Fiftydriver
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Was able to work with a customers rifle I just finished up this week. This rifle is one of my APS Stalker Hunter rifles chambered in my relatively new 27 Stalker.
I apologize for the poor lighting. We have another rather significant weather event coming in today so got out early to accuracy test but as such, with the clouds, the morning light is pretty dark.
APS Stalker Hunter Specs:
APS Stalker Hunter receiver
27 Stalker chambering
Benchmark #4 contour SS, 9 twist, 5R barrel, 27" finish length, fluted
Small APS Painkiller muzzle brake
Bead Blast matte finish on barreled receiver
McMillan Game Warden, Carbon fiber shell, textured flat black painted finish
Pillar bedding with glass bedding full receiver length. Barrel free floated
Jewell trigger set at 1 lb
HS Precision detachable magazine system
3 Nightforce Ultralight Tactical 0.885" height rings
Vortex PST 5-25x 50mm with ebr-7c reticle
Load development for 170 gr Berger Elite Hunter
Scope zeroed at 300 yards
The bare rifle weight is 7.5 pounds and rifle with optics is right at 9.5 lbs. Relatively light for this class of performance.
Yesterday I was able to do the load development and velocity testing at the shop. I have done several full load developments with my 27 Stalker using the 170 gr Berger with RL33 powder. Typically, with this bullet weight when used in this 27" barrel length, you can expect to see 3280-3300 fps. This is quite impressive considering that my old 270 Allen Magnum(7mm RUM based) wildcat, out of a full 30" barrel will produce this same level of velocity. Again, 27" barrel for the 27 Stalker, 30" barrel for the 270 Allen Magnum.
However, I am always taking the opportunity to test new powders with my wildcats so that I can provide my customers with as much load data as possible. I have used the relatively new Ramshot LRT powder in several of my wildcats in the past, such as the 25 Stalker, 7mm Allen Magnum and 300 Allen Xpress. usually with very good results.
Wanted to see what it would do in my 27 Stalker. So I started with 94.0 gr and worked up from there with the following specs:
Peterson brand freshly formed 27 Stalker brass (300 Norma Mag parent case)
170 gr Berger Elite Hunter
Ramshot LRT powder
Fed-215 primer
3.590" OAL
94.0 gr............3222 fps
95.0 gr............3274 fps
96.0 gr............3283 fps
97.0 gr............3334 fps
98.0 gr............3378 fps
99.0 gr............3408 fps
100.0 gr..........3431 fps
101.0 gr..........3487 fps roughly 99% load density
Interestingly enough, the most pressure signs I saw were in the 94.0 to 96.0 gr loads..... Ramshot LRT is a ball powder. As such, most ball powders really do not like to be loaded much below 5 percent of their top working pressures. Below this, they will often show some strange behavior until you get into the proper working pressure ranges. That said, you need to know what your doing. If you see pressure signs, its always best to stop and figure out whats going on before you increase or decrease your powders charges. Know the powder your using and know that type of powders characteristics and personalities before experimenting.
Going into this, I knew I would be on the low end of pressures with this 94.0 gr starting load and was expecting some pressure signs. You can also see by the initial four velocity averages, that the velocity gains are quite inconsistent. Decent jump from 94 to 95, then nothing really from 95 to 96 and then a large jump from 96-97 grains. Its at this point that in my opinion, we have entered the proper working pressure range for the 27 Stalker and this combo.
From 97.0 gr and up, you can see that the velocity increases are much more consistent and predictable which tells us the powder is now igniting and burning consistently.
As mentioned earlier, I saw some slight pressure signs in the 94-96 grain range. These signs were a slightly shiny ejector ring on the case head and slightly heavy bolt lift on fired cases. At 97.0 gr load, the ejector mark on the case head went away, as did the increased effort on bolt lift.
The slight ejector ring did not appear again until the 101.0 gr load and nearly 3500 fps. Yes, 3500 fps with a 170 gr, 0.662 bc bullet in a 7.5 lb rifle and 27" barrel length.
This was one of those times when I thought we must be running a bit to much pressure. To check this, I took a case that had been fired with the 101.0 gr load (3487 fps), resized it, reloaded it with same load, fired, reloaded again, same load and repeated four times to see if after a few firings maybe we would start to see some of those tale tail signs that we are a bit to high in pressure. That being usually a bit sticky extraction, bit more bolt lift. I am happy to say, none of that appeared on the fourth firing and primer pocket was staying tight so I would predict AT LEAST 6 firings at this level, perhaps the 8 firings per case I demand from my recommended loads.
However, as this rifle will be going to an area that will likely be warmer then where I am, I decided to throttle this hot rod back slightly and went with the 99.0 gr load which averaged roughly 3410 fps. Hard to believe I am saying a THROTTLED back load at 3410 fps with this 170 gr bullet.
Wanted to share another pic of my first three Stalker wildcats. From left to right: 6.5-06 with the 130 gr Accubond for comparision (3130 fps), 25 Stalker w/ 100 gr Barnes TTSX (4050 fps), 26 Stalker w/ 156 gr berger (3300 fps) and the 27 Stalker w/ 170 gr berger (3410 fps).
Now to be fair, I have not yet tested the 26 Stalker and the 156 gr berger with Ramshot LRT powder. I am suspecting that once I do a full load development, this wildcat will also reach the 3400 fps level with the big 156 gr.
This morning when accuracy testing this rifle again, I was racing to beat a storm that was baring down on us. I did get done before the snow hit but the wind was certainly there, 12-18 mph variable wind. Zeroed the rifle at 300 yards where it was shooting 1/3 moa pretty easily. Then tested at 800 yards. Groups were very good but point of impact was roughly 3/4 moa higher then it should have been with the advertised BC which I have found in the past to be pretty close. This was likely due to the stronger wind running up the face of the valley wall I was shooting at causing and up drift. Still groups were easily 1/2 moa. Within my required standards before shipping rifle.
Just for your information, here is what the drop chart looks like with this rifle with 300 yard zero, 10 mph wind:
Yards...........Drop.........drift
175 top........+2.9"........0.5moa
300.............zero..........0.75
400.............-1.5moa....1.0
500.............-3.25.........1.25
600.............-5.0...........1.5
700.............-7.0...........1.75
800.............-9.25.........1.75
900.............-11.25.......2.0
1000...........-13.75.......2.0
Retained velocity and energy at 1000 yards: 2273 fps 1950 ft/lbs
Supersonic velocity range limit at my 3400 ft elevation: 2550 yards
All from a 7.5 lb rifle!!!
I apologize for the poor lighting. We have another rather significant weather event coming in today so got out early to accuracy test but as such, with the clouds, the morning light is pretty dark.
APS Stalker Hunter Specs:
APS Stalker Hunter receiver
27 Stalker chambering
Benchmark #4 contour SS, 9 twist, 5R barrel, 27" finish length, fluted
Small APS Painkiller muzzle brake
Bead Blast matte finish on barreled receiver
McMillan Game Warden, Carbon fiber shell, textured flat black painted finish
Pillar bedding with glass bedding full receiver length. Barrel free floated
Jewell trigger set at 1 lb
HS Precision detachable magazine system
3 Nightforce Ultralight Tactical 0.885" height rings
Vortex PST 5-25x 50mm with ebr-7c reticle
Load development for 170 gr Berger Elite Hunter
Scope zeroed at 300 yards
The bare rifle weight is 7.5 pounds and rifle with optics is right at 9.5 lbs. Relatively light for this class of performance.
Yesterday I was able to do the load development and velocity testing at the shop. I have done several full load developments with my 27 Stalker using the 170 gr Berger with RL33 powder. Typically, with this bullet weight when used in this 27" barrel length, you can expect to see 3280-3300 fps. This is quite impressive considering that my old 270 Allen Magnum(7mm RUM based) wildcat, out of a full 30" barrel will produce this same level of velocity. Again, 27" barrel for the 27 Stalker, 30" barrel for the 270 Allen Magnum.
However, I am always taking the opportunity to test new powders with my wildcats so that I can provide my customers with as much load data as possible. I have used the relatively new Ramshot LRT powder in several of my wildcats in the past, such as the 25 Stalker, 7mm Allen Magnum and 300 Allen Xpress. usually with very good results.
Wanted to see what it would do in my 27 Stalker. So I started with 94.0 gr and worked up from there with the following specs:
Peterson brand freshly formed 27 Stalker brass (300 Norma Mag parent case)
170 gr Berger Elite Hunter
Ramshot LRT powder
Fed-215 primer
3.590" OAL
94.0 gr............3222 fps
95.0 gr............3274 fps
96.0 gr............3283 fps
97.0 gr............3334 fps
98.0 gr............3378 fps
99.0 gr............3408 fps
100.0 gr..........3431 fps
101.0 gr..........3487 fps roughly 99% load density
Interestingly enough, the most pressure signs I saw were in the 94.0 to 96.0 gr loads..... Ramshot LRT is a ball powder. As such, most ball powders really do not like to be loaded much below 5 percent of their top working pressures. Below this, they will often show some strange behavior until you get into the proper working pressure ranges. That said, you need to know what your doing. If you see pressure signs, its always best to stop and figure out whats going on before you increase or decrease your powders charges. Know the powder your using and know that type of powders characteristics and personalities before experimenting.
Going into this, I knew I would be on the low end of pressures with this 94.0 gr starting load and was expecting some pressure signs. You can also see by the initial four velocity averages, that the velocity gains are quite inconsistent. Decent jump from 94 to 95, then nothing really from 95 to 96 and then a large jump from 96-97 grains. Its at this point that in my opinion, we have entered the proper working pressure range for the 27 Stalker and this combo.
From 97.0 gr and up, you can see that the velocity increases are much more consistent and predictable which tells us the powder is now igniting and burning consistently.
As mentioned earlier, I saw some slight pressure signs in the 94-96 grain range. These signs were a slightly shiny ejector ring on the case head and slightly heavy bolt lift on fired cases. At 97.0 gr load, the ejector mark on the case head went away, as did the increased effort on bolt lift.
The slight ejector ring did not appear again until the 101.0 gr load and nearly 3500 fps. Yes, 3500 fps with a 170 gr, 0.662 bc bullet in a 7.5 lb rifle and 27" barrel length.
This was one of those times when I thought we must be running a bit to much pressure. To check this, I took a case that had been fired with the 101.0 gr load (3487 fps), resized it, reloaded it with same load, fired, reloaded again, same load and repeated four times to see if after a few firings maybe we would start to see some of those tale tail signs that we are a bit to high in pressure. That being usually a bit sticky extraction, bit more bolt lift. I am happy to say, none of that appeared on the fourth firing and primer pocket was staying tight so I would predict AT LEAST 6 firings at this level, perhaps the 8 firings per case I demand from my recommended loads.
However, as this rifle will be going to an area that will likely be warmer then where I am, I decided to throttle this hot rod back slightly and went with the 99.0 gr load which averaged roughly 3410 fps. Hard to believe I am saying a THROTTLED back load at 3410 fps with this 170 gr bullet.
Wanted to share another pic of my first three Stalker wildcats. From left to right: 6.5-06 with the 130 gr Accubond for comparision (3130 fps), 25 Stalker w/ 100 gr Barnes TTSX (4050 fps), 26 Stalker w/ 156 gr berger (3300 fps) and the 27 Stalker w/ 170 gr berger (3410 fps).
Now to be fair, I have not yet tested the 26 Stalker and the 156 gr berger with Ramshot LRT powder. I am suspecting that once I do a full load development, this wildcat will also reach the 3400 fps level with the big 156 gr.
This morning when accuracy testing this rifle again, I was racing to beat a storm that was baring down on us. I did get done before the snow hit but the wind was certainly there, 12-18 mph variable wind. Zeroed the rifle at 300 yards where it was shooting 1/3 moa pretty easily. Then tested at 800 yards. Groups were very good but point of impact was roughly 3/4 moa higher then it should have been with the advertised BC which I have found in the past to be pretty close. This was likely due to the stronger wind running up the face of the valley wall I was shooting at causing and up drift. Still groups were easily 1/2 moa. Within my required standards before shipping rifle.
Just for your information, here is what the drop chart looks like with this rifle with 300 yard zero, 10 mph wind:
Yards...........Drop.........drift
175 top........+2.9"........0.5moa
300.............zero..........0.75
400.............-1.5moa....1.0
500.............-3.25.........1.25
600.............-5.0...........1.5
700.............-7.0...........1.75
800.............-9.25.........1.75
900.............-11.25.......2.0
1000...........-13.75.......2.0
Retained velocity and energy at 1000 yards: 2273 fps 1950 ft/lbs
Supersonic velocity range limit at my 3400 ft elevation: 2550 yards
All from a 7.5 lb rifle!!!
