Does Berger Make Jump Irrelevant?

Mikecr said:
Same as any other.
Seating tests also do not have to be taken to lands. We don't even have to know where the lands are.
Click to expand...
I may have been confused on this issue. I thought seating depth was only critical for peak pressures and accuracy
when nearing the lands. Evidently not so. Or, does it simply make less difference, but still SOME difference,
even when no where near the lands ?
 
Jester560 said:
With VLD Hunting bullets, in my hunting rifle, seating g depth mattered huge.

Jam= 1.75 moa
.01 off= 1.75 moa
.02 off =1.25 moa
.03 off = 1moa
.04 off = .5moa
.05 off = 1.25 moa

.043 off = .25moa rifle will shoot sub 1" 5 shot groups at 400 yards with my son shooting it. With me, 2 inches at 400.
Click to expand...
Tell me if my math is wrong. A very mild cartridge eats lands at the rate of 0.003 per 100 rounds. A barrel burner eats that in 20 rounds. That's more than 0.01 in 100 rounds for a barrel burner like say 264 WM. I can't see how chasing 0.003 inch seating depth adjustments makes sense.

Please tell me where I'm wrong?

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I let the target tell me.
And it does just that. Like the above example I see widening and narrowing with each adjustment, and it very visibly forms a trend!
When I get excited is when 2 different depths show basically the same tight group size.
I jump somewhere in the middle and go a while.

I don't load hundreds of rounds at a time, though. Probably more like 30-40
 
Phil Rizzo said:
I let the target tell me.
And it does just that. Like the above example I see widening and narrowing with each adjustment, and it very visibly forms a trend!
When I get excited is when 2 different depths show basically the same tight group size.
I jump somewhere in the middle and go a while.

I don't load hundreds of rounds at a time, though. Probably more like 30-40
Click to expand...
So, you adjust seating depth every 30-40 rounds? If you actually test seating depth every 30-40 rounds, about all you ever do with the rifle is chase the lands.
 
No. But I may bump powder up to compensate if needed, to raise pressure.
I've wiggled it out a tad also,
No need to do a full seating test if you KNOW you are very, very close to what it prefers.
IMG_9232.jpeg

This what I call a stable area. Node. Whatever the name.
 
Last edited:
Maybe you're close because seating depth with a good rifle doesn't make much difference most of the time. It would take 30 shots at each depth to really tell if 0.003 makes a difference. After 60-90 rounds of testing the rifle needs another depth.

3-5 shot groups lead people astray every day. Well except if seating depth doesn't matter. Then any answer is correct.
 
Last edited:
Not when they repeat over multiple days and different conditions.
Guess I'm not a stats guy.
But if I get the results I want repeatedly and the load doesn't fall apart, I really could care less about stats, methods, weather or anything else.
Results trump all the rest for Me.
When I start out tight with a load, like above, and use consistent methods of producing it, I have a little wiggle room for a bad day.

Somebody else can use most of their barrel life proving and disproving. Or not.
That's up to them and their requirements.
 
hemiford said:
How do you test seating depth on a Weatherby with 3/4 of an inch freebore ?
Click to expand...
I have my own Weatherby reamers in 300/340/375 Weatherby, all have .500" of freebore just how Roy Weatherby designed them before they were submitted to SAAMI, the only list of these original proprietary specs are held by CIP. 378 Weatherby was .750" and 460 Weatherby was 1.00" freebore when developed.
Seating depth tuning is not governed by distance to lands, it is the harmonics of the bullets BARREL TIME that is changing with seating in or out.
There are many seating lengths that will be apparent when tested within a magazine length restriction, often being .020"-.030" wide.
Even .100" off the rifling can be just as accurate as .010" off.

Cheers.
 

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