It is well known that the more shots you fire, the bigger your group will be. Rifles print their shots in a roughly Gaussian distribution. To get a realistic assessment of the accuracy of any rifle/load/shooter combination, at least 10 shots are needed. Two groups will give you a better idea than one. Averaging many such groups and determining their standard deviation is much better. Firing only a small number of shots, coupled with the human tendancy to consider our best results as "typical", obscures the truth.
Here I will present an unflinching view of the accuracy that I have been able to obtain shooting cast bullets in sporting rifles.
Phase One - Field Style Shooting
All groups were fired at an outdoor range, while sitting at a wooden bench, my elbows resting on the bench, roughly equivalent to a field sitting position (as my local range does not permit actual field shooting). Sighting equipment was either irons, or low power hunting telescopes.
Average group size from 2014 through 2016 was calculated. This is the good, the bad, and the ugly, all lumped together, representing 2,500 shots. Average accuracy for seven rifles was 5.0 MOA extreme spread, with a standard deviation of 2.0 MOA. Ouch!
This is of course contrary to the perception that one might get from browsing the internet, where "sub MOA" groups are spoken of as routine. While I didn't expect that level of accuracy, I thought that a 5 MOA average should allow further refinement. Should your own results fall closer to mine than that of the "sub MOA" crowd, please do not despair. Firing cast bullets from rifles has a learning curve which requires persistence to master, along with a tolerance for frustration.
At this point, I fired a 100 shot comparison data base with a Anschutz 1710 .22lr, shooting in the same manner, although aided by a target telescope. My smallest 10 shot, 100 yard group was 1.375", and the largest 2.5". The average for all was 2.0 MOA, with a standard deviation of 0.54. The normal distribution tells us there is a 97.5% probability that any subsequent shots fired would fall within a "cone of fire" two standard deviations larger than the average, or just over 3 MOA.
Now, you don't have to be a math freak to make these calculations. I have trouble with simple arithmetic, so I just Google "online standard deviation calculator", enter my extreme spreads, and then hit the "calculate" button. There may be better ways to assess your rifle's accuracy, but none are simpler.
I consoled myself with the thought that if 3 MOA represents realistic field accuracy for me, that I should be satisfied if my cast loads approach this. It is unlikely that I can sit in my garage and concoct anything to significantly better than what RWS and Federal have done.
I am assuming that you fully understand the major aspects of casting lead bullets, handloading ammunition, and handling firearms. If you are a novice in any of these areas, please do not proceed until you have developed a realistic appreciation of their dangers. You should also know of the controversies which swirl about the creation of reduced loads. If after appropriate study and due reflection you have decided that the inherent risk is acceptable to you (and to those around you), read on.
Decades ago, Col. E.H. Harrison, USA (ret.), who conducted extensive and elegant research into the use of cast bullets in rifles, stated "cast bullet loads require the strongest lead alloys practicable. Disregarding this causes failure. Tradition, regrettably kept alive in published information, has been a heavy handicap." My initial results, generally employing scrap alloy, certainly support his contention!
Recalling that warning, published in the 1979 NRA book "Cast Bullets", I loaded the lead pot with linotype. This was key to improving my results, as the good advice immediately bore fruit.
A load for the .358 Winchester.
Ruger 77 Mk II Frontier (16 1/2" barrel, 1 in 12" twist) - with forward mounted 4X Weaver scope.
Bullet: Accurate Molds 36-302DG gas checked, cast of linotype, and sized to 0.360"
Weight 278.5 grains, with GC and lube.
Brass: Hornady
Primer: S&B Large Rifle Magnum
Powder: Accurate Arms 4064, 38.5 grains
Light roll crimp. Cartridge OAL 2.755"
1735 fps - average 3.1 MOA, standard deviation 0.16 MOA over a 30 shot database (three 50 yard ten shot groups).
Here's ten shots on a standard NRA 50 yard smallbore rifle target. Groups are still good with 39.0 grains of powder, but open sharply at 40.0.
Nothing fills out a mold like linotype, and the results speak for themselves, but the stuff is expensive. It is also brittle, tending to shatter on impact, so hunters don't like it.
Dennis Marshall and others have told us for years that heat treating will allow the use of softer, less expensive alloys. This is worth considering, as it allows you to use that scrap which you have collected in full throttle loads. The simplest way to do this is by dropping bullets from the mold directly into a bucket of water, but unless your casting rhythm and mold release is absolutely consistent, substantial variations in hardness may result. For precise control, a toaster oven can be employed.
Air cooled bullets cast from scrounged alloy measured BHN 11. Baking for 30 minutes at 440 F, followed by a cold water quench, produced substantial hardening.
They weighed 298 grains, so I cut the powder charge by half a grain, and loaded them up. Five days later (to allow them time to fully harden) I shot this group:
With 10 shots into 2.75 MOA, it lay well within the grouping provided by linotype.
Changing to adequate alloy - linotype or via heat treating - made a real difference, refreshing me and boosting my spirits.
I became interested in what a rifle firing cast bullet ammunition could really do, independent of my own skill (or lack thereof). Col. Harrison had stated, back in '79, that a skilled rifleman, firing a target rifle from bench rest, could "readily" obtain 1.5 MOA.
Phase Two - Benchrest Style Shooting
In late 2018, I mounted a Weaver 20X scope on a little Sauer 101 "Scandic" .243 Winchester carbine, and acquired sandbags for it, fore and aft. These pretty much took me out of the picture, allowing a focus on rifle and ammunition performance alone.
A load for the .243 Winchester.
Sauer 101 Scandic (19 1/2" barrel, 1 in 10" twist) - with 20X Weaver scope.
Bullet: SAECO 243, cast of linotype, and sized to 0.244".
Weight 80.5 grains, with GC and lube.
Brass: PPU
Primer: S&B Large Rifle Magnum
Powder: Alliant #2400, 12.3 grains (thrown from a Little Dandy #15 rotor).
Light taper crimp. Cartridge OAL 2.650"
1656 fps. Average 1.34 MOA, standard deviation of 0.44 MOA, over a 70 shot database (fourteen 100 yard five shot groups).
This is a typical 100 yard benchrest group.
Not "sub MOA", but respectable. Now, that was shot with a selected load which proved a bit more accurate than most. At 100 yards, the average extreme spread of ALL 85 five shot groups that I fired with this rifle was 1.59", (largest 3.13", smallest 0.75"), with a standard deviation of 0.48". Col. Harrison was proven correct, and I was pleased.
Removing the T20, I substituted a 3X Leupold, and fired 25 rounds with the rifle simply cradled in my hands.
The groups opened to an average of 2.04 MOA, demonstrating why "bench rest" technique is required to evaluate a rifle's intrinsic accuracy.
While the little Sauer is at the top end of production rifles, my .30-06 Remington 721, manufactured in 1952, was designed to be affordable. Neverthless, it held its own..
Patterned after the Guy Loverin designed Lyman 311467, the Accurate Molds 31-173B performed best in this rifle. With a 24X scope, 10 consecutive 5 shot groups averaged 1.54" at 100 yds. Standard deviation was 0.54". Lube the bottom two grooves, and seat it so that your case mouth is 1/2 way up the 3rd band (COL 3.136").
14.2 grains of IMR Blue shotgun powder (dropped from my Little Dandy #20 rotor) provided a MV of 1580 fps. That can get lost in the big .30-06 case. Stay alert! You don't need a double charge.
The Remington is stocked for iron sights. Once I was done with ammmunition testing, I fitted a Williams WGRS-700 aperture.
With 50 yard groups similar to this, I can live with it.
Summing Up
To paraphrase the late Frank Marshall (who forgot more about cast bullet shooting that most of us will ever know):
“There is nothing complicated about cast bullet shooting. The typical shooter simply desires reasonably consistent performance. Group sizes around 2" at 100 yds. are entirely adequate for informal shooting and are quite easily obtained with ordinary rifles."
"The difference between hunting performance at 2 m.o.a. and benchrest cast bullet performance at less than 1 m.o.a. is what brings all the skullduggery and witchcraft out. But the factors needed to bridge that gap are rarely significant in ordinary rifles, and of no particular concern to the shooter looking for an ‘adequate’ load.”
So, hang in there, my friends. With persistece and reasonable effort, you too can find cast bullet happiness!