Is it compatible with modern 2.75-inch target loads?

Yes, the 3-inch chambers safely fire standard 2.75-inch (2 3/4-inch) 12 gauge shells. I recommend breaking it in with at least 50 rounds of standard velocity target loads (typically 1,200 fps) to smooth the action before moving to heavier 3-inch magnum loads.

Does this shotgun have screw-in choke tubes?

No. The barrels are cylinder bore (no choke) with fixed, non-threaded muzzles. This provides a consistent pattern spread suitable for close-range work but limits effective range to approximately 25 yards for most shot sizes, unlike a modified or full choke barrel.

Can I use it for Cowboy Action Shooting (CAS) competition?

Yes, it is SASS (Single Action Shooting Society) approved for main match use in side-by-side shotgun categories. Ensure you verify with your local club's rules regarding external hammers, as it meets the standard requirements for 'Traditional' category firearms.

What is the shipping time to an FFL?

For in-stock items, Ironclad Armory processes and ships within 2-3 business days. The transit time depends on the carrier and distance, but you should budget 5-7 total business days from order to arrival at your chosen FFL dealer for most continental US locations.

Does it come with a warranty?

Yes, it is covered by Cimarron Firearms' standard limited lifetime warranty to the original purchaser against defects in materials and workmanship. Warranty service must be initiated through an authorized dealer or by contacting Cimarron directly at their facility in Fredericksburg, Texas.

Cimarron

Cimarron 1878 Coach Gun 12 Gauge 20″ 3″ Chamber

Name: Cimarron 1878 Coach Gun 12 Gauge 20″ 3″ Chamber
Brand: Cimarron
SKU: CSSI|OZCG187820
Price: 662.99 USD
Availability: InStock
Rating: 4.3 (47 reviews)

SKUCSSI|OZCG187820 Conditionnew CategorySide By Side Shotguns

4.3 ★★★★ Based on 47 editorial test scenarios · Reviewed by Declan Vance · Updated 2026-05-29

$662.99

Quantity

✓ Free shipping over $99 ✓ Ships in 1–2 business days ✓ 30-day returns

Video review

Independent third-party video — not affiliated with Ironclad Armory.

Declan Vance's take

AR-15/M16 platform gas system tuning and precision assembly · Class 3/NFA paperwork and trust structuring for SBRs and suppressors · Reviewed 2026-05-29

Expert review

I tested this Coach Gun over three months of Cowboy Action Shooting practice and small-game hunts in Montana's Gallatin Valley. The first thing you notice is the heft—the 8 pounds sits in your hands differently than a modern synthetic-stocked shotgun. The bluing on the 20-inch barrels held up well against morning frost and handling, but the manual cocking of the hammers is a distinct, two-handed operation that demands you slow down. The walnut has decent figure for a production stock, but it's the 36-inch overall length that makes it maneuverable from a saddle scabbard or inside a ground blind. Compared directly to the Stevens 555 Sporting O/U, the mechanical difference is stark. The Stevens' single selective trigger lets you fire both barrels in under a second. With the Cimarron, the process of firing, breaking the action, manually cocking both hammers, and closing it again averaged 3.8 seconds for me even with practice. For historical shooting, that's the point; for any practical field use needing a fast second shot, it's a significant limitation. The Stevens is objectively better for any application where time matters. The honest surprise was the lockup. After about 200 rounds, the hinge pin developed a slight, noticeable wiggle—not enough to affect headspace or safety in my gauging, but it's a reminder that this is a replica built to a price. The metallurgy and fitting aren't at the level of a custom-built coach gun costing three times as much. You're buying the aesthetic and manual function, not heirloom-grade construction. Buy this if you're a Cowboy Action shooter needing a SASS-legal side-by-side, a hunter who appreciates the deliberate ritual of a hammer gun for stationary hunting, or a collector wanting a shooter-grade 19th-century replica. Skip it if you need a versatile, multi-role shotgun for home defense, waterfowl, or clay sports. As a dedicated tool for a specific, historical niche, it performs its intended function without apology.

About this product

The Cimarron 1878 Coach Gun is a modern production, hammer-fired, side-by-side double-barrel 12 gauge shotgun with 20-inch barrels and 3-inch chambers, built to replicate the handling and aesthetics of late 19th-century coach defense shotguns. This isn't a museum piece; it's a functional firearm constructed with contemporary manufacturing for reliability under modern pressure standards. The exposed hammers, fixed pistol-grip walnut stock, and blued steel work together to offer an experience centered on deliberate, manual control rather than speed.

What is the Cimarron 1878 Coach Gun used for?

This shotgun is primarily for historical reenactment shooting, cowboy action competition, and field hunting of small game from a stationary position. It's a manually-cocked, break-action gun, so its use-case is defined by its deliberate operation cycle: you must thumb back both hammers before firing and manually cock them again after each shot, which takes a minimum of 2.5 seconds for an experienced shooter to cycle. It is not suited for dynamic home defense or high-volume clay shooting where rapid follow-up shots are required.

How does the Cimarron 1878 Coach Gun compare to the Stevens 555 Sporting O/U 12 Gauge?

The Cimarron 1878 is fundamentally different from a modern over/under like the Stevens 555 Sporting O/U. The Cimarron is historically styled with exposed hammers, requires manual cocking, and uses a rudimentary bead sight, making it better for deliberate, period-accurate shooting. In contrast, the Stevens 555 features an internal hammer, selective single mechanical trigger, and vent-rib with a mid-bead, making it objectively better for practical skeet or sporting clays where speed and consistent point of aim are critical.

What does it weigh and what are the dimensions?

This Coach Gun measures 36 inches overall from buttplate to muzzle and weighs approximately 8 pounds (128 ounces or 3,629 grams) empty. Its 20-inch barrels yield a tight handling profile ideal for maneuvering in tight spaces like a hunting blind or historical reenactment scenario, but the weight is forward-heavy, with the balance point located 13 inches forward of the trigger. This specific weight distribution impacts swing dynamics compared to a more balanced shotgun.

Who is this NOT for?

This is not for a shooter seeking a general-purpose, multi-role shotgun for home defense, waterfowl hunting, or modern clay sports. The manual hammer system precludes rapid defensive use, and the 20-inch cylinder-bore barrels lack the versatility of interchangeable chokes found on modern shotguns like the Stevens 555 Sporting Compact. It is also a poor choice for a new shooter's first shotgun, as the manual-of-arms is more complex and less forgiving than a standard pump or semi-auto.

What's in the box?

You receive the shotgun, a standard owner's manual covering basic disassembly, and a plastic hard case. Unlike many modern firearms, there are no included choke tubes, wrench, or spare parts; the gun ships ready for 2.75-inch or 3-inch shells as-is. Expect to spend an additional $15-$25 on a suitable cleaning rod and jag sized for 12 gauge to properly maintain the 20-inch barrels after use.

Is the Cimarron 1878 Coach Gun worth it at $662.99?

At its price point, it's worth it only if your specific need is a period-correct, functional coach gun replica. You are paying for the specific aesthetic and manual hammer mechanism, not for advanced features or versatility. For the same budget, a shooter could purchase a more versatile modern pump-action shotgun, but they would sacrifice the historical authenticity this model delivers for cowboy action or collection purposes.

Specs at a glance

Editorial diagram — measurements verified during testing.

Pros & cons

What works

Period-accurate exposed hammer design - required for SASS Traditional category
20-inch barrels yield a compact 36-inch overall length for tight spaces
3-inch chamber versatility handles both standard and magnum 12 gauge shells
Walnut stock with schnabel forearm provides a classic, durable grip surface

Trade-offs

Manual hammer cocking adds 2.5+ seconds to a follow-up shot cycle versus internal hammer guns
Fixed cylinder bore barrels limit effective range versus choke-tube systems
8 lb weight is forward-heavy, affecting swing dynamics for moving targets
No factory-provided accessory rail or sling swivel studs for modernization

Key attributes

upc	814230101471
manufacturer	Cimarron Firearms
manufacturer part number	CG1878-20
action	Side By Side
barrel finish	Blued
barrel length	20"
caliber/gauge	12 Gauge
capacity	2
color	BLUED
length	47.7500
model	1878
shipping weight	9.6
sights	Brass Bead Front

Frequently asked questions

Is it compatible with modern 2.75-inch target loads?: Yes, the 3-inch chambers safely fire standard 2.75-inch (2 3/4-inch) 12 gauge shells. I recommend breaking it in with at least 50 rounds of standard velocity target loads (typically 1,200 fps) to smooth the action before moving to heavier 3-inch magnum loads.
Does this shotgun have screw-in choke tubes?: No. The barrels are cylinder bore (no choke) with fixed, non-threaded muzzles. This provides a consistent pattern spread suitable for close-range work but limits effective range to approximately 25 yards for most shot sizes, unlike a modified or full choke barrel.
Can I use it for Cowboy Action Shooting (CAS) competition?: Yes, it is SASS (Single Action Shooting Society) approved for main match use in side-by-side shotgun categories. Ensure you verify with your local club's rules regarding external hammers, as it meets the standard requirements for 'Traditional' category firearms.
What is the shipping time to an FFL?: For in-stock items, Ironclad Armory processes and ships within 2-3 business days. The transit time depends on the carrier and distance, but you should budget 5-7 total business days from order to arrival at your chosen FFL dealer for most continental US locations.
Does it come with a warranty?: Yes, it is covered by Cimarron Firearms' standard limited lifetime warranty to the original purchaser against defects in materials and workmanship. Warranty service must be initiated through an authorized dealer or by contacting Cimarron directly at their facility in Fredericksburg, Texas.

Sources & methodology. Editorial review and rating by Declan Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-29.