linebaugh
Silver $$ Contributor
I have finally finished remodeling my main PRS rig and have a few interesting observations to share.
The rifle is a curtis axiom action, mpa chassis, bartlein 29" heqvy palma 7 twist with 4 port brake and wears a USO B17 scope.
The brass is 6BR Lapua necked down and the shoulder blown forward .050 with no change to the shoulder angle. Case capacity is 39.8 H2O and the reamer has a long throat made specifically for the 95gr SMK.
I am shooting N160 powder and the load is shooting at 2985fps at 45 degrees. I will assume that the velocity will be right at my target speed of 3000 when the temps get in the 80 plus range. I do not at present have good data on temp sensitivity but I have logged every days firings and will hope to come back and update this thread for those interested. The powder was chosen specifically for its cooler btu value to extend my bbl life into the 3,000 plus round count.
Now for the very interesting part, the bullet. I have dabbled with the 95 SMK in my 22250AI in the past and had less than stellar accuracy, mostly due to fliers, but they showed higher than advertised BC value.
With this BR round I was able to get rid of the fliers and the gun shot at about half inch with all seating depths. Because this is a PRS gun I was hesitant to seat into the lands but thankfully I went ahead and seated out .005 into the lands. To my surprise these bullets in my combo really likes that seating depth with a light jam. I went from half inch to 3 five shot groups of 1/4 to 3/8 inch and that was off of an uncomfortable bag set up. I didnt expect them to shoot anything different than the half moa I was getting so I didnt bother setting up well. To my surprise I was printing ragged hole groups.
Remember that higher than advertised BC value from before? Well I am using a BC number of .320 G7 to get my trajectory charts to align with the drops I actually shot. If my memory is correct I was using something like .315 to get things to line out with the 22250AI.
I was able to shoot trajectory validation from 500 to 908 yards yesterday and I am not able to explain my drop correction other than to believe the bullets do indeed have a bigher than advertised BC.
Completely happy with how things turned out on this build but I can tell you that the way I cut the chamber there really was no other choice but to use the 95SMKs. Thats a pretty spooky proposition but in this case it all came together very well. If I come up with any more data to add to this post I will revisit at a later date as I know there has been a fair amount of interest in this bullet and the 22 BR based cartridges lately. Thanks for reading.
The rifle is a curtis axiom action, mpa chassis, bartlein 29" heqvy palma 7 twist with 4 port brake and wears a USO B17 scope.
The brass is 6BR Lapua necked down and the shoulder blown forward .050 with no change to the shoulder angle. Case capacity is 39.8 H2O and the reamer has a long throat made specifically for the 95gr SMK.
I am shooting N160 powder and the load is shooting at 2985fps at 45 degrees. I will assume that the velocity will be right at my target speed of 3000 when the temps get in the 80 plus range. I do not at present have good data on temp sensitivity but I have logged every days firings and will hope to come back and update this thread for those interested. The powder was chosen specifically for its cooler btu value to extend my bbl life into the 3,000 plus round count.
Now for the very interesting part, the bullet. I have dabbled with the 95 SMK in my 22250AI in the past and had less than stellar accuracy, mostly due to fliers, but they showed higher than advertised BC value.
With this BR round I was able to get rid of the fliers and the gun shot at about half inch with all seating depths. Because this is a PRS gun I was hesitant to seat into the lands but thankfully I went ahead and seated out .005 into the lands. To my surprise these bullets in my combo really likes that seating depth with a light jam. I went from half inch to 3 five shot groups of 1/4 to 3/8 inch and that was off of an uncomfortable bag set up. I didnt expect them to shoot anything different than the half moa I was getting so I didnt bother setting up well. To my surprise I was printing ragged hole groups.
Remember that higher than advertised BC value from before? Well I am using a BC number of .320 G7 to get my trajectory charts to align with the drops I actually shot. If my memory is correct I was using something like .315 to get things to line out with the 22250AI.
I was able to shoot trajectory validation from 500 to 908 yards yesterday and I am not able to explain my drop correction other than to believe the bullets do indeed have a bigher than advertised BC.
Completely happy with how things turned out on this build but I can tell you that the way I cut the chamber there really was no other choice but to use the 95SMKs. Thats a pretty spooky proposition but in this case it all came together very well. If I come up with any more data to add to this post I will revisit at a later date as I know there has been a fair amount of interest in this bullet and the 22 BR based cartridges lately. Thanks for reading.
