Some advice needed on revolver behaviour

[pattern14]

Some months back I posted my first thread concerning a .455 revolver of uncertain origin. Thanks to all who gave me some great feedback and info; however it has led to another aspect. This particular revolver is chambered for the original Mk 1 round in black powder, has very fine fixed sights, and seems to shoot quite well with my experimental loads ( 2.5 gns of trailboss and 220 gn RN lead projectiles). But it shoots high at 25 metres ( close enough to 25 yds for non-metric people). when i suggested using heavier projectiles to lower the P.O.I, I got a reply saying I was possibly heading in the wrong direction. Lighter bullet weight would lower it instead as there was less muzzle flip, less time spent in the barrel etc. I didn't argue because it hadn't occurred to me before, and there is always something new to learn.

I studied physics in high school, so have a basic grasp, but can some one out there explain in lay mans terms ( i.e keep it simple) how this works? It is a classic 1890's collectable in original condition, so I can't change it or mod the sights, I just want it to hit the metal silhouette at the standard target range......

[Winger Ed.]

Are you sure you have a good sight picture?

With fixed sights, I've had to adjust mine sometimes to fit the gun for different ranges.
If its a good accurate, safe load, I'd try that.

[7br]

Basically, during recoil, the muzzle is rising. The faster the bullet leaves the barrel, the less time the muzzle has to rise.

Sent from my SM-G930V using Tapatalk

[BK7saum]

Faster and lighter will impact lower on the target.

[megasupermagnum]

As strange as it sounds, I too have found heavy bullets generally high higher, and lighter bullets generally lower.

[Outpost75]

A revolver firing is a pendulum in motion. Heavier bullets which have a greater recoil impulse, and which are launched a lower velocity will have a longer bore time which results in the bore swinging through a greater arc before the bullet exits the barrel, resulting in a higher angle of departure than a lighter bullet, having a lesser recoil impulse, and shorter bore time, resulting in a reduced angle of departure at muzzle exit.

[Groo]

Groo here
Also remember , military training uses the belt buckle hold on BP guns due to the rainbow path of the bullet.
Many old single action colts [ cav model ] shoot very high at 25.
Aim point is the belt buckle [shiny on uniforms] allowing hits out to max range [maybe 100 yds or more]

[bigted]

A revolver firing is a pendulum in motion. Heavier bullets which have a greater recoil impulse, and which are launched a lower velocity will have a longer bore time which results in the bore swinging through a greater arc before the bullet exits the barrel, resulting in a higher angle of departure than a lighter bullet, having a lesser recoil impulse, and shorter bore time, resulting in a reduced angle of departure at muzzle exit.

This is a very concise answer. Think "dwell" time of the boolit in the barrel.

Outpost describes this really good.

[gwpercle]

A Layman's Explanation :
With the same exact sight picture .

A Heavy boolits , moving at a lower velocity will hit higher on the target .
A lighter boolit , moving at a faster velocity will hit lower on the target .

One gun and one load can be regulated to strike the target dead center (POA = POI ) at only one distance . It might be 5 yards or 25 yards .

I have no idea why ...it's just the way it is .
Some fixed guns are nightmares ...some , like the model 58 in my avatar seem to shoot just about all loads close enough to each other that it's really puzzling and the reason I hang on to it....
That old fix sighted 41 magnum is rather magical in that respect .
Gary

[bigted]

This needs to be tempered with other facts that effect the overall trajectory.

The same facts that heavy boolits shoot higher then lite boolits needs to be known that this is at a certain range and as this range extends ... the force of gravity takes over and we get back to what is expected. That consists as thus;

As the range extends, your heavy boolit will do its rainbow trajectory and as it hits its top of the curve, they fall like a rock ( well kinda ). The liter boolit will extend beyond the heavy long after the heavy begins its fall to earth. In other words, at a certain point the rainbow trajectory between heavy and lite boolits will cross paths and that liter boolit will then print higher on the extended target than will the heavy.

So you see that lets say (arbratarilly) that our range is 10 yards. Initially the heavy boolit prints higher on this target then the liter boolit does. The DWELL time and slower velocity is in affect as stated above.

At an extended range ... lets say 50 yards (again arbritrarilly) that we observe that now the liter boolit prints higher on the target then the heavier [as would have been expected all along]. So gravity takes over at a point and our boolits begin to act like what makes sense all along.

Interesting to say the least.

[Oyeboten]

Please post us some images of the old Webley? So we can see it?

If memory serves, the BP era .455 Webley Bullets were 265 Grains...and were so off and on again later, with some being lighter at times.

Do you know what your Cylinder Bore and Barrel's Groove-to-Grooves diameters are?

Modern .45 Colt Bullets tend to be .452.

Bullets for the old Webley or other .455s, usually need to be 455 or .456-ish...one of my S&W 2nd Model Hand Ejector .455s these are .457.

.452 Bullet with a light charge might not even engage the Rifling at all with the vast majority of .455 Revolvers.

[pattern14]

Thanks for all the feedback....I'm still waiting for my bullet mold to arrive ( post has slowed right down ). The factory cast bullets I'm using are 45 cal Australian made "redback", probably more suited to the 45 Colt and such, although they stick pretty well in the muzzle, and just don't drop in. The factory colt ammo drops into the muzzle right down to the casing. One problem is probably the sights. It has the worst set up I have ever seen, and I'm considering just painting fluoro red on the front and fluoro green on the back to get a better picture. Black powder is impossible to get where I am, so Trail Boss is it for now. Having a lot of fun with it, and everything works so well for an old gun....let you know when I make some more progress.