I'm currently reloading for my .270 Win using H4350 and 140 gn Nosler ballistic tips. I've decided to bump my powder up by 1/2 a grain and am curious, will this significantly impact my rifle's point of impact? I know I'll have to test it and plan to, I'm just curious what difference I'd be looking at out of the gate?
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POI change 270
- Thread starter montana09
- Start date
big al hunter
New member
I would expect a slight change in POI. I usually shoot 5 shot groups, with the same bullet and 1/2 grain increment changes from group to group when working up a load.. The group generally moves around a little. Sometimes an inch, sometimes less, sometimes more. Not usually a big jump though.
Don Fischer
New member
Doesn't matter the change. Just live with it and adjust sight's as needed. May be little may be a bunch. In my 6.5x06 I switched fron 140 gr Hornadys to 140gr Nosler's and even changing bullet I had the same group in the same spot! That don't happen often but you never really know till you try!
When you fire a rifle whose boreline is above the point of support on your shoulder (most rifles except for some of the bullpup designs) it applies a force that pivots the gun upward (a recoil moment around the point of support). The upward flip bends the barrel, as shown in the animation about 2/3 of the way down this page.
At short ranges, like 100 yards, a difference in POI depends on what position the barrel bending was in when the bullet exited the muzzle. Your heavier bullets will tend to go slower and take longer to reach the exit so that the barrel will bend further. At the same time, your recoil is greater so the gun rises more, though the end of the barrel will bend down further. Sometimes the bending compensates for the difference in bullets weight's effect on barrel time and pressure, but sometimes it doesn't. Exactly what you will experience depends on the gun specifics. So the bottom line is, you shoot and see.
At short ranges, like 100 yards, a difference in POI depends on what position the barrel bending was in when the bullet exited the muzzle. Your heavier bullets will tend to go slower and take longer to reach the exit so that the barrel will bend further. At the same time, your recoil is greater so the gun rises more, though the end of the barrel will bend down further. Sometimes the bending compensates for the difference in bullets weight's effect on barrel time and pressure, but sometimes it doesn't. Exactly what you will experience depends on the gun specifics. So the bottom line is, you shoot and see.