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Cartridge Comparisons

Twenty Caliber Cartidge Dimensions

Name	Parent	Body Length	Diameter	Angle	Neck Length	OAL	Capacity	Notes
20-222*	222	1.2603	0.3580	23	0.3033	1.712	27.9	222 necked down with no changes
20-250*	22/250	1.5100	0.4156	28	0.2300	1.910	47.0	22/250 necked to .204
20 Bobcat	222	1.3330	0.3660	40	0.2870	1.700	27.5	.223 neck, 40' minimum taper
20 BR*	6mm BR	1.0710	0.4600	30	0.2675	1.535	37.9	6mm BR necked to .204
20 BR Impr*	6mm BR	1.1278	0.4620	40	0.3002	1.562		6mm BR improved, necked to .204
20 Classic*	30/30	1.2041	0.4090	35	0.2258	1.552		30/30 shortened, improved
20 Dasher*	6mm BR	1.1973	0.4600	40	0.2281	1.560	38.2	6mm BR improved, necked to .204
20 Duster* (1)	222	1.3350	0.3650	40	0.2510	1.670		Sharp angle, minimum taper 2933
20 Duster* (2)	222	1.4190	0.3650	40	0.2140	1.712		Sharp angle, minimum taper 5353
20 Extreme	222	1.2600	0.3480	29	0.2150	1.585	26.0	222 improved, necked, shortened
20 Mink	22 Hornet	0.8554		30	0.2290	1.145		22 Hornet necked & improved
20 Practical	223	1.4370	0.3540	23	0.2030	1.760	30.3	.223 to .20 cal
20 PPC*	6mm PPC	1.0749	0.4310	30	0.2741	1.517	33.5	6mm PPC necked to .204
20 Pup	6mm PPC			30				6mm PPC shortened .173
204 Ruger*	222 Mag	1.5346	0.3608	30	0.2173	1.863	32.4	SAAMI Standard
20 Squirrel*	22 Hornet	0.6250	0.2930	30	0.2738	0.919
20 Tactical*	223	1.4150	0.3600	30	0.2500	1.755	30.2	.223 with 30 degree shoulder
20 TNT*	17 Rem	1.3470	0.3580	23	0.2650	1.770	29.1	17 Rem necked up with no changes
20 VarTarg*	221 FB	1.0660	0.3600	30	0.2163	1.400	23.3	Sharp angle, minimum taper
20 VarTarg Turbo*	222	1.2800	0.3600	30	0.2160	1.614	29.3	Shorter, Sharp angle, minimum taper
222 Remington*	222	1.2640	0.3570	23	0.3127	1.700	28.6	SAAMI Standard

An asterisk* after the cartridge name indicates that the above dimensions have been obtained from actual reamer prints. The others are from the best reliable sources available to me. Remember, many of these are wildcats and therefore non-standard so the dimensions may vary. Special thanks to the members of the Saubier small caliber forums and to Pacific Tool & Gauge for their assistance.

The 20 Duster dimensions are from PT&G prints 2933 (1) and 5353 (2). As you can see, the dimensions are different but both are referred to as 20 Duster.

General Comparative Cartridge Data for Select Standardized Cartridges



Caliber	Case OAL	Water Grs	Neck Length
17 Fireball	1.42	23.8	0.222
204 Ruger	1.85	32.4	0.2
20 Tactical	1.766	30.2	0.25
20 VarTarg	1.4	23.3	0.217
22 Hornet	1.403	14.9	0.3857
218 Bee	1.345	19.3	0.2559
221 Fireball	1.4	24.1	0.2025
222	1.7	28.6	0.3127
223	1.76	30.6	0.2027
22/250	1.92	47	0.248
243	2.045	54.8	0.2407
244	2.233	56.2	0.3508
6mm BR	1.56	39.4	0.322
257 Rob.	2.233	57.1	0.3213
257 40 degr	2.233	60.3	0.321
7mm/08	2.035	55.2	0.2842
308	2.015	55.8	0.3034
30-06	2.494	67.1	0.3854