The Rifle:
My rifle is a 6.5 PRC built on an Origin short action with a 22-inch Proof prefit. The barrel has a 1:7.5 twist (I was assured this would be enough to stabilize the 135s as I live and shoot above 3500’.) I'm currently using the Hawkins Precision Hunter magazines, which allow for a cartridge overall length of 2.980.
The Challenge:
I'm sure my journey would have been much easier on a mid-length or long action, but I have a short action and wanted to see if I could build an acceptable load within these parameters. Failing there I could resort to single feed, but would prefer not to.
Initial Measurements and Recommendations:
I measured the chamber and found the jam at a COAL of 3.125. Now, I know the recommended jump starts around 0.025 off the lands, but given my constraints, I began tests at 2.980 and planned for seating depth tests after identifying the right powder charge.
Powder Selection and Testing:
I started with RL 26, using once-fired Hornady brass with Federal 210 match primers. My ladder tests revealed nodes around 58 grains and 60 grains. However, seating depth tests hinted that magazine-length was probably my best bet.
Component Changes and Further Testing:
A back-order of Peterson brass arrived, prompting a fresh start. I also explored Vitavuori powders, specifically n565 and n560. Nick Depperschmidt Of Hawkins Precision had written a great piece on Powder selection for the 6.5 PRC and found n565 to be promising. I had also read that n560 was a suitable replacement for rl26 and was eminently more available so I built ladders for all three and resumed testing.
I experimented with neolube #2, as neck lube, hoping to refine my SD/ES numbers further still. After acquiring a VLD seating stem, the results were promising. Despite impressive speeds from n560 and RL26, I landed on n565, because of its reputed temperature stability and single-digit ES/SD's.
Application:
The ballistic calculator gave me confidence in my chosen load, suggesting it would maintain its required velocity for expansion up to over 850 yards. After some range time to true velocity and BC, I prepped 40 rounds for hunting season.
Now it also happens that I had the extremely Good Fortune of drawing a mountain goat tag this year - In fact, this was one of the main factors pushing me to do all this work. the hunt story is one I will tell at another time in another place, but it ended with a 467-yard broadside shot in minimal wind. I was able to watch the impact through my scope and after absorbing the shot the Billy only took a couple of steps before drawing his last. I did not spend a lot of time examining the wound Channel but did find what appeared to be too petal exits quite a ways from the main tract. I've taken a good number of animals with Hammer Hunter 124’s going close to the same speed out of a 6.5cm, and I would say that the bulldozer represents about a perfect balance between those and the more traditional monolithics, with an obvious advantage where external ballistics are concerned. I would have absolutely no hesitation sending one of these through an elk, and I hope to see my wife do so soon.
Closing Thoughts:
Being new to this, I'm all ears for feedback and insights. I'm curious about others' experiences with similar loads, especially in medium or long actions. Have others considered building a rifle around the SBD2? Also, does anyone care to explain this SG issue to me like I'm 5? should I reconsider running the 135s in a 1:7.5 barrel? Thanks.
My rifle is a 6.5 PRC built on an Origin short action with a 22-inch Proof prefit. The barrel has a 1:7.5 twist (I was assured this would be enough to stabilize the 135s as I live and shoot above 3500’.) I'm currently using the Hawkins Precision Hunter magazines, which allow for a cartridge overall length of 2.980.
The Challenge:
I'm sure my journey would have been much easier on a mid-length or long action, but I have a short action and wanted to see if I could build an acceptable load within these parameters. Failing there I could resort to single feed, but would prefer not to.
Initial Measurements and Recommendations:
I measured the chamber and found the jam at a COAL of 3.125. Now, I know the recommended jump starts around 0.025 off the lands, but given my constraints, I began tests at 2.980 and planned for seating depth tests after identifying the right powder charge.
Powder Selection and Testing:
I started with RL 26, using once-fired Hornady brass with Federal 210 match primers. My ladder tests revealed nodes around 58 grains and 60 grains. However, seating depth tests hinted that magazine-length was probably my best bet.
Component Changes and Further Testing:
A back-order of Peterson brass arrived, prompting a fresh start. I also explored Vitavuori powders, specifically n565 and n560. Nick Depperschmidt Of Hawkins Precision had written a great piece on Powder selection for the 6.5 PRC and found n565 to be promising. I had also read that n560 was a suitable replacement for rl26 and was eminently more available so I built ladders for all three and resumed testing.
I experimented with neolube #2, as neck lube, hoping to refine my SD/ES numbers further still. After acquiring a VLD seating stem, the results were promising. Despite impressive speeds from n560 and RL26, I landed on n565, because of its reputed temperature stability and single-digit ES/SD's.
Application:
The ballistic calculator gave me confidence in my chosen load, suggesting it would maintain its required velocity for expansion up to over 850 yards. After some range time to true velocity and BC, I prepped 40 rounds for hunting season.
Now it also happens that I had the extremely Good Fortune of drawing a mountain goat tag this year - In fact, this was one of the main factors pushing me to do all this work. the hunt story is one I will tell at another time in another place, but it ended with a 467-yard broadside shot in minimal wind. I was able to watch the impact through my scope and after absorbing the shot the Billy only took a couple of steps before drawing his last. I did not spend a lot of time examining the wound Channel but did find what appeared to be too petal exits quite a ways from the main tract. I've taken a good number of animals with Hammer Hunter 124’s going close to the same speed out of a 6.5cm, and I would say that the bulldozer represents about a perfect balance between those and the more traditional monolithics, with an obvious advantage where external ballistics are concerned. I would have absolutely no hesitation sending one of these through an elk, and I hope to see my wife do so soon.
Closing Thoughts:
Being new to this, I'm all ears for feedback and insights. I'm curious about others' experiences with similar loads, especially in medium or long actions. Have others considered building a rifle around the SBD2? Also, does anyone care to explain this SG issue to me like I'm 5? should I reconsider running the 135s in a 1:7.5 barrel? Thanks.
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