wierd problem sighting in 30-30

[sherm]

I'm at the range today sighting in my new VX-3 on a marlin 30-30.
i was using the Hornady leverrevolution bullets. I had bought a box last year that had 6 rounds left in it. I also had a new box i purchased this year.

I used the old ammo first( only 1 yr. old) I had the group at 2" consistently at 100 yds. Then i switched to the new ammo. the new ammo shot 5" low consistenly. Same ammo, same bullet, different lot number. This seemed really strange to me.

Is this new ammo under powered ? Has anyone else ever had this much of a difference just by going to a different lot # ?

 

[mustanger98]

I haven't noticed it personally, but stuff like this is why we sight in with whichever box, or couple or three of boxes of whichever lot#, of ammo we'll be shooting in the field. No real big surprises that way.

 

[ken grant]

There is a chance the older ammo was the slowest and the newer was the fastest.
Recoil starts as soon as the bullet begins to move and a slower bullet lets the rifle rise more in recoil before the bullet exits the barrel and makes it shoot high.
A faster bullet exits before the rifle rises as much and can shoot lower.

This shows up more with handguns than with rifles but it happens with both.

Also barrel harmonics can play a part as well depending on when the bullet exits in the cycle and where the barrel is pointing at that time.

 

[trstafford]

Were they the same bullet weight? Heavier bullets usually shoot higher

 

[sherm]

yes, it was the exact same ammo, just different lot#

 

[Sistema1927]

There was a recall of Hornady .30-30 Lever-Revolution ammo earlier. I wonder if you were shooting some the stuff that was recalled.

 

[Roadkill]

I've experienced the same problem with my 30-30 336. I use pulled 150g milsurp spire point fmj for single shot target practice and 150g Remington coreloks for hunting. Same gun, same 27g load of IMR 4895, the milsurps shoot 8" lower at 100 yds. As said, different lots of bullets hit differently. I'll set my scope for the sp coreloks soon and it will stay that way all hunting season.

 

[Horsemany]

point of impact change

I can't think of why the point of impact would change so dramatically but I did have one thing to add. I know it doesn't make sense but a lower point of impact is generally acheived with hotter ie. faster loads. This is a common problem with old Milsurp guns who's iron sights don't zero any lower than 200 or 300 yards. It is common for some to shoot 12 to 18 inches hight at 100. If taller front sights aren't available, the other way to cure this is to handload hot loads and lower the point of impact. I know it seems like the opposite would be the case, but generally speaking the faster they are the lower the POI. You might try calling Hornady. Their facility is just an hour west of me and they have outstanding customer service and people who really know their stuff. Good Luck.

Horsemany