal for plenty of shooters. Verify the muzzle details, test your ammunition, and read your state's hunting rules before you take it into the field.

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 a 16-inch .300 BLK too long for a suppressor?

No. Suppressors work on any barrel length they are rated for. A longer barrel makes the whole setup longer, but it also means a standard rifle configuration.

Can I hunt with a suppressed .300 BLK?

It depends on your state. Some states allow suppressors for hunting, others do not, and caliber and bullet rules differ by species. Check your state wildlife agency's regulations before you go.

Is subsonic .300 BLK appropriate for hunting?

Subsonic full metal jacket rounds are generally not designed for expansion, and many jurisdictions regulate bullet types for big game. Read the regulations before relying on any load for hunting.

Does the Resolute have the same thread pitch as other CMMG models?

Do not assume. Confirm the thread pitch on the exact model's listing or the maker's documentation.