375 point of impact different bullet weights

[gearguywb]

I was at the range yesterday working with a 375 for an upcoming moose hunt. This particular gun likes heavy bullets (300's).

Zeroes at 200, shot to confirm at both 300 and 100.

After a lot of work, I was simply not comfortable at 300 with the scope at max magnification and no type of hold over reticle.

I would caution that changing bullet weights may/may not mean simply moving elevation. There can certainly be windage adjustments needed as well.

There is no way I would consider two different bullet weights unless I got lucky and they shot to the same POI.

KISS. The last thing you want going through your mind as you are setting up a shot is "I wonder if I have the correct zero dialed in"

 

[Hunter-Habib]

Even though I personally never use any bullet weight other than 300Gr for .375 Holland & Holland Magnum, the 270Gr Barnes TSX will suit your needs very well for both Cape buffalo and hippopotamus.

 

[Luvthunt]

To answer your orginal question. I reload the 260 Nosler Part. for my 375 using Re15. I also reload 300 gr Nosler Part. Using IMR 4350.
With a 2” high poi on the 260s my 300s poi is 4”+ low at 100. in my rifle.

 

[375Fox]

To answer your orginal question. I reload the 260 Nosler Part. for my 375 using Re15. I also reload 300 gr Nosler Part. Using IMR 4350.
With a 2” high poi on the 260s my 300s poi is 4”+ low at 100. in my rifle.

Thank you. I was starting to regret making this thread. That answers my question. It’s unfortunately no different than the 250 gr Barnes compared to the 300 gr swifts. I won’t be buying a box to try now. Thanks for saving me a few dollars.

 

[375Fox]

I was at the range yesterday working with a 375 for an upcoming moose hunt. This particular gun likes heavy bullets (300's).

Zeroes at 200, shot to confirm at both 300 and 100.

After a lot of work, I was simply not comfortable at 300 with the scope at max magnification and no type of hold over reticle.

I would caution that changing bullet weights may/may not mean simply moving elevation. There can certainly be windage adjustments needed as well.

There is no way I would consider two different bullet weights unless I got lucky and they shot to the same POI.

KISS. The last thing you want going through your mind as you are setting up a shot is "I wonder if I have the correct zero dialed in"

My 375 seems very forgiving. I’ve shot a lot of different rounds through it and surprisingly no left right adjustments with any 300 gr soft or 250 gr TTSX. Woodleigh hydro solids do go left hard for whatever reason although appear perfectly centered at 50 yards. Here are 6 different 300 gr bullets. This includes one very questionable box of federal 300 gr TBBC I bought from a classified ad. I need to run them through a chronograph because they shoot so low. That’s actually what caused me to shoot all these compare.

 

[dchum]

Just sight it in for the 260 accubonds when you get to new area? Might just spend an extra 15 mins shooting at the box. Not just the usual one shot check and go.

Just an idea.

 

[sgt_zim]

I saw that. Looks like the distances are in meters and you're measuring drop in inches. On the TTSX, for example, if I use 185 yards as a zero, the arc indicated in your notes doesn 't comport with the calculator. But if I use 185 meters (202 yards), then the data line up nicely with a MV of ~2700 fps.

For the Woodleighs, if I assume an MV of 2450 and a 164 yard zero (your notes look like 150 meters), the calculator shows 19.4" of drop at 325 yards (just a little short of 300 meters). That lines up really closely with your field data.

The other thing is if you're shooting factory ammo, most of the mfgs overstate velocity by at least a little bit, sometimes by quite a lot, by 100 fps or more.

I've put a lot of my loads in front of a LabRadar, and the data I get from the measured MV and calculated BCs always line up really closely with what the Hornady calculator indicates what the arc should be.

If you're shooting factory loads, I'd be really curious what a chrony says about actual MV. Since the mfgs can't really fudge on the BCs (too many LabRadars and Garmins floating around to get away with that), they have to "fudge" somewhere. Most guys who shoot factory ammo will just assume the MV published on the box is accurate and go from there. And most guys who reload seldom shoot factory ammo. I haven't shot factory in almost 20 years.

 

[375Fox]

I saw that. Looks like the distances are in meters and you're measuring drop in inches. On the TTSX, for example, if I use 185 yards as a zero, the arc indicated in your notes doesn 't comport with the calculator. But if I use 185 meters (202 yards), then the data line up nicely with a MV of ~2700 fps.

For the Woodleighs, if I assume an MV of 2450 and a 164 yard zero (your notes look like 150 meters), the calculator shows 19.4" of drop at 325 yards (just a little short of 300 meters). That lines up really closely with your field data.

The other thing is if you're shooting factory ammo, most of the mfgs overstate velocity by at least a little bit, sometimes by quite a lot, by 100 fps or more.

I've put a lot of my loads in front of a LabRadar, and the data I get from the measured MV and calculated BCs always line up really closely with what the Hornady calculator indicates what the arc should be.

If you're shooting factory loads, I'd be really curious what a chrony says about actual MV. Since the mfgs can't really fudge on the BCs (too many LabRadars and Garmins floating around to get away with that), they have to "fudge" somewhere. Most guys who shoot factory ammo will just assume the MV published on the box is accurate and go from there. And most guys who reload seldom shoot factory ammo. I haven't shot factory in almost 20 years.

The distances are in yards measured with a Leupold range finder. The bench unfortunately couldn’t be at 200 anymore due to various reasons. I did get my answer I was looking for in this thread. There is a 6” difference in point of impact at 100 with 260 gr accubond compared 300 gr grain Nosler partions. That’s close enough to swift A frames to answer my original question.

I unfortunately never learned to reload. I know I don’t have patience to learn now or enjoy shooting enough to justify it. I only shoot to practice for hunts. I do have an individual reload for me for certain calibers and bullets, but generally factory ammo is suitable for what I need.

 

[sgt_zim]

Fair enough, then. I suspect your factory loads on the 300s probably are in the neighborhood of 2400 fps, maybe even 2375. My 286 gr A Frames at 2475 are a bit flatter than what you're getting.

If you know somebody with a chrony, it'd be worth it to put 4 or 5 bullets across it.

In all candor, I shouldn't haver brought 2 rifles on my safari last week. I used to work out ballistic tables by hand when I was younger, and memorized the arcs. I had a few moments of serious confusion/deep thinking on what my arc was, with 2 totally different cartridges. 3 or 4 seconds spent remembering my cartridge/load was the difference a couple times between putting the game in the salt and not shooting at all. It was all good, though, I ended up with a terrific zebra, even for all the minor confusions.

I'd absolutely just go with the A Frames and zero somewhere between 150 and 200.

My next safari will be 2 guns, but the 280AI is going to be for the missus, and I'll use my 9.3 for everything.