case capacity sensitive powders

[chas442]

It appears that the general consensus is that rifle cartridges for the most part are most consistent when the powder charge is at or near 100% capacity. I am sure there are a lot of handloaders that are using powders that do not totally fill the case and still get excellent accuracy.
I would appreciate it if those handloaders would relate their experiences with less than full cases. If you could include the powder type, chrono info if available and the caliber used. Actual powder charge is not necessary but could be helpful.

 

[Cemetery21]

I use AA 2200 in some .223 and .20 Practical loads. Near max loads are well below the body/shoulder junction and they touch holes at 100 yards.
Two years ago, I built 2 .20 Practical rifles for prairie dog hunting. I had less of my preferred powder than I did 2200, and powder was hard to get. So, I worked up loads for one of them with 2200 and it shoots as well as the one using Xterminator. I've used 2200 for some bolt gun 223 loads for years with excellent results. Seems to burn cleaner and equals the velocity on my warm loads with powders that fill to the base of the neck.
You should get a lot of response from Garand shooters because they have to use faster powders due to the design/construction of the gas system.

 

[Bart B.]

As long as charges less than 100% load density rest in the same place the same way for every shot, it won't make any significant difference. Just pick up, handle, then load them the same way for each shot.

 

[outlawjw]

Most of my best loads are 89 to 93% case fill 1/2 min or less with 50 to 150 fps less than max. But I do work up loads for hunting with Max or higher velocities generally with 1 min to a little less in accuracy. In all cases I limit myself to a range that will cause DRT hits with the loads & bullet combinations .
Have worked up tighter groups I would consider for comp but generally at a much reduced load , like 80 to 84% case capacity

 

[DeadEye9]

It appears that the general consensus is that rifle cartridges for the most part are most consistent when the powder charge is at or near 100% capacity. I am sure there are a lot of handloaders that are using powders that do not totally fill the case and still get excellent accuracy.
I would appreciate it if those handloaders would relate their experiences with less than full cases. If you could include the powder type, chrono info if available and the caliber used. Actual powder charge is not necessary but could be helpful.

I use a combination of compressed and non compressed loads depending on bullet I'm using in .223/5.56. For the 69gr BTHPs(Sierra MatchKing, Barnes Match Burner, etc.) I run nearly a full case (~25.5gr) of Varget with excellent results. For my 52gr BTHP Hornady Match load however I use CFE223 at around 27.3gr. I load the 69 @ 2.235" & the 52 at 2.205". I always use CCI small rifle primers for this caliber and my brass typically consists of IMI, LC, WCC, TAA NATO as well as FC, Speer, PSD/PMC commercial brass. I've found all of these cases to work well for my needs. I run these loads in 16-18" ARs with 1:9 twists and get around 3/4 MOA with both loads. Different approaches, same results. In the case of the 52gr this is a very low pressure/tame loading. It could be cranked up much hotter/ faster with a different powder or even more of the same powder however for this particular load there was no need. I went as high as 28+ Grains CFE with that bullet and velocity increased but accuracy did not. If I were looking for a varmint killing load maybe 28+gr and 3450+fps would be the ticket, but for accuracy in my semi auto rigs it's the 27.3 @ 3275 fps load that gets the nod. I also run less than full cases of H335 for my homegrown M193 55gr FMJ BT loads. Without checking my notes I think my go to target load gets 25gr even @ 2.215" with a Winchester bullet. That's roughly 3025fps from a carbine if memory serves.