Caliber comparison

.243 Win. vs 6.5x55 SE

.243 Win. or 6.5x55 SE? In short: According to the C.I.P., the 6.5x55 SE has the longer case (55 mm vs 51.94 mm). The C.I.P. allows the higher maximum pressure for the .243 Win. (4,150 bar vs 3,800 bar). Muzzle energy of the factory loads in the catalog, as stated by the manufacturers: .243 Win. 2,053–2,901 J; 6.5x55 SE 2,378–3,152 J. Bullet weights: .243 Win. 55–105 gr; 6.5x55 SE 120–156 gr. In the gun catalog: .243 Win. 20 models; 6.5x55 SE 2 models. Standards retrieved on 10/27/2026; catalog date at the bottom of the page.

Specifications side by side

.243 Win. and 6.5x55 SE: standards and manufacturer data
Spec	.243 Win.	6.5x55 SE
Ignition	Centerfire	Centerfire
Nominal size	6.17 mm	6.5 mm
C.I.P. designation	243 Win.	6,5 x 55 SE
Maximum pressure Pmax (C.I.P.)	4,150 bar	3,800 bar
Maximum case length (C.I.P., L3)	51.94 mm	55 mm
Maximum overall length (C.I.P., L6)	68.83 mm	80 mm
Bullet diameter (C.I.P., G1)	6.17 mm	6.71 mm
Maximum average pressure, MAP (SAAMI, transducer)	60,000 psi	51,000 psi
Factory loads in the catalog (manufacturers)	67 (14)	44 (11)
Bullet weight (manufacturer data)	55–105 gr (3.56–6.8 g)	120–156 gr (7.78–10.1 g)
Muzzle velocity V0 (manufacturer data)	853–1,196 m/s	723–895 m/s
Muzzle energy E0 (manufacturer data)	2,053–2,901 J	2,378–3,152 J
of which lead-free	9	9
Models in the gun catalog	20	2
Shooting disciplines in Germany (by name / by caliber range)	6 / 148	12 / 153

The C.I.P. and SAAMI each measure chamber pressure by their own method, so their figures are shown side by side and not converted from one to the other.

Factory loads: range of manufacturer figures in the catalog

Only current products are counted. Bullet weight, velocity and energy appear only where the manufacturer states them; they apply to the manufacturer’s test barrel.

.243 Win.

Bullet weight, lower end of range: 55 gr (3.56 g) (source: nosler.com)
Bullet weight, upper end of range: 105 gr (6.8 g) (source: geco-ammunition.com)
Muzzle energy, lower end of range: 2,053 J (source: hornady.com)
Muzzle energy, upper end of range: 2,901 J (source: hornady.com)

6.5x55 SE

Bullet weight, lower end of range: 120 gr (7.78 g) (source: hornady.com)
Bullet weight, upper end of range: 156 gr (10.1 g) (source: sellier-bellot.cz)
Muzzle energy, lower end of range: 2,378 J (source: sellier-bellot.cz)
Muzzle energy, upper end of range: 3,152 J (source: hornady.com)

Guns in the catalog

The catalog lists no model in both chamberings.

Shooting disciplines in Germany

Approved rulebooks of German shooting associations: .243 Win. 6 by name, 148 by caliber range; 6.5x55 SE 12 by name, 153 by caliber range. In 146 disciplines, both cartridges are allowed.

A discipline for your gun type in an approved set of sport regulations does not yet mean you have a recognized need. An association your club belongs to must certify, under its sport regulations, that the gun is approved for a discipline and required for it; on top of that come twelve months of sport shooting in a club, the shooting activity record, acquisition spacing, the quota and the minimum age. The association certifies, the authority decides. The wording of the regulations governs.

What this comparison does not say

This comparison puts specifications side by side. Which cartridge may be fired in a particular gun is determined solely by the caliber marking on the barrel or by the gun manufacturer.

How a cartridge performs on target depends on bullet, load, barrel length and distance. This page does not rate which cartridge is “better”.

Sources and date

C.I.P. data sheet 243 Win., dated 05/15/2002
ANSI/SAAMI Z299.4 — Centerfire Rifle Ammunition (Z299.4-2025), 243 Winchester: Velocity & Pressure Data, p. 17 (PDF p. 30)
C.I.P. data sheet 6,5 x 55 SE, dated 05/22/2013
ANSI/SAAMI Z299.4 — Centerfire Rifle Ammunition (Z299.4-2025), 6.5x55 Swedish: Velocity & Pressure Data, p. 11 (PDF p. 24)
Manufacturer data in the Waffenschrank ammunition catalog: geco-ammunition.com, hornady.com, nosler.com, sellier-bellot.cz

Standards retrieved on 10/27/2026. Our own presentation of individual figures, not an official reproduction; the original document prevails. Waffenschrank is not affiliated with the C.I.P. or SAAMI.

Specifications come from the source cited alongside them; counts are based on our catalog as of the date stated. Not legal advice: what follows from these figures in a given country is decided by that country’s law. Waffenschrank is not affiliated with the manufacturers named.

More comparisons

Catalog as of 10/16/2026