Thread: .303 British Load Data Variations

Greetings all,
It has been raining in HB for the last two days and I have been thinking about the widely different load data observed for the .303. Generally the data shot in actual .303 rifles seems to be much slower than the Hodgdon data. I collected data from a range of scources and corrected velocities for 38 grains of AR2206H/ H4895 and IMR4895 with both 174 and 180 grain projectiles. Hodgdon data shows data for both the 174 and 180 grain with the same start and max loads. The wide variation of projectiles makes direct comparision difficult as does the two types of 4895. Hodgdon lists both H and IMR data but the later was shot at a different times using different pressure systems.
Once the weather clears I thought it would be useful to compare velocities of identical loads in my two .303 rifles. While both rifles are Lee Enfield No4 Mk1 made in 1942 there barrels are quite different. The iron sight rifle has a five groove well used but servicable barrel and the scoped rifle a two groove near new barrel. Crush length for the old style Hornady 174 grain round nose is 83.5mm for the former and 79.3mm for the later. Current style Hornady 174 grain round nose reduces this length for the scoped rifle to 77.6mm. Some hard data is always better than a pot full of opinions. I will get on to this tomorrow after I have dealt with a tree that has come down on the drive.
Regards Grandpamac.