Buddy is going to B.C Sunday to hunt a mountain goat.

He bought 4 boxes of Nosler trophy grade 180 grain accubonds in .300 win mag.

For the past month he has been shooting at various ranges preparing for this hunt.

Tuesday, he is shooting out to 400 yards. Everything is money. He cracks open a fresh box and puts one dowmrange at 400 yards. Bullet hits 12” high. Shoots again. It’s 1 1/2” away, 12” high but good left to right.

Shoots at 100 and it’s still very high. Shoots again and it’s almost touching the first shot.

He freaks out

Yesterday he goes back to the range and pulls two random shells from the other boxes and shoots. Everything is bsck to where it was. Shoots a third shot from the original box and it’s way high.


Has anyone heard of this before? Are those shells loaded super hot?

Check the lot numbers on the boxes

Yes, it's called a powder charge variation inside the case that is changing up the speeds and pressures, effecting the trajectory. If it's not that, it could be different lot numbers of ammo. This is why having a chronograph when shooting is helpful to know this for sure.

Different lot #s in my opinion. I first experienced this with federal fusion. A major disappointment. It was the only gun I didn’t reload for. Now my only factory ammo is 9mm or rimfire.

Nosler Custom is supposed to be good stuff; at least the price says so. Factory ammo isn't always consistent, as Chad has pointed out several times before, especially between lots. I had a similar experience earlier this week, sighting in a .30-30 I haven't shot in decades. Got it where I wanted it with one old box of Remington green-and-yellow box. Opened up another old similar box (different vintage, different lot no) and it shot consistently 5" higher at 100 yards. At that point, I was nearly out of ammo. Went to Academy and bought two new boxes of the same lot and will try again next week.

Bet it's a different lot number. Seen it more times than I can remember. I'll be spotting for someone, and a round will splash way high, or way low.

One shot, I will say "was that your fault?"
No.
"Did you just change lot numbers of ammo?"
Yes.

And this is another reason we hand load.

I have inspected some of the most expensive ammo out there, and it have the worst powder charge consistencies I've seen (2.5 grain internal spreads). Just because something is expensive, doesn't mean that it's good.

I pulled apart some Nosler .300 WSM ammo. Think the box had a price tag of $70.00 and the powder charge varied 3.0 gr. Plus the powder was compressed so tight I had to dig it out with a dowel rod.

Here, I finally found the post I made about expensive factory ammo. Here's a direct link- HERE!!!

http://texashuntingforum.com/forum/ubbthreads.php/topics/6062258/1

I posted up another one where I found a 2.5 grain spread on some expensive Weatherby ammo. I can't seem to find that write up I did on it. But the point is, a lot of factory ammo will have a large variation like this. And the smaller the diameter of the bullet and the larger the case volume, to worse it is. The smaller opening causes the powder to hang up or bridge, and not go into the case as fast to fill the round as accurately. This is why the 257 Wby or other similar magnum rounds with a smaller diameter opening is worse on consistency inside the case.

I was needing some 280ai brass so I decided to try the Nosler Trophy grade ammo with the 140 accubond. Have 4 boxes heading this way. Hopefully will not be disappointed. Love the 130 accubond in my 260.

Could even that large a difference in charge weight affect his impact by the report 12"? In my Nosler manual it shows a 4gr spread in tested loads across several powders- the greatest deviation in velocity was 200fps for a 4gr difference in charge weight- at 400 yards this equates to a 4 to 5" shift in POI-- again this is according to book math and a ballistic calculator.

Could there be another variable at play? If he shot several rounds and then loaded a round into the chamber and let it sit would the temp rise enough (coupled with a change in charge weight) to increase velocity to the point where he is 12" high?

As far as factory ammo, the Nosler stuff is the next best I've seen to HSM. I was shooting factory Nosler 130gr through my 6.5x284 this weekend- the 3 shots I chrono'd were within 4fps of each other.

Another thing to check, did they accidentally put 150grs in a 180 box? Weigh 4-5 of the suspect box and compare to the control group.

Trajectory wise, it may be a 4"-5" POI change simply due to the change in velocity. But you are also not accounting for the actual POI shift from a 100 yard zero. As you increase powder, the bullet goes faster and your actual POI will move upwards on the target. So, you can have 2 major changes. The POI change from the round going faster (trajectory), and the POI shift from the round impacting higher from the increased velocity. As I test loads in rifles, the POI shift moves up as the powder charges get hotter. If a group was dead center on say 69 grains of powder, I will often dial down a click on the next load of 69.5 grains to account for the POI shift and keep the group more centered on my target.

I see said the blind man- I had held a 100yd zero constant. Accounting for increased velocity causing an above 0 impact at 100 yards it could account for as large a gap as 12" down the line at 400.