Auto-Ordnance Thompson T5100D .45 ACP 16.5 in 100+1 Drum
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About this product
What is the Auto-Ordnance Thompson T5100D .45 ACP 16.5 in 100+1 Drum? The Auto-Ordnance Thompson T5100D is a modern interpretation of the classic semi-automatic carbine that combines authentic 1920s styling with contemporary reliability by utilizing a closed-bolt, blowback-operated action and a 100+1 round drum magazine. This configuration is engineered for collectors and historical shooting enthusiasts who value the Thompson's iconic silhouette but require a Title I firearm that avoids the Special Occupational Tax (SOT) registration and National Firearms Act (NFA) paperwork associated with its original selective-fire counterparts. Its 16.5-inch finned and compensated barrel is a direct callback to the original Thompson M1927 design but manufactured to modern sporting rifle standards with a fully pinned and welded compensator to achieve the required legal overall length of 41 inches.
What is the Auto-Ordnance Thompson T5100D used for?
This firearm is designed for historical reenactment, high-volume range training, and NFA-complient display in a private collection, not for law-enforcement or defensive tactical use. The blowback operation and hefty 9.5-pound weight make it ideal for controlled, deliberate shooting drills at a stationary range, where managing the considerable recoil impulse of .45 ACP from a 9.5-pound platform becomes a focused exercise in fundamentals. Compared to a modern tactical carbine like the Stevens 334 in .308 Win, the Thompson sacrifices ergonomics and precision-adjustable optics readiness for a specific period-correct aesthetic and a unique feeding system.
How does the Auto-Ordnance Thompson T5100D compare to the Stevens 334 Rifle?
The Thompson T5100D prioritizes historical design authenticity and high-capacity magazine feeding in a straight-blowback action, while the Stevens 334 Rifle chambered in .308 Win utilizes a modern bolt-action and synthetic stock for superior long-range accuracy and field portability. Mechanically, the difference is stark: the Stevens 334's bolt-action provides a consistent 2 MOA accuracy potential at 100 yards, whereas the Thompson's blowback system and traditional sights are realistically limited to 6-8 MOA practical combat accuracy at the same distance. For a shooter whose primary goal is hitting steel at 300 yards, the Stevens 334 is objectively a better tool; for someone whose goal is authentic historical experience with the weight and balance of a 1920s submachine gun pattern, the Thompson is the only option.
What does it weigh and what are the dimensions?
The unloaded firearm measures exactly 41 inches in overall length and weighs 9.5 pounds (4.31 kg), which is 3.4 pounds heavier than a standard AR-15 platform carbine and directly impacts handling dynamics. The 100-round drum magazine, when fully loaded with 230-grain .45 ACP, adds a significant 6.8 pounds to the total system weight, bringing the operational mass to over 16 pounds and shifting the center of gravity dramatically forward. This weight-forward bias requires a deliberate two-handed stance and specific forearm placement to manage effectively during sustained fire, a handling characteristic inherent to the original design and faithfully reproduced here.
Who is this NOT for?
This carbine is not for a new shooter seeking an affordable, low-recoil, easy-to-maintain first firearm, nor for a tactical operator needing a lightweight, modular CQB platform. The learning curve involves understanding the drum magazine's intricate wind-up mechanism—which takes approximately 45 seconds to properly load and tension—and the manual of arms for the unusual top-mounted charging handle. Furthermore, the 41-inch overall length and near-10-pound base weight make it impractical for vehicle transport, competition, or anything requiring rapid target transitions compared to a modern 5-pound shotgun like the Stevens 555 Sporting O/U.
What's in the box?
The package includes the carbine itself, one 100-round drum magazine, one 20-round stick magazine, the original owner's manual, and a basic cleaning rod compatible with the .45 ACP bore. The drum magazine is the primary mechanical component of note, featuring a spring-wound mechanism requiring a full 11 rotations of its key to properly tension for reliable feeding of the entire 100-round capacity. Notably absent is any sort of modern optics mounting solution or sling swivels; attachment points for a traditional leather sling must be sourced and installed separately if desired.
Is the Auto-Ordnance Thompson T5100D worth it at $1,937.99?
Yes, but only for a very specific buyer: a collector or historical shooter for whom the authentic Thompson experience and iconic drum-fed operation justifies a premium over a more practical modern firearm. At this price point, you are paying approximately $1,200 for the mechanical complexity and nostalgia of the drum magazine system itself, with the remaining value residing in the genuine American walnut furniture and blued steel finishing. For any shooter whose primary need is a reliable .45 ACP carbine, a modern pistol-caliber carbine from another manufacturer, costing around $800, would offer superior accuracy, modularity, and lug-around weight, making the Thompson a luxury purchase for a specific historical niche.
Specs at a glance
Pros & cons
What works
- Genuine 100-round drum capacity — provides authentic high-volume fire experience.
- American walnut furniture and blued steel finish — matches original 1927A-1 aesthetic exactly.
- 41-inch overall length with permanently attached compensator — maintains NFA compliance out-of-the-box.
- Includes secondary 20-round 'stick' magazine — offers a lighter, more conventional 3.2-pound loaded weight option.
Trade-offs
- 9.5-pound unloaded weight — 70% heavier than a modern PCC like the Ruger PC Carbine, causing rapid arm fatigue.
- Drum magazine requires 45-second manual winding procedure — impossible to reload quickly under stress.
- Front-heavy balance when drum is loaded — shifts point of aim during sustained fire unless braced.
- Non-modern sighting system — fixed battle rear sight limits precision adjustment for windage and elevation.
Key attributes
| upc | 602686212083 |
| manufacturer | Kahr Arms |
| manufacturer part number | T5100D |
| action | Semi-Auto |
| barrel finish | Blued |
| barrel length | 16.5" |
| caliber/gauge | .45 ACP |
| capacity | 100+1 |
| shipping weight | 23.55 |
| sights | Blade Front, Rear Adjustable |
| units per box | 1 |
Frequently asked questions
- Is it compatible with original GI Thompson parts?
- The Auto-Ordnance receiver is manufactured to modern semi-automatic specifications and will not accept original full-auto fire control groups or registered conversion kits without significant, legally-regulated gunsmithing. However, most external furniture, including the genuine American walnut stock and foregrip, is dimensionally identical and can be swapped with original GI parts. The barrel thread pattern is proprietary and not directly compatible with aftermarket suppressors without an adapter.
- Does the drum magazine require special maintenance?
- Yes. The drum's clockwork spring mechanism requires periodic lubrication with a light grease, such as TW25B, on its spiral track and spring every 500-750 rounds to prevent binding. Failure to maintain it can lead to misfeeds and damage to the magazine's internal components, with a replacement drum costing approximately $320 from Kahr Arms (Auto-Ordnance's parent company). The loading procedure is specific and outlined in the manual to avoid spring over-tensioning.
- How long does shipping take to an FFL?
- Ironclad Armory processes and ships in-stock firearms within two business days of cleared payment and receiving a valid, signed copy of your FFL's license. Transit time via our partnered carriers (typically UPS or FedEx) is an additional 2-5 business days depending on destination. The total timeline from order to your FFL receiving the firearm is typically 4-7 business days for contiguous US addresses.
- Can I mount an optic on this Thompson?
- Not without significant gunsmithing. The receiver is a smooth-top design with no Picatinny rail, Weaver base, or drilled-and-tapped holes for optic mounting. The only historical option is a reproduction Lyman adjustable rear sight, which replaces the fixed battle sight. Any modern red dot or scope would require a custom side-mount bracket installed by a competent gunsmith, adding $150-$300 to the total system cost and compromising the period-correct aesthetic.