The .22 Hornet features a maximum case length of 1.403 inches (35.64 mm), a rim diameter of 0.350 inches (8.89 mm), a base diameter of 0.298 inches (7.57 mm), a shoulder diameter of 0.276 inches (7.01 mm), a neck diameter of 0.243 inches (6.17 mm), a neck length of approximately 0.260 inches (6.60 mm), and a maximum overall cartridge length of 1.723 inches (43.76 mm). Published numerical values represent nominal design targets, maximum manufacturing limits, or MIN/MAX tolerance windows depending on whether SAAMI or C.I.P. standards are cited. SAAMI governs voluntary specifications in North America, whereas C.I.P. enforces legal proof standards across Europe. Internal case capacity and physical dimensions vary among manufacturers like Winchester, Remington, Hornady, and Prvi Partizan (PPU) due to brass wall thickness differences. Precise knowledge of these dimensions ensures safe headspacing on the rim, correct rim clearance, precise reloading die setup, and proper operating pressures.
22 Hornet Case Dimensions
| Case Dimension | Inches | Millimeters | Specification Type | Source | Notes |
| Case Length | 1.403 in | 35.64 mm | Maximum | SAAMI Standard | Tolerance: -0.020 in (-0.51 mm) |
| Rim Diameter | 0.350 in | 8.89 mm | Maximum | SAAMI Standard | Tolerance: -0.010 in (-0.25 mm) |
| Rim Thickness | 0.065 in | 1.65 mm | Maximum | SAAMI Standard | Tolerance: -0.010 in (-0.25 mm) |
| Base Diameter | 0.298 in | 7.57 mm | Maximum | SAAMI Standard | Tolerance: -0.008 in (-0.20 mm) |
| Shoulder Diameter | 0.276 in | 7.01 mm | Maximum | SAAMI Standard | Shallow tapered body transition |
| Neck Diameter | 0.243 in | 6.17 mm | Maximum | SAAMI Standard | Measured with bullet seated |
| Neck Length | 0.260 in | 6.60 mm | Nominal Reference | C.I.P. / Reference | Distance from neck-shoulder junction to mouth |
| Shoulder Angle | 5.0 degrees | 5.0 degrees | Nominal | SAAMI Standard | Taper angle leading to shallow shoulder |
| Overall Cartridge Length | 1.723 in | 43.76 mm | Maximum | SAAMI Standard | Nominal testing length is 1.723 in (43.76 mm) |
| Case Capacity | 14.0 gr H2O | 0.91 cm³ | Nominal Average | Hornady / Nosler | Varies by manufacturer (13.0 to 14.5 gr H2O) |
| Maximum Pressure | 43,000 PSI | 2,965 bar | Maximum Allowable | SAAMI MAP | C.I.P. Pmax is set at 3,000 bar (43,511 PSI) |
Understanding The 22 Hornet Case Dimensions
Evaluating the .22 Hornet technical profile requires understanding how each structural measurement operates within a firearm chamber:
- Case Length: The distance from the case head face to the mouth. Proper trim length ensures the case mouth does not pinch in the chamber throat, preventing severe pressure spikes.
- Rim Diameter: The outer edge of the protruding rim. Because the .22 Hornet is a rimmed cartridge, this feature locates the cartridge in the chamber and provides a surface for extraction.
- Rim Thickness: The vertical depth of the rim. This dimension establishes headspacing inside the chamber, making rim thickness critical for consistent primer ignition.
- Base Diameter: The exterior body width located forward of the rim. It governs fit within the rear portion of the chamber.
- Shoulder Diameter: The case width where the gentle body taper transitions into the neck area.
- Neck Diameter: The outer neck measurement with a seated projectile. Clearance between the outer neck and chamber neck allows clean release of the bullet upon firing.
- Neck Length: The length of straight cylindrical brass gripping the projectile. A long neck provides adequate bullet tension and concentric alignment.
- Shoulder Geometry: Consists of a gentle body taper ending in a shallow 5 degree shoulder. Unlike modern sharp-shouldered cartridges, this design relies on traditional rimmed geometry.
- Overall Cartridge Length: The base-to-tip length of a finished round. This ensures proper feeding through rotary and box magazines.
- Case Capacity: The volume of water held by an unprimed, fired case filled flush to the mouth. Small volume changes significantly impact peak pressure in this compact case.
22 Hornet Case Dimensions In Inches And Millimeters
The following conversion table lists key SAAMI and C.I.P. .22 Hornet dimensions in both imperial and metric units.
| Dimension Description | Inches (Imperial) | Millimeters (Metric) | Type / Definition |
| Maximum Case Length | 1.403 in | 35.64 mm | Upper limit for raw brass length |
| Minimum Case Length | 1.383 in | 35.13 mm | Lower SAAMI manufacturing limit |
| Trim-To Case Length | 1.393 in | 35.38 mm | Recommended handload prep target |
| Maximum Rim Diameter | 0.350 in | 8.89 mm | Rim width for headspacing and extraction |
| Minimum Rim Diameter | 0.340 in | 8.64 mm | Lower limit for rim machining |
| Maximum Base Diameter | 0.298 in | 7.57 mm | Width forward of rim wall |
| Maximum Shoulder Diameter | 0.276 in | 7.01 mm | Junction point near neck taper |
| Maximum Neck Diameter | 0.243 in | 6.17 mm | Exterior neck with loaded bullet |
| Bullet Diameter | 0.224 in | 5.69 mm | Modern standardized projectile diameter |
| Maximum Overall Length (COAL) | 1.723 in | 43.76 mm | Maximum length for magazine clearance |
22 Hornet Case Length
The maximum published case length for the .22 Hornet is 1.403 inches (35.64 mm) under SAAMI standards, while C.I.P. lists maximum case length as 35.64 mm. The standard trim-to length for handloaders is 1.393 inches (35.38 mm), providing a 0.010 inch safety margin below the absolute limit.
During firing, internal pressure expands thin .22 Hornet brass against chamber walls, stretching the case forward. Repeated sizing operations draw metal toward the mouth. If brass stretches beyond 1.403 inches, the mouth can crimp against the chamber neck taper, locking the projectile in place during ignition. This obstruction causes rapid pressure spikes, making routine trimming vital for safe operation.
22 Hornet Base And Rim Dimensions
The .22 Hornet uses a rimmed design with a maximum rim diameter of 0.350 inches (8.89 mm) and a maximum base diameter of 0.298 inches (7.57 mm). Rim thickness measures a maximum of 0.065 inches (1.65 mm).
Headspacing for the .22 Hornet occurs entirely on the front face of the rim rather than on the shoulder or body taper. The rim seats directly against the counterbore or face of the barrel. Because headspacing depends on rim thickness, variations in rim manufacturing affect firing pin impact consistency and ignition reliability. The exposed rim gives extractors in bolt-action, single-shot, and lever-action firearms a secure gripping surface for positive case removal.
22 Hornet Shoulder And Neck Dimensions
The shoulder and neck configuration of the .22 Hornet reflects early 20th-century metallic cartridge engineering:
- Shoulder Diameter: 0.276 inches (7.01 mm) maximum.
- Shoulder Angle: Approximately 5.0 degrees (shallow body taper).
- Neck Diameter: 0.243 inches (6.17 mm) maximum with a seated projectile.
- Neck Length: Approximately 0.260 inches (6.60 mm).
Unlike modern bottlenecked cartridges with steep shoulders (such as 30 degrees or 40 degrees), the .22 Hornet features a long, gradual body taper ending in a subtle shoulder transition. The relatively long 0.260 inch neck provides substantial contact surface to hold light .22 caliber projectiles straight. However, because .22 Hornet brass walls are notably thin, handloaders must exercise care when seating projectiles to prevent crushing the neck or shoulder area.
22 Hornet Case Capacity
Water capacity for the compact .22 Hornet case ranges between 13.0 grains H2O and 14.5 grains H2O (0.84 cm³ to 0.94 cm³) on a fired case filled level with the mouth, averaging roughly 14.0 grains H2O.
Internal capacity varies noticeably across brass brands:
- Winchester / Hornady Brass: Tends to yield average internal capacities around 13.8 to 14.2 grains H2O.
- Remington Brass: Features slightly thicker internal walls in some production lots, yielding capacities closer to 13.0 to 13.5 grains H2O.
- Prvi Partizan (PPU) Brass: Features thicker base and wall geometry, resulting in slightly lower internal volume.
Because total powder charge weight in the .22 Hornet is small (often 9.0 to 13.0 grains of fast-burning powder), a 0.5 grain capacity difference between brass brands alters chamber pressure significantly. Capacity figures across brands are not interchangeable.
22 Hornet Bullet Diameter
Modern production .22 Hornet barrels and ammunition are standardized around a 0.224 inch (5.69 mm) bullet diameter. SAAMI bullet tolerances span from 0.221 inches to 0.224 inches.
Historical considerations apply to older rifles:
- Pre-WWII / Vintage Rifles: Older firearms (often built before or during the 1930s) frequently featured tighter 0.222 inch (5.64 mm) bore dimensions.
- Modern Firearms: Standardized with 0.224 inch (5.69 mm) groove diameters.
- Bore Diameter (Land to Land): 0.219 inches (5.56 mm).
- Groove Diameter (Groove to Groove): 0.224 inches (5.69 mm).
Common bullet weights for the .22 Hornet range from 35 grains to 45 grains. Broad-nosed or short blunt-profile projectiles are typically chosen to satisfy length constraints imposed by vintage rotary or box magazines.
22 Hornet Overall Cartridge Length
SAAMI specifies a maximum overall cartridge length (COAL) of 1.723 inches (43.76 mm) for the .22 Hornet. Standard testing length is also set at 1.723 inches.
Magazine dimensions in vintage and modern rifles dictate overall length restrictions. Older box magazines or rotary designs (such as those in Ruger Model 77/22 Hornet rifles) feature tight interior length limits. Seating long, pointed spitzer bullets too far out causes feeding jams. Consequently, many factory loads utilize short polymer-tipped, hollow-point, or soft-point bullets designed to fit within the 1.723 inch maximum length requirement.
22 Hornet Dimensions vs Similar Cartridges
Comparing the .22 Hornet with other small-bore centerfire cartridges highlights its slender, compact geometry.
| Cartridge | Bullet Diameter | Case Length | Overall Length | Rim / Base Diameter | Case Capacity | Source |
| .22 Hornet | 0.224 in (5.69 mm) | 1.403 in (35.64 mm) | 1.723 in (43.76 mm) | 0.350 in / 0.298 in | ~14.0 gr H2O | SAAMI |
| .22 K-Hornet | 0.224 in (5.69 mm) | 1.390 in (35.31 mm) | 1.723 in (43.76 mm) | 0.350 in / 0.298 in | ~16.5 gr H2O | Reference |
| .17 Hornet | 0.172 in (4.37 mm) | 1.350 in (34.29 mm) | 1.723 in (43.76 mm) | 0.350 in / 0.298 in | ~13.6 gr H2O | SAAMI |
| .218 Bee | 0.224 in (5.69 mm) | 1.345 in (34.16 mm) | 1.680 in (42.67 mm) | 0.408 in / 0.349 in | ~18.0 gr H2O | SAAMI |
| .222 Remington | 0.224 in (5.69 mm) | 1.700 in (43.18 mm) | 2.130 in (54.10 mm) | 0.378 in / 0.376 in | ~27.0 gr H2O | SAAMI |
| .223 Remington | 0.224 in (5.69 mm) | 1.760 in (44.70 mm) | 2.260 in (57.40 mm) | 0.378 in / 0.376 in | ~31.4 gr H2O | SAAMI |
| 5.7x28mm | 0.224 in (5.69 mm) | 1.135 in (28.83 mm) | 1.594 in (40.49 mm) | 0.312 in / 0.312 in | ~13.0 gr H2O | C.I.P. |
Dimensional similarities do not indicate interchangeable ammunition. Each cartridge requires its specific dedicated chamber.
22 Hornet vs 223 Remington Case Dimensions
The .22 Hornet and .223 Remington fire identical 0.224 inch diameter bullets, but their case construction differs fundamentally:
- Rim Style: The .22 Hornet is a rimmed cartridge (0.350 in rim diameter) that headspaces on its rim. The .223 Remington is a rimless cartridge (0.378 in rim diameter) that headspaces on its shoulder.
- Case Length: The .22 Hornet case length is 1.403 inches (35.64 mm), compared to 1.760 inches (44.70 mm) for the .223 Remington.
- Body Taper: The .22 Hornet uses a tapered body (0.298 in base tapering to 0.276 in shoulder) with a shallow shoulder, while the .223 Remington uses a straighter body with a 23 degree shoulder.
- Capacity and Pressure: The .223 Remington holds over double the internal volume (~31.4 gr H2O vs ~14.0 gr H2O) and operates at a higher SAAMI maximum pressure (55,000 PSI vs 43,000 PSI).
22 Hornet vs 17 Hornet Case Dimensions
The .17 Hornet is a modern wildcat-derived commercial cartridge created by Hornady using the .22 Hornet as its parent case:
- Parent Design: Both cartridges share the exact same rim diameter (0.350 in), rim thickness (0.065 in), and base diameter (0.298 in).
- Shoulder Geometry: The .17 Hornet features a sharp 25 degree shoulder blown outward to maximize body volume, while the standard .22 Hornet retains its original gentle taper and shallow shoulder.
- Neck and Bullet Diameter: The .17 Hornet uses a 0.193 inch neck diameter holding a 0.172 inch projectile, whereas the .22 Hornet uses a 0.243 inch neck holding a 0.224 inch projectile.
- Case Length: The .17 Hornet case is shortened slightly to 1.350 inches (34.29 mm) compared to the .22 Hornet’s 1.403 inches (35.64 mm).
22 Hornet vs 218 Bee Case Dimensions
The .218 Bee was developed as a direct competitor to the .22 Hornet in lever-action and bolt-action rifles:
- Parent Design: The .218 Bee is derived from the .25-20 Winchester parent case, making it wider at the base than the .22 Hornet.
- Rim and Base Size: The .218 Bee features a larger 0.408 inch rim diameter and 0.349 inch base diameter, compared to the .22 Hornet’s 0.350 inch rim and 0.298 inch base.
- Case Length: The .218 Bee case length is 1.345 inches (34.16 mm), slightly shorter than the .22 Hornet at 1.403 inches (35.64 mm).
- Capacity: The wider body of the .218 Bee yields higher internal capacity (~18.0 gr H2O vs ~14.0 gr H2O), granting slightly higher velocities with 40 to 45 grain bullets.
22 Hornet Chamber And Case Dimensions
Chamber geometry for the .22 Hornet reflects its reliance on a rimmed headspace design.
SAAMI chamber specifications establish these spatial relationships:
- Headspace Control: Headspace is established between the bolt face and the barrel counterbore face, matching the rim thickness space (0.065 in to 0.072 in).
- Chamber Neck: The chamber neck diameter is cut to a minimum of 0.246 inches, providing roughly 0.003 inches of radial expansion room around a maximum 0.243 inch loaded neck.
- Chamber Length: Chamber length is cut beyond the maximum 1.403 inch brass specification to prevent the mouth from touching the throat transition under pressure.
- Body Clearance: Body dimensions in the chamber allow sufficient room for tapered brass to load and extract smoothly, particularly in vintage single-shot and bolt-action firearms.
22 Hornet Case Forming And Resizing
The .22 Hornet originated as a wildcat development during the 1920s at Springfield Armory, based on the black powder .22 WCF (.22 Winchester Center Fire) parent case. Winchester standardized the commercial design in 1930.
Understanding its history helps clarify sizing mechanics. Because the .22 Hornet relies on thin body and neck brass, sizing dies must be adjusted with care. Full-length sizing dies press the tapered body back into factory specifications and restore the neck diameter. Handloaders often utilize neck-sizing dies or shoulder-improving wildcats (such as the .22 K-Hornet) to minimize brass working, extend case life, and enhance body alignment within the chamber.
22 Hornet Manufacturer Specifications vs Actual Measurements
Measured dimensions often vary when comparing official standards, factory ammunition, and fired brass:
- SAAMI Standards: Define maximum voluntary cartridge and minimum chamber limits for North America. Drawings state maximum safe production ceilings.
- C.I.P. Specifications: Regulate mandatory dimensions across European proof houses. C.I.P. lists maximum case length at 35.64 mm and maximum pressure (Pmax) at 3,000 bar.
- Factory Ammunition: Ammunition from Winchester, Hornady, Remington, or PPU is built slightly below maximum limits (often 0.002 to 0.004 inches smaller) to guarantee universal chambering.
- Fired Brass: Fired brass expands outward to match individual chamber walls, resulting in larger body and neck dimensions than unfired factory rounds.
- Resized Brass: Brass drawn through resizing dies returns toward SAAMI minimum dimensions, with minor dimensional variations caused by brass spring-back.
Official SAAMI and C.I.P. specification sheets serve as the authoritative standard for base dimensions.
Common Questions
What are the 22 Hornet case dimensions?
Key maximum specifications under SAAMI drawings include a case length of 1.403 in (35.64 mm), rim diameter of 0.350 in (8.89 mm), rim thickness of 0.065 in (1.65 mm), base diameter of 0.298 in (7.57 mm), shoulder diameter of 0.276 in (7.01 mm), neck diameter of 0.243 in (6.17 mm), and COAL of 1.723 in (43.76 mm).
What is the 22 Hornet case length?
The maximum SAAMI case length is 1.403 inches (35.64 mm), with a minimum manufacturing length of 1.383 inches (35.13 mm). Recommended handloading trim-to length is 1.393 inches (35.38 mm).
What is the 22 Hornet rim diameter?
The maximum rim diameter is 0.350 inches (8.89 mm), with a manufacturing tolerance of -0.010 inches (-0.25 mm).
What is the 22 Hornet base diameter?
The maximum base diameter measured directly forward of the rim is 0.298 inches (7.57 mm).
What is the 22 Hornet shoulder diameter?
The maximum shoulder diameter at the body-neck transition is 0.276 inches (7.01 mm).
What is the 22 Hornet neck diameter?
The maximum neck diameter of a loaded round with a bullet seated is 0.243 inches (6.17 mm).
What is the 22 Hornet case capacity?
Nominal water capacity averages 14.0 grains H2O (0.91 cm³), generally spanning between 13.0 and 14.5 grains H2O depending on brass brand wall thickness.
What is the 22 Hornet overall cartridge length?
Maximum overall cartridge length (COAL) is 1.723 inches (43.76 mm) to ensure proper clearance in rifle magazines.
How does 22 Hornet compare with 223 Remington case dimensions?
The .22 Hornet is a rimmed, tapered cartridge (0.350 in rim, 1.403 in length, ~14.0 gr capacity) that headspaces on its rim, while the .223 Remington is a larger rimless cartridge (0.378 in rim, 1.760 in length, ~31.4 gr capacity) that headspaces on its shoulder.
How does 22 Hornet compare with 22 K-Hornet case dimensions?
The .22 K-Hornet is an improved version of the .22 Hornet created by blowing out the body taper to a sharp 33 degree shoulder, increasing case capacity from ~14.0 gr H2O to ~16.5 gr H2O while retaining the same 0.350 in rim.
How does 22 Hornet compare with 17 Hornet case dimensions?
The .17 Hornet is derived from the .22 Hornet parent case, sharing its 0.350 in rim and 0.298 in base, but features a shorter case length (1.350 in vs 1.403 in), a sharp 25 degree shoulder, and a smaller neck (.193 in vs .243 in) for .172 caliber bullets.
What is the 22 Hornet maximum pressure?
The SAAMI Maximum Average Pressure (MAP) is 43,000 PSI. C.I.P. establishes maximum pressure (Pmax) at 3,000 bar (43,511 PSI).