R8 bullet jump???

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Beretta Shooter
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R8 bullet jump???

Post by Beretta Shooter »

So continuing on from my .300WM load development I have managed to source a box of 178GR ELDX to try and will also be changing powders due to supply issues.
My next question is how do people find the R8 in relation to bullet jump? I would normally start my load development at the bullet manufacturers COAL and once I find my node alter bullet jump until I’m happy with the load etc but thought asking on here may save me some time and components in the long run.

Thanks BS



Gamsjagd
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Re: R8 bullet jump???

Post by Gamsjagd »

I just keep messing with the seating die until the bullet doesn't touch. Then screw with depth .010-.030.

Blueranger
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Re: R8 bullet jump???

Post by Blueranger »

Hornady makes a nice device to check this. As with most devices or methods to verify when the bullet touches the lands some practice will help with accuracy, but nice feature is that you can verify the seating depth with different bullet ogives. I usually check it about 3 times to make sure the reading are somewhat consistent.

Beretta Shooter
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Re: R8 bullet jump???

Post by Beretta Shooter »

Sorry I was meaning do people find that the R8 like a bullet to have a good jump to the lands or very little jump?

Gamsjagd
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Re: R8 bullet jump???

Post by Gamsjagd »

Every cartridge I shoot is different. The higher pressure cartridges seem to shoot a little better with less jump.

Honestly though I have pretty good luck with everything within factory specs.

secondtry
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Re: R8 bullet jump???

Post by secondtry »

Beretta Shooter wrote:
Mon Oct 03, 2022 4:21 am
Sorry I was meaning do people find that the R8 like a bullet to have a good jump to the lands or very little jump?
I think you'll find that jump is related more to the bullet than to the make of rifle.

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stokesrj
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Re: R8 bullet jump???

Post by stokesrj »

Secondtry is correct, optimum bullet jump is determined by the bullet first and the rifle second. In general a tangent ogive bullet is the least sensitive bullet design and will work well with a wide range of jump distances. Conversely a secant ogive bullet design (VLD) is the most sensitive and will sometimes have nodes that shoot well when even .005" change in the distance from the ogive to the lands will degrade accuracy. Of course tangent ogive bullets have the least efficient BC and secant ogive bullets have some of the highest BC. The Berger Hybrid designs have very high BC and are less demanding of a specific jump distance than VLD designs which is why they are designed with two radius ogive. The combination of a tangent ogive to the point the bullet will engage the rifling makes it less sensitive to jump distance and the second radius being secant creates a sleek nose that produces a high BC.
For the 300 Win Mag, I some times see groups in the .3" range at 300 meters in our test tunnel shooting the hybrid designs of the elite hunter and long range hybrid target designs with very flat BC's and almost no care about seating depth. The # 30555 30 Cal 205 gr Elite Hunter is just about optimum for the 300 Win Mag seated to magazine length.
Robert J Stokes

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Re: R8 bullet jump???

Post by Beretta Shooter »

stokesrj wrote:
Fri Oct 28, 2022 7:17 pm
Secondtry is correct, optimum bullet jump is determined by the bullet first and the rifle second. In general a tangent ogive bullet is the least sensitive bullet design and will work well with a wide range of jump distances. Conversely a secant ogive bullet design (VLD) is the most sensitive and will sometimes have nodes that shoot well when even .005" change in the distance from the ogive to the lands will degrade accuracy. Of course tangent ogive bullets have the least efficient BC and secant ogive bullets have some of the highest BC. The Berger Hybrid designs have very high BC and are less demanding of a specific jump distance than VLD designs which is why they are designed with two radius ogive. The combination of a tangent ogive to the point the bullet will engage the rifling makes it less sensitive to jump distance and the second radius being secant creates a sleek nose that produces a high BC.
For the 300 Win Mag, I some times see groups in the .3" range at 300 meters in our test tunnel shooting the hybrid designs of the elite hunter and long range hybrid target designs with very flat BC's and almost no care about seating depth. The # 30555 30 Cal 205 gr Elite Hunter is just about optimum for the 300 Win Mag seated to magazine length.
Apologies for only just replying to this as I haven’t been on the forum much over the last week or so.
Thank you very much for the in depth reply, I plan to start working up a load with the 178GR ELDX very soon but will start at the recommended data from Hornady and increasing OAL to reduce jump if the groups aren’t what I’m looking for. I may also try the 205gr elite hunters if I can source a box.

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