Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

[quickdtoo]

I'm working on loads for my 260 Remington using Berger 130gr VLD Hunting bullets which I've never used before, did a little research on seating depth for VLD bullets, found this interesting tech note by Berger on Benchrest Central, just thought I'd share. 

Tim

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

Background

VLD bullets are designed with a secant ogive.  This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection).  While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifles.  It can be difficult to get the VLD to group well (poor accuracy).

For years we encouraged shooters to use a base of cartridge to end of bearing surface OAL (I will use the term COAL to represent this dimension) which allows the VLD to touch the rifling or to be jammed in the rifling.  This provided excellent results for many shooters but there were others who did not achieve top performance with the VLD jammed in their rifling.  These shooters were left with the belief that the VLD bullets just won’t shoot in their rifle.

Other groups of shooters were discouraged by our recommendation to touch the rifling.  Some of these shooters knew that at some point during a target competition they will be asked to remove a live round.  With the bullet jammed in the rifling there was a good chance the bullet will stick in the barrel which could result in an action full of powder.  This is hard on a shooter during a match. 

Yet another group of shooters who were discouraged by our recommendation to touch the rifling are those who feed through magazines or have long throats.  Magazine length rounds loaded with VLDs could not touch the lands in most rifles (this is the specific reason that for years we said VLD bullets do not work well in a magazine).  When a rifle could be single fed but was chambered with a long throat a loaded round that was as long as possible still would not touch the rifling.

Until recently, shooters who suffered from these realities were believed to be unable to achieve success with VLD bullets.  Admittedly, we would receive the occasional report that a rifle shot very well when jumping the VLD bullets but we discounted these reports as anomalies.  It was not until the VLD became very popular as a game hunting bullet that we were then able to learn the truth about getting the VLD bullets to shoot well in a large majority of rifles.

After we proved that the Berger VLD bullets are consistently and exceptionally capable of putting game down quickly we started promoting the VLD to hunters.  We were nervous at first as we believe the VLD needed to be in the rifling to shoot well and we also knew that most hunters use a magazine and SAMMI chambers.  Our ears were wide open as the feedback was received.  It was surprising to hear that most shooters described precision results by saying “this is the best my rifle has ever shot.” 

We scratched our heads about this for awhile until we started getting feedback from hunters who were competition shooters as well.  Many were the same guys who were telling us for years that the VLDs shoot great when jumped.  Since a much larger number of shooters were using the VLD bullets with a jump we started comparing all the feedback and have discovered the common characteristics in successful reports which gave us the information needed to get VLD working in your rifle.  We were able to relay these characteristics to several shooters who were struggling with VLD bullets.  Each shooter reported success after applying our recommendation.


Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

Solution

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 COAL 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. 

Note: When discussing jam and jump I am referring to the distance from the area of the bearing surface that engages the rifling and the rifling itself.  There are many products that allow you to measure these critical dimensions.  Some are better than others.  I won’t be going into the methods of measuring jam and jump.  If you are not familiar with this aspect of reloading it is critically important that you understand this concept before you attempt this test.

Many reloaders feel (and I tend to agree) that meaningful COAL adjustments are .002 to .005.  Every once in a while I might adjust the COAL by .010 but this seems like I am moving the bullet the length of a football field.  The only way a shooter will be able to benefit from this situation is to let go of this opinion that more than .010 change is too much (me included). 

Trying to find the COAL that puts you in the sweet spot by moving .002 to .010 will take so long the barrel may be worn out by the time you sort it out if you don’t give up first.  Since the sweet spot is .030 to .040 wide we recommend that you conduct the following test to find your rifles VLD sweet spot.

Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:
1.   .010 into (touching) the lands (jam) 6 rounds
2.   .040 off the lands (jump) 6 rounds
3.   .080 off the lands (jump) 6 rounds
4.   .120 off the lands (jump) 6 rounds

Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:
1.   .010 off the lands (jump) 6 rounds
2.   .050 off the lands (jump) 6 rounds
3.   .090 off the lands (jump) 6 rounds
4.   .130 off the lands (jump) 6 rounds

Shoot 2 (separate) 3 shot groups in fair conditions to see how they group.  The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin.  Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005.  Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards). 

Regards,
Eric Stecker
Master Bulletsmith

[necchi]

That's good info, I take it secant ogive=really long. I've had to mess with the Barnes TTSX like described too.

But I have a question for the experianced;
 If/when beginning the load development we have 2 significant variables; Charge and COAL, both playing huge factors in group size.
 So what is best to find first?
      *Use a random designated powder charge,(low side/safe) and play with seating, coming back to tune the charge.
         or
      *Select a specific COAL, work the charge till ya find a good one, THEN go back to find the sweet "jump".
 
 I guess I'm useing about 40-45 shot's to find the right combo of charge and seating/COAL. Is there a better way or is that what it takes?
 Each bullet I play with requires the same mix of variables too prove. I'm learning things about my guns as I do this, and it's fun shooting, but the $$ are starting to pinch!

[smith85619]

that's a good question, I need to know the answer to this as well.  Do you need to find the right charge or the right COL first?

[LaOtto222]

I am not really sure there is a right and wrong answer to this question. Personally I pick a OAL and work with powder charges first. I usually have a bullet in mind for the task at hand. It is the most expensive part of reloading and I want the bullet to perform as needed. If I can't get it to work, I then try different seating depths with the best looking powder charge. But that is me. I pick the OA length to start with by looking at seating depth of the bullet, the jump to the lands, and magazine length. I want to be close to the lands, but if the bullet is barely into the neck, I do not like it, so I seat the bullet at a decent amount of depth. I want enough bullet friction to hold the bullet well. So basically, I seat the bullet out as far as I dare and if I have to work with OAL length I start seating deeper, but after I have worked with powder charges and different powders. Changing bullets is my last resort - I picked the bullet to begin with because of it's characteristics. I built a 223 with 1 - 14" twist specifically for 40 grain boat tailed bullets, but if it did not work out, I still could shoot 50 grain bullets. I built a 22 BR with 1-8" twist for VLD bullets, 75 to 80 grains. Like I said I do not think there is any right answer, I am sure there are folks that start with a specific powder charge and vary the bullet seating with success, I just think it is more economical to vary the powder charge first because I think you will find the best load quicker that way. Good Luck and Good Shooting

[roper]

Berger posted that deal about VLD on LR hunting site afew months back and I think it came about because of the VLD hunting bullets.

I pick up some Berger 185gr 30 cal VLD hunting bullets to try.  There a pretty long bullet 1.380" half of the is from ogive forward they work in my 30-338 mag.

I have a pretty good load for that rifle and what I'll do is load afew about 2gr less and see how that load handles those bullets at .050" off if everything is good than I'll adjust back up and start playing with seating depth might have to adjust neck tension.

I load at the range and if I find something good I can fine tune same time.

[Grumulkin]

Seat the bullet as close to the lands as possible without actually touching them provided that the bullets are seated deep enough to hold them firmly and provided the cartridges aren't too long to feed through the magazine.

I shoot Berger VLDs in a 257 Weatherby Magnum and a 300 Weatherby Magnum and despite being a bit off the lands in both cartridges, they shoot very well.

[Idaho_Elk_Huntr]

I got lucky yesterday. Loaded some 6mm Rem with RL22 and Berger 105 Hunting bullets. Sighted it at 100 and moved to 200 and shot 6 rounds. .010 off the lands. I will play with it just to see if it will do any better but this is good enough.  Also shot some TTSX's in it with about the same group size