VLDs and seating depth

[mshelton]

We all know that VLDs are picky and sometimes like huge jumps, sometimes like jam.

Is there any resource that explains why this is, is it a matter of matching leade/throat to the ogive? I know hybrid bullets aren't as sensitive so I'm wondering if there is something that can be set up on the reamer for a specific secant ogive to help reduce this sensitivity. And I gues what's the actual science/physics behind the sensitivity.

 

[dkhunt14]

I have never had a gun that shot VLD's better jumping. They always did better jamming. Sometimes I don't think that some shooters don't actually know where touch is in their gun. I have seen guys tell me they are jumping 50 or 100 and they open their bolt and let a bullet stuck in the rifling. I can put them in 10 thous and never stick a bullet. So how far in is that 100 jump? This is comparing 6 Dashers and 300 WSm's and over 5 years of shooting these two. This is also light and heavy and they had multiple barrels. Some guys say they jump them and shoot better. I just know my guns have not shown this and neither has most of my buddies guns. Now this is with checking marks on bullets after steelwooling them. Matt

 

[dmoran]

If you want a matching lead angle, you can have an elliptical throat reamer made (PT&G make them).

Much like Matt, not once have I got best accuracy from a jump with VLD's. I've got good accuracy, but not best accuracy.
I start at engravement (slight hash marks), and work it both directions. Some times ending up with faint marks, but there still marked (ITL).
Donovan

 

[jlow]

So Donovan, I don’t shoot VLDs but have loaded boat tail bullets close to the lands. What I notice is the longer the bullet sticks out of the case, the harder it is to keep it concentric. So my question is when you jam a VLD, does that automatically line the bullet up relative to the case and that is why it shoots better jam than jump?

 

[dmoran]

No matter what the bullet type, the lead diameter will be contacting the bullet when there seated long, unless all run-out aspects are dead inline (ammo, chamber, bolt-face). But yes, I do see merit to jamming with ammo that has runout. And without a doubt, with ammo that has high amounts of runout, no matter what the bullet shape, VLD or not.

The chambers throat can be looked at as a bullet straightener. But the downside to the concept would be the pre-load aspect to the effected side, and the subsequent extra induced friction flutter.
Basically we need the bullet deformation to be square all the way around the bullet, as in a harmony sense to balance. And is where a "perfect" found seating depth is more optimal to do so, and is why other seating positions can effect accuracy so abruptly (primarily to vertical dispersion) - IMO.

Donovan

 

[22BRGUY]

My experience with VLD's so far is they like jammed.

 

[jlow]

Thanks guys!

 

[timeout]

OK, I'll be the odd man out. I have two rifles that shoot the VLD's better jumped and I mean jumped a bunch. And yes, I do know where touch is in my rifles.

 

[NorCalMikie]

Knowing where the lands "start" makes a BIG difference when setting OAL. And the measurement to the lands will change over time. Check it often.
I load "everything" (except my gas guns) .010 into the lands and build my loads from there. You back back off from that point.
The larger calibers seem to like more of a jump than the smaller ones. .030+ works nice in a H.S. Precision in .308.

 

[expiper]

well since you asked,,,I think it has more to do with the type of powder being used ,,for instance in a 6mm BR ,,I have used many bullets some VLD and some Hybrids and some Flat base,,,and in most instances they like to be jammed,,,,,,then for the last cupla yrs I have been toying with various "larger" 6mm ctgs...and in them ,,which use powders much slower than 4895/Rx-15,,every bullet that likes jam in the BR's seems to do better with .030-.050" of jump,,,,could it be that the slower powders like/need some dwell time to burn cleanly and efficiently and give good vel. ,,ES/SD and group good,,,,just my finding with my meager experience,,,Roger

 

[HTSmith]

I shot nearly a whole box of Berger 105 VLD Hunting bullets in my 6br at various degrees of jam. Groups were decent. Started backing up and they closed at every increment. Bug holed at .030 off. Could be a rare, but that is what happened with my rifle/load.

 

[JDMock]

Eric Stecker (head man at Berger) told me to not be afraid of jumping VLD bullets. Many rifles including mine shoot the 105 VLd and the 105 Hybrid very well in my Dasher when they are seated from .020-.030" off jam, i.e. jumped. Other barrels may prefer being seated into the lands.....that is why we must test each. James

 

[nastynatesfish]

I shoot mine with about 130 thousands jump. I loaded from 30in to here.

These are out of my 7rem mag and a 140 Berger. Mine always shoot better jumped than jammed

 

[Catfur]

My 6mm Rem likes a jump of around .100" with the 105 VLDs.

 

[mshelton]

Still curious as to why this happens.

 

[BigDMT]

I've had good luck with Berger VLD's jamming them and have had just as good luck jumping them a long ways in magnums that I want to feed from a magazine. So in my experience, I can get VLDs to shoot very well either way.

 

[Steve Ladino]

The hunting VLD's in my 6BR (105) like to be .020 off