Cartridges: .30-06 Update

.30-06 Update
by Germán A. Salazar
I know that a lot of you share my passion for keeping the .30-06 alive as an accuracy cartridge; hopefully some of the things I've been doing recently will be of interest to you. As always, my application is NRA Highpower prone matches, iron sights, at 300, 500, 600 and 1000 yards and the loads and equipment at intended for that use.

One of the great virtues of the .30-06 is its flexibility; that is, the ability to accurately shoot a variety of bullet weights across a fairly broad range of muzzle velocities. In some situations - 1000 yard shooting for instance - the best choice is a heavy bullet at a relatively high muzzle velocity. Mid-range matches (300 to 600 yards) by contrast, can be effectively fired with a lighter load, something similar to the old Lake City M72 match load. And, of course, there's always the choice of having a single "do everything" load, which will necessarily be biased toward the heavier load in order to be effective at long-range.

For several years, my "do everything" load has been a moly-coated 190 Sierra Match King at approximately 2800 fps using H4350 in a 28" barrel. With most brass types, such as Winchester, Lapua or Lake City, this requires about 53.5 gr. of H4350 (less with bare bullets). The load performs very well at all distances, but is a bit heavier than you really need at the shorter distances and there might be some room for improvement for long-range. Accordingly, I've been working on two newer loads, one tailored to long-range and the other for the occasional 300 yard match and sometimes at 500 yards.

The Mid-Range Loads
The light load isn't anything very original. As I mentioned above, it is closely related to the M72 match load. As most of you know, M72 featured the military match 173 gr. FMJ bullet at a nominal muzzle velocity of 2640 fps in a 24" barrel although it tends to chrono right at 2800 in my 28" barrels. Part of the difference results from the military arsenals' protocol of measuring velocity 78 feet from the muzzle whereas most reloaders measure velocity 10 feet from the muzzle. If you're not very familiar with National Match ammunition, Ray Meketa's excellent article on the topic on its history is worth reading. The exact load for the NM ammo varied over the years, principally as powder lots varied, but was usually in the range of 47 to 48 grains of IMR 4895.

The first use for my version of the NM load was for the 2010 Arizona Mid-Range State Championship. That match is fired from 600, 500 and 300 yards, and I wanted a light load for the 300 yard stage at the end of the day. A day at the range with the chrono led me to a nice, mild load with the 155.5 gr. Berger at 2830 fps from a 28" barrel using 48.5 gr. of a surplus lot of 4895. The exact charge for loads with commercial 4895 will differ a bit, just look for an MV in the low 2800 fps range for a mild, accurate load. My load worked out very nicely, with 300 yard scores of 150-6X on the first day and 150-10X winning that stage on the second day of the event.

After that match, I was sufficiently satisfied with the new light load that a little further experimentation seemed worthwhile. When a 500 count box of Sierra 168 gr. Match King bullets came along at a good price from a fellow club member, it was the obvious next step. With no range availability for the chrono session, I cut the load down to 47.0 gr. in deference to the heavier 168 gr. bullet and its 0.370" bearing surface compared to the 155.5 Berger's 0.265" bearing surface. I estimate the MV of this load to be about 2750 fps but haven't checked it yet. A quick 10 shot test at 500 yards was promising, so I shot the load in two matches under relatively mild conditions.

The first match on Nov. 13, 2010 resulted in a score of 599-41X (199-12X, 200-14X, 200-15X). The second match with the load, on December 12, 2010 ended up at 598-44X (199-14X, 199-15X, 200-15X);not too shabby, and both scores were match winners. When I see the X count get over 40X, there's no doubt in my mind that the load is working. The only question was: how will perform in windier conditions?

On February 12, 2011, I shot the load again, this time with plenty of wind. I was ready to crank on the windage knob and I wasn't disappointed! During the course of the match I found myself working in a 4 moa range on the windage knob - at one point making a 3 moa change from one shot to the next to put those two shots in the same spot in the 10 ring! At the end of the day, my score of 597-34X (198-11X, 200-13X, 199-10X) was second to Mid Tompkins shooting a .243 (599-37X) - not disappointing at all. Nonetheless, the 168 is at its best at 300 yards or a calm day at 500 yards, especially with this light load. As I said, not a super original load, by any means, but once again proving the wisdom of those who came before us.

The Long-Range Loads
A specialized load for 1000 yard shooting with the .30-06 might seem a bit redundant in light of the good performance at that distance of my standard load. However, Berger's high BC 210 gr. bullets made this an interesting project. This project, in fact, is far from finalized, but I'll give you a bit of background on it and where it stands right now.

A couple of years ago, when Bob Jensen and I were pressure testing some .30-06 loads, we found that using H4831sc with the 200 and 210 grain bullets, we were unable to reach SAMMI maximum pressure. There simply wasn't enough case capacity in the Winchester, Lapua and Lake City brass we were using and we reached the point of noticeable powder crunching at about 8,000 psi below maximum allowable pressure. We switched to H4350, which is really more suited to the .30-06 case and had no problems reaching SAMMI maximum, then we worked down from there to find our accurate load. That is my usual method for developing a load when using the pressure testing equipment: find instrumented max pressure and work down - that avoids the problem of going past maximum.
Norma .30-06

That should have been the end of the load development project for the 200 gr. and 210 gr. bullets, but it wasn't. As it turns out, those mild H4831sc loads, just happened to shoot exceptionally well at mid-range and left me curious about the powder's potential for long-range. The MV of the full-charge yet reduced pressure load with the 210 Berger is 2600 fps, whereas the H4350 load achieved 2700 fps; that leaves a remaining velocity at 1000 yards of 1.299 mach and 1.366 mach respectively. Either will do fine at 1000 yards as they are safely above the 1.2 mach "magic number." My interest in increasing the charge has more to do with testing for accuracy than in increasing MV for its own sake.


Winchester .30-06
With the goal of modestly increasing the powder charge to get a bit closer to the pressure range at which I normally find good accuracy, I began a long project of weighing and checking the case capacity of just about every type of .30-06 brass I could get my hands on. The four that are shown here, Norma, Winchester, Lake City and Lapua, are the most easily found makes of good quality brass. I found some heavier types, such are Remington and Federal that were close to 200 gr., and many more in between the weights shown.

With all this data in hand, I decided to focus on the Norma brass for long-range load development with H4831sc and the 200 gr. and 210 gr. bullets.

The Norma brass, which weighs approximately 176 gr., allows the use of approximately 2 gr. more powder than I previously used before the powder crunching becomes excessive (by my subjective standards of "excessive"). Of course, because the case has more internal capacity, the effect of this additional powder is not as great as if two grains of powder were added to the previously used, lower capacity case. Nonetheless, I think this brass will be useful in my experimentation.
Lake City 62 Match

Despite having one of the country's great 1000 yard ranges within a few miles of home, my opportunities for 1000 yard shooting are actually quite limited. Our club has only a dozen or so days scheduled on that range and these are largely compressed into a three month time frame in the Fall. Accordingly, much of my testing and load development takes place at 500 yards and 600 yards as those matches are held with far greater frequency.

In November of 2010, I fired the Arizona Long Range State Championship matches (two days at 1000 yards) with my standard load of 53.5 gr. of H4350 and the Sierra 190 Match King at 2800 fps. This was before I had the Norma brass and those two matches provide a good baseline for further testing.  In the first match, I shot a 585-21X (196-06, 198-08, 191-07) followed by a rain shortened 388-13 the second day (198-07, 190-06) for a total of 973-34X. Conditions were cold and windy with rain increasing until the last stage of the match had to be cancelled. Although not ideal conditions for a baseline test, conditions are often unpredictable at 1000 yards and five strings of fire gives a good idea of the load's capabilities.

Lapua .30-06
The next 1000 yard match on the schedule was January 23; I loaded the Norma brass with 56.5 gr., 57.0 gr. and 57.5 gr. of H4831sc and the 210 Berger BT. The top load is 1.0 gr. above my previous load with the Lapua brass and I expected it to be about equal in pressure and velocity to that load. If the load performed well, with no signs of excessive pressure, I planned to increase incrementally from there at the next session

Unfortunately, the wind on the 23rd was so strong that the match was cancelled as it was impossible to manipulate the targets into the frames and dust storms were blowing down the range. A few hours later, when the wind was down to 25 mph or so, a handful of us managed to shoot a string for practice. With the 57.5 gr.load, I shot a 195-10X which left me very encouraged as the 210 Berger held good windage and the load showed minimal elevation dispersion.

With the 1000 yard matches almost done for the season, I next tried the combination at a 600 yard match. Owing to the limited supply of the 210 Bergers on hand, I loaded the Norma brass with 57.5 gr. of H4831sc and the 200 gr. Sierra Match King. The Sierra 200 has a bearing surface of approximately 0.480", essentially the same as the 0.481" bearing surface of the Berger 210 BT (see, Litz, Applied Ballistics for Long Range Shooting, 2009, p. 469). Bearing surface is an important determinant of pressure; drawing on the data from the earlier pressure tests, I was aware that the load would generate very similar pressure with either of these two bullets. The lower BC of the Sierra was not an important factor for a 600 yard match and I was principally interested in pressure and elevation dispersion.

Norma .30-06 Fired with 57.5 gr. H4831sc, moly-coated 200 gr. Sierra
The 600 yard match proved to be a good test of the load under relatively calm conditions. A total score of 597-37X (199-13, 199-14, 199-10) showed excellent performance and no signs of excessive pressure as shown in the photo of the fired cases. In each stage I managed to shoot one high shot when my follow-through was less than perfect, but overall I was very pleased with the load's performance.

I won't have another opportunity to shoot 1000 yards until late April when Phoenix's notorious spring winds will be in full force. I'm hopeful that the 210 Berger will be a good choice then. In the meantime, I plan to test a slight increase in the load at some of our mid-range matches. This is an interesting and promising project, but it's far from complete at this point.
 

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