Powder charge and seating depth

[6pakzak]

To my original question, seat bullet closest to lands like cortina says and find charge and then seat to best group, will charge stay the same?

 

[WildRose]

I read tests on this, many, and in most cases it's been an improvement, IDK for sure but I'm thinking probably makes more of a difference if bullet has a longer jump to lands

Depending on the bullet you're certainly correct. VLD type bullets have a much more abrupt engagement to the lands than do more traditional bullets so they really don't like much jump at all.

The Secant Ogive bullets make that long transition easily on a long slow ride and are somewhat self aligning where the Tangent Ogive bullets just slam into it and may or may not self alight with a longer jump.

Secant vs Tangent Ogive.

 

[WildRose]

To my original question, seat bullet closest to lands like cortina says and find charge and then seat to best group, will charge stay the same?

If I remember right he says find a charge to start and then tune it when you have good results that would be your final OAL and charge.

 

[6pakzak]

If I remember right he says find a charge to start and then tune it when you have good results that would be your final OAL and charge.

He says it's about combustion, so if I had to seat bullet let's say .040 away from from starting point to get good group that would change my combustion so would that effect my es

 

[6pakzak]

Personally I tried seating out incrementally from shortest coal according to book and groups got worse as I seated out farther so I think I'm gonna end up close to where I'm at anyways

 

[WildRose]

He says it's about combustion, so if I had to seat bullet let's say .040 away from from starting point to get good group that would change my combustion so would that effect my es

It changes everything including peak pressures. The closer you are to the lands the more danger there is of serious pressure spikes with even very small increases in your load.

Personally I load just sort of mag length, work up the most accurate charge I can find and then tweak the seating depth to see if I can improve.

 

[Mikecr]

Depending on the bullet you're certainly correct. VLD type bullets have a much more abrupt engagement to the lands than do more traditional bullets so they really don't like much jump at all.

This is decades old perpetuated misinformation.
Hell, I knew the VLD needed seating declarations were hogwash back in the 80s..
It NEVER was true, as any of us doing actual full seating testing seen for ourselves.

 

[WildRose]

This is decades old perpetuated misinformation.
Hell, I knew the VLD needed seating declarations were hogwash back in the 80s..
It NEVER was true, as any of us doing actual full seating testing seen for ourselves.

Misinformation? Berger is giving us misinformation along with everyone who's done those tests who tells us they get the best accuracy from their VLD's loading them closer to the lands rather than farther away or all of the other companies producing non VLD's that tell us their's do better seated farther out?

 

[treeman59]

I usually seat the bullet for what it calls for from the book or bullet makers website, then I start low on charge and work up till I get good groups but what if my es is high say 30 fps it would mean my load is not good cause the high es. So Cortina says to start with seating depth 20 thousands shorter than what your bullet jams into lands, for 223 that would put me at 2.290, work up charge till you get low es and don't worry about group till you get that, once you do then go down on seating depth till groups are good and pretty much your done, besides getting at least 2 good and seating accordingly. Well the bullet manufacturer is saying to seat at 2.225 so it will take a lot of shots to get there from 2.290 if it does shoot better at 2.225 so now let's say I have a good powder charge and my bullet shoots best at 2.225, well the pressure is going to increase and is my es still gonna be good like when I started at 2.290 to find that charge. I will also say that I'm getting good groups at 2.225 and I tried making it longer and the groups fell off more the longer I made it, I went to 2.250 and stopped there cause it kept getting worse. Because of the cold and lots of snow here I haven't been using the Chrono so my groups are good at 100 and hopefully my spreads are low, if not, then what, change powder, primer? But my main question is why not seat or at least start where manufacturer recommends and if my final seating is very far from where I worked up charge will the charge stay the same, I don't think it would.

Coal is according to Sammi chamber or magazine length. Better to find the lands first and start .020" shorter than that. In my experience vlds like to be close to the lands and typical match bullets work better .025 - .040" off the lands.

 

[Hugnot]

Powder charge:
Some cartridges, like .300 WM are loaded to fit 3.34-inch magazine lengths when actually the cartridge would be best suited to be loaded at 3.6 inches and gain about 8% more powder capacity (powder charge increase). True magnum length actions intended for .300 H&H & .375 H&H would work. My rifle has no magazine being a single shot and has a chamber cut to conform to a sample 3.6-inch inert round. To a lesser extent, same for the .243 Win, a sample 2.825-inch COAL inert round, that fits inside the magazine, was provided for the chamber cutting. Berger 6mm, 95 grain VLD bullets are seated with COAL somewhat shorter than 2.8 COAL. Rounds feed real good & accuracy is good, in compliance with Berger directives in regard to seating depths. The 6mm 95 VLD has a real good form factor, lighter weight for higher velocities but has an abrupt ogive transition requiring seating depth adjustments.

Bullet type - tangent ogive bullets, as defined in the Berger manual, are more forgiving than the secant ogive variety in regard to seating depth ... Tangent - "smooth junction with bearing surface good for self-aligning, Secant - "abrupt juncture, not good for self-aligning... sensitive to seating depth". Apparently, this has led to the "hybrid" type bullet, in an effort to have similar form factors as a secant ogive bullet but with the self-aligning features as a tangent ogive bullet.

Looking at the Berger VLD bullets an abrupt ogive transition is easily observed. The transition is not as easily seen in Hornady bullets, also secant ogive types. I seat both brands deep enough for clearance & periodically adjust for throat erosion. Berger has made zillions of VLD bullets and there has to be validity in seating depth recommendations. Having a nice precise chamber also helps.

 

[Kmccord]

Misinformation? Berger is giving us misinformation along with everyone who's done those tests who tells us they get the best accuracy from their VLD's loading them closer to the lands rather than farther away or all of the other companies producing non VLD's that tell us their's do better seated farther out?

Well, depends on your rifle, the one I loaded for a 7mm Rem Mag with the 168 HVLD bullet, it liked it at .050 off the lands. I think all of them are going to be running several nodes on seating depth, you may get good at .010 off, then no good at .020 then better at .030 then better at .040 and start to open up again sort of like a powder charge. That is what I observed with the 7mag and a few other rifles.

 

[Tulsa Reiner]

So if
So if I'm understanding what your saying you seat at the lowest coal and then work your powder up from beginning load?

@6paksak: don't confuse COAL (cartridge overall length, base to tip) with CBTO (case base to ogive) which has to be measured with something like the Hornady Bullet Comparator system.
I've learned from the folks here on the forum that CBTO is much more reliable.

 

[QuietTexan]

Trust me I don't think concentricity is the end all be all but in my rifles it has been a definite improvement, no crazy fliers anymore, other rifles may not be so sensitive, from what I can gather it seems like neck tension is the biggest factor and I'm sure with what Cortina is using he don't have to worry about runout. That's why I got the mandrels you suggested, to work on neck tension, my 223 shot it's best group using them, AR-15 and bolt. Keeping it straight is just another part of keeping it the same and it really makes me happy when the gauge hardly moves and I like to be happy, lol.

I agree with you, concentricity does make better groups. What I'm getting at is along the lines of one of Mike's points, if you want to test something get out of the node. So while a honed die is the best option long run, in the short run experimenting with the bushings and mandrels in a not-good place for concentricity is fine because you know you can tune out the effects induced by it because you've done it.

Let me try another way - accept worse groups while you're messing with the neck setting and deciding which spec to get a honed die for. The groups will get better when you start using the correctly spec'd die and runout gets better again. Or you might already have the spec, if you're happy with the bushing mandrel you have, order the die for that spec. But you just introduced annealing, so it might take a few loads to get to a consistent spec again.

One more anecdote - when testing a barrel tuner, you WANT bad groups so you can really see how the tuner moves them. So you have to find a bad load to test the one particular thing you're changing. If you shoot one hole at 100, there's no real way other than going really far away to see the changes. If you shoot 3" at 100 yards you can see the tuner swing the group around. You want to see the effects of seating depth, so pick a charge weight that makes bad groups so you can see the group size move with seating depth. When you bring the depth and charge node together, you should have a resilient, long lasting load going forward that doesn't need to be tweaked for a while.

 

[Tulsa Reiner]

Ok quiet texan I know you know, I know he don't neck size only, please save me the trouble of looking through all these videos of his, I'm guessing collet FL die or custom FL die, probably custom?

We've probably all seen the video in which EC is wearing a tee shirt with a target on it, and bullet holes scattered all over the place. Inscription: "I neck size"