Boolit wt vs POI changes

[mjac]

Recently, developing loads, my Savage 340 18.5" barrel, 30-30 was shooting a Ranchdog GC PC boolit (167.0g wt) 2" low at 50 yds. The load was a 23g H4895 with good accuracy. I purposely made no scope adjustments.
A day or so later I was shooting the same rifle using a 311041 GC Lubed boolit (181.3g wt) 6.5" low at 50 yds. The load was 34.5g Leverevolution with very good accuracy. Again no scope adjustments were made.

The loads were not chrony'ed.

Unfortunately I do not have any RD's loaded to recheck the earlier 2" low finding to determine if its a scope issue. The scope, btw is a Weaver Classic Extreme 1.5x4.5x24.

My question, if you will indulge this cast shooting rookie, will shooting a 14.3g heavier boolit likely to cause a drop difference of 4.5" over the same distance?

Thank you

[Rcmaveric]

Bullet weight, velocity, harmonics and ballistics all play a role in POI. As long as the grouping is good then your rifle and scope is fine. Sight your riffle for what you normally use and then hold over for your plinking ammo. I use a ballistic reticle scopes to make it easier for hold over.

Sent from my SM-N970U using Tapatalk

[mjac]

Correct.
While I can only guesstimate the lighter boolits' speed, the heavier boolits' speed has been reported as +/- 2000 and the other factors are nearly the same. It seems that the 311041 POI should have a higher, not lower POI than the RD. Thus my surprise of an opposite 4.5" difference.
I have gone ahead and made scope adjustments to accommodate the better group (311041/Leverevolution won this contest). My next shooting in a few days should reveal more.
Thanks

[Larry Gibson]

The adage that "heavier bullets hit higher" is generally applicable only to revolvers especially at the shorter distance you're using. Not only do the variables Rcmaveric mentions come into play but also the recoil dynamics are different with a rifle.

[mjac]

I am familiar with the opinions expressed and agree but really, a 4.5" difference?
Although I am very reluctant to say, without trial, my scope may be the problem. Further I have purchased another 3030. A long sought after bucket list bolt gun and the scope will be moved to the new to me rifle. Scope problems may show up.
Thank you both for your input.

Mike

[Norske]

Suspect scopes are the reason i have a "proof scope." It's an old 10X Weaver target scope; nothing to go wrong in such a simple device. It's dim by modern standards, but gets mounted on any rifle that suddenly seems inaccurate.

[John Boy]

Although I am very reluctant to say, without trial, my scope may be the problem.
So,you answered your own post... just adjust your scope settings instead of try to fiddle with a different reload when your scope can be adjusted for any reload - even using different height blocks to shoot at 1000 yards

[kungfustyle]

It looks like you are using an almost max load with the Leverevolution powder and a Mid/lower end load from the 4895, They are just different. If you have the 311041's at 2200 fps and the Rd's at 1900 fps that very well could give you the two different poI's. A better test would be with the same boolit and different powders. Time of flight is what is causing the variance.

[mjac]

Suspect scopes are the reason i have a "proof scope." It's an old 10X Weaver target scope; nothing to go wrong in such a simple device. It's dim by modern standards, but gets mounted on any rifle that suddenly seems inaccurate.

Thanks. Down the road I may try out a similar method.

[mjac]

It looks like you are using an almost max load with the Leverevolution powder and a Mid/lower end load from the 4895, They are just different. If you have the 311041's at 2200 fps and the Rd's at 1900 fps that very well could give you the two different poI's. A better test would be with the same boolit and different powders. Time of flight is what is causing the variance.

Yeah, it was quite a stiff load and I did expect some difference.

[mjac]

So,you answered your own post...

Not so fast. It may be one explanation but in the absence of wildly expanding groups among other groups fired that session, the scope *may* not be at fault. Plus, by answering my own post, I get to increase my post count :)



...just adjust your scope settings instead of try to fiddle with a different reload when your scope can be adjusted for any reload - even using different height blocks to shoot at 1000 yards

"Purposely" is used to describe an action done intentionally, deliberately, or for a specific reason.

[Mr_Sheesh]

Friend used to re-adjust their scope regularly. They had this problem where they'd forget what they'd set it up for, lower POI by 5-6 MOA thinking it was set for their other round, and miss their shot, like 50% of the time, hunting. That turned me completely off on the "fiddle with the scope" concept; I do that in "greyware" i.e. in my head, very doable and works well, and leave the scope settings strictly alone. Just a finnickiness of mine :)

If you do change elevation, check zero with the round you'll be hunting with, start of each season. You don't want to wound an animal, or worse, just wound a paper target; Wounded paper targets are scary dangerous! :P

[popper]

Ballisticaly, drop is function of fps and BC which is usually unknown accurately. I dope the scope for playing but would use a known load for serious hunting. Check the scope before a hunt.