The Mossberg 940 Pro for 3-Gun: What It Does Out of the Box

I run a Mossberg 940 Pro. This is a short page about why, and it comes down to a single idea: most competition shotguns need work before they are competition shotguns, and this one needs less of it.

Nothing on this page sells you a gun or a gun part. Receivers, barrels, bolt carrier groups, triggers, gas blocks, suppressors and magazines are not sold on Amazon, this site monetizes through Amazon, and a buy button next to any of them would point somewhere that cannot sell you one. Those rows link to the vendor I used, unmonetized. The only things here anyone is paid for are the accessories — optics, mounts, furniture — and they are marked as such.

The loading port is the whole argument

If you have read what makes a good 3-Gun shotgun, you know the shape of this. Matches are decided at the loading port. The factory port on most shotguns is sized for somebody calmly loading two shells for birds, and competition loading pushes four at speed, at an angle, without looking. So people take their new gun to a smith and pay to have the port opened, the edges taken off and the lifter smoothed.

That work traces back through Mossberg's JM Pro line — the competition series developed with Jerry Miculek — into the 940 platform. What the 940 Pro gives you is a gun that arrives with the competition-oriented loading geometry already there, rather than a gun plus a gunsmithing bill.

The practical version of that: you can take it out of the box, put shells on your belt, and go shoot a match. Your loading will be bad, because loading is a skill, but the gun will not be the thing holding you back.

Gas, and what that means for you

The 940 is a gas-operated semi-auto. Against an inertia gun like a Benelli that means softer felt recoil, because the gas system spreads the impulse out over a longer moment instead of delivering it as one hit.

The cost is a gas system, and gas systems need cleaning. Mossberg positions the 940 series around extended round counts between services, which is a claim I will report and not personally certify — I have not counted rounds between cleanings and I am not going to invent a figure. What is fair to say is that this is a gas gun, gas guns get dirty in the gas system, and if you shoot it a lot you will be cleaning it.

The wider gas-versus-inertia argument, and where the Benelli, Beretta and Stoeger tiers sit around this gun, is on the shotgun editorial.

What you still have to buy

Nothing on the gun. Everything on your belt.

Somewhere to carry shells. This is the actual next purchase and it is not close. Shell caddies and quad loaders covers the whole category, including the load-two versus load-four decision you should make before you buy any of it.
Hearing protection that clears the stock. A shotgun stock and a deep ear-muff cup are in direct conflict, and the muff loses at the exact moment it matters. See eye and ear protection for competition.
A way to get it to the bay. Three guns is a logistics problem — the match-day checklist has the full list.
Cleaning gear you will actually use. Gas guns earn this. Best gun cleaning kits.

What I am not going to tell you

Capacity, weight, barrel length and the exact configuration of any current 940 variant. Mossberg revises the line, the specification differs by variant, and their own product page is the only place worth taking those numbers from. A page that invents a capacity figure to look authoritative is worse than one that sends you to look.

And, as everywhere else on this site: no round counts, no measured patterns, no failure rates. I own the gun and shoot it. That is not the same as testing it, and this site does not blur the two.

Questions

Frequently asked

Is the 940 Pro enough gun for a serious 3-gun shooter?

At club level, comfortably. At the top of the sport people are running Benellis and Berettas with a lot of work in them, and that is a real gap. It is not a gap that is costing a club shooter places.

Does it still need loading-port work?

Far less than a field gun does, which is the point of the model. Whether a competitive shooter eventually wants more done to it is a different question, and one worth asking after a season rather than before your first match.

Gas or inertia for a first competition shotgun?

Whichever you have shot and liked. Gas is softer and needs cleaning; inertia is simpler and hits harder. That is genuinely a preference, and the full version of the argument is on the shotgun editorial page.

Keep reading

Receipts

Sources

We do not run a testing lab and we do not pretend to. Where a measured number came from a manufacturer's published specification or someone else's lab, we name them and link them. Where we could not verify something, we say so on the page rather than quietly leaving it out. Read the full method.