Mk 7z vs my Match Loads

I had 190 rounds of Winchester made1943 MkVIIz. I tore down two of the cartridges and weighed the (WC846?) Ball powder and both weighed out @ 44.6grns. Unfortunately I discovered that the two MkVIIz bullets had two different weights, with one weighing 171.9 and the other weighing 175.2. I took the remaining 46 rounds from the original 48 round cardboard box and chronographed those rounds with the chronograph set up exactly 8 feet from the end of the muzzle. The averaged FPS was recorded @2398.6 with only four of those reaching the Golden MkVIIz 2440 FPS. At 100 yards my first two ten shot groups averaged 1.47" MOA. At 200 yards the following two sets of ten shot groups averaged 2.94" MOA.  The remaining 6 rounds were sent down range towards an 8" metal circular plate @ 300 yards. All six rounds hit their mark and staying at just under a 6" spread. 

I wanted to compare that to some modern handloads I had worked on. Using the 174grn FMJ-BT PPU projectiles and 39.0grns of IMR4064, IMR4895, Norma 202, and Varget with Federal GM215M primers for ignition, I loaded 4 sets of 20 rounds of each powder and recorded a averaged FPS of 2382 for the IMR4064, a FPS of 2387 for the IMR4895,  2442 FPS for the Norma 202 and 2414 FPS for the Varget. The accuracy for each was recorded at, from best to average to below par @ 100 yards was as such.

Norma 202/39.0grns = 1.28" 

IMR4064/39.0grns = 1.55"

IMR4895/39.0grns = 1.67"

Varget/39.0grns 1.74"

The Varget numbers had me perplexed because Hodgdons load data shows a minimum 37.0grns and a maximum of 41.1grns so I assumed that using the middle ground charge of 39.0grns would have produced tighter groupings. I was dismayed to learn that almost all other sources of information showed that 39.1grns of Varget was at maximum charge weight. I reduced the charge weight to match my IMR3031 load of 36.0grns and gained a significant amount of accuracy back albeit at a loss of FPS. The chronographed averaged FPS was recorded at 2364 while the averaged ten shot group measured in at 1.497" @ 100 yards.

(I have noticed in the past that pushing the 174grn SP/BTHP/FMJ-BT projectiles over 2450 to 2500 plus FPS has a tendency to cause erratic flight patterns if not causing some of those bullets to lose complete stability and go divergent on all three axis.)

My accuracy load using 36.3grns of IMR3031, Federal GM215M primers,.311 174grn FMJ-BT projectiles and a C.O.L. 3.110" as well as my load using 39.7grns of VihtaVuori N540,  Federal GM215M primers, .311 174grn FMJ-BT projectiles with a C.O.L.  of 3.110" outperform the Winchester MkVIIz Ball Ammunition by more than .55" under MOA for both loads as well as having the FPS down to 2144 for the IMR3031 and 2368 for the VVN540.

For hunting using the 180grn SP I have found that 36.0grns to 38.0grns of IMR3031 will also outperform the MkVIIz ammunition out to 200+ yards with a mean spread of 2.2 MOA @ 200 yards.

The averaged deviation in muzzle velocities from low to high using the 174grn FMJ-BT was recorded between 12 - 15 FPS. 

It should be notated here that the averaged weight of the 174grn FMJ-BT projectiles were 174.7. The lowest weight recorded was 172.4 and the heaviest weight recorded was 176.2. The deviations in MV, bullet drop and on-target spread is due in large part to the projectiles non-consistency in weight...

The rifle used for testing was my French Resistance No4Mk1 Maltby.  It is as it was the day it left the factory with nothing modified by way of barrel bedding so, given that, the testing was as it would have been using a factory spec'd rifle with factory spec'd MkVIIz ammunition and then compared with modern-day handloads using very mild load data. 

Many, many moons ago, I was told by a very well known LR shooter, knowledgeable with the Lee-Enfield that "Accuracy is best achieved by decreased velocities" and "Speed is your enemy." I have lived by that principle for almost 40 years now and it has yet to fail me. My accuracy load for hunting using either a 150grn SPT or a 180grn SPT is with 36.3grns of IMR3031. It is also my accuracy load using a 174grn BTHP SMK. Load data shows a C.U.P. of 42,400 for all three bullet weights and a mean MV of 2303 with a plus of 8 - 10 FPS for the 174grn HPBT...

I have done my research and my work-ups and have a reliable and accurate handload, be it a 150grn or 180grn hunting round or, a 174grn BTHP/FMJ-BT target round.

I did my fair share of competitive shooting and I have done and continue to do practical deer hunting. In that regards, my main objective is to be able to consistently and accurately hit a moving target at no greater than 300 yards. Anything beyond that is a waste of precious resources. 

Competitive Target Shooting is a good way to hone your skills at accurately hitting stationary targets all the way out to 1000+ yards and I did enjoy it for a time and occasionally still do but, I like knowing that I can pretty much hit anything moving out to 300+ yards reliably. My handloads are very consistent, accurate, and reliable. That is why I started using the VihtaVuori N540. It covers all three of my rifle calibers, .243W,  .308W,  and .303B and at the minimum charge weights for each caliber I keep the pressures down while still maintaining accuracy. I still keep IMR3031 on deck for the Enfields but, only for hunting purposes...

I got lucky on the .308 loads, the Varget powder charge required to work the electronic targets at 1000 yds also gave best accuracy by far at 600 and 800 yds. But it’s a stout load, the recoil is noticeably more than 40.0 gr. I’m carefully monitoring headspace and throat erosion to be sure I’m not causing excessive wear on the rifle. I plan to use it exclusively for long range use, perhaps 4 or 5 times a year. 

I will load 30 rounds; three rounds at each charge weight starting at 39.4 gr in increments of .3 grains up to 42.1 grains.  These will be individually weighed.