Same load but vertical POI shift of half a Mil?

[5RWill]

Here is my groups from almost a year ago. Both are Hornady 178gr BTHP, Nosler brass, Fed 210m. The left is 45gr of varget the right is 45.5gr. COL is 2.865. The right is what i had settled on, but got pressure signs.

So backed down to 45gr loaded about 40rds to take them out the next day and chrono them. Granted i cleaned my rifle recently i wouldn't think it would be this drastic of an impact. Hell maybe it's me but my friend who also shoots shot the group in the top left corner. Going to retest the tracking on my SN-3 but i just can't see it being the problem as i've tested it before. Maybe it's just me having not shot consistently in a very long time? I do know i need to tighten my load preferences/procedures back up. Had some ES that was uncharacteristic of me. Last i was shooting Berger 175gr BT LRs @ 2618 with a ES of 12 and a SD of 4.5 out of the ones i had chronoed. These ranged from 2684 to 2728 even.

 

[Drifter™]

New vs fired brass perhaps?

 

[5RWill]

While one set of the 50 pieces out of the hundred I have has been fired less they've both been fired 4+ times. This was the 50 that will need trimming next time and had been fired more. So to an extent newer brass vs older brass. Both sets of 50 would be on the same firings but my dad took my first set of 50 for his .308 so i had to order another. If it warms up a bit i might run the 25rds through and see if it drops down more.


Sent from my iPhone using Tapatalk

 

[milo 2.0]

Personally, I don't think it's your load, even if your barrel sped up after slight breakin, it wouldn't be that high. I suppose I'll get flamed for this, but I think it's the scope, all that cranking on the turrets over time, it just has a new zero. Not saying the scope doesn't track right or anything it's probably fine there, just shifted over time.
I crank a couple of mine up to 70moa and back, I've seen this also, of course you notice it at the most inopportune times. I hate to say this too, but my Leupold scopes seem to hold better than my NF's.

 

[5RWill]

I'm thinking the same, i just don't want to say it about my SN-3 i guess. We'll see though. I only have half a Mil of room beyond my zero stop too. So it's literally a hard stop, which i don't want.

 

[milo 2.0]

Just on Sunday, a friend shooting a 300 Norma mag, had some zero issues, bad at 300 yards, we zeroed it there, because there was no 200 yard target, and he was able to get back to shooting, but he was high and left, bad.
A relatively newer NF.

 

[5RWill]

Same load but vertical POI shift of half a Mil?

I ran out to 300yds using a zero half a mil below my stop (where it ends) and it was spot on for the plate we were shooting.

The thing is the scope doesn't get roughly used I haven't gotten a chance to shoot comp so it's just been bench work. Never had a problem in five years of owning it.

That said there is a spec in the scope that I noticed this year to the left of the top end of the reticle. It can only be seen at 3x and I never noticed it before.

I thought about sending it in but figured id test tracking first as I've never had a problem with it.

Maybe a different lot of varget might be the culprit?


Sent from my iPhone using Tapatalk

 

[milo 2.0]

Maybe a different lot of varget might be the culprit?


Sent from my iPhone using Tapatalk

Maybe??
I don't shoot Hodgdon powders, irrelevant here, but I see more of this, lot to lot inconsistencies, with Hodgdon extreme powders, than any other!
Not to be an ass, but if that happened to me, I'd switch. Let us know what you find, may have to run a 200 yard zero with your scope situation.

 

[918v]

A different lot of Varget is the culprit.

 

[5RWill]

A different lot of Varget is the culprit.

Think so? That drastic? I need to get a bulk thing of varget if this is the case.

 

[Gunfighter14e2]

Have you gained or lost much weight? Was your clothing layers the same?

 

[5RWill]

I mean i lost some weight but only like 7lbs. My friend however is the same size, yet same results. Not sure either of those two things are going to factor much as long as fundamentals are decently sound. Going to test tracking while i'm home this weekend if we get a break from moving rice. Dope was spot on out to 300yds, 1.2 Mils just like my old load. Though i had to start from 1/2 mil below my zero. I hope it's the powder. The bore had been cleaned until i shot these groups so maybe it just needs to become fouled again? Though IIRC clean bore rounds are usually a lower shift of POI right?

 

[5RWill]

Think i've found the cause. Checking my action screws...hell the freaking front action screw is finger loose. Going to take it apart tonight and re-torque it down. Knew that Borka torque driver would be of great use

 

[milo 2.0]

Good, hope that was it! I'm surprised your groups were that good with a loose screw, must have a good technique!
I have a story on a rear action screw being loose, it drove a number of people batshit crazy till found. Groups in the.2's, 5 minutes later, a solid 5" group.

 

[5RWill]

I hope that's the problem. I'm sure it is. Gonna have to call the local smith. I can't remember what the torque settings were for his bedding compound


Sent from my iPhone using Tapatalk

 

[5RWill]

Shot this today. 20mph crosswinds. 100yds.

Still a tad high. Just gonna adjust I guess. Maybe it's my breathing I did have two that were in the bullseye in the middle.


Sent from my iPhone using Tapatalk

 

[5RWill]

Maybe it is fouling, it has shifted down from when i last shot.