Monday, December 16, 2013

Load development, 30-06 version....

They laughed.

They called me a dreamer

One load that shoots great in three completely different rifles..... they said I was hunting a unicorn.  Well folks... there's a plate of grilled unicorn chops waiting on the table.

The three rifles, all in 30-06, are an M1 Garand, an 03-A3 Two groove Springfield, and an Interarms Mauser.  All are box stock, the military rifles in full as-issued trim, and the Mauser sporting a simple inexpensive 4x scope.

The goal.... one handload recipe that shoots very, very well in all three rifles.  Given that, the press will be engaged and ammo cans full of the recipe will be loaded  (Given available supplies, of course.)

First, a little history on the 30-06 round.  

The 1903 Springfield rifle, admittedly a pilfered design variation of the 1898 Mauser, was designed for a rimless bottle-necked cartridge of high capacity.  After the US military came up against the flawless dependability of the little 1895 Mauser rifles in the hands of Spanish soldiers in Cuba, with their flat shooting high velocity 7mm cartridges, they knew they had to improve their armory.

At first, the 03 Springfield was supplied a cartridge loaded with a 220 grain blunt slug last known in the 30-40 Krag.   Seeing the Germans field a 150 grain Spitzer pointed bullet in their 8x57mm ammunition, the US army realized quickly the better ballistics offered by the new bullet was a winner, and the 03 round was redesigned to suit.... and renamed the 30 caliber round of 1906, or 30-06 as it's still named to this day.

Being faced with a serious demand for long range performance during WW1, mostly for machine gun fire, the Army switched to a 173 boat tail bullet at somewhat higher pressures. This extended the useful range of the 30-06 from about 4000 yards to almost 6000, with better accuracy to boot.  

After the war, the 30-06 round was redesigned with a lighter powder charge and a 150 grain bullet to reduce velocity, recoil.... and range.  The wartime round was found to have TOO much oomph for the army firing ranges of the day, and rather than enlarge the ranges they simply de-oomphed the ammo.

Since that time the 30-06 M-2 150 grain load has been the standard military loading.  There have been a number of specialized recipes since then, and an uncountable number of civilian loadings.  The 30-06 has taken just about every known game on every continent in the world, and was the target competition cartridge of choice for several generations.  Military snipers used the 30-06 rifle from early the1900's all the way into VietNam and Korea.  To this day, it's still a popular sporting cartridge, surely due to a long history of Just....Plain..... Working.

The 30-06 is typically found in commercial loadings with bullets ranging from 150 to 180 grains.  Hand loaders have somewhat wider options, and data is available for bullets weighing in at 110 grains, all the way up to 220 grains, and a plethora of cast bullet loads as well.  When it comes to versatility, the '06 has earned its reputation as one of the most flexible cartridges there ever was.

Now, over the years I've experimented with most of the possible loadings in this genre, excepting the sabot reduced caliber rounds featuring .22 caliber bullets at .220 swift velocities.  This time, the goal is something different.  One load, one recipe, that will make multiple rifles each perform as if the load was designed solely for it alone.  To reach that goal, it was a trip back to basics.   Careful case preparation, a bullet noted for accuracy in this caliber, and a powder literally designed for the 30-06 cartridge.

Of the three rifles, the joker in the deck is the M1.  It's built for a certain range of bullets and a very specific pressure curve to operate it's gas system.  A bullet too heavy, or a powder too slow, and the rifle can be damaged.  Both the two-groove Springfield and the Mauser performed better with a bullet heavier than the standard 150 grain bullet used in the M-2 loading, and 180 grain is widely considered the edge of too heavy for an unmodified Garand. Taking all into account, a 168 match style bullet was chosen.  All three rifles shot it decently.

There are a number of good bullet makes and models in the 168 grain weight for 30 caliber rifles.  If a stellar performing load was found, then it might be possible to substitute bullets with little loss of accuracy.

Thus began an odyssey of load development, experimenting with various powders, charge weights, primers, bullet seating depths, and crimp amounts.  Each factor opened a new vista of possibilities and variations.

Like many trips, no matter the miles out it on, it was only to return home and find the best answer was right where we began.

IMR-4895 was originally a military powder, and it was designed expressly for the 30-06 cartridge.  It supplies the pressure curve the M1 requires, when mated with suitable bullets.  In addition, it burns efficiently at the pressure generated in the 30 caliber bore, and proper loads usually fill the 30-06 case nicely for a consistent burn and stable velocities.

Running through various charge weights of IMR4895, each rifle responded best to slightly different amounts of powder, but there was a pattern.  Followed to it's logical conclusion, a load with exactly 47 grains was tried in all three rifles... with astonishing results.

The Garand

The Springfield

The Interarms Mauser

All groups were fired from the bench, but rested from the hand. The military rifles were fired in five shot groups, and the light barrel sporter in three shot groups.  Using 'The Load', the Garand could hold groups under 2", the Springfield cut .5" off that, and the Mauser easily, shockingly,  kept all it's bullets touching at 100 yards.  In the group shown here for the Mauser, the bullet hole to the top side was actually a called flier  (God Bless those Appleseed skills!).

Here's the recipe:

  • Cases:  Remington brass. Full length sized, and trimmed to 2.495".  Case mouth chamfered inside and out, and then internally polished with a brass bore brush mounted in a low speed drill.  The flash holes were de-burred, and the primer pockets squared and trued with a Sinclair tool.  Cases were decapped and polished prior to sizing and prep work, and then polished again to remove lube.
  • Primers:  CCI Large rifle Benchrest primers, seated using an RCBS press mounted Ram-Prime tool to assure seating depth and pressure.
  • Powder:  Exactly 47.0 grains of IMR 4895, thrown from a Hornady measure and then trickled a granule at a time into an RCBS 10-10 beam scale.
  • The bullet:  A Hornady 168 grain BTHP
  • Bullets were seated to an overall length of exactly 3.30", with a comparator based measured length of 3.70", using a standard RCBS seating die.
  • Case necks were crimped using a LEE Factory Crimp Die.
That's it.  That's the magic load, which appears to be basically a traditional accuracy recipe for most 30-06 rifles.  I wouldn't skip a single step, believing every detail to be important.

The load fit's, functions, and fires reliably in all three rifles.  Beyond that, it provides accuracy and consistency that is nothing short of astounding.

So... having found 'the load', case prep work has begun on what my Daddy would have called a 'Big 'Ol Mess' of cases (in excess of three hundred) and as supplies are found they'll all be loaded to these specs.


Anonymous said...

Great article! I've always been a fan of the 30-06 for the same reasons that you talked about. It's not the newest or sexiest...but it works like a champ!
I'm really enjoying your articles on reloading too. I haven't done any since I was a teenager in the 80's with my dad and have been wanting to get into it. Time to break out the old Rockchucker!
Let me also say thank you for puting out such an enjoyable blog. It's always informative and a genuine pleasure to read, I'm really glad I found it.
Anon in the Ozarks.

Firehand said...

May I ask, what charge range did you find listed for that weight bullet? I can't find some notes right now, 47.0 is right at max for the Garand, is it not?

Carteach said...

IMR shows 48 to 52.2 grains of 4895 in that bullet weight. It's actually on the bottom end of reliably operating the Garand.