7mm RM 100 yard sight in variance

[Scottish Mag]

I spent some time Sat on the range, and has just worked up some loads of 168 bergers over h1000. Outside of the fact some of the loads were showing pressure, I had a question looking for some help on:

I ran a group of 3 Rem 150 gn Accupoints through, and they were exactly where I wanted them, 2.5" high at 100. This was simply to verify the prior zero as I had left it.

I then ran the 168 Bergers I loaded. I was surprised that this load shot dead on, but 4 inches right. I was surprised that there was this much spread between the two loads.

Has anyone had this same experience? I know I will have to re-zero if I choose to go with a different load. I left it zeroed for the 168's.

Sidenote: Rifle is a stock Rem 700 Sendero with a Mark 4 scope.

 

[davkrat]

I've had two loads spread all over the paper in every direction imaginable. You'd think the vertical would change but horizontal be consistent but I am usually 1-2" in all directions when I switch loads. I'm getting to where I only load one bullet per gun and gave up on switching around. Just another excuse to buy another gun.

 

[tinman13kup]

I've had the same thing happen when I was working up a round for my 30-06. Even with the same bullet, different powder might change POI from left to right of bull. It doesn't really matter where it hits, it's the grouping that counts. If you're only getting 3" groups, then perhaps it's time to check another powder/bullet combo.

 

[baldhunter]

Very common.You can find some bullets that will shoot very close,but then some will shoot much different.

 

[Browninglover1]

My worst experience with this happened while sighting in my bosses gun. I had it dialed in and dead center at 100 yards after just 2 shots plus one more to verify using very cheap old ammo out of a 7mm. I then switched over to the rounds he wanted me to sight in with so he could practice before hunting season and I shot 3 rounds that didn't even hit the little target stand I was shooting at. The bullets had shifted 14 MOA to the right. That's the most extreme example and he didn't believe me until he went out and witnessed the same thing for himself.

 

[rscott5028]

My worst experience with this happened while sighting in my bosses gun. I had it dialed in and dead center at 100 yards after just 2 shots plus one more to verify using very cheap old ammo out of a 7mm. I then switched over to the rounds he wanted me to sight in with so he could practice before hunting season and I shot 3 rounds that didn't even hit the little target stand I was shooting at. The bullets had shifted 14 MOA to the right. That's the most extreme example and he didn't believe me until he went out and witnessed the same thing for himself.

As you stated, that's pretty extreme.

I'd be curious to know how you explain it. ...featherweight gun + featherweight barrel + big caliber + radically different bullet weights/loads?

-- richard

 

[Camshaft]

I shot this weekend and and when switching from 165gmx bullets with superformance powder, to 208Amax bullets loaded with h4831sc my point of impact shift was 3"high and 5"left. This is quite common.

 

[Browninglover1]

As you stated, that's pretty extreme.

I'd be curious to know how you explain it. ...featherweight gun + featherweight barrel + big caliber + radically different bullet weights/loads?

-- richard

The gun was an old Sako (not real light) with a Leupold scope that I had installed for him. He gave me some Remington 150 grain core-lokt bullets to get it on paper and then some Federal Premium 160 grain Accubonds that he wanted to hunt with.

Like I stated earlier I sighted in with the cheap stuff and then when switching to the Federal Premium the bullets landed just over 14 inches to the right of where the Remington ammo shot. Just to be sure I fired a group with the Remington stuff and it was dead center. To this day I have no idea what would cause such a radical shift in POI. My guess would be the bedding and the non floated barrel but I honestly don't know and didn't really investigate too much because it wasn't my gun and he didn't care. By the way it shot 1 MOA with the Remington for 3 shots and would hove around 1 MOA with the Federal Premium for 5 shot groups.