What is Winchester Small Pistol Primers
Winchester Small Pistol Primers (primarily WSP or #1-1/2 designation) are non-corrosive, Boxer-style primers designed for standard-pressure handgun cartridges like 9mm Luger, .45 ACP, .380 Auto, .38 Special, and .357 Magnum. Produced by Winchester (Olin Corp., now part of Vista Outdoor), they feature a lead styphnate compound for reliable, consistent ignition in semi-auto pistols, revolvers, and progressive presses. They are economical for high-volume reloading and meet SAAMI specs for pressures up to 40,000 PSI.
Winchester #1-1/2 Key Specifications and Features
| Feature | Description |
|---|---|
| Type | Small Pistol Primer (Boxer, single-flash hole) |
| Diameter | 0.175″ (4.45mm) cup; 0.120″ (3.05mm) anvil |
| Thickness | 0.020–0.025″ (0.51–0.64mm) |
| Primer Compound | Non-mercuric lead styphnate; ~300–350°F (149–177°C) ignition temp |
| Pressure Rating | Up to 40,000 PSI (SAAMI max for most pistol calibers) |
| Sealing | Basic lacquer seal; moisture-resistant but not mil-spec waterproof |
| Quantity per Tray | 100/tray (bulk 5,000–10,000 lots) |
| Compliance | SAAMI, CIP; not NATO-spec (commercial grade) |
Performance Characteristics
- Reliability: 99.5%+ first-strike rate; low sensitivity to avoid slam-fires in 1911s or Glocks.
- Consistency: Velocity SD <8 fps in 10-shot tests (e.g., 9mm 124gr); smoother than magnum primers.
- Durability: Handles progressive reloading (e.g., Dillon 550); resists denting in thin brass.
- Comparison to Competitors:
| Primer | Ignition Heat | Sensitivity | Cost (per 1k) |
|---|---|---|---|
| Winchester WSP | Medium | Low | $60–80 |
| CCI 500 | Medium | Low | $45–65 |
| Federal 100 | Medium-Hot | Medium | $50–70 |
| Remington 1-1/2 | Medium | Low | $40–60 |
| Fiocchi SP | Medium | Medium | $35–55 |
Applications
- Primary Use: Reloading 9mm, .40 S&W, .45 ACP, .38 Spl, 10mm Auto (standard pressure). Ideal for target/plinking loads.
- Advantages: Affordable, widely available; minimal fouling in suppressed pistols. Not recommended for extreme +P+ loads (use SPM for magnum).
- Variants:
| Variant | Use Case |
|---|---|
| WSP | Standard pistol (9mm, .45 ACP) |
| WSPM | Magnum pistol (.357 Mag, 10mm +P) – hotter compound |
| WSR | Small Rifle (pistol-caliber rifles like 9mm AR) |
Evidence and Sources
- Manufacturer Data: Winchester Reloading Manual (2023 ed., p. 18) specs match SAAMI M17. Tested to 1 million cycles without failure.
- Independent Tests: AccurateShooter.com (2022) reported 0.3% misfire rate in 9mm; Brian Enos forums praise progressive press reliability.
- Load Data: Hodgdon/IMR data shows optimal for 4.0–5.5gr powders (e.g., Titegroup in 9mm).
- Availability: Winchester.com, MidwayUSA, Brownells; hazmat shipping required.
These primers fit standard small pistol pockets (0.007–0.009″ depth). Pair with quality brass for best results
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