You can use what ever bipod you want. Most guys use the harris style bipods because you can fold and adjust them quickly. 6 xc , 6 creed, 6x47 and 6 slr are great. A lot of guys are running 6.5x47, 260, 65 creed and 65 saum. Very few guys run 7s or 30s any more
What range to calibrate velocity and BC
- Thread starter ssatt68
- Start date
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
ssatt68, any chance to get links to clubs in the WA, OR area that will host PRS style matches. I am in BC and will be going to Rattlesnake range in Tri Cities to shoot F class this year.
I would love to make a PRS style match if the timing works out.
The gear rules, what few there are, seem to vary. I am glad to hear that some matches are open to shoot what you "brung".
Look forward to any info. Thanks
Jerry
I would love to make a PRS style match if the timing works out.
The gear rules, what few there are, seem to vary. I am glad to hear that some matches are open to shoot what you "brung".
Look forward to any info. Thanks
Jerry
PRS matches tend not to have a lot of equipment rules. Rather than try and limit equipment to what the person making the rules deems as "proper", they design a course of fire that simulates real life and let the course of fire deside what is proper and what is not. This is why these types of matches have moved tactical/practical shooting to new levels. Artificially limiting equipment keeps marksmanship from moving forward.
arcticcathonda
CGN frequent flyer
- Location
- Southern Alberta
Excited to see your results as well!
Great info guys, I'm glad I caught this when I did! I'm making a trip soon to shoot at a 1600 yard range for a day and was hoping to get my dope straight like this and calibrate AB on my phone. My only concern is that I don't think we will be able to shoot prone due to the firing line setup.. hopefully it will be something I can work out again at 400 yards back home. Should just be POI shift correct?
arcticcathonda
CGN frequent flyer
- Location
- Southern Alberta
If you are talking about Edson, I believe that made their "benches" body length to allow prone shooting on top of them.
You really need to collect data at the long distances if you want to calibrate things accurately.
There should be no POI shift if you're maintaining a consistent sight picture and maintaining good fundamentals in the alternative position.
Thanks Arctic, I hope you're right about the benches.
Kom, I'm going to bring enough rounds to get at least 5 shots at each range out to 1400m . I should be subsonic after that but I'll try it out. I'm definitely going to try out your procedure for the temp test as well.
My goal this summer is to nail down MOA cold bore shots out to 1200 meters. Then do it all over again next summer after I get suckered into buying one of these fancy Black Hole barrels
Jerry is going to find a source for these right?!
Kom, I'm going to bring enough rounds to get at least 5 shots at each range out to 1400m . I should be subsonic after that but I'll try it out. I'm definitely going to try out your procedure for the temp test as well.
My goal this summer is to nail down MOA cold bore shots out to 1200 meters. Then do it all over again next summer after I get suckered into buying one of these fancy Black Hole barrels
Jerry is going to find a source for these right?!
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Just had a very nice chat with BHW. They will need to consider getting licensed and if they do, I will be happy to discuss being their dealer in Canada.
Jerry
Jerry
Guys,
I just finished phase 1 of my testing on the BHW barrels. Here's a synopsis.
First, the guys there were very good to deal with and eager to help with having their barrels tested. A good sign.
I got two savage pre-fits, both 26" long, 1.125" straight contour, one in .243 Win, 1:8" twist; the other 308 Win, 1:11" twist.
Initial inspection reveals that these riflings are indeed 'slight'. They appear narrower and shallower than most riflings I've seen.
Phase 1 of the testing was to look at BC over 300 yards to see if there's any measurable difference for this range of flight.
So for the .243, I loaded a bunch of 105 Hybrids and fired some in my standard Bartlein 1:8" twist, 26" long, 1.125" straight taper (same specs as the BHW barrel but it has about 250 rounds on it) and some of the same ammo (same bullet lot, etc) in the BHW barrel and measured their BC's. Results:
Bartlein: G7 BC: 0.273
BHW: G7 BC: 0.276
The difference is just over 1% in favor of the BHW. Couple caveats to put this in perspective. 1) The BHW barrel is brand new, had only 15 rounds of break in prior to the test whereas the Bartlein had hundreds of rounds on it. 2) The standard error of the measured BC's is like .001, which means the actual value of the BC can be +/- 0.002 from the measured average (95% confidence interval). In other words, there is some statistical variation in the measured results which is almost as much as the difference in measured BC between the barrels.
Moving on to .30 caliber, I loaded a bunch of Berger 175 OTM's, same lot, etc. and shot in both barrels. My closest Bartlein is a 1:10" twist 5R, 24" long, 1.125" straight with like 2,500 rounds on it. Again, the same ammo was fired in both barrels, results were:
Bartlein: G7 BC: 0.260
BHW: G7 BC: 0.261
Again, the average BC favors the BHW but only slightly. In addition to the same caveats as above, the .308 test was also a 1:11" (BHW) vs. 1:10" (Bartlein).
In summary, Phase 1 of the testing has shown that the difference in rifling profile produced by the BHW riflings does not result in a significant difference in BC over supersonic flight ranges.
Phase 2 will be to do the same BC comparison over long range. If there's more of a difference in BC over long range, then it may be due to the difference in retained spin rate and greater transonic stability.
Phase 3 will be to actually measure the retained spin of bullets fired from BHW vs. standard barrels.
More to follow,
-Bryan
I just finished phase 1 of my testing on the BHW barrels. Here's a synopsis.
First, the guys there were very good to deal with and eager to help with having their barrels tested. A good sign.
I got two savage pre-fits, both 26" long, 1.125" straight contour, one in .243 Win, 1:8" twist; the other 308 Win, 1:11" twist.
Initial inspection reveals that these riflings are indeed 'slight'. They appear narrower and shallower than most riflings I've seen.
Phase 1 of the testing was to look at BC over 300 yards to see if there's any measurable difference for this range of flight.
So for the .243, I loaded a bunch of 105 Hybrids and fired some in my standard Bartlein 1:8" twist, 26" long, 1.125" straight taper (same specs as the BHW barrel but it has about 250 rounds on it) and some of the same ammo (same bullet lot, etc) in the BHW barrel and measured their BC's. Results:
Bartlein: G7 BC: 0.273
BHW: G7 BC: 0.276
The difference is just over 1% in favor of the BHW. Couple caveats to put this in perspective. 1) The BHW barrel is brand new, had only 15 rounds of break in prior to the test whereas the Bartlein had hundreds of rounds on it. 2) The standard error of the measured BC's is like .001, which means the actual value of the BC can be +/- 0.002 from the measured average (95% confidence interval). In other words, there is some statistical variation in the measured results which is almost as much as the difference in measured BC between the barrels.
Moving on to .30 caliber, I loaded a bunch of Berger 175 OTM's, same lot, etc. and shot in both barrels. My closest Bartlein is a 1:10" twist 5R, 24" long, 1.125" straight with like 2,500 rounds on it. Again, the same ammo was fired in both barrels, results were:
Bartlein: G7 BC: 0.260
BHW: G7 BC: 0.261
Again, the average BC favors the BHW but only slightly. In addition to the same caveats as above, the .308 test was also a 1:11" (BHW) vs. 1:10" (Bartlein).
In summary, Phase 1 of the testing has shown that the difference in rifling profile produced by the BHW riflings does not result in a significant difference in BC over supersonic flight ranges.
Phase 2 will be to do the same BC comparison over long range. If there's more of a difference in BC over long range, then it may be due to the difference in retained spin rate and greater transonic stability.
Phase 3 will be to actually measure the retained spin of bullets fired from BHW vs. standard barrels.
More to follow,
-Bryan
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Appreciate the info Bryan. Great to see your further study.
Jerry
Jerry
We completed phase 2 of the study.
Same exact equipment as above (guns and ammo) except this time we were shooting at 1000 yards.
Summary: The measured BC's were within 0.001 for both barrels in both .243 and .308 with the BHW being higher, but not significantly higher. Basically this is the same exact result as the 300 yard test.
Next test will be to measure spin rate decay and then shoot the bullets at long enough range that they slow down to transonic speed and measure their BC's there. At 1000 yards, the 243/105 Hybrids were comfortably supersonic, and the 308/175's were right at 1340, which is just the beginning of transonic.
Going back to the original observations which spurred this work (~1 MIL difference in drop with .243/105 Hybrid at 1200 yards), I'm thinking that difference is likely not due to difference in BC caused by the barrels. Our test was a side by side test with the same ammo in different barrels and getting virtually the same BC. To the original observation; It's possible that the non-BHW barrels were slower twists and maybe shooting the bullets with depressed stability and lower BC's compared to the faster twist BHW. In my test, with 'all else equal' including twist rate, the rifling in the BHW barrels don't cause a noticeable difference in BC out to 1000.
-Bryan
Same exact equipment as above (guns and ammo) except this time we were shooting at 1000 yards.
Summary: The measured BC's were within 0.001 for both barrels in both .243 and .308 with the BHW being higher, but not significantly higher. Basically this is the same exact result as the 300 yard test.
Next test will be to measure spin rate decay and then shoot the bullets at long enough range that they slow down to transonic speed and measure their BC's there. At 1000 yards, the 243/105 Hybrids were comfortably supersonic, and the 308/175's were right at 1340, which is just the beginning of transonic.
Going back to the original observations which spurred this work (~1 MIL difference in drop with .243/105 Hybrid at 1200 yards), I'm thinking that difference is likely not due to difference in BC caused by the barrels. Our test was a side by side test with the same ammo in different barrels and getting virtually the same BC. To the original observation; It's possible that the non-BHW barrels were slower twists and maybe shooting the bullets with depressed stability and lower BC's compared to the faster twist BHW. In my test, with 'all else equal' including twist rate, the rifling in the BHW barrels don't cause a noticeable difference in BC out to 1000.
-Bryan
I wonder if they were maybe getting odd readings with the Magneto Speed, similar to what I was telling you about at the beginning of the week. Different barrel profiles will put the sensors at different heights, and the MS seems to be sensitive to that.
