As most experienced handloaders should know by now, gun powders vary in burn rate depending on application and other conditions, despite where they may appear in a list of powders from the fastest to the slowest. Such caveats are made in most reloading manuals, with the attendant cautions.
Yet most Internet “handloaders”, in looking for the “right” powder for their new-to-them rifle, want answers or suggestions as to the best powder to start with, and perhaps finish with. To be fair, we all need solid information from manuals when we begin the reloading process of an unfamiliar cartridge. In my more recent situation, it was nearly six years ago when I purchased a new rifle chambered for the 9.3 X 62 “Mauser”. (Of course, “Mauser” is not part of the official nomenclature, but was added due to the new (in 1905) cartridge being originally chambered in Mauser 98 rifles.)
Because of a lot of indispensable handloading experience with a .35 Whelen and a .350 Remington Magnum, both within .008″ of the same bore diameter as the 9.3 X 62mm (.366-caliber), I was not completely in the dark as to what powders might work best. So I started with Alliant Reloader 15, which had worked very well in those two. It gave best results overall in each, both in accuracy and speed. However, I was to learn some additional lessons over the next few months about the matter of assumptions when it concerns the supposed behaviour of a particular powder under certain conditions.
Too many variables are involved in starting a reloading process for a new rifle, especially if it also relates to a new cartridge as well, to justify certain assumptions.
Here are some issues I had learned in using RL-15 in the .35 Whelen, the .350 Rem Mag and a .375 H&H. While it worked very well as a medium burn-rate powder in all three, there were some surprises. What were they?
First off, it worked a whole lot better in the .350 Rem Mag than in the .35 Whelen, which are supposed to be nearly ballistic twins in potential. As before explained, my .35 Whelen (not “Whelan” as some write it) was chambered in a semi-auto Remington 7400 with a very long magazine clip and throat to match. Bullets could be seated to a COL of around 3.40″ allowing the use of 63 grains of RL-15 behind the 250gr Hornady SP and 250gr Speer SPHC for an MV of slightly over 2600 fps without any issues whatsoever. Yet in working toward the same load when applied to the 250gr Nosler Partition, some primers were blown. Not only that, but I had to reduce loads for the Nosler to around 57 grains of RL-15 for less than 2500 fps! If we pay attention, we can learn something of value from such experiences — and NOT only what some may believe.
In applying RL-15 to loads in my 26″ .375 H&H, I was getting a consistent 2700 to 2715 fps behind 300gr Hornadys (the 300gr Nos. Part. had not yet returned to their repertoire.) and, as I recall, the 300 Sierra as well. But IMR4320 was doing the same thing within a grain or two. The IMR4320 was a book load for a 26″ barrel that showed within 5 fps the results I was getting from my 26″ Browning. And I had thought RL-15 was a “new” miracle-working powder! In powder lists of fastest to slowest, both RL-15 and IMR4320 now appear on the same line, indicating they have an equivalent burn rate. Yet no one ever mentioned that in “the literature” of the time.
(Very similar powders in burn rate and application)
Back to the .350 Rem Mag — It was the re-introduction of the .350 Rem Mag which had a heavy laminated stock, a steel rib on the barrel (for nostalgic reasons, though the original was plastic – not practical other than to add weight) and a heavy barrel (to add more weight, since the originals – M600 and 660s — where deemed too light creating dislike for those with sensitive shoulders). It was designated Model 673. I’d owned the original “Classic” when it appeared, and it was a beautiful rifle with walnut stock, 22″ barrel and short M7 action. But it wouldn’t produce the velocities I wanted with the powders available at the time, so it was traded for another 1895 Marlin in .45-70. However, when I bought (or traded for) the M673, it was obviously too heavy, but had the short action and a 22″ barrel — that produced the “goods” from RL-15. As mentioned, the .35 Whelen wouldn’t safely reach 2500 fps from the 250gr Nosler Partition. The most I could use of RL-15 behind the 250 NP was 57 grains for around 2475 fps from a COL of 3.40″. In contrast, the .350 Rem Mag would barely allow a COL of 2.82″. 60.5 grains of RL-15 was ALL I could get into a case and seat the 250 Speer Grand Slam to within 2.8″ to 2.82″ COL. That load gave me .338 Win Mag ballistics — I kid you not! And safely! The 250gr Speer GS worked best because it was shorter than the 250gr Nosler Partition and the 250 Speer HC. It would still give me about 2700 fps from those two and 2710 fps from the GS. The last group I ever fired from that rifle was with the 250gr GS at an average of three at 2738 fps into 3/8″ (one ragged hole) at 100 yards! The rifle was a club but would it shoot! And all that from an application of RL-15. Notice: RL-15 would NOT safely deliver 2500 fps from the 250gr Nosler Partition in my 22″, .35 Whelen with a COL of 3.40″, while it safely gave 2695 fps from the 250gr Nosler Partition and over 2700 fps from the 250gr Speer Grand Slam with a COL of 2.80 – 2.82″ COL in the .350 Remington Magnum! I guarantee this: You will not see that in any of the reloading books!
(The Remington 750 semi-auto in .35 Whelen nearly identical to my former M7400)
Yea, I know, lots of handloaders believe they know the answers to such matters, and most would say it was because the Nosler Partition is a “harder” bullet than the Speer or Hornady, and you NEVER use the same loads for different manufactured bullets. Some truth there, but that doesn’t ALWAYS work out that way either. As a matter of fact, I was able to use the same basic load for the 250 NP in the .350 Rem Mag as the 250gr Speer GS, minus 1/2 grain, and that was due to the fact of the 250 Speer GS being shorter than the 250 NP allowing that 1/2 grain extra while keeping the COL at an absolute max of 2.82″, not as a result of any disparity in the hardness factor between the two. I couldn’t get that 1/2 grain extra into the case using the longer Partition. At an average of 2695 fps, the Nosler still came within 15 fps of the Speer. So why did the .35 Whelen only safely allow 2475 fps from the same 250 Nosler Partition from an equal length barrel as the .350 Rem Mag, both made by Remington? There IS a meaningful disparity between 3400 ft-lbs from the Whelen and over 4000 ft-lbs from the .350 Rem Mag at the muzzle of rifles using the same premium bullet intended for big and possibly dangerous game! Other factors are involved which we’ll get into next time when matters that affect burn rate are discussed. With tongue in cheek I pose the following question: Could it possibly be that all barrels from the same manufacturer are not equal even though “the book” says they should be?
(My former M673 in .350 Remington Magnum.)
So! I assumed RL-15 to be by far the best for my new 9.3 X 62! It came close, but 3rd place isn’t gold!
This is off-topic somewhat, but it needs to be mentioned again because of some remarks made above regarding the overall “clubiness” of the Remington M673 compared to their “Classic” in the same chambering of .350 Remington Magnum. I would still have the “Classic” today if RL-15 were available at the time. And I would still have the M673 IF it had not been made in reaction to complaints over “felt recoil” of the models 600 and 660. What I wanted was what the Classic delivered in form and weight but with the ballistics that I got from the Model 673! Now that I have the T3 TIKKA Lite in 9.3 X 62, and a “new” powder that delivers more than expected, I have more than the two Remingtons could come up with even IF the Classic could have produced what RL-15 did in the M673! So the RIGHT powder in a particular application is THAT important to at least some of us.
All of the above is to highlight some powder application issues that will receive attention in that which follows in Part 2. In doing so, it will be necessary to give some basics on powder fabrication and function. This may seem boring to those somewhat advanced in knowledge and experience of these issues but, believe me, there are still many mysteries entailed even for the professionals. I will try to explain some of it, but it is like a slippery slope rather than hard physics. There are many generalities but few hard facts, as most seem to think are presented in their reloading books. I’d say, reloading books are Reloading 101 — excellent for beginners, not Reloading 404! And yet some manuals are better than others in that regard.
As always, I must state the following: THESE ARE/WERE MY LOADS IN MY RIFLES. YOU ALONE ARE RESPONSIBLE FOR SAFE HANDLOADING PROCEDURES. MY LOADS ARE NOT RECOMMENDATIONS, THEY ARE SIMPLY EXAMPLES OF POSSIBILITIES UNDER CERTAIN, AND PERHAPS “UNIQUE” CONDITIONS.
So, if this intrigues you, come back again where we’ll get into Reloading 202, and maybe 303.
FOR ANYONE INTERESTED: A member of our range, by the name of “Mike”, has a “pile” of once-fired Federal factory .308 Winchester brass, and some .30-06 as well, that he’d like to get rid of for about $50 Cdn. I’m unsure of how this would work for U.S. citizens, but for some Canadians he may be reached at 1-289-314-1215. Mike lives in The Greater Toronto Area.