I won a Sierra Bullet Certificate at a PRS Match, so I decided to take the oppurtunity to test out the new 30 Caliber 200 grains Sierra Match King (#2231). This is one of the new high bc 30 caliber bullets launched this year and is probably their response to the 200.20x Berger Hybrid and 215gr Hybrid bullets. Sierra reports a measured G1 BC of .715 above 2000fps, and recommends a 9 twist barrel.
Rifle
The rifle I am using is a custom Sako TRG/S with a Lilja Mk.13 contour 1:10 twist barrel. This is less than the optimized twist rate specified by Sierra. According to my calculations, I am getting a gyroscopic stability factor of between 1.44 to 1.5 depending on temperature. I am also using the A191 Match chamber that is optimized for the heavy for caliber bullets. I am loading these bullets to 3.700 OAL which is the maximum length I can fit in an AICS CIP Magazine. These are much longer than SAMMI length.
Powder
I am using H1000. It is my go-to powder for 300 Winchester Magnum because it produces good velocities, good accuracy, and is stable across a wide range of temperatures. I feel that even a "bad load" with H1000 is still a pretty good load.
Brass
I am using Norma 300WM Brass. Norma brass is noticeably lighter than the other brands I have looked at. It probably offers increased powder capacity. I haven't done a water test to verify it. Norma brass is the best brass I have been able to consistently get, however I don't have super strong feelings about it one way or the other. I think there might be more companies making better brass that wasn't available when I got my Norma brass. Norma has so far been good to me.
Primers
I am using CCI 450 (whatever the standard large-rifle primer is). I shoot in a hot environment and so far have had no ignition issues to speak of. None that have shown up in the field, or on the target. However if I was in a colder climate, I would strongly consider the CCI magnum primers for peace of mind, or at least test the standard primers in cold weather before offering a verdict.
Dies/Press/Powder Throw.
I am full length sizing my cases with an RCBS die that has a neck bushing. I cannot recall the neck bushing, but I think it provides 1 to 2 thousandths of neck tension. It's not a lot.
I am seating with a Forster Benchrest Seating die.
All loading is done on a Harrels Press.
I throw my charges with the standard RCBS Charge Master. I set the charge and I will pull powder out or trickle it in to get to the final charge. I don't have a lab scale to see how accurate the charge master is, but internet lore says that it's to within about 2/10ths of a grain.
Load Development Method.
I loaded 15 rounds of ammo in groups of 3 separated by 1 grain increments from 77 to 81 grains with the intention of shooting them over the chronograph to get an idea of pressure limits for this bullet and powder combination. So far the other two heavy bullets I have used in this rifle have been exceptionally accurate in the 2900 to 2975fps range; those two being the 220 Lapua Scenar L, and the 215gr Berger Hybrid.
I fired 3 shot groups at 100 yards with a Magnetospeed Chronograph, and wrote down the velocities for each. I did give the barrel some time to cool, but maybe not as much as I should. I mainly look at group size and velocity spread to decide what loads are worth pursuing, but I do not put a huge stake in a 100 yard test with 3 shot groups. My main goal is to get a range of safe loads and velocity numbers.
If there is something that stands out as exceptional, I will test it at distance in the future, but I think that good ammo comes from mostly good reloading practices and not finding the perfect load.
Results
Weather. 75 degrees. Rainy. 66% humidity. Station Pressure of 29.92. DA 450ft.
77 Grains.
1: 2893
2: 2918
3: 2932
SD:20
ES:37
This might be a bad load, or it might be the velocity speeding up as the barrel gets hotter. I am not 100% sure.
78 Grains
1: 2953
2: 2949
3: 2949
SD:2
ES:4C
Change +36fps
This load might be the low node. I might have also got 3 rounds where the Chargemaster scale was dead on. This is a load that is worth pursuing in the future at distance as it produced a good group, good numbers, and is one that I feel would be plenty safe in hot weather. My trigger discipline on this group was also good and I felt I shot close to my potential.
79 Grains
1: 2991
2: 2978
3: 3000
SD:11
ES:22
Change: +39fps
The numbers are pretty representative of how the Chargemaster and H1000 perform if you pick a load at random. It's nothing to brag about but would be pretty good factory ammo.
80 grains
1: 3012
2: 3017
3: 3033
SD:11
ES:21
Change: +31fps
I let the barrel cool from the previous strings, so starting on a slightly colder barrel may have skewed the results slightly. Still pretty run-of-the-mil numbers.
81 grains
1: 3080
2: 3083
3: 3077
SD:3
ES:6
Change +60
This load stood out for a few reasons. It produced a group as well as the 78gr load, but I also put in a little extra effort to make sure I pressed the trigger straight to the rear because my previous two groups were a little big. I think my previous groups were a little big due to poor fundamentals more than anything else. I wanted to end on a high note.
It also stood out because it produced the second lowest velocity spreads over 3 rounds.
And it stood out because it showed a 60 fps change over 1 grain of powder. If velocity = pressure, then I suspect that I am close to the maximum load for this rifle. If I was to further increase the powder charge, I would definitely do it in 1/2 grain or less increments.
Conclusion
The 78 grain and 81 grain loads are definitely worth revisiting in the future. My gut tells me that 78.5 grains is probably the safest bet for great ballistic performance and accuracy. 2900-2975fps has been a sweet spot for the other heavy bullets I have tried.
None of the loads exhibited any of the obvious signs of over-pressure. No stiff bolt lift. No ejector marks. All of the primers have nice rounded edges.
The next step I will take is shooting 4 5 shot groups at a 1000 yard target (preferred) or 600 yard target (likely) and let the barrel thoroughly cool for a total composite group of 20 shots. I would prefer to do it on a hot day as well so that I can eliminate pressure concerns with the 81 grain load; personally my intuition says that it's too hot...but my bold curiosity wants to see how far I can push a cartridge designed in the 1950's.
Rifle
The rifle I am using is a custom Sako TRG/S with a Lilja Mk.13 contour 1:10 twist barrel. This is less than the optimized twist rate specified by Sierra. According to my calculations, I am getting a gyroscopic stability factor of between 1.44 to 1.5 depending on temperature. I am also using the A191 Match chamber that is optimized for the heavy for caliber bullets. I am loading these bullets to 3.700 OAL which is the maximum length I can fit in an AICS CIP Magazine. These are much longer than SAMMI length.
Powder
I am using H1000. It is my go-to powder for 300 Winchester Magnum because it produces good velocities, good accuracy, and is stable across a wide range of temperatures. I feel that even a "bad load" with H1000 is still a pretty good load.
Brass
I am using Norma 300WM Brass. Norma brass is noticeably lighter than the other brands I have looked at. It probably offers increased powder capacity. I haven't done a water test to verify it. Norma brass is the best brass I have been able to consistently get, however I don't have super strong feelings about it one way or the other. I think there might be more companies making better brass that wasn't available when I got my Norma brass. Norma has so far been good to me.
Primers
I am using CCI 450 (whatever the standard large-rifle primer is). I shoot in a hot environment and so far have had no ignition issues to speak of. None that have shown up in the field, or on the target. However if I was in a colder climate, I would strongly consider the CCI magnum primers for peace of mind, or at least test the standard primers in cold weather before offering a verdict.
Dies/Press/Powder Throw.
I am full length sizing my cases with an RCBS die that has a neck bushing. I cannot recall the neck bushing, but I think it provides 1 to 2 thousandths of neck tension. It's not a lot.
I am seating with a Forster Benchrest Seating die.
All loading is done on a Harrels Press.
I throw my charges with the standard RCBS Charge Master. I set the charge and I will pull powder out or trickle it in to get to the final charge. I don't have a lab scale to see how accurate the charge master is, but internet lore says that it's to within about 2/10ths of a grain.
Load Development Method.
I loaded 15 rounds of ammo in groups of 3 separated by 1 grain increments from 77 to 81 grains with the intention of shooting them over the chronograph to get an idea of pressure limits for this bullet and powder combination. So far the other two heavy bullets I have used in this rifle have been exceptionally accurate in the 2900 to 2975fps range; those two being the 220 Lapua Scenar L, and the 215gr Berger Hybrid.
I fired 3 shot groups at 100 yards with a Magnetospeed Chronograph, and wrote down the velocities for each. I did give the barrel some time to cool, but maybe not as much as I should. I mainly look at group size and velocity spread to decide what loads are worth pursuing, but I do not put a huge stake in a 100 yard test with 3 shot groups. My main goal is to get a range of safe loads and velocity numbers.
If there is something that stands out as exceptional, I will test it at distance in the future, but I think that good ammo comes from mostly good reloading practices and not finding the perfect load.
Results
Weather. 75 degrees. Rainy. 66% humidity. Station Pressure of 29.92. DA 450ft.
77 Grains.
1: 2893
2: 2918
3: 2932
SD:20
ES:37
This might be a bad load, or it might be the velocity speeding up as the barrel gets hotter. I am not 100% sure.
78 Grains
1: 2953
2: 2949
3: 2949
SD:2
ES:4C
Change +36fps
This load might be the low node. I might have also got 3 rounds where the Chargemaster scale was dead on. This is a load that is worth pursuing in the future at distance as it produced a good group, good numbers, and is one that I feel would be plenty safe in hot weather. My trigger discipline on this group was also good and I felt I shot close to my potential.
79 Grains
1: 2991
2: 2978
3: 3000
SD:11
ES:22
Change: +39fps
The numbers are pretty representative of how the Chargemaster and H1000 perform if you pick a load at random. It's nothing to brag about but would be pretty good factory ammo.
80 grains
1: 3012
2: 3017
3: 3033
SD:11
ES:21
Change: +31fps
I let the barrel cool from the previous strings, so starting on a slightly colder barrel may have skewed the results slightly. Still pretty run-of-the-mil numbers.
81 grains
1: 3080
2: 3083
3: 3077
SD:3
ES:6
Change +60
This load stood out for a few reasons. It produced a group as well as the 78gr load, but I also put in a little extra effort to make sure I pressed the trigger straight to the rear because my previous two groups were a little big. I think my previous groups were a little big due to poor fundamentals more than anything else. I wanted to end on a high note.
It also stood out because it produced the second lowest velocity spreads over 3 rounds.
And it stood out because it showed a 60 fps change over 1 grain of powder. If velocity = pressure, then I suspect that I am close to the maximum load for this rifle. If I was to further increase the powder charge, I would definitely do it in 1/2 grain or less increments.
Conclusion
The 78 grain and 81 grain loads are definitely worth revisiting in the future. My gut tells me that 78.5 grains is probably the safest bet for great ballistic performance and accuracy. 2900-2975fps has been a sweet spot for the other heavy bullets I have tried.
None of the loads exhibited any of the obvious signs of over-pressure. No stiff bolt lift. No ejector marks. All of the primers have nice rounded edges.
The next step I will take is shooting 4 5 shot groups at a 1000 yard target (preferred) or 600 yard target (likely) and let the barrel thoroughly cool for a total composite group of 20 shots. I would prefer to do it on a hot day as well so that I can eliminate pressure concerns with the 81 grain load; personally my intuition says that it's too hot...but my bold curiosity wants to see how far I can push a cartridge designed in the 1950's.
