6.5 140 AccuBond BC off?

[bboswell]

I’m gonna say the BC is off. However, those speeds seem slow for a prc. If I recall, nosler BC isn’t as high as they claim. Check Bryan Litz numbers. You’re running the same set up I intend to. I’ll probably run a 140 Berger for targets. Those accubonds are lightning out of a gun barrel on critters.

What velocity would you expect? I am pleased since most 140g loads I see posted are mid to upper 2900fps

[meltingfeather]

Every shot for the whole work up was chrono’d on the LabRadar, speeds have been consistent, I had several charges in the very low teens for SD and this one that was 6 on the first group, I went one size smaller on bushing and SD 4 was the result.

Doesn’t seem to be an outlier.

Well that sure is hard to beat!
I’d keep shooting at different ranges and it’ll come out. If the BC really is that far off that would surprise me, but jot as much as somethings I’ve seen.
Curious for the resolution.

[Radar]

Mirage was vertical, I had 8mph wind dang near perfectly in my face.

I thought G7 was better for really high BC bullets and G1 was better for std flat base bullets? Anyway I ran my info with G7 and it was off even more.

Have fresh loads, will confirm zero, then shoot a box to verify turrets and then de-shoot distance. U fortunately 400 is all I have available during deer season but that been enough to get real close on everything else I have done.

That vertical mirage can be a problem, head winds push the bullet down and tail winds lift the bullet up.

Brent, you got a good load going on with the numbers you posted, so somewhere in your data inputs something is off or it was the shooting conditions. I had assumed you were using the LR Accubonds, not the standard version thus the G7 reference.

If you were close by here we could shoot out of the shop window to 800 yards, we have targets set up every 100 yards. We can shoot out farther but got to move the cows.

[trophy8]

What velocity would you expect? I am pleased since most 140g loads I see posted are mid to upper 2900fps

I’d expect closer to 3100. BUT there’s a lot of bearing surface on an accubond.

[bboswell]

Scope I think

Shot at 100, 1st shot in my 1” dot, dialed 3moa up and it only went up 2.26”, dialed 3moa right and it went 3.13 right then returned to zero.

This round ES was 12, SD 6

[RifleBowPistol]

Where you shooting into a wind or with the wind. Or was wind a factor. Then altitude, temperature and air density should be factored in. 350 is not that far. But everything I have listed will be a factor in bullet drop. Altitude is not really that important, air density is more important, altitude affects air density.

The thing I found many years ago, when shooting at much longer ranges, was shooting with the wind or into the wind, could have a lot of effect on bullet drop. Not sure how much it would affect the bullet drop at only 350 yards with a bullet that should have pretty good BC numbers.

One more thing you can do to help determine if you BC numbers are good, is to set up the chronograph at 350 yards and shoot through it at that range. Then see what numbers you get for velocity. See how those numbers compare to what Nosler has in the back of their loading manual for that bullet at the muzzle velocity, closest to the muzzle velocity you are getting.

[Radar]

Scope I think

Shot at 100, 1st shot in my 1” dot, dialed 3moa up and it only went up 2.26”, dialed 3moa right and it went 3.13 right then returned to zero.

This round ES was 12, SD 6

Is your scope MOA or Mil? Do you have your software set up for MOA or Mil?

[bboswell]

Is your scope MOA or Mil? Do you have your software set up for MOA or Mil?

MOA and yes

[meltingfeather]

Is your scope MOA or Mil? Do you have your software set up for MOA or Mil?

Not a bad thought

[bboswell]

Side note that just occurred to me, initial data powder was dumped and then trickled manually up to weight on my beam scale. Today’s data was run on an RCBS Chargemaster Lite. The first 5 charges went to the beam and were perfect so I stopped the dbl check.

Neither ES nor SD seem to have suffered from the change.

[1longshot]

If you don’t mind telling us, what was the brand of scope and what is your final load data for the 6.5 prc. I’ll be starting to work up a load for my own after the season is over.

[trophy8]

Scope I think

Shot at 100, 1st shot in my 1” dot, dialed 3moa up and it only went up 2.26”, dialed 3moa right and it went 3.13 right then returned to zero.

This round ES was 12, SD 6

What scope?

[bboswell]

If you don’t mind telling us, what was the brand of scope and what is your final load data for the 6.5 prc. I’ll be starting to work up a load for my own after the season is over.

Quick loads gave this. Hornady brass, Viht N165, Fed 215, 140 Accubond, 60.5 grains, 100% case fill, 100% powder burn, 64.2k, 2990 fps.

Both pressure and speed came well under that charge so work up carefully.

LRP scope

[sierracharlie338]

I had a guy run quick load for me about a month ago. The numbers were drastically off. All the data was specifically measured for my rifle and load, even H2O capacity, but still off by a good bit.

With your SDs and ES I would try another scope and see if the problem persists.


Sierracharlie out....