Lead to copper

Leica Fortis 6 - Bright and powerful.
T

Timmy k

Well-Known Member
This isn't a which is best topic more of a zeroing issue.
So I've got a 270 and was using 140gr lead but I've decided to start using copper.
I had it zeroed at 50m with the lead and tried the coppers and it was miles out. About 12 inches. Is it normal for them to be that different or could I have knocked something out of place, I'm a newby, so be kind.
Cheers
 
Timmy k said:
This isn't a which is best topic more of a zeroing issue.
So I've got a 270 and was using 140gr lead but I've decided to start using copper.
I had it zeroed at 50m with the lead and tried the coppers and it was miles out. About 12 inches. Is it normal for them to be that different or could I have knocked something out of place, I'm a newby, so be kind.
Cheers
Click to expand...
12 inches which way?
 
12 inches down and maybe an inch or two to the left.

I understand a change of bullet would have a different point of impact, I just found it alot for 50 meters
 
I did check the sight was tight and the mod was screwed tight, couldn't think of anything else to check. But with it now grouping well after adjustment of the scope surely it was down to bullet change, or maybe I'm a **** shot.
 
When swapping from lead to solids the common choise is for a lighter bullets. If this is apply to you at 50m the POI could still be lower than previous because the trajectory will reach the maximum hight later.
 
Sorry I just realised I didn't state the weight of the copper, so the lead was 140gr and the copper is 120gr
 
You should go back to a spotless bore , before mixing . Its a good time to have the bore looked at with a bore scope . You also need to find what copper suits it all over again . swiching about lead to copper and back tends to lead to problems
 
Recoil and Harmonics are the issue,

As soon as the firing pin starts to move the rifle moves in the opposite direction. As the bullet accelerates the muzzle starts to climb, and the bullet will start to leave at some point during this climb. Barrels also vibrate like a piece of spaghetti with all the vibrations caused 60,000 psi accelerates a bullet from zero to 3 times the speed of sound over the length of the barrel.

A lighter and faster bullet will leave the barrel earlier in the recoil movement and thus will tend to shoot lower than a slower and heavier bullet.

Its why all rifles are fussy in the ammo they use and why there can be quite large changes in zero when you change anything on a rifle.

And if you have ever used open target type sights, movement of the sight is very little for there to be quite substantial changes in point of impact on target. The same applies to postion of the muzzle as the bullet leaves the barrel.
 
You must log in or register to reply here.

Similar threads

Lead and copper through the same barrel
Replies
16
Views
626
muddy42
M
Quickload and none toxic rounds
Replies
10
Views
398
Apthorpe
A
Switching to Non-toxic
2 3
Replies
43
Views
2K
Bowland blades
Bowland blades
308W & 130gr or 150gr Copper on small deer?
Replies
13
Views
717
3595wilk
3595wilk
Federal Power Shock 130gn Copper inconsistent group
Replies
4
Views
694
Electric Ian
Electric Ian
ALLHONE hunting knives designed and made in NZ
Back
Top