I have question for the techical Brains on here.
I have a 460 Weatherby being delivered in the near future. The iron sights are regulated with factory 500grain ammo.
My question is. I will most likely not use weatherby factory ammo. As only the solids are worth anything, the softs come unglued. So I will have ammo loaded that may not attain the weatherby factory specs...
changing the point of impact.
With a reduction in velocity will the point of impact go up or down and by how much? AT say 50 and 100 yards.
Is there sort of chart or formula?
All things equal, how will the point of impact change with the increase or decrease in velocity.
I need to know if I must order higher or lower front sights beads to get the regulation spot on again.
Many thanks
Leon

There should not be any difference at 50 or 100yds for about +/- 100fps.

You need to shoot it with the loads you are going to use.

There might be or might not be any different.

Technically speaking you are talking about sighting in a rifle. Regulation is the art of welding or bending barrels to a point of impact such as done with double rifles..

As to your post and all understand what you are saying, A person needs to sight in his own rifle as eyesight comes into play and our eyes are different so what sights in for me may be inches high, low, or wide for someone else..One does this with irons with a 3 corner file for instance, wherein you shoot and file the sight to move the zero to where you want it vertically, Use a hammer or whatever to move it horizontally. Its normally called filing in to zero..Go slowing and shoot a lot so that you don't go too far, as you stop when the required POI is attained. Its not complicated but tedious.

As to the location of your shots, that has more to do with barrel harmonics and a different load can go off center from your present POI in any direction..Its maybe safe to say more velocity will shoot high, and lower velocity will shoot low, but that's guess and by gosh, shooting until the load hits right where you aim is the only thing you can take to the bank.

I have found in the majority of instances that a solid can come to zero with the addition of one or two grains of powder when a gun is sighted in with softs, but agaib you must shoot it to know.

As to softs and solids, don't underestimate one of todays softs, several of them work just fine on all but perhaps head shots on elephant. Ihave seen todays softs kill elephants quite well with body shots and high velocity big bore rifles and you will get quicker kills with the soft as a rule..Im not at all anti solid, used lots of them, but there is a need and a place for softs in all sporting calibers.

Lots of things come into play, but in general I've found that a slower velocity bullet will strike the target higher than a faster one, at least at 50 yds. I'm afraid you are going to have to shoot it to find out. Have your rifle builder provide you with some extra front beads of different sizes.

Why deliberately wildcat a rifle. Just make up reloads that come to factory POI. Varying velocity is not necessarily going to change the POI, Different powders and bullets can do that irrespective of velocity. I would be doing my best to try and get your reloads to factory POI so that you could use factory ammunition if you wish or need to or someone else that may acquire your Weatherby may do so.

The rifle has had sights regulated to a weatherby factory ammo. As Ray stated had the sights filed.
Westley don't load ammo for the 460 so they sighted the rifle/cut the sights for with factory ammo.
As Bitterroot said I need a few different bead options in case the POI needs shifting. In which case I think I need higher to bring the POI down.
Ray, I predominantly use sofre and firm believer. The factory 500 from weatherby are standard jacteked softs and these don't hold up at Lott velocities from what I've seen in the field.
Thanks for for your inputs

eagle27,

In Africa we don't get the imported powders that attain factory spec. Factory ammo is also hard to come by, very expensive and as I mentioned the factory softs are not something I'm going to rely on.
There's a company in Austria, I think, called LfB. I've ordered there ammo which clocks 2500fps, which is plenty for intents and purposes. I wanted know if there will a POI differnce between 2500 and 2600. So the tha I can order appropriate height bead(s).
Will keep you all posted
Thanks

quote:

I wanted know if there will a POI differnce between 2500 and 2600

As I stated there might be a difference or there might not be any.

Your just guessing until you shoot the load you want to use.

Ok all the tech stuff has been covered so why don't you install a Lyman, Redfield, Marble, or Williams fully adjustable peep sight, take out the aperture and toss it, so you can use the sight as a Ghost sight..Then you can use any ammo available, have the fastest of iron sights, and the most accurate sighting short of a scope..Just my two bits.