Pistol · SAAMI
.45 GAP
Glock's .45-caliber cartridge in a 9mm-length case, allowing a standard-frame Glock to chamber .45-caliber bullets.
- Caliber
- 0.452″ · 11.48 mm
- Introduced
- 2003
- Case
- Rebated
- Parent
- .45 ACP
- Primary use
- Law Enforcement, Self Defense
- Status
- Active
- Introduced
- 2003
- Type
- Pistol
- Origin
- United States
- Inventor
- Ernest Durham / Glock / CCI-Speer
- Manufacturer
- Speer, various
- Standard
- SAAMI
- Status
- Active
- Availability
- Limited
- Case capacity
- 21.4 gr H₂O
- Twist (typical)
- 1:16
- Primer
- Small Pistol
- Case type
- Rebated
- Max pressure
- 23,000 psi
- Eff. range
- 50 yd
- Max range
- 100 yd
- Recoil
- 3–5 ft·lb
- Subsonic
- Capable
Ballistics
Published velocity/energy data isn't available for .45 GAP. Parent case: .45 ACP.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
CIP TDCC · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 11.48 | 0.452 | ✓ |
| Neck ⌀ | 12.01 | 0.473 | ✓ |
| Shoulder ⌀ | n/a | ||
| Shoulder angle | n/a | ||
| Base ⌀ | 12.09 | 0.476 | ✓ |
| Rim ⌀ | 11.94 | 0.470 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.24 | 0.049 | ✓ |
| Neck length | n/a | ||
| Case length | 19.18 | 0.755 | ✓ |
| Overall length | 27.18 | 1.070 | ✓ |
Size vs familiar rounds
Drawn at true 1:1 — every case is accurate relative to the others. Absolute size depends on your screen's pixel density, so measuring one against a real ruler may be off. .45 GAP is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Reloading costestimate cost per round vs factory
Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.
Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.
Firearms chambered in .45 GAP
12 models in the database chamber .45 GAP. Browse all →
Lineage
Connected reference
History
Developed in 2003 by Glock and CCI-Speer to allow Glock to offer a .45-caliber pistol on their standard-frame (not large-frame) action. The short case fits in a 9mm-sized frame while delivering .45 ACP ballistics. Several US state police agencies adopted it, including New York State Police, South Carolina Highway Patrol, and others. Ammunition availability has fluctuated; some agencies have transitioned back to 9mm.
FAQs
- What twist rate does .45 GAP use?
- .45 GAP typically uses a 1:16 twist rate.
- What bullet diameter is .45 GAP?
- .45 GAP uses a 0.452″ (11.48 mm) diameter bullet.
- Is .45 GAP still in production?
- .45 GAP is active; typical availability is limited.
- What is .45 GAP used for?
- .45 GAP is primarily used for law enforcement, self defense.
- What is .45 GAP based on?
- .45 GAP is derived from the .45 ACP case.
Sources & provenance
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
- Standard C.I.P. — C.I.P. TDCC — Tables of Dimensions of Cartridges and Chambers
- Standard SAAMI — ANSI/SAAMI Z299.3-2022 — Centerfire Pistol & Revolver Voluntary Performance Standards · grain_ballistics, representative_gun archived
- Manufacturer Speer — Lawman Handgun Training 45 G.A.P. 185 Grain TMJ (SKU 53979) · grain_ballistics, representative_gun
- Manufacturer DoubleTap Ammunition — 45 GAP 185gr Controlled Expansion JHP 20rds · grain_ballistics, representative_gun archived
- Manufacturer Speer — Lawman Handgun Training 45 G.A.P. 200 Grain TMJ (SKU 53980) · grain_ballistics, representative_gun archived
- Manufacturer DoubleTap Ammunition — 45 Gap 200gr Bonded Defense JHP · grain_ballistics, representative_gun archived
- Manufacturer DoubleTap Ammunition — 45 Gap 230gr Bonded Defense JHP · grain_ballistics, representative_gun archived
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 31 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →