How far have you jumped?

[ndlawrence]

So I've had a Sako Classic in 7x64 for a couple of years. Haven't even shot it yet.. I finally picked up some dies. These rifles come with a 1:10" twist barrels. I picked up some 131gr Hammer Hunter Bullets, the heaviest I could stabilize with a 1:10".

Loaded 1 road to spec and fired it off, made my CBTO gauge from the case and started measuring the CBTO when the bullet is kissing the lands. I was surprised to see that bullet was completely out of the neck about 1/8". I got a theoretically CBTO of 3.223" to touch the lands. Found the max COAL the would fit in my factory magazine, which yields a CBTO of 2.739".

You can do the math but the minimum jump is going to be a whopping 0.484". I did some research and seems like the european chambers for the 7x64 are throated for bullets more like a 175gr round nose. I checked a box of Norma Tip Strike 160gr and they will have a jump of 0.591" in this rifle.

What's the furthest any of you have jumped a bullet?

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[mt100gr.]

I'm jumping .284 Berger VLDs 0.13 in a Tikka 7mmRM with great results. You're talking about a leap!!

Did you just load your 1 spec round to maximum magazine length? I guess I'd load a few more and shoot a group. If I liked it , I'd load a few more and check them over the chronograph.

 

[1shotgear]

Factory guns are typically cut with very long throats because most bullets shoot fairly well with a large amount of jump. This is how factory rifles can be guaranteed to shoot 1 MOA with any high end factory ammo. However, if you are wanting to use projectiles with aggressive ogives that are seating depth sensitive (Berger VLD), you will run into issues sense these projectiles usually shoot best with a short amount of jump or a jam. Considering the Hammer Hunters have a relatively forgiving ogive they will probably shoot well with the long jump. Keep us posted on how it shoots!

 

[hodgeman]

I've had good results with ELDX and Accubonds with jumps between 0.100" and 0.200"

 

[ndlawrence]

I'm jumping .284 Berger VLDs 0.13 in a Tikka 7mmRM with great results. You're talking about a leap!!

Did you just load your 1 spec round to maximum magazine length? I guess I'd load a few more and shoot a group. If I liked it , I'd load a few more and check them over the chronograph.

No, I loaded it a good bit short of that based on what I had found. I am going to proceed with load development and see how it goes...

Factory guns are typically cut with very long throats because most bullets shoot fairly well with a large amount of jump. This is how factory rifles can be guaranteed to shoot 1 MOA with any high end factory ammo. However, if you are wanting to use projectiles with aggressive ogives that are seating depth sensitive (Berger VLD), you will run into issues sense these projectiles usually shoot best with a short amount of jump or a jam. Considering the Hammer Hunters have a relatively forgiving ogive they will probably shoot well with the long jump. Keep us posted on how it shoots!

I will!

 

[Trippy]

Damn, here I was worried about my Tikka starting with a jump of .140" because of the stock magazine.

 

[robtattoo]

I have the same issue with my 9x57 Mauser. I don't remember the exact measurement, but it was around a half inch with 250gn Speers, slightly more with factory Kynoch 245s (loaded in around 1950)
It seems to shoot just fine though so I honestly quit worrying about it!

 

[BBob]

However, if you are wanting to use projectiles with aggressive ogives that are seating depth sensitive (Berger VLD), you will run into issues sense these projectiles usually shoot best with a short amount of jump or a jam.

This was once thought gospel but VLD's can shoot with large amounts of jump. I've been doing it for a very long time now.

From Berger: "The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a CBTO that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands."

VLD - Making it Shoot

VLD bullets are designed with a secant ogive. Berger VLD bullets are consistently and exceptionally capable of putting game down quickly

bergerbullets.com

 

[1shotgear]

This was once thought gospel but VLD's can shoot with large amounts of jump. I've been doing it for a very long time now.

From Berger: "The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a CBTO that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands."

VLD - Making it Shoot

VLD bullets are designed with a secant ogive. Berger VLD bullets are consistently and exceptionally capable of putting game down quickly

bergerbullets.com

They definitely can shoot well with a large jump! However, they are probably one of the pickiest bullets to seating depth out there. It’s all about finding the sweet spot. The VLDs are one of our favorite bullets!

 

[tdhanses]

They definitely can shoot well with a large jump! However, they are probably one of the pickiest bullets to seating depth out there. It’s all about finding the sweet spot. The VLDs are one of our favorite bullets!

I haven’t found that they are picky, I’ve shot a few 1000 of them in 270wsm, 6.5cm and 300wsm, all loved a jump in the range of .08-.1. I’ve found them to do well but their sweet spots seem to be where they jump.