max Varget load for .311" Hornady FMJ BT 174 gr

[AussieInUtah]

The published Varget powder max load for the Hornady .311" FMJ BT 174 gr bullet is 39.1 gr. At 39.0 gr, I am only getting 2234 fps. But I want to drive this bullet at 2440 fps to replicate the military load. The max published load for the SMK 174 gr HPBT bullet is 42.0 gr.

Can I safely increase the powder charge to about 39.5 or 40 gr with the Hornady bullet? Why is the published max load for the SMK bullet of the same weight so much higher?

I'm a bit new to reloading and don't want to blow up my rifle. It seemed to me that the primers were flattening with the 39 gr load but I couldn't see any obvious problems with the cases.

 

[bigedp51]

The loads in the Hornady reloading manual for the .303 British are with the rifle, cases and components listed. Your barrel and cases on "YOUR" Enfield could develop more or less chamber pressure than the load listed in the Hornady manual. On top of this the Hornady manual lists a newer Mk.2 Enfield which would have a tighter bore.

Please take note American made commercial .303 cases are your limiting factor as these cases are not made to military standards. On top of this American commercial ammunition is loaded to less than 43,000 cup due to the older Enfield rifles still being used today with their lower pressure rated cartridges. (17.5 and 16.5 tsi)

If you fire form your cases to headspace on the shoulder instead of the rim your cases will last much longer when reloaded.

Because Hornady used a Enfield Mk.2 for the loading information and not a universal receiver and pressure testing barrel I will assume Hornady was looking at the pressure signs on "their" cases.

Hodgdon's manuals list 41 grains of Varget at 2440 and 43,800 cup with the 174 grain HPBT (46,000 cup or 49,000 psi = 18.5 tsi or maximum rated chamber pressure)

NOTE: In 1914 the British enlarged the Enfield .303 chamber in length and diameter to make room for the mud of Flanders. American manufactures kept the earlier civilian chamber standards making military chambers very hard on commercially made .303 cartridge cases. At this time Serbian made Prvi Partizan .303 cartridge cases are .010 thicker in the base web area and better suited to the larger military chamber.

 

[AussieInUtah]

Is there enough similarity between the SMK 174 gr HPBT and the Hornady 174 gr FMJ BT that you can use loading data interchangeably between the two bullets?

 

[Slamfire]

I chronographed Winchester silvertips in my Mk II, it did not exactly beat any velocity records.

Go out and develop your loads over a chronograph. Based on the Greek ball, just get your velocities at 2400 fps and you are there.


No. 4 MkII mfgr 12/53

174 grain Greek Ball HXP 70

8 Feb 2012 T = 50 °F

Ave Vel = 2423
Std Dev = 14
ES = 53
High = 2456
Low = 2403
N = 14


180 grain Winchester Silvertip Factory Ammunition

8 Feb 2012 T = 50 °F

Ave Vel = 2297
Std Dev = 14
ES = 46
High = 2319
Low = 2273
N = 10