Author: britrifles
Subject: .303 Chrono Results
Posted: October 12 2019 at 6:33am
I finally had the opportunity to chronograph some Mk VIIz Service Ball ammunition and my .303 hand loads. I also made some direct comparisons between the Mk VII service bullet and the 174 gr Sierra MatchKing by pulling bullets from the Mk VIIZ cartridges and substituted the bullet with the 174 SMK. These results may be of interest.
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Subject: .303 Chrono Results
Posted: October 12 2019 at 6:33am
I finally had the opportunity to chronograph some Mk VIIz Service Ball ammunition and my .303 hand loads. I also made some direct comparisons between the Mk VII service bullet and the 174 gr Sierra MatchKing by pulling bullets from the Mk VIIZ cartridges and substituted the bullet with the 174 SMK. These results may be of interest.
Rifle: 1944 BSA No. 4 Mk I(T), No. 32 Mk III scope, Long Branch 6 groove barrel
Temp: 50 deg F
Chrono: Shooting Chrony Alpha Master 15 feet from muzzle
Acronyms:
Mean Velocity (MV)
Extreme Spread (ES)
Standard Deviation (SD)
Sierra MatchKing (SMK)
Cartridge Overall Length (COL)
All groups 10 shots from bench
1. Dominion Arsenal DAC 1951 Mk VIIZ Service Ball Ammunition (174 gr, .312 dia flat base bullet).
MV 2412 fps
ES 78 fps
SD 25 fps
Group Size 2.2 in.
2. R-P Case, WLR primer, 40.0 gr. Varget, 174 gr SMK, 3.05 COL
MV 2368 fps
ES 64 fps
SD 21 fps
Group Size 2.0 in.
3. DAC ‘51 MK VIIZ, bullet pulled and substituted with 174 gr SMK
MV 2507 fps
ES 44 fps
SD 14 fps
Group Size 2.0 in.
4. R-P case, WLR primer, 40.0 gr. Varget, 174 gr DAC MK VII Service Bullet, 3.05 COL
MV 2366 fps
ES 47 fps
SD 15 fps
Group Size 1.5 in.
DAC 1951 MK VIIz was loaded for the 1952 DCRA matches and clearly performs well and still retains the specified velocity. The bullet quality appears to be on par with the SMK for group size, although the SMK gives slightly higher velocity in the same load, particularly with the DAC military case.
My No. 4 .303 match load of 40 gr Varget with 174 gr SMK runs just under MKVII specified velocity. I expect pressures are somewhat lower than MK VII given the slower powder and faster bullet.
Here’s what the sight picture looks like thru the No. 32 Scope, the chrono can be seen in the field of view.
Results with pulled DAC 1951 MK VII service bullet loaded into R-P Case, 40.0 gr Varget.
