The .220 Swift features a maximum case length of 2.205 inches (56.01 mm), a rim diameter of 0.473 inches (12.01 mm), a rim thickness of 0.049 inches (1.24 mm), a base diameter of 0.445 inches (11.30 mm), a shoulder diameter of 0.402 inches (10.21 mm), a neck diameter of 0.260 inches (6.60 mm), a neck length of approximately 0.263 inches (6.68 mm), and a maximum overall cartridge length of 2.680 inches (68.07 mm). Published numerical specifications represent nominal engineering targets, maximum manufacturing boundaries, or MIN/MAX tolerance windows depending on whether SAAMI or C.I.P. standards are cited. SAAMI regulates voluntary specifications in North America, while C.I.P. enforces mandatory proof standards across Europe. Internal case capacity and actual physical measurements show subtle variations across manufacturers such as Hornady, Winchester, Remington, Nosler, and Norma. Understanding these standardized measurements ensures proper semi-rimmed headspacing, reliable extraction, precise reloading die setup, and safe operating pressures.
220 Swift Case Dimensions
| Case Dimension | Inches | Millimeters | Specification Type | Source | Notes |
| Case Length | 2.205 in | 56.01 mm | Maximum | SAAMI Standard | Tolerance: -0.020 in (-0.51 mm) |
| Rim Diameter | 0.473 in | 12.01 mm | Maximum | SAAMI Standard | Tolerance: -0.010 in (-0.25 mm) |
| Rim Thickness | 0.049 in | 1.24 mm | Maximum | SAAMI Standard | Tolerance: -0.010 in (-0.25 mm) |
| Base Diameter | 0.445 in | 11.30 mm | Maximum | SAAMI Standard | Tolerance: -0.008 in (-0.20 mm) |
| Shoulder Diameter | 0.402 in | 10.21 mm | Maximum | SAAMI Standard | Body wall tapers to body-shoulder junction |
| Neck Diameter | 0.260 in | 6.60 mm | Maximum | SAAMI Standard | Measured with bullet seated |
| Neck Length | 0.263 in | 6.68 mm | Nominal Reference | C.I.P. / Reference | Distance from neck-shoulder junction to mouth |
| Shoulder Angle | 21.0 degrees | 21.0 degrees | Nominal | SAAMI Standard | 42 degrees included angle |
| Overall Cartridge Length | 2.680 in | 68.07 mm | Maximum | SAAMI Standard | Nominal testing length is 2.680 in (68.07 mm) |
| Case Capacity | 47.0 gr H2O | 3.05 cm³ | Nominal Average | Hornady / Nosler | Varies by brand (46.0 to 48.0 gr H2O) |
| Maximum Pressure | 62,000 PSI | 4,275 bar | Maximum Allowable | SAAMI MAP | C.I.P. Pmax is set at 4,300 bar (62,366 PSI) |
Understanding The 220 Swift Case Dimensions
Evaluating the .220 Swift technical profile requires understanding how each structural measurement operates within a firearm chamber:
- Case Length: The total distance from the exterior face of the case head to the mouth. Proper case length prevents the mouth from wedging into the chamber throat, preventing severe pressure spikes.
- Rim Diameter: The outer boundary of the semi-rim. It matches standard .30-06/.308 bolt faces (0.473 in) while extending slightly beyond the 0.445 inch case base to provide positive extraction.
- Rim Thickness: The vertical depth of the rim wall. In original chamber designs, this dimension established primary headspacing.
- Base Diameter: The exterior body width located forward of the extractor groove. It governs fit within the rear portion of the chamber.
- Shoulder Diameter: The case width where the body taper transitions into the shoulder angle.
- Neck Diameter: The outer neck measurement with a seated projectile. Proper 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 generous neck length ensures proper alignment and bullet retention.
- Shoulder Geometry: Consists of a gentle body taper ending in a 21 degree shoulder angle. In modern handloading, headspacing is often set off this shoulder rather than the semi-rim.
- Overall Cartridge Length: The base-to-tip length of a assembled round. This guarantees fit in standard short-action or standard-length magazine boxes.
- Case Capacity: The volume of water held by an unprimed, fired case filled flush to the mouth. Volume directly influences peak pressure and velocity potential for given powder charges.
220 Swift Case Dimensions In Inches And Millimeters
The following reference table converts primary SAAMI and C.I.P. .220 Swift dimensions into imperial and metric units.
| Dimension Description | Inches (Imperial) | Millimeters (Metric) | Type / Definition |
| Maximum Case Length | 2.205 in | 56.01 mm | Upper limit for raw brass length |
| Minimum Case Length | 2.185 in | 55.50 mm | Lower SAAMI manufacturing limit |
| Trim-To Case Length | 2.195 in | 55.75 mm | Recommended handload prep target |
| Maximum Rim Diameter | 0.473 in | 12.01 mm | Upper boundary for bolt face fit |
| Minimum Rim Diameter | 0.463 in | 11.76 mm | Lower boundary for rim machining |
| Maximum Base Diameter | 0.445 in | 11.30 mm | Max expansion zone near case head |
| Maximum Shoulder Diameter | 0.402 in | 10.21 mm | Junction point where body meets shoulder |
| Maximum Neck Diameter | 0.260 in | 6.60 mm | Exterior neck with loaded projectile |
| Bullet Diameter | 0.224 in | 5.69 mm | Standard projectile outside diameter |
| Maximum Overall Length (COAL) | 2.680 in | 68.07 mm | Maximum length for magazine clearance |
220 Swift Case Length
The published maximum case length for the .220 Swift is 2.205 inches (56.01 mm) under SAAMI standards, while C.I.P. documentation lists maximum case length as 56.01 mm. The recommended trim-to length for handloaders is 2.195 inches (55.75 mm), establishing a 0.010 inch safety margin below the absolute maximum.
During the firing cycle, internal pressures pushing extreme velocities (often exceeding 4,000 ft/s) cause .220 Swift brass to stretch significantly. High operating pressures combined with a tapered body profile draw brass forward toward the neck rapidly. If a case stretches beyond the 2.205 inch maximum limit, the case mouth can pinch into the chamber neck, pinching the bullet and causing dangerous chamber pressure spikes. Frequent trimming is essential when reloading this cartridge.
220 Swift Base And Rim Dimensions
The .220 Swift features a semi-rimmed design with a maximum rim diameter of 0.473 inches (12.01 mm) and a maximum base diameter of 0.445 inches (11.30 mm). Rim thickness measures a maximum of 0.049 inches (1.24 mm).
Because the 0.473 inch rim diameter matches the standard .30-06 Springfield/.308 Winchester bolt face, the .220 Swift works with widely available bolt platforms. However, because the base diameter directly in front of the extractor groove measures 0.445 inches, the rim protrudes approximately 0.014 inches radially past the body wall, forming a semi-rimmed case profile. While early rifles headspaced on this small rim, modern commercial chambers and resizing dies headspace off the 21 degree shoulder to minimize case stretching and improve accuracy.
220 Swift Shoulder And Neck Dimensions
The shoulder and neck geometry of the .220 Swift reflects mid-1930s cartridge design:
- Shoulder Diameter: 0.402 inches (10.21 mm) maximum at the body-shoulder junction.
- Shoulder Angle: 21.0 degrees (42.0 degrees included angle).
- Neck Diameter: 0.260 inches (6.60 mm) maximum with a seated bullet.
- Neck Length: Approximately 0.263 inches (6.68 mm).
The 21 degree shoulder angle and body taper allow smooth chambering and extraction under high pressures. The relatively long 0.263 inch neck provides substantial bearing surface to grip .224 caliber projectiles concentric to the bore. However, the combination of a tapered body and shallow 21 degree shoulder contributes to faster forward brass flow compared to modern 30 degree shoulder designs, requiring handloaders to monitor case wall thickness to avoid head separation.
220 Swift Case Capacity
Published and measured water capacity for .220 Swift brass typically spans between 46.0 grains H2O and 48.0 grains H2O (2.98 cm³ to 3.11 cm³) when measured level with the case mouth on a fired case, averaging roughly 47.0 grains H2O.
Internal capacity varies across different ammunition manufacturers:
- Winchester Brass: Historically features thin case walls, yielding higher internal capacities near 47.5 to 48.0 grains H2O.
- Hornady / Nosler Brass: Averages approximately 46.8 to 47.3 grains H2O.
- Norma / Lapua Brass: Demonstrates thicker case construction, resulting in slightly lower internal volume closer to 46.0 to 46.5 grains H2O.
Because small volume changes alter peak combustion pressures in high-velocity rounds, load data developed in light, high-capacity brass should not be applied directly to heavier, lower-capacity brass without stepping down powder charges.
220 Swift Bullet Diameter
The standardized bullet diameter for the .220 Swift is 0.224 inches (5.69 mm). SAAMI bullet tolerances range between 0.221 inches and 0.224 inches.
It is vital to distinguish bullet diameter from barrel dimensions:
- Bullet Diameter: 0.224 inches (5.69 mm).
- Bore Diameter (Land to Land): 0.219 inches (5.56 mm).
- Groove Diameter (Groove to Groove): 0.224 inches (5.69 mm).
Common .224 caliber commercial projectiles used in the .220 Swift weigh between 40 grains and 60 grains. Traditional 1:14 inch barrel twist rates in standard production rifles favor lighter 40 to 55 grain bullets to achieve optimal gyroscopic stability at hyper-velocities.
220 Swift Overall Cartridge Length
SAAMI specifies a maximum overall cartridge length (COAL) of 2.680 inches (68.07 mm) for the .220 Swift, while specifying a minimum testing length of 2.600 inches (66.04 mm).
The 2.680 inch limit allows the .220 Swift to fit inside standard short-action and medium magazine boxes. Factory ammunition generally measures between 2.650 inches and 2.680 inches. When handloading longer polymer-tipped or high-BC bullets, seating depth must be managed carefully to ensure rounds cycle reliably through magazine wells while avoiding contact with the chamber throat rifling.
220 Swift Dimensions vs Similar Cartridges
Comparing the .220 Swift against structurally similar high-velocity .22 caliber cartridges illustrates its size, geometry, and internal volume.
| Cartridge | Bullet Diameter | Case Length | Overall Length | Rim / Base Diameter | Case Capacity | Source |
| .220 Swift | 0.224 in (5.69 mm) | 2.205 in (56.01 mm) | 2.680 in (68.07 mm) | 0.473 in / 0.445 in | ~47.0 gr H2O | SAAMI |
| .22-250 Remington | 0.224 in (5.69 mm) | 1.912 in (48.56 mm) | 2.350 in (59.69 mm) | 0.473 in / 0.470 in | ~44.5 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 |
| .224 Valkyrie | 0.224 in (5.69 mm) | 1.600 in (40.64 mm) | 2.260 in (57.40 mm) | 0.422 in / 0.421 in | ~34.5 gr H2O | SAAMI |
| .225 Winchester | 0.224 in (5.69 mm) | 1.930 in (49.02 mm) | 2.500 in (63.50 mm) | 0.473 in / 0.422 in | ~41.5 gr H2O | Historical |
| .223 WSSM | 0.224 in (5.69 mm) | 1.670 in (42.42 mm) | 2.360 in (59.94 mm) | 0.535 in / 0.555 in | ~54.0 gr H2O | SAAMI |
| .204 Ruger | 0.204 in (5.18 mm) | 1.850 in (46.99 mm) | 2.260 in (57.40 mm) | 0.378 in / 0.376 in | ~32.5 gr H2O | SAAMI |
Dimensional similarities do not indicate interchangeable ammunition. Each cartridge requires its specific dedicated chamber.
220 Swift vs 22-250 Remington Case Dimensions
The .220 Swift and .22-250 Remington are classic high-velocity .22 caliber varmint rounds, but their physical profiles differ significantly:
- Parent Design: The .220 Swift is derived from the 6mm Lee Navy parent case, resulting in a long 2.205 inch body with a semi-rimmed base. The .22-250 Remington is built on the .250-3000 Savage case, using a shorter 1.912 inch body with a true rimless base.
- Base and Rim Geometry: Both share a 0.473 inch rim diameter, but the .22-250 Remington has a wider base (0.470 in) flush with its rim. The .220 Swift has a narrower base (0.445 in) relative to its rim, creating its semi-rimmed shape.
- Case Capacity: The longer .220 Swift holds approximately 47.0 grains H2O compared to 44.5 grains H2O in the .22-250 Remington, granting the Swift a slight velocity advantage with equal barrel lengths.
- Overall Length: The .220 Swift requires a maximum COAL of 2.680 inches, whereas the .22-250 Remington uses a more compact 2.350 inches.
220 Swift vs 223 Remington Case Dimensions
Comparing the .220 Swift to the widely used .223 Remington shows two different performance classes:
- Bolt Face and Rim Size: The .223 Remington uses a small 0.378 inch rim diameter and 0.376 inch base diameter. The .220 Swift uses a standard 0.473 inch rim and a 0.445 inch base.
- Case Length: The .220 Swift case length (2.205 in / 56.01 mm) is significantly longer than the .223 Remington (1.760 in / 44.70 mm).
- Shoulder Angle: The .220 Swift uses a 21 degree shoulder angle, while the .223 Remington uses a 23 degree shoulder angle.
- Capacity and Velocity: The .220 Swift holds roughly 50% more water volume (~47.0 gr H2O vs ~31.4 gr H2O), producing substantially higher muzzle velocities.
220 Swift vs 225 Winchester Case Dimensions
Winchester introduced the .225 Winchester in 1964 as a potential replacement for the .220 Swift, though both are now distinct legacy designs:
- Base and Rim Profile: Both cartridges feature semi-rimmed case designs with 0.473 inch rim diameters. However, the .225 Winchester has a base diameter of 0.422 inches compared to the .220 Swift’s 0.445 inches.
- Case Length: The .220 Swift is longer at 2.205 inches (56.01 mm), compared to the .225 Winchester at 1.930 inches (49.02 mm).
- Shoulder Geometry: The .225 Winchester features a steeper 25 degree shoulder, whereas the .220 Swift uses a 21 degree shoulder.
- Case Capacity: The .220 Swift holds roughly 47.0 grains H2O versus ~41.5 grains H2O for the .225 Winchester.
220 Swift Chamber And Case Dimensions
Chamber geometry is engineered slightly larger than maximum cartridge dimensions to ensure smooth feeding and extraction in production rifles.
SAAMI chamber specifications establish these spatial relationships:
- Headspace Control: Modern SAAMI chamber drawings establish headspace from the bolt face to a 0.375 inch datum line on the 21 degree shoulder, rather than relying on the semi-rim face.
- Chamber Neck: The chamber neck diameter is cut to a minimum of 0.264 inches, providing approximately 0.004 inches of total neck clearance around a maximum 0.260 inch loaded case neck.
- Chamber Length: Chamber length is cut slightly beyond the maximum 2.205 inch brass boundary (typically 2.215 inches minimum) to avoid pinching the mouth during firing.
- Body Clearance: Chamber walls feature roughly 0.002 to 0.004 inches of clearance over maximum case body dimensions to prevent sticking under high pressure.
220 Swift Case Forming And Resizing
The .220 Swift was developed commercially by Winchester in 1935, utilizing the 6mm Lee Navy semi-rimmed case as its foundation. Engineers necked the case down to .224 caliber, adjusted body taper, and set the shoulder angle at 21 degrees.
Understanding these dimensional mechanics helps handloaders set up resizing equipment properly. Because high operating pressures stretch the tapered brass body rapidly, full-length sizing dies must be set to bump the shoulder back slightly (typically 0.001 to 0.002 inches) without over-working the shoulder junction. This prolongs brass life and helps prevent premature case head separation.
220 Swift Manufacturer Specifications vs Actual Measurements
Differences often appear when comparing official standard drawings, commercial factory ammunition, and fired brass measurements:
- SAAMI Standards: Define voluntary maximum cartridge and minimum chamber limits for North American manufacturers. Drawings represent safety ceilings rather than exact factory ammunition dimensions.
- C.I.P. Specifications: Establish mandatory legal limits across European proof houses. C.I.P. lists maximum case length at 56.01 mm and sets maximum allowable pressure (Pmax) at 4,300 bar.
- Factory Ammunition: Loaded factory rounds from Winchester, Hornady, or Federal are manufactured slightly below maximum SAAMI limits (often 0.002 to 0.005 inches smaller) to ensure effortless chambering.
- Fired Cases: Upon ignition, thin brass expands to fill the chamber, causing fired dimensions to reflect the individual rifle’s chamber size.
- Resized Cases: Processing brass through sizing dies restores dimensions back toward SAAMI minimums, with minor variations caused by metal elasticity.
Official specification drawings from SAAMI and C.I.P. remain the authoritative baseline for primary case measurements.
Common Questions
What are the 220 Swift case dimensions?
Key maximum specifications under SAAMI drawings include a case length of 2.205 in (56.01 mm), rim diameter of 0.473 in (12.01 mm), rim thickness of 0.049 in (1.24 mm), base diameter of 0.445 in (11.30 mm), shoulder diameter of 0.402 in (10.21 mm), neck diameter of 0.260 in (6.60 mm), shoulder angle of 21 degrees, and COAL of 2.680 in (68.07 mm).
What is the 220 Swift case length?
The maximum SAAMI case length is 2.205 inches (56.01 mm), with a minimum manufacturing limit of 2.185 inches (55.50 mm). The standard trim-to length for handloading is 2.195 inches (55.75 mm).
What is the 220 Swift rim diameter?
The maximum rim diameter is 0.473 inches (12.01 mm) with a manufacturing tolerance of -0.010 inches (-0.25 mm), matching standard .30-06/.308 bolt face dimensions.
What is the 220 Swift base diameter?
The maximum base diameter measured forward of the extractor groove is 0.445 inches (11.30 mm).
What is the 220 Swift shoulder diameter?
The maximum shoulder diameter at the body-shoulder junction is 0.402 inches (10.21 mm).
What is the 220 Swift neck diameter?
The maximum neck diameter of a loaded round with a bullet seated is 0.260 inches (6.60 mm).
What is the 220 Swift case capacity?
Nominal water capacity averages 47.0 grains H2O (3.05 cm³), spanning from 46.0 to 48.0 grains H2O depending on brass brand wall thickness.
What is the 220 Swift overall cartridge length?
Maximum overall cartridge length (COAL) is 2.680 inches (68.07 mm) to fit standard short-action magazine boxes.
How does 220 Swift compare with 22-250 Remington case dimensions?
The .220 Swift features a longer semi-rimmed case (2.205 in case length, 0.445 in base diameter) holding ~47.0 gr H2O, while the .22-250 Remington features a shorter rimless case (1.912 in case length, 0.470 in base diameter) holding ~44.5 gr H2O.
How does 220 Swift compare with 223 Remington case dimensions?
The .220 Swift uses a larger 0.473 in rim, 2.205 in case length, and holds ~47.0 gr H2O, whereas the .223 Remington uses a smaller 0.378 in rim, 1.760 in case length, and holds ~31.4 gr H2O.
How does 220 Swift compare with 225 Winchester case dimensions?
Both feature semi-rimmed 0.473 in rims, but the .220 Swift is longer (2.205 in vs 1.930 in), has a wider base (0.445 in vs 0.422 in), and holds more case capacity (~47.0 gr H2O vs ~41.5 gr H2O).
What is the 220 Swift maximum pressure?
The SAAMI Maximum Average Pressure (MAP) is 62,000 PSI. C.I.P. establishes maximum pressure (Pmax) at 4,300 bar (62,366 PSI).