My issues with the Berger method…..

[dale guthormsen]

I also start long and work back in .003" increments. I haven't had any issues finding a node, mine are usually .006-9 wide or maybe a bit better.

I found using .005" you will likely find a load that shoots decent but you may be on the edge of a node or a very small node and hard to keep in tune.

once you found one shouldnt you work aroind it to find the exactbest oal?

 

[Taylorbok]

once you found one shouldnt you work aroind it to find the exactbest oal?

It's tough to alter seating depth less than 3 thou repeatable, even with micrometer dies

 

[kaseyfied]

So tell me what you guys think then.. 20 thou off lands.. 93.7 grains n570 230 otms.. that's a neck tension test at 250yards.. bottom right 1k...top right 2k...top left 3k...middle 5k... nothing shot great.. velocity average around 3060.. first 3 were 3064...3065...3064...2k tension 3071...3065...3061... 3k was 3058...3070..3066...5k was 3055..3066..3075

Kasey

 

[cjuve]

So tell me what you guys think then.. 20 thou off lands.. 93.7 grains n570 230 otms.. that's a neck tension test at 250yards.. bottom right 1k...top right 2k...top left 3k...middle 5k... nothing shot great.. velocity average around 3060.. first 3 were 3064...3065...3064...2k tension 3071...3065...3061... 3k was 3058...3070..3066...5k was 3055..3066..3075

Kasey

Is this a 300 NMAI?

 

[kaseyfied]

Is this a 300 NMAI?

Yes... not a hot load.. can go up to around 3150 but this node is so wide I stopped..

 

[cjuve]

Yes... not a hot load.. can go up to around 3150 but this node is so wide I stopped..

Did you use a long range ladder, a chronograph or an OCW to determine the node?

 

[kaseyfied]

Chrono.. and 300 yard ladder

 

[cjuve]

Chrono.. and 300 yard ladder

If you have not done a seating depth test yet that is the direction that I would go. The hybrid ogive has a different method than the VLD. I had the best success at .035 off.
Those diagonal groups are interesting as well, I had a load that would print 1/2" at 100 that blew up to 1 MOA at 600 that was all diagonal. I cured it with more powder.

How to Load a Hybrid Bullet

Berger Hybrid Bullets were designed to be easy to load and tune to your rifle. Follow these simple steps to get started.

bergerbullets.com

 

[cajun]

Measuring the base of bullet to the ogive of the meplat with a comparator is BTO (Base to Ogive). The Ogive is where the bullet transitions from the straight bearing surface to the start of the taper of the nose.

So, in measuring 100 Berger bullets in a box, I have found very little difference in the BTO (base to Ogive). About .0015". I have done this on occasion early one, but now usually pull 10 from a single box and check.

I actually do not measure COAL (Cartridge Overall Length-from case head to bullet tip) hardly ever. Just to make sure they will fit in a magazine.

I want my CBTO (Cartridge Base to Ogive) to be exactly the same in every round I build. At least within .0005" (not .005"). Meaning the exact same jump to lands from round to round. CBTO consistency is WAY more important than COAL, where meplats (the point or tip of the bullet) can vary as much as .010" even when the BTO is within .001". This is due to the manufacturing process of pointing the bullet.

And since the seating stem in your seating die does not support off the Ogive, but near the tip of the bullet, having consistent BTO and nose shapes makes a huge deal in getting CBTO consistent. If you load some brands, you will seat 10 bullets, and get 10 different CBTO measurements, as much as .00" in some cases....ahem....ELD-X). Berger is usually within .0005" or exact, with maybe one in 10 at .001" different that needs a tweak to the die (if you are that anal about it....which I am). I try to keep all my loaded rounds with .0005" CBTO. 5/10000ths (or half a thou as some call it). Not 5/1000ths.

Consistency is very important in reloading. However at some point there is a diminishing return on effort. If 1/2 of one thousandth in cbto difference is causing issues maybe you are not in a good node or just too close to the lands. As mentioned in the link above you can find accuracy by jumping bullets and not have to be worried about a few thousandths in throat erosion or cbto length which is essentially the same thing. Ps this is not an inditement on your efforts just my opinion.

 

[Mikecr]

The hybrid ogive has a different method than the VLD.

I don't see a significant difference in the testing method.
It's still coarse adjustments, followed by finer adjustments,, same as VLDs or any other kind of bullet.
The test holds as something that should be done -instead of just pulling anecdotal numbers out of our behinds.

 

[kaseyfied]

I don't see a significant difference in the testing method.
It's still coarse adjustments, followed by finer adjustments,, same as VLDs or any other kind of bullet.
The test holds as something that should be done -instead of just pulling anecdotal numbers out of our behinds.

But I like pulling stuff outta the air and my butt lol

 

[QuietTexan]

Consistency is very important in reloading. However at some point there is a diminishing return on effort. If 1/2 of one thousandth in cbto difference is causing issues maybe you are not in a good node or just too close to the lands. As mentioned in the link above you can find accuracy by jumping bullets and not have to be worried about a few thousandths in throat erosion or cbto length which is essentially the same thing. Ps this is not an inditement on your efforts just my opinion.

I hear what you're saying and I agree - depth shouldn't need to be 0.0005" to be accurate. But to me the point of pushing for consistency is to minimize tolerance stacking.

I try to get 0.001" consistency in CBTO seating - not because being outside of that will push me out of a good node, but because it removes a variable from that can be compounded by something else. If you push for the best precision possible on easy processes, you create more leeway on the harder/less quantifiable processes.

Charge weights should be to within 0.05gn easily on a manual or electronic balance. Bullet BTOs should be within 0.0015" by buying decent bullets. Cartridge BTO should be within 0.001" by buying and running a quality seating die. Concentricity should be 0.002" or less by buying and running a quality sizing die or die/mandrel combo. Brass neck thickness shouldn't vary more than 0.002 if you buy good brass. There's no need to accept a ton of variance on these easy things.

Throat erosion is a perfect example - if I want the load to be tolerant to erosion over 300 rounds, I have to seat on the tight end of a depth node so that as the throat erodes longer the depth is resilient to that change. If I'm throwing 0.5gn powder weight variances on top of this there's no resilience because of the stack of variances. So I'll weigh charges to 0.05gn so that seating depth is the variable I'm building a lot of slack into by holding another variable very tight.

Lance holds his CBTOs very tight. Maybe he does that because he's using Lee dippers for powder weights (kidding kidding) The overall combination of processes is important to consider. I view BTO stuff as easy to manage, so I push for very tight tolerances there.

 

[Taylorbok]

So tell me what you guys think then.. 20 thou off lands.. 93.7 grains n570 230 otms.. that's a neck tension test at 250yards.. bottom right 1k...top right 2k...top left 3k...middle 5k... nothing shot great.. velocity average around 3060.. first 3 were 3064...3065...3064...2k tension 3071...3065...3061... 3k was 3058...3070..3066...5k was 3055..3066..3075

Kasey

I don't fiddle with neck tension. I run 3k and forget about it and tune with powder/ seating depth. None of your groups are terrible. I Would pick one and start a seating depth test. the center group seems to have the least vertical. just start pushing the bullet in .003" at a time until you get 2 or 3 groups in a row that shoot good. and choose the longest seating depth. this will allow for the most throat erosion before it falls out of tune.

 

[cjuve]

I don't see a significant difference in the testing method.
It's still coarse adjustments, followed by finer adjustments,, same as VLDs or any other kind of bullet.
The test holds as something that should be done -instead of just pulling anecdotal numbers out of our behinds.

Agreed, it is always best to take a straight line between A & B and targets tell the truth