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Posted: 6/7/2017 3:28:35 PM EDT
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can we talk about this here? is it techy enough? probably been talked about before but lets do it again.
maximum point blank range maximum point blank range.... if we determine that distance is between 50 and 100 yards, is there a down side? assuming one does not plan on engaging past 200 +/- or is this just splitting hairs? |
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I stumbled across this mindset/theory a few days ago, in relation to using 300 BLK as a hunting round with a low power variable optic. I ran the numbers in Strelok, and it actually makes pretty good sense in a hunting application. With a 30ish yard zero, the round is +/- 3" from the target out to roughly 180 yards if I recall correctly. Then, you have your BDC reticle for longer ranges if you feel brave enough to hunt that far out. For a red dot, it makes even more sense. There is nothing in most red dot reticles that you can use as a holdover, so for consistency, being able to aim center mass, and only deviate +/- 3" from the target is huge. This is one of the reasons the 50 yard/200 meter(218 yards) zero is so popular. It seems MPBR is just a continued evolution of that concept.
For true precision shooting (think benchrest), it would seem much less useful. |
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Quoted:
can we talk about this here? is it techy enough? probably been talked about before but lets do it again. maximum point blank range maximum point blank range.... if we determine that distance is between 50 and 100 yards, is there a down side? assuming one does not plan on engaging past 200 +/- or is this just splitting hairs? Whoa. That link/web site is messed up. |
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I found p hit to increase 10% at unkown range vs a standard zero.
Target at unkown range 100 yard zero with 75 grain bullet .357 bc. In the following examples it says 250 yards, but you the shooter don't know that for sure. If you have to take a shot and you are unsure how far the range is then it can be safe to say you may be off 50 or 25 yards meters etc depending on your experience and how your perception of the targets size is relative to the actual size of the target. 
Target at same unkown range, sighted in at 233 yards: 
Do you see all those other variables we can improve? Splitting hairs yes. But each hair you split can eventually be a haircut. Improve rifle precision, improve the ammo by decreasing the SD and ES, and choose ammo that has a higher BC and bucks the wind better. Eventually the percentage points will tip the hat in favor of a solid hit at unkown ranges. It may be a few percentage points, but do you want to leave them on the table? People will say its not worth the trouble, and that a 50 yard zero is fine. I agree I used a 50 yard zero for years and a red dot to hit targets out to 400 yards including 300-400 yard movers in competiton. It works fine. But with study of the benefits you may come to the same conclusion as me... That each variable you control eventually leads to increases in hit percentage. Controlling for unkown range with a zero based on the size of your target is just one of many such items we can control and add in our favor. Your mileage may vary. Some combinations of barrel length and projectile choice will benefit more or less. Each rifle and projectile will need to be chronographed. You will need a ballistic calculator. Then you have to decide your vertical resolution. Will your ammo stay inside your vertical resolution? If its too innacurate then it could hit far higher or lower than you want. Hence the need for match ammo. |
| MPBR will vary depending on what size target you want to hit. The size of that target is very subjective. The only negative I can think of for it is that your zero target will be at an odd range. This may not be possible for some to do and doesn't have a round reference point for future use like a 100/150/200/250/300 zero does. |
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One other thing. If you have multiple rifles with different external ballistics the same far zero for both would be better IMO. That way you would have very similar hold overs at farther distances and not have to memorize two different hold overs. Easy way to experiment is get a good 100 yard zero and dial out to your chosen MPBR zero and start shooting at unkown ranges with a dead hold. My glass is zeroed at 100 yards and if i want my 233 yard zero i dial into it and leave it there. |
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Quoted:
I stumbled across this mindset/theory a few days ago, in relation to using 300 BLK as a hunting round with a low power variable optic. I ran the numbers in Strelok, and it actually makes pretty good sense in a hunting application. With a 30ish yard zero, the round is +/- 3" from the target out to roughly 180 yards if I recall correctly. Then, you have your BDC reticle for longer ranges if you feel brave enough to hunt that far out. For a red dot, it makes even more sense. There is nothing in most red dot reticles that you can use as a holdover, so for consistency, being able to aim center mass, and only deviate +/- 3" from the target is huge. This is one of the reasons the 50 yard/200 meter(218 yards) zero is so popular. It seems MPBR is just a continued evolution of that concept. For true precision shooting (think benchrest), it would seem much less useful. ....continued evolution... i like that! |
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Just use this, not all rifle, optic, and ammo combinations are equal.. http://www.hornady.com/ballistics-resource/ballistics-calculator Bryan Litz modern advancments used a doppler to measure the real BC during flight and my hornady 75 grainer wasn't quite what hornady advertised. It was .357 for Litz and Hornady reports .395! Quite the difference. Also mr_h consider that people moved to a 50 yard zero because it offered a more useful vertical resolution vs a 100 yard zero. Moving that out further with the use of a ballistic calc and better ammo just expands on the concept. |
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Yes each rifle is distinct based on barrel length, bc, and velocity. Easy way to experiment is get a good 100 yard zero and dial out to your chosen MPBR zero and start shooting at unkown ranges with a dead hold. My glass is zeroed at 100 yards and if i want my 233 yard zero i dial into it and leave it there. Quoted:
Quoted:
One other thing. If you have multiple rifles with different external ballistics the same far zero for both would be better IMO. That way you would have very similar hold overs at farther distances and not have to memorize two different hold overs. Easy way to experiment is get a good 100 yard zero and dial out to your chosen MPBR zero and start shooting at unkown ranges with a dead hold. My glass is zeroed at 100 yards and if i want my 233 yard zero i dial into it and leave it there. |
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i see this article more centered on iron and RDS's. i dont think anyone would ever zero a scope with this....although i am considering it for my trijicon accupoint 1-4x and see how that works out, especially since it has the triangle post reticle. 
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Poor data analysis and dumb.
They correctly point out that with a 50Y zero the "MPBR" for a 4" circle is 259 yards. And then go on to demonstrate a MPBR to 300 yards using a 6" circle. If you engage that same 6" circle with a 50Y zero, your MPBR is a little farther than 300yards (depending on ammo type), and the hits from 0-259 yards are more centered than they are with their own method (because of the smaller circle). |
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This is an old concept, harkens back to the days of hunting before fancy range finders, simple duplex scopes, inaccurate scope adjustment, etc...
http://www.chuckhawks.com/mpbr_hunting.htm http://www.chuckhawks.com/rifle_trajectory_table.htm |
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