Author Topic: Bullets falling upward? (Read 571 times)

Pookee · « **on:** August 20, 2004, 10:54:16 AM »

Just tried a new load (32 H&R Mag, 130 Spire Point going about 1500 fps).
Zeroed at 25yds. and the point of impact is 1ft high at 100yds.
Don't bullets usually drop?

skb2706 · « **Reply #1 on:** August 20, 2004, 11:11:40 AM »

If you are dead on at 25 yds. it is very likely you will be high at 100yds. Remember that your line of site (the line that would be the center of your scope to your target) starts out at least 1 1/2" above your bore.....maybe less if you are not using a scope. The bore is actually pointed slightly up to achieve a center hit at 25 yds. This upward angle.....slight as it may be is still projecting the bullet upward out at 100 yds. Sight in the gun for 50 yds. and you will get the best of both the long and short range.

Steve P · « **Reply #2 on:** August 20, 2004, 04:03:57 PM »

You must be shooting with a scope? Sounds like your scope may not be parallel with the bore. Need a shim in front ring?

Steve

Pookee · « **Reply #3 on:** August 21, 2004, 12:58:15 AM »

What skb2706 says seems to make sense. The scope (or iron sights) are not tuned to be parallel to the bore. Does recoil play into this equation as well?

Double D · « **Reply #4 on:** August 21, 2004, 02:16:12 AM »

Recoil does have some effect, but not to to the effect you are describing.

If you are shooting a standard factory barrel and you have the correct scope base SKB2706 seems to be headed in the right direction. You simply need to adjust your scope.

If you have an after market or factory barrel with any taper then Steve P is right, you need to shim under the front ring or under the front of the base.

I had this problem yesterday sighting in my wife's Martini cadet. I am using a Contender Base on a straight taper barrel on that rifle. I shoot the gun at 25 yards to get the scope near Center. It was center for windage and about 6 inches high at 25 yards. I then shoot the 100 yard target and was 26 inches high. I had to add .020 shim under the front of the base to get it zero at 100 yards.

A handy material for making shims is aluminum beverage cans. The aluminum is easily cut with scissors and is a uniform .005 thick. You can trim it up so it is under a scope base and not seen. When I use it I punch a hole through it and put it under the scope base under a screw hole and run the screw through it. It bends easily to conform to the barrel radius.

It is a common fallacy that you can sight your gun in at 25 yards and it will be dead on at 100. It just doesn't work that way.

LAREDOBOB · « **Reply #5 on:** August 23, 2004, 04:15:01 AM »

It's simple, Your scope is UPSIDE DOWN. he he :-D

skb2706 · « **Reply #6 on:** August 23, 2004, 04:20:00 AM »

makes sense to me..........if you turn it 90 degrees will it shoot around corners ?

Lone Star · « **Reply #7 on:** August 23, 2004, 03:33:25 PM »

It is absolutely normal and not a freak of nature. This is exactly what happens to scoped rifles when they are zeroed at 25 yards. There is nothing wrong with the way the scope is mounted for goodness sakes! :wink: The bullet crosses the line of sight twice, once at 25 (or 20) yards and again at a longer distance. A .30-06 for example when zeroed at 25 yards is spot on around 250 yards, depending on the load.

If the scope was not "aligned" with the bore the bullet would not go where the scope pointed. As long as the bullets hit at 20 yards they will stay above the line of sight (in other words above the crosshairs) until they drop below at some much longer distance. The closer the scope's centerline is to the bore centerline, the smaller this effect is. That's one reason it is rarely noticed with irons.

This image is from Remington's site and shows the bullet rising above the line of sight ( scope mounted 1.5" above the bore) and then dropping down below it again. This is exactly the way it works.

wheelgun · « **Reply #8 on:** August 24, 2004, 02:15:55 AM »

I agree with lone star every rifle or pistol I have ever shot was and will be high at a 100 yards.The bullet is still climbing at 25 yards.This is just my opinion and may be wrong but it is what I have I have seen with all of my guns.

KYODE · « **Reply #9 on:** August 24, 2004, 02:29:46 AM »

a bullet NEVER climbs. it is falling imediately after leaving the barrel. the force of gravity is the culprit.
a chart such as that, shows a bullets path across "line of sight" of the scope. it is not actual bullet path from the barrel.

Steve P · « **Reply #10 on:** August 24, 2004, 03:33:05 PM »

We are all in agreement. But are we all looking at the same thing? In the chart above on the '06 trajectory with 140 grain bullet stays within a 4" impact zone out to 250 yards. A 32 mag bullet should stay within about a 4" impact zone out to 100 yards. So why is impact on at 25 yards and 12" high at 100 yards? Can only be due to scope and bore not being close to parallel. If they were correct alignment, bullet should drop below line of sight before 100 yards. Impact point should be about 3-4" low at 100 if dead on at 25. (Just my $.02.) I don't have my loads and charts here at work to get actual 32 mag bullet weight, velocity, and tragectory.

Check bullet tragectory chart for weight and velocity. zero at 25 comes back into zero when? what is max rise during flight from zero to zero. Doubt very much it is 12" in 32 mag.

I would shim the front scope mount or raise the front sight blade height if open sights.

Steve

Pookee · « **Reply #11 on:** August 24, 2004, 06:32:03 PM »

The load produced about 1900 fps and the weight of the bullet was 110 grains.

Pookee · « **Reply #12 on:** August 24, 2004, 06:34:57 PM »

BTW,
Is'nt the scope "alligned" in a way when it is zeroed?