Do you use MPBR (Maximum Point Blank Range)

DougK

DougK

New member
I am going to be sighting in my .223 and am thinking about using MPBR. Using a 55gr at 3240 fps muzzle velocity, if I sight 1.4 inches high at 100 yards I will never be more thab 1.5 inches high or 1.5 inches low out to approximately 230 yards.

Does anyone have experieince with MPBR?

Thanks
Doug
 
Probably closer to a 200 yard pbr based on the above info, but it does depend on the bullet.

It's an interesting calculation but only tells you what your firearm would do if shot from a vise with no human or natureal intervention and does not take wind into consideration.

Also, if your rifle does one moa consistently then you need to add a half inch to each side of the calc and that alone takes you to a 4" circle of fire. Then, there are all the other things that effect mpbr in the field. When you add them all up, it's more a matter of the shooters ability to estimate range, read the wind, maintain a good hold, etc.

Still, MPBR is a good measure to start from.
 
I don't subscribe the the MPBR. I do however know most varmint caiibers will sight in at 1+" high at 100 yds and be pretty much dead on at 200 then -5 at 300 yds and -15 at 400 yds and -30 at 500 yards. This will work on most calibers, not all. Its easy to remember.
 
I sight my calling rifles 1 to 1.5 inch's high at 100 yards and my Big Game rifles 2 inch's at 100 yards . /ubbthreads/images/graemlins/grin.gif
 
The best thing to do is find a 300 yard or longer range and shoot paper from 100 to all the way out. It is worth finding such a range even at current gasoline prices.
 
Ditto what Pete said...
Actual shooting in varying conditions doesn't always jive with where your bullet "should" be hitting at a given range.
 
For a hunter, the maximum point blank range method makes very good sense. I say this even though I don't use a "strict" maximum point blank range method. What I use is somewhat of a variation of that method. For coyotes I zero about 1&1/2" high at 100 yards. Now I know that if a coyote is within 250 yards or so, I can hold dead on. If he looks like he is 300 yards or a bit further, I hold high on his back. I feel that my 85 grain ballistic silver tips zipping out of the muzzle at a bit over 3600 fps has fairly flat trajectory. For me to NOT take advantage of zero that allows me to hold dead on for longest range possible would be foolish.
 
If you have a .223 sighted dead on at 100 running the vel you are saying, you will be no more than 2" low at 200. If you hold the backbone of a yote out to 300 you will still be on the money.

I don't use the MPBR for shooting longrange. I use a laser rangefinder and inch come ups on my target knobs.
 
I agree. I believe the MPBR method is good for novice shooters, or at least novice when it comes to shooting long range. The main problem that I have and especially the
amt. of rise some say to use on a big game caliber is the fact it is very easy to hit too high for example at 200 yards if the maximum rise is 275-300 yards. Years ago, been there, done that. With the smaller arch like a Varmit rifle, it is still easy to shoot over a crow or Groundhog on his all fours.
First of all, it is important to know the range & then holdover or clicks can be calculated. Get a range finder.
I like reticles like the Varmit Hunter, Bal.Mil-Dot or Bal.
Plex out to 4-500 yards & for longer ranges, click up.
 
Most ballistic calculators seem to default to a 1.5" scope heoght which does take in most conventional rifles. If not exactly correct, it's close eonough. OTOH, some of the guys shooting ar types probably have much higher scope heights. Ditto some of the fal guns and certainly an SKS. The higher scope heights will make a dramatic change in the PBR arc.

Coloradoete has it right on, IMO. Calculators are fun but actual testing at range will often illustrate that the ballistic calculators are not a reliable estimator of trajectory.
 
"actual testing at range will often illustrate that the ballistic calculators are not a reliable estimator of trajectory."

I have found just the opposite. The ballistics programs are excellent trajectory predictors, at least all of the ones I have owned. The secret is to not use the default settings. To have them accurate you must plug in all the actual values for things like:
scope height, measured muzzle velocity, altitude(very important), temperature, barometric pressure, humidity, etc.
Even at 1000 yards every program I have ever tried has been within 1 MOA, usually less.

Jack
 
Quote:
"actual testing at range will often illustrate that the ballistic calculators are not a reliable estimator of trajectory."

I have found just the opposite. The ballistics programs are excellent trajectory predictors, at least all of the ones I have owned. The secret is to not use the default settings. To have them accurate you must plug in all the actual values for things like:
scope height, measured muzzle velocity, altitude(very important), temperature, barometric pressure, humidity, etc.
Even at 1000 yards every program I have ever tried has been within 1 MOA, usually less.

Jack




That has been my experience too.

...and i also apply the CMPBR method (conservative MPBR) to the tune of about 1/2 tgt. size.
 
"If you have a .223 sighted dead on at 100 running the vel you are saying, you will be no more than 2" low at 200. If you hold the backbone of a yote out to 300 you will still be on the money."
-------------
My old Speer #11 manual says that a 55 grain speer at 3200 fps will strike 11.8" low at 300 if you have it set for 100 yard zero. /ubbthreads/images/graemlins/smile.gif
 
Quote:
"actual testing at range will often illustrate that the ballistic calculators are not a reliable estimator of trajectory."

I have found just the opposite. The ballistics programs are excellent trajectory predictors, at least all of the ones I have owned. The secret is to not use the default settings. To have them accurate you must plug in all the actual values for things like:
scope height, measured muzzle velocity, altitude(very important), temperature, barometric pressure, humidity, etc.
Even at 1000 yards every program I have ever tried has been within 1 MOA, usually less.

Jack



Oh, I agree that if all is entered the results are usually pretty close. An example of where it is not reliable is the "scope height" setting. The flaw here is the distance of the objective lense from the muzzle.

Even more flawed is the use of iron sights where the correct procedure is to measure the height of the front sight, but that does not take into account the sight radius from front sight to rear aperture. This is a source of major differences but you must actually lay those out on paper to see them. While you can change the scope height entry you cannot make any entry to account for the angle of view from objective lens to line of bore or for the angle between the front and rear sight as it compares to the line of the bore.

Like you said, altitude is very important and given our original questioners load data, it could make a difference of almost 200 inches at 1000 yards between 500' and 10,000 feet. Just another reason why the calculators are not that practical in the field unless you are shooting paper with all the local factors known.
 
My experience with MPBR has not been good. The reason is that this method puts the highest point of the trajectory in the range that I most commonly do my shooting. Most of my shooting is done between 100 and 200 yards. Why would I want a trajectory that shoots 3 to 4" high at 150 yards. A 200 yard zero means I aim dead on out to 250 (generally speaking, your results may vary) and compensate 6 to 8" at 300, depending. This way I am never more than 1.5" of of dead on for 90% of all my shooting. My 2 cents.
 
Engine6,
The most important consideration when applying the maximum point blank range method is knowing the size of the target you are aiming at. This means that your maximum point blank range would be less for a field mouse hunter than it would be for a moose hunter. /ubbthreads/images/graemlins/smiliesmack.gif
 
I like the MPBR method for coyotes useing a flat trajectory rifle.I seldom shoot past 300 yards so it works pretty well for me.If you are shooting 500 or more yards,it is not for you.The only problem with shooting that kind of distance is wind drift.You can use a range finder to determine distance but it is hard to determine how fast the wind is blowing.For coyotes i would recomend keeping your shots inside 400 yards.I have taken groundhogs out past 500 yards but wouldnt try it on a coyote.I guess it all depends on how good you are with your rifle.Just remember practice,practice,practice
 
True Mr. Cronk, I was speaking in terms of a 4" (+ or -) MPBR trajectory, i.e., a big game rifle. Nevertheless, the problem I have had with this type of zero is germane. The point of the MPBR trajectory is to maximize your rifles range (of a specific game) and eliminate the need for hold over or under out to that range. The price paid for the extended range without hold over is placing the apex of your trajectory (whatever the apex may be) at an earlier point. Speaking generally, I don't want the the point of trajectory with the highest calculated error to be at the range I expect to shoot most of my game. As I tried to point out, this is the case for me.

I shoot most of my field mice between 100 and 200 yards, so I find it impractical to sight in my mouse rifle for MPBR for field mice because it then shoots 1" high at 150 yards. So if I'm off 1/2" I shoot high. I suspect your mouse hunting in Iowa differs from the conditions I have in Idaho so the MMPBR (maximum mouse point blank range) method may work well for you. Moose is another story. I have yet to hunt mice or moose in Iowa, if I do maybe I'll rezero my rifles.
 
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