.243 Winchester

Rifle Also: .243 Win

Based on the .308 Winchester case necked down to 6mm. Excellent dual-purpose cartridge: light bullets for varmints, heavy bullets for deer. Low recoil makes it ideal for youth and recoil-sensitive hunters. Flat trajectory for long-range shooting.

Best For

Hunting Varmint Hunting Competition

Ballistics (Typical Factory Load)

3,100

Muzzle Velocity

fps

1,945

Muzzle Energy

ft-lbs

Typical Bullet

grains

6.5

Bullet Diameter

0.395

Ballistic Coeff.

G1 BC

62,410

Max Pressure

PSI

73.15

Case Length

🔧 Handloading Data

Reference load data for experienced reloaders. Always start at the start charge and work up. Consult official manuals before loading.

Bullet	Powder	Start	Max	Velocity	COAL	Source
70 gr (4.5 g) SP	Hodgdon H4895	34.0 gr 2.2 g	38.0 gr 2.46 g	3,400 fps	2.650	Hodgdon
80 gr (5.2 g) SPBT	Hodgdon Varget	36.0 gr 2.33 g	39.5 gr 2.56 g	3,200 fps	2.650	Hodgdon
80 gr (5.2 g) SPBT	IMR 4064	35.0 gr 2.27 g	38.5 gr 2.49 g	3,150 fps	2.650	IMR
95 gr (6.2 g) SPBT	Hodgdon H4350	40.0 gr 2.59 g	43.5 gr 2.82 g	2,950 fps	2.650	Hodgdon
100 gr (6.5 g) SPBT	Hodgdon H4831	40.0 gr 2.59 g	44.0 gr 2.85 g	2,900 fps	2.650	Hodgdon
100 gr (6.5 g) SPBT	Alliant Reloder 17	40.0 gr 2.59 g	43.5 gr 2.82 g	2,920 fps	2.650	Alliant

📐 Measurement Guide for Reloaders

Powder Charge

Measured in grains (1 grain ≈ 0.065 grams) using precision digital or mechanical scales. Maintaining strict powder weight is crucial for safety and velocity consistency.

Cartridge Overall Length (COAL)

Total length from case base to bullet tip. Checked with digital calipers. Must be within manufacturer's specified range to fit and feed from your firearm's magazine.

Cartridge Base to Ogive (CBTO)

Precision shooters measure to the ogive — the curved part of the bullet that first contacts the rifling — for more accurate bullet seating depth and consistency.

Case Length & Headspace

Brass stretches with firing. Measure case length to know when to trim. Use headspace comparators to check shoulder bump-back during sizing.

Neck Tension

The grip the brass has on the bullet. Measured with ball micrometers by comparing neck wall thickness before and after bullet seating.

Pressure Signs

Inspect fired brass for over-pressure: flattened primers, ejector marks, case head expansion. If unsure, reduce charge and consult your load manual.

⚠️ Always consult established reloading manuals (Hodgdon, Hornady, Lyman) for your specific bullet and powder combinations. For experienced reloaders only.

Technical Specifications

Bullet Diameter	6.5 mm
Case Length	73.15 mm
Max Chamber Pressure	62,410 PSI
Type	Rifle

Compatible Firearms (71)

Howa 1500 Alpine