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Glock 47 vs Glock 17: Technical Differences, Performance Insights & Training Applications

The Glock 47 MOS is, in practical terms, a Gen-5 Glock 17-sized pistol redesigned for modularity and agency logistics. Dimensionally and ballistically it’s almost identical to the G17 Gen-5, but the G47’s shortened dust-cover / recoil-system choice, MOS slide, and parts-compatibility decisions are what make it different — and valuable — to agencies and shooters who want a highly modular platform.

1) Origins and intent — why Glock made the G47

• Glock 17 (Gen-5): the long-running full-size 9×19 service pistol in Glock’s lineup; refined through the Gen-5 program to remove finger grooves, add ambidextrous controls, a flared magwell and the Marksman Barrel (GMB). It remains the baseline full-size duty pistol. GLOCK

• Glock 47 (MOS): developed originally for U.S. federal agencies (notably CBP/USBP) and later released commercially. Glock’s stated purpose: take the proven full-size G17 form and make it more modular/logistically simple by changing the dust-cover/recoil system and adding MOS optics capability — enabling cross-model parts commonality (G17 Gen-5 MOS, G19 Gen-5 MOS, G45 MOS). That agency/logistics origin explains the core design tradeoffs. GLOCK+1

2) Hard specs — what the factory pages show (direct comparison)

Bottom line from specs: barrel, slide and overall dimensions are the same between the two; the measurable weight difference is small (~28 g unloaded), and trigger/ballistic geometry are essentially identical. The meaningful differences are design choices (dust cover/recoil system, MOS), not barrel length or frame size. GLOCK+1

3) The technical difference that matters: shortened dust-cover / recoil system & modularity

• Shortened dust cover (and resulting recoil-system choice): the G47 uses a shortened dust-cover design that enables the pistol to use a Glock 19 (shorter) recoil spring system while retaining a full-size (G17-length) slide and barrel. Practically, that means the G47 can accept slide assemblies (and therefore barrels/recoil springs) that are common across Gen-5 G19/G45/G17 families — enabling swap-out configurations (full-size slide, compact slide, or vice-versa) while keeping the same frame. This is the fundamental engineering reason the G47 is marketed as “modular” for logistics and parts commonality. Police1+1

• Parts compatibility payoff: because Glock deliberately maintained cross-compatibility (G47 ↔ G19 Gen-5 MOS ↔ G45 MOS ↔ G17 Gen-5 MOS in many internals), agencies can standardize on magazines, many internals, holsters and spare parts more easily — reducing inventory complexity. That’s not an academic point: agencies buying thousands of pistols save dollars and maintenance headaches with common parts. 

4) Optics and accessory differences

• G47 MOS: supplied with Glock’s MOS (Modular Optic System) slide — factory-milled plate options let users mount common micro-red-dots with adapter plates. For agencies and modern shooters who favor optics on duty pistols, the G47 ships ready for that ecosystem. 

• G17 Gen-5 (FS) as listed: the standard G17 Gen-5 page does not show the MOS slide variant — G17 MOS variants exist in Glock’s catalog, but the model the user linked (G17 Gen5 FS-US) is the standard Gen-5 configuration (flared magwell, GMB barrel, Gen-5 controls) and may not include MOS milling unless a specific MOS variant is purchased. (If optics are a hard requirement, specify the MOS variant or buy the MOS-milled model.)

5) Handling and shootability — what shooters will notice

• Ergonomics: both guns are Gen-5 Glock ergonomics (no finger grooves, beavertail, changeable backstraps). Grip feel and trigger distance are the same; holster fit for typical G17 holsters will generally be compatible with the G47 because external dimensions are the same. 

• Reload speed / magwell: both Gen-5 frames have a modest flared magwell compared to older Gens; the G17 advertises a flared magwell and front-frame cutouts to speed reloads. G47 inherits the Gen-5 frame features, so reloading ergonomics are not materially different. 

• Perceived recoil & balance: because barrel/slide length and weight distribution are so close, recoil impulse and balance will feel extremely similar to the end user. The minor weight difference (≈28 g) is negligible in dynamic handling. 

6) Practical examples — how you might use each gun

1. Agency / fleet context (where G47 shines): an agency that wants a single frame type for both full-size and compact slide assemblies can issue G47 frames and swap slide assemblies (G17 full slide or G19 compact slide) depending on mission. Logistics are simplified because many internal parts are common; optics are factory ready (MOS). This reduces spare parts lists and training variation. Police1+1

2. Duty / competition user wanting a simple G17: if you want a classic G17 experience — a proven full-size duty pistol with Gen-5 refinements — a standard G17 Gen-5 (non-MOS) may be fine, and it’s slightly lighter unloaded. If you do not intend to swap slides or standardize across multiple slide lengths, the G17 gives the same ballistics at marginally less weight and a wider variety of holster/aftermarket options that are explicitly listed for the G17. GLOCK+1

3. Optics-first civilian / competitive shooter: buy the MOS variant (G47 MOS or G17 MOS) you prefer. G47 MOS gives you a Gen-5 full-size frame with factory MOS and modular slide compatibility; G17 MOS variants exist if you prefer the traditional G17 configuration. Compare exact SKU features before purchase. GLOCK+1

7) Common questions & clarifications (mythbusting)

• “Is the G47 just a G17 with a different name?” — Not exactly. Dimensionally and in many specs the pistols are extremely close; but the G47’s dust cover/recoil-system choice and MOS emphasis give it unique modular behavior and parts commonality that G17 (standard) does not explicitly provide. For agencies and modular-minded users that matters; for casual shooters who want a straight full-size Glock, the difference may be minor.

• “Will G17 holsters fit the G47?” — In most cases yes: overall dimensions and slide length match the Gen-5 G17. However, some holsters that index off frame dust-cover geometry or include rails/covering accessory slots could show minor differences — always verify holster fit before relying on it for duty/LE use. GLOCK

• “Can I swap a G19 slide onto a G47 frame (or vice-versa)?” — That is the modular idea: the shortened dust cover and recoil-system choices were specifically made so G47 frames and Gen-5 G19/G45 slide assemblies are largely interchangeable in many configurations — enabling a full-size grip with a compact slide or a compact slide with the same frame. Always follow Glock’s documented interchangeability and gunsmithing guidance. 

8) Purchasing advice — pick the right tool for the mission

• If you represent an agency or fleet: strongly consider the G47 MOS for its logistics and MOS readiness. Common parts and optics readiness reduce lifecycle cost and simplify training. Police1

• If you want a straight, proven full-size service pistol with the broadest aftermarket support and the classic G17 platform: the G17 Gen-5 is still the default and an excellent choice. If you want optics, choose a G17 MOS variant specifically.

• If you like modularity but are a civilian buyer: the G47 is compelling if you foresee changing slide lengths or want a ready-to-go optics slide out of the box. If not, a standard G17 will perform identically in all shooting fundamentals.

9) Conclusion — real difference in one sentence

G17 Gen-5 = the classic full-size duty Glock with Gen-5 refinements; G47 MOS = the same full-size form with a shortened dust cover/recoil choice and factory MOS, engineered for modular interchangeability and agency logistics. For most shooters the two feel and shoot the same; for procurement officers and modular shooters the G47’s parts commonality and MOS readiness are the decisive advantages.