Importance of Powder Weight

[CroceF]

Starting in 1975, accuracy tests at 300 yards commenced in a huge warehouse in Houston, TX. After several years and hundreds of thousands of rounds, many fired by the country's top shooters, some, to me anyway surprising conclusions were arrived at. Among them this one about powder:

"In this shortened 22PPC, he used IMR4198 exclusively. He adopted this powder after Don Geraci, an advocate of 4198, visited the warehouse. Although 4198 has a reputation for varying considerably from lot to lot, Virgil never bothered to lay in a big supply of any particular batch. “I just went out and bought some when I needed it,” he said. “Lot number didn’t make any difference.”

Within limits, neither did powder charge. Virgil threw his charges from a Culver conversion, and the grain-cutting operation obviously gave him reasonably consistent results with the long, little kernels, considering the excellence of the resulting groups. He did, however, later use a Belding & Mull powder measure in order to lessen the grain-cutting problem.

Powder charges, as long as they were fairly consistent and bracketed within a couple of grains, were not important, he said. On one occasion, as an experiment Virgil shot one group with his 6PPC barrel on the Cooper action using a 53 Culver setting of Winchester 748, the next 52 and the third 51. All three groups were identical.

I find that statement somewhat incredulous but wish I were wrong on that point. Sure would be nice to be able stop weighing and fussing with powder loads. How do members of this forum feel about it?

The entire article, a 10 or 15 minute read, can be seen here:

http://www.angelfire.com/ma3/max357/houston.html

 

[bsumoba]

this might be true for 100, maybe 200 yard shooting. But, for guys shooting 600+ yards, a half grain spread could result in bad ES/SD and as a result, huge vertical dispersion.

I know powder weight will vary depending on the atmospheric conditions that day. This is why I reload as close to the day I am going to shoot the match and I do not split reloading days (say I need to shoot 80 rounds in a match, I will not reload say 40 rounds one day, then 40 rounds another day).

 

[LHSmith]

In the story, Virgil commits so many no-no's now known to degrade accuracy that I lost count in the first few paragraphs. For one thing, all their load data was good for only one thing - shooting inside a warehouse. In registered competition there is always "some" condition you have to adjust to ...match to match....and often shot to shot. Truth be known, the warehouse most likely had condition(s) that perhaps Virg knew how to adjust for.

 

[Fire306]

My father used to talk about a benchrest shooter he knew years ago that shot 222's, he said precise measuring of the powder charge was not important. He said when this guy reloaded the 222 he would scoop the powder into the case, level it off with the top of the neck and seat a bullet. Never weighed the charge.
I agree with whoever said, I think load charge isn't as important shooting inside 300 yards and most benchrest competitions are. Its when you stretch out distances that velocity spread shows a difference on target.

 

[amamnn]

as pertains to short range---it's not that the weight or mass of a given powder varies with conditions (mainly temperature) but volume varies--this becomes a factor for people who load at the match especially in the warmer climates where the temperature can change a lot through the day. This becomes something of a self fulfilling prophecy - I have to load at the match because the conditions vary which makes my volumetric measure inaccurate and I have to run the load up a couple of clicks because I am loading at the match where the temperature varies the volume of my powder as compared to its mass so I'd better load at the match so I can adjust the volume of powder-- this does not take into account the more complicated condition factors experienced in longer ranges........there, loads may be adjusted for reasons besides the "fluff" factor of powder as the day warms up.

 

[Danattherock]

I've linked that test, and the exact paragraph you posted, recently.

I have reads lots of threads here lately with folks bitching about scales not being accurate to 1/2 tenth, but I have not seen anyone post results where accuracy was effected by powder variations that small. Easier to complain about scales, no doubt. I think the Warehouse testing was rather extensive and I'm inclined to believe the claims. But I use a Chargemaster, so what do I know. Hah.


Dan

 

[CroceF]

In the story, Virgil commits so many no-no's now known to degrade accuracy that I lost count in the first few paragraphs. For one thing, all their load data was good for only one thing - shooting inside a warehouse. In registered competition there is always "some" condition you have to adjust to ...match to match....and often shot to shot. Truth be known, the warehouse most likely had condition(s) that perhaps Virg knew how to adjust for.

What you say is unarguable LH. At the beginning of the article I believe the writer stated that the warehouse provided ideal conditions. No wind, mirage to deal with etc etc so the variables encountered in the field were nullified. The only variable were those made or committed by the shooters. That is the peg that he hangs his hat on.

 

[CroceF]

My father used to talk about a benchrest shooter he knew years ago that shot 222's, he said precise measuring of the powder charge was not important. He said when this guy reloaded the 222 he would scoop the powder into the case, level it off with the top of the neck and seat a bullet. Never weighed the charge.
I agree with whoever said, I think load charge isn't as important shooting inside 300 yards and most benchrest competitions are. Its when you stretch out distances that velocity spread shows a difference on target.

I agree with what you say. Distance certainly does exacerbate the deviations. In the article it was stated that the distance inside the WH was 300 yards.

 

[rcol317]

Interesting note on 222's. I'm a "measure each load" guy but I have 222 Rem mag that shoots under 1/2 MOA with 24.5,25 or 25.5 grains of powder and many powders work well. I have some that .5 of a grain difference make a big difference. I'm sure the rifle, caliber and powders all make the difference.

 

[Brians356]

I agree with what you say. Distance certainly does exacerbate the deviations. In the article it was stated that the distance inside the WH was 300 yards.

I believe all Virgil's serious testing was at 100 yards, and the groups < 0.100" he coveted were certainly printed at 100. The warehouse was indeed much larger.

Edit:

Quote from the article: " ... in the warehouse they rarely fired at 200 and 300 yards."

 

[6BRinNZ]

My father used to talk about a benchrest shooter he knew years ago that shot 222's, he said precise measuring of the powder charge was not important. He said when this guy reloaded the 222 he would scoop the powder into the case, level it off with the top of the neck and seat a bullet. Never weighed the charge.
I agree with whoever said, I think load charge isn't as important shooting inside 300 yards and most benchrest competitions are. Its when you stretch out distances that velocity spread shows a difference on target.

I agree with what you say. Distance certainly does exacerbate the deviations. In the article it was stated that the distance inside the WH was 300 yards.

It doesn't even have to be velocity variations to cause issues. If you follow Erik cortinas 100 yard long range load dev process you will see that he advises that you look for a series of charges say .5 grns apart where the POI doesn't change. If you conduct that test yourself I would be surprised if you don't find powder charges where .5 grn or less increase produces a jump higher or lower in POI even though that group size might be small and in turn a series of charges where the POI change is minor or non existent.

The upshot is if you were shooting charges that bridged this jump/change in POI then you would be guaranteed to struggle at pretty much any distance even if the ES/SD numbers were within acceptable limits.

None of this disputes the testing in the warehouse and its results - like all things it is the application of the conclusions that determines whether or not you are successful.

Personally I don't get too hung up on it all and follow some simple rules i.e. for long range ES/SD is important and therefore whatever I can do to minimise has value.

 

[M14AMU]

My father used to talk about a benchrest shooter he knew years ago that shot 222's, he said precise measuring of the powder charge was not important. He said when this guy reloaded the 222 he would scoop the powder into the case, level it off with the top of the neck and seat a bullet. Never weighed the charge.
I agree with whoever said, I think load charge isn't as important shooting inside 300 yards and most benchrest competitions are. Its when you stretch out distances that velocity spread shows a difference on target.

" he would scoop the powder into the case, level it off with the top of the neck and seat a bullet"

Hmmm....what did he use to seat the bullet? Possibly a 40# sledge??

 

[daniel brothers]

with the correct type of powder that gave a safe load for that case size, it is possible to scoop... level... and crush seat a bullet for a safe and accurate load.

 

[Brians356]

with the correct type of powder that gave a safe load for that case size, it is possible to scoop... level... and crush seat a bullet for a safe and accurate load.

That's exactly how many chaps loaded the 22 Hornet - a "case full" of H4227 under a 40-grain bullet was "the load" for woodchucks.

 

[Tempest]

After spending much of this winter chrono'ing loads at various powder charges to find my node at given temp, and seeing the velocity spread, I will stick with precisely weighing them.