The “best” load for a rifle is assumed by many shooters to be the one that contains enough powder to maximize velocity without getting signs of excessive pressure. However, I don’t necessarily agree with that.
Sometimes a shooter does need the most velocity he or she can get, for example for shooting very long distances, to get sufficient stopping power at longer distances, or simply to minimize trajectory. However, sometimes factors like consistency, accuracy, recoil, case life, and barrel life are just as, or more, important than high velocity.
I found what I think is a good example this last weekend.
I have been doing load development for my Sako TRG 42 338 Lapua bolt rifle. The 338 Lapua round, and this rifle, both support very long range shooting. I like that, as I finally have access to a long range shooting range, with Larue popper targets that can handle 338 Lapua, and where I can teach myself all about proper consistent hold, wind doping, holdover, and scope adjustments. However, case life and barrel life are also concerns for me, as new Lapua cases cost about $2.75 each now (recent price increase), and barrel life can be dramatically short when loading to the full power levels that the cartridge can support. And, the maximum rnage available to me is 1000 yards, which is far shorter than full power 338 Lapua loads will support. Why beat up the cases, the rifle, me, and my wallet by loading higher power, more costly loads than I require for the circumstances available to me? And, if could shoot loads that are easier on the cases, won’t they not only last longer, but also perform more consistently for more of their life?
So, I studied several loading manuals, settled on Lapua cases, the Sierra 300g Matchking bullet, Federal Large Rifle (215) primers, and Hodgdon Retumbo powder. The accepted minimum and maximum loads for this combination, per the Hodgdon loading manual, are 85.0 grains and 94.0 grains respectively. The Hodgdon manual in fact says that the 85g load delivers 2376 fps while generating only 41,100 CUP pressure, while the 94.0g load delivers 2654 fps at the expense of much higher pressure: 53,400 CUP. So, you get only 278 fps, or 11.7% more velocity while creating almost exactly 30% more pressure!
Another way of looking at this is more positive: By accepting 10.5% less than maximum velocity, you cut pressure by 23%.
This disproportional relationship, of relatively large pressure reductions producing only relatively smaller velocity losses, is true of every powder I have ever examined. I wondered what kind of different velocity / accuracy / pressure combinations I could find if I started at 85g and worked my way upward to say 91 grains or so, a grain at a time, and then in finer increments.
That proved very interesting.
By loading up a large number of cartridges, and firing them at 100 yards in multiple sessions, it very quickly became apparent that for MY specific TRG rifle, all the loads in that range except 86.0 grains were very accurate, with only very small changes in elevation, but the 87.0 grain load consistently made better groups over time than any of the others did. The difference was enough to show up at each range session. Even my shooting buddy remarked on how good it looked. When I stretched it out to 250, 500, 750, and 1000 yards, it continued to perform consistently. I began to view this load with increasing favor. I wondered though if it had “enough” velocity to make for good terminal ballistics at 1000 yards.
This past weekend I took my brand new CED M2 chronograph out to the range, and did some velocity measurement for this load. The results were surprisingly good:
Average fps was 2573 fps! This is 97% of the fps listed by Hodgdon for the “maximum” load (the max load by the way also is slightly compressed, making it impossible to sue with Redding Competition dies, as the compression hurts the internals of these precision dies).
The Extreme spread was 37 fps.
The standard deviation was 10.3, which I’m told is pretty good.
Here’s the best part: When I was down to only 56 cartridges left, I fire one shot to get a point of impact versus point of aim at 100 yards, adjusted the scope, and then fired a 5-shot group at the corner of an orange square on the target. I messed up one of the shots a bit. Here is a scanned image of the target sheet:
Note that even with the one slightly messed up shot, the entire 5-shot group is only 5/8 inch.
Note that without that one shot, the other 4 make a 3/8 inch group (actually just a bit less than 3/8 inch).
I can live with that.
But, it gets better.
Plugging the numbers into the “Shooter” app on my iPhone, and doing some additional math, the muzzle energy is over 4400 ft lb. Going to the full Hodgdon maximum would have given me 4700, an increase of only 6%.
Going to the full Hodgdon load would also use 8% more powder, and generate a lot more pressure that would degrade case life. And, per the handy barrel life worksheet that someone posted the link to recently, going to that maximum load would also cut projected barrel life from 2200 rounds to 1550. So, by going with the lighter load, I get over 40% longer barrel life.
At 1000 yards, I still have almost 1700 ft lb of energy. To put that in perspective, this is 3 times as much energy as my 308 LMT MWSE will have at that range. It’s also about 3 times what a 357 Magnum revolver has at the MUZZLE. Both the 308 and the 357 are viewed as good stoppers of both 4-legged and 2-legged predators, so having that much more energy on tap with my “mild” 338 Lapua load gives me a warm feeling about carrying adequate stopping power.
And here’s another zinger: If I ran the maximum Hodgdon load, I’d still have only 1800 ft lb of energy at 1000 yards. That’s an increase of under 6%. And, per the Shooter app, my scope adjustment would only be 2 MOA smaller (about 28 MOA versus about 30 MOA).
So, in summary, my mild load gives me great consistency, superb accuracy, less recoil, long case life, and way longer barrel life. What’s not to like?
For me, this milder load is the “best” load for my circumstances. “Your mileage may vary.”
Jim G
Sometimes a shooter does need the most velocity he or she can get, for example for shooting very long distances, to get sufficient stopping power at longer distances, or simply to minimize trajectory. However, sometimes factors like consistency, accuracy, recoil, case life, and barrel life are just as, or more, important than high velocity.
I found what I think is a good example this last weekend.
I have been doing load development for my Sako TRG 42 338 Lapua bolt rifle. The 338 Lapua round, and this rifle, both support very long range shooting. I like that, as I finally have access to a long range shooting range, with Larue popper targets that can handle 338 Lapua, and where I can teach myself all about proper consistent hold, wind doping, holdover, and scope adjustments. However, case life and barrel life are also concerns for me, as new Lapua cases cost about $2.75 each now (recent price increase), and barrel life can be dramatically short when loading to the full power levels that the cartridge can support. And, the maximum rnage available to me is 1000 yards, which is far shorter than full power 338 Lapua loads will support. Why beat up the cases, the rifle, me, and my wallet by loading higher power, more costly loads than I require for the circumstances available to me? And, if could shoot loads that are easier on the cases, won’t they not only last longer, but also perform more consistently for more of their life?
So, I studied several loading manuals, settled on Lapua cases, the Sierra 300g Matchking bullet, Federal Large Rifle (215) primers, and Hodgdon Retumbo powder. The accepted minimum and maximum loads for this combination, per the Hodgdon loading manual, are 85.0 grains and 94.0 grains respectively. The Hodgdon manual in fact says that the 85g load delivers 2376 fps while generating only 41,100 CUP pressure, while the 94.0g load delivers 2654 fps at the expense of much higher pressure: 53,400 CUP. So, you get only 278 fps, or 11.7% more velocity while creating almost exactly 30% more pressure!
Another way of looking at this is more positive: By accepting 10.5% less than maximum velocity, you cut pressure by 23%.
This disproportional relationship, of relatively large pressure reductions producing only relatively smaller velocity losses, is true of every powder I have ever examined. I wondered what kind of different velocity / accuracy / pressure combinations I could find if I started at 85g and worked my way upward to say 91 grains or so, a grain at a time, and then in finer increments.
That proved very interesting.
By loading up a large number of cartridges, and firing them at 100 yards in multiple sessions, it very quickly became apparent that for MY specific TRG rifle, all the loads in that range except 86.0 grains were very accurate, with only very small changes in elevation, but the 87.0 grain load consistently made better groups over time than any of the others did. The difference was enough to show up at each range session. Even my shooting buddy remarked on how good it looked. When I stretched it out to 250, 500, 750, and 1000 yards, it continued to perform consistently. I began to view this load with increasing favor. I wondered though if it had “enough” velocity to make for good terminal ballistics at 1000 yards.
This past weekend I took my brand new CED M2 chronograph out to the range, and did some velocity measurement for this load. The results were surprisingly good:
Average fps was 2573 fps! This is 97% of the fps listed by Hodgdon for the “maximum” load (the max load by the way also is slightly compressed, making it impossible to sue with Redding Competition dies, as the compression hurts the internals of these precision dies).
The Extreme spread was 37 fps.
The standard deviation was 10.3, which I’m told is pretty good.
Here’s the best part: When I was down to only 56 cartridges left, I fire one shot to get a point of impact versus point of aim at 100 yards, adjusted the scope, and then fired a 5-shot group at the corner of an orange square on the target. I messed up one of the shots a bit. Here is a scanned image of the target sheet:
Note that even with the one slightly messed up shot, the entire 5-shot group is only 5/8 inch.
Note that without that one shot, the other 4 make a 3/8 inch group (actually just a bit less than 3/8 inch).
I can live with that.
But, it gets better.
Plugging the numbers into the “Shooter” app on my iPhone, and doing some additional math, the muzzle energy is over 4400 ft lb. Going to the full Hodgdon maximum would have given me 4700, an increase of only 6%.
Going to the full Hodgdon load would also use 8% more powder, and generate a lot more pressure that would degrade case life. And, per the handy barrel life worksheet that someone posted the link to recently, going to that maximum load would also cut projected barrel life from 2200 rounds to 1550. So, by going with the lighter load, I get over 40% longer barrel life.
At 1000 yards, I still have almost 1700 ft lb of energy. To put that in perspective, this is 3 times as much energy as my 308 LMT MWSE will have at that range. It’s also about 3 times what a 357 Magnum revolver has at the MUZZLE. Both the 308 and the 357 are viewed as good stoppers of both 4-legged and 2-legged predators, so having that much more energy on tap with my “mild” 338 Lapua load gives me a warm feeling about carrying adequate stopping power.
And here’s another zinger: If I ran the maximum Hodgdon load, I’d still have only 1800 ft lb of energy at 1000 yards. That’s an increase of under 6%. And, per the Shooter app, my scope adjustment would only be 2 MOA smaller (about 28 MOA versus about 30 MOA).
So, in summary, my mild load gives me great consistency, superb accuracy, less recoil, long case life, and way longer barrel life. What’s not to like?
For me, this milder load is the “best” load for my circumstances. “Your mileage may vary.”
Jim G
