Re: Different in powder loads
Posted: Mon Aug 31, 2020 10:36 am
Sierra Ed VI, the latest manual published last year, quotes two Viht loads for the company's 52-55gn bullet range.
AR-15 load (long-throat AR-15A2 HBar 5.56mm military chamber test rig) pressure curves suited to gas operation.
Federal case; Rem 7 1/2 primer; 20-inch barrel / military chamber
Viht N135: ............. Minimum: 23.2gn ................ Maximum: 25.6gn for 3,050 fps
Bolt-gun load (SAAMI 223 chamber, 24-inch test barrel)
Winchester case, Win WSR primer, COAL: 2.250" for 55 GameKing and 2.260" for 55 BlitKing.
Viht N133: .............. Minimum: 22.4gn (3,000 fps) ................ Maximum: 23.0gn for 3,100 fps
Note, no charges are shown below 22.4gn, so Sierra does not advise starting at lower levels.
Of the two I'd recommend the bolt action load as it's firstly much better suited to use in a commercial 223 Rem rifle rather than that for the 5.56 military chamber, and secondly I obtained best results from N133 of all the Viht range for this bullet weight in the days when I loaded a lot of 52-69gn Sierra and Hornady bullets.
AR-15 load (long-throat AR-15A2 HBar 5.56mm military chamber test rig) pressure curves suited to gas operation.
Federal case; Rem 7 1/2 primer; 20-inch barrel / military chamber
Viht N135: ............. Minimum: 23.2gn ................ Maximum: 25.6gn for 3,050 fps
Bolt-gun load (SAAMI 223 chamber, 24-inch test barrel)
Winchester case, Win WSR primer, COAL: 2.250" for 55 GameKing and 2.260" for 55 BlitKing.
Viht N133: .............. Minimum: 22.4gn (3,000 fps) ................ Maximum: 23.0gn for 3,100 fps
Note, no charges are shown below 22.4gn, so Sierra does not advise starting at lower levels.
Of the two I'd recommend the bolt action load as it's firstly much better suited to use in a commercial 223 Rem rifle rather than that for the 5.56 military chamber, and secondly I obtained best results from N133 of all the Viht range for this bullet weight in the days when I loaded a lot of 52-69gn Sierra and Hornady bullets.