Problems with POI change during testing

[SJshooter]

I was at the range yesterday doing load testing with .308, using the OCW method.
Load:
H380 45.5-46.6gr in .3gr increments (5 rounds of each 8 different charges)
Hornady 150sp (I got a crapton with my press and I'm trying to make use of them)

Distance: 100yds

My problem was that I zeroed the scope 1/2 inch low at 100 with the base load, shot those five, then when I went to move to the next load, I was off the top of the paper with the next charge weight. Thats over 3inches of elevation difference. So I wasted two rounds, one that I wasnt expecting, and one shot on larger paper to find POI, measure that with mil reticle and clicked down. I was back on paper, shot the remaining three,then moved on.

The same thing happened with the next weight! Way high! But I guessed and corrected the same amount and got back on only wasting one this time.

My question is, is it normal to have this much change in elevation at 100? Anyway I can correct before I fire the first round?

Ive been reloading for a while in .223 and never had this problem that I can remember...

Thanks in advance for any tips and advice.

 

[alpha6164]

Re: Problems with POI change during testing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SJshooter</div><div class="ubbcode-body">I was at the range yesterday doing load testing with .308, using the OCW method.
Load:
H380 45.5-46.6gr in .3gr increments (5 rounds of each 8 different charges)
Hornady 150sp (I got a crapton with my press and I'm trying to make use of them)

Distance: 100yds

My problem was that I zeroed the scope 1/2 inch low at 100 with the base load, shot those five, then when I went to move to the next load, I was off the top of the paper with the next charge weight. Thats over 3inches of elevation difference. So I wasted two rounds, one that I wasnt expecting, and one shot on larger paper to find POI, measure that with mil reticle and clicked down. I was back on paper, shot the remaining three,then moved on.

The same thing happened with the next weight! Way high! But I guessed and corrected the same amount and got back on only wasting one this time.

My question is, is it normal to have this much change in elevation at 100? Anyway I can correct before I fire the first round?

Ive been reloading for a while in .223 and never had this problem that I can remember...

Thanks in advance for any tips and advice. </div></div>


No it does not make sense at all. I was doing load testing yesterday for my 208amax out of 308 and shot groups from 43.1-44.3gr also in 0.3gr increments and my POI never shifted once. Not only that my POI was identical to my 175smk load as well.

 

[SJshooter]

Re: Problems with POI change during testing

Funny that you compared the 208 POI to 175's. I shot 180's before testing and they were Mils off.

Also, I check my rings, base, and stock to make sure nothing was loose. Everything was rock solid.

 

[jsthntn247]

Re: Problems with POI change during testing

168 Berger's hit 17" to the right of the 178 amax's at 600 yards in my gun.

 

[BuzzBoss915]

Re: Problems with POI change during testing

What kind of scope? You say everything was rock solid. That makes the scope suspect. BB

 

[oldfatguy]

Re: Problems with POI change during testing

OCW is best shot round robin. You shoot one rnd of each charge weight at its' own spot on the target and repeat till all the rounds have been fired. This is to reduce the variability of fouling, barrel heating, and such. I've always waited a timed 2 minutes between shots so the barrel only gets warm, not too hot to hold onto.

Have never seen the change in POI you are seeing. If your mount and rings are tight then maybe your scope is having problems.

OFG

 

[SJshooter]

Re: Problems with POI change during testing

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jsthntn247</div><div class="ubbcode-body">168 Berger's hit 17" to the right of the 178 amax's at 600 yards in my gun. </div></div>
Granted, thats odd that they are that far off, but at 100 yds it would only equate to less than 3 inches change of POI.

I'm using a Falcon Menace 4-14. Parallax adjusted correctly.

I doubt its the scope because I did have two good groups several charge weights later.

Could it just be that velocity changed THAT much? I doubt it.