Glock357
Active Member
I have been reloading and learning and I thought I would share my results with you all. I worked up the loads published either in the powder or the bullet manuals, or in the case of SPEER 130 gr SPBT I used the data published by other reloaders as my maximum loads.
All the data have been collected over two shooting sessions in 43 and 64 F average temperatures. I used the Caldwell chronograph and the companion ipad app to record the speed of the bullets. I had troubles getting the chronograph to work consistently as clouds were moving in and out so some speed data is missing. Also whenever I wasn’t able to record at least five shots the standard deviation was not calculated. Similarly with estimating the group size if I did not fire 3 or more shots the group size was not estimated. The group size was estimated as the diameter of the largest circle that can fit over a group, or in other words, the distance between the two bullet holes that are furthest apart. I always used the center of a bullet hole to make the measurements.
All the shots were fired from the same rifle with a bison armory barrel: 20 inch stainless 1:11 twist 4 groves, 11 degree crown and rifle length gas system with SPCII chamber. (see http://www.mdshooters.com/showthread.php?t=139167)
I am reporting results for Hodgdon 322, Benchmark, IMR 8208 XBR all with CCI41 primers.
I loaded the Hornady 110 gr V-max, 120 gr SST and the Speer 130 gr SPBT.
The Hornady 110 gr V-max measures 1.0350-1.0385' in length with 0.37 BC
The Hornady 120 gr SST measures 1.117-1.120’ in length with 0.400 BC
The Speer 130 gr SPBT measures 1.0800-1.0905' in length with 0.449 BC
All are 0.277’ in diameter.
For all the reloads I used the Hornady 6.8 spc case once fired trimmed to 1.675’. Its weight is 119 grains and its water capacity is 36.4 grains.
All the bullets were loaded to 2.294-2.300’ case overall length.
Just for comparison below I am listing the speeds and groups for the factory loads I had on hand (all at 100 yards):
Hornady 110 V-max : fps: 2701 +- 39 group: 0.759’
Hornady 120 SST : fps: 2652 +- 17 group: 1.1’
S&B 110 gr FMJ : fps: 2733 +- 19 group: 0.751’
Now for some reason these loads were pretty hot in my rifle with the Hornady 110 V-max the hottest with a couple of cases failing to eject. Even though the S&B was the fastest it was the mildest of the bunch (probably uses a slower powder). Is it possible that factory ammo manufacturers stopped loading for the older SAAMI chambers or my 20 inch barrel makes such a difference?
Please note that the comments and conclusions I make only apply to this caliber and my rifle. You might experience different results in other calibers and rifles.
All the data have been collected over two shooting sessions in 43 and 64 F average temperatures. I used the Caldwell chronograph and the companion ipad app to record the speed of the bullets. I had troubles getting the chronograph to work consistently as clouds were moving in and out so some speed data is missing. Also whenever I wasn’t able to record at least five shots the standard deviation was not calculated. Similarly with estimating the group size if I did not fire 3 or more shots the group size was not estimated. The group size was estimated as the diameter of the largest circle that can fit over a group, or in other words, the distance between the two bullet holes that are furthest apart. I always used the center of a bullet hole to make the measurements.
All the shots were fired from the same rifle with a bison armory barrel: 20 inch stainless 1:11 twist 4 groves, 11 degree crown and rifle length gas system with SPCII chamber. (see http://www.mdshooters.com/showthread.php?t=139167)
I am reporting results for Hodgdon 322, Benchmark, IMR 8208 XBR all with CCI41 primers.
I loaded the Hornady 110 gr V-max, 120 gr SST and the Speer 130 gr SPBT.
The Hornady 110 gr V-max measures 1.0350-1.0385' in length with 0.37 BC
The Hornady 120 gr SST measures 1.117-1.120’ in length with 0.400 BC
The Speer 130 gr SPBT measures 1.0800-1.0905' in length with 0.449 BC
All are 0.277’ in diameter.
For all the reloads I used the Hornady 6.8 spc case once fired trimmed to 1.675’. Its weight is 119 grains and its water capacity is 36.4 grains.
All the bullets were loaded to 2.294-2.300’ case overall length.
Just for comparison below I am listing the speeds and groups for the factory loads I had on hand (all at 100 yards):
Hornady 110 V-max : fps: 2701 +- 39 group: 0.759’
Hornady 120 SST : fps: 2652 +- 17 group: 1.1’
S&B 110 gr FMJ : fps: 2733 +- 19 group: 0.751’
Now for some reason these loads were pretty hot in my rifle with the Hornady 110 V-max the hottest with a couple of cases failing to eject. Even though the S&B was the fastest it was the mildest of the bunch (probably uses a slower powder). Is it possible that factory ammo manufacturers stopped loading for the older SAAMI chambers or my 20 inch barrel makes such a difference?
Please note that the comments and conclusions I make only apply to this caliber and my rifle. You might experience different results in other calibers and rifles.
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