Die that seats off ogive

[Bart B.]

Better get your barrels changed out quick

What depth do you claim they are?

Check specs and tolerances for barrel bores and grooves in:

http://www.saami.org/specifications_and_information/publications/download/Z299-4_ANSI-SAAMI_CFR.pdf

Save a copy for reference.

Lead slug your barrels then measure them with calipers.

 

[Bart B.]

I was told by berger that the main variations in a bullet are due to the die wear. Lot sare changed when dies are changed

Surely, Berger can observe jacket and core material properties. Sierra, Lapua, Hornady and all custom shops can.

Back in the early 1970's when long, heavy 7mm match bullets were introduced, it took near 10 years before material was good enough that 168 grain 7mm match bullets shot as accurate as 200 and 220 grain 30 caliber ones.

'Twas another 5 years before 6.5mm then 6mm long and heavy ones shot as well.

To say nothing about air bubbles in lead core wires.

 

[muleman69]

21st Century claim:

"Notice how the bullet is contained in the seater stem. There is about 1/4" of ojive contact, making it possible to hold overall length to 1/2 thousands, .0005. Also helping to keep bullet in line with case."

Across all lots of a given bullet? Their tips vary that much and more from any point on the ogive in a given lot. Few lots of bullets are made with the same ogive pointing die shape.

Can dies be made that hold such tolerances on bullets they profile and point?

So in your opinion is the century dies the way to go?

 

[Bart B.]

Straight loaded cartridges start with straight case necks centered on case shoulders. Neck wall spread no more than .001". As long as case mouths diameters are no more than .001" smaller than bullet diameter, most any seater will seat bullets very straight. Less difference is often better.

Case neck clearance to chamber neck has no effect centering rimless bottleneck cartridge bullets in the bore when rounds are fired. Case neck axis alignment to case shoulder axis controls that. Smaller case neck to chamber clearance can increase case life as the brass is worked less when sized then fired.

 

[Ledd Slinger]

What depth do you claim they are?

Check specs and tolerances for barrel bores and grooves in:

http://www.saami.org/specifications_and_information/publications/download/Z299-4_ANSI-SAAMI_CFR.pdf

Save a copy for reference.

Lead slug your barrels then measure them with calipers.

Cheezus! I was just kidding. Groove dia minus bore dia, cut that number in half. Not rocket science. If you were exactly 4 thou deep on a 300 bore, you'd be too deep. Groove dia is usually measured in 10 thou. Stupid joke. Sorry.

 

[Texas10]

i can see the value in this, but am trying to understand how you get perfect concentricity of bullet to stem when setting the JB. with wilson type seaters where the stem doesn't float misalignment in the bedding process seems it would affect loaded round runout? have you tested/measured this, either directly on cartridges or on the target? thanks

This is a really good question, one that I have thought a lot about, but never came up with any good answers. Looking at all the pieces of a seating die, all the tolerance stack that plays into off axis seating, bedding the seating stem to a particular batch of bullets certainly helps if done correctly.

By that I mean not building in an off axis error while the epoxy cures. Certainly not impossible, but also not easy without specialized tooling. Perhaps using the actual bullet as a shape (coated with abrasive) to mill the barely cured epoxy would do the trick. I wouldn't wait until the epoxy had a chance to fully cure though.

I got better (enough) results by swapping my seating stem with the alternate one Hornaday supplies with their competition dies. To get better than that would require a ton more work, and since I don't shoot competitively, I prefer to shoot more, and work less. JMOP.

 

[Ledd Slinger]

i can see the value in this, but am trying to understand how you get perfect concentricity of bullet to stem when setting the JB. with wilson type seaters where the stem doesn't float misalignment in the bedding process seems it would affect loaded round runout? have you tested/measured this, either directly on cartridges or on the target? thanks

Good question.

So of course I had to have a round with virtually no runout to bed the stem. Then the lock nut cannot be tightened so as to ever so slightly float the stem with whatever the threads will allow. I bottom the stem out to limit exposure of the die to overflow, then just back it off with the slightest turn so it isn't jammed. I did this all in my Coax press so the die would also be floating. So of course with the stem all the way down, the weight of the Coax press handle will be pushing on the round because that's not the correct seating depth. Don't want this either. So I used a long framing clamp to just barely take the weight off the round. This way the die, stem, and loaded round are all floating in harmony and alignment.

I'm not saying it is THE method to use or that it will be easily repeatable with every seater stem. My initial measurements on dummy rounds show good results. I will have more data after loading ammo today.

 

[Ledd Slinger]

Forgot to mention bullet bearing suface runout on dummy rounds is .001", but that's also the runout on the brass (Dummy round cases are made with cull pieces). So there might not be any actual bullet runout. Havent tested it completely yet. Will get more more data with runout and seating depth consistency when I load up test ammo with good brass today

 

[Bart B.]

There are no standards for ammo runout measuring tools and gauges. The same round used across all and their setup method, a 2 thousandths or more so read across all is normal. A bullet whose axis is perfectly aligned with its case body axis will usually show up to a thousandth or more runout.

None position cartridges headspacing on their shoulders for measuring the same as they are in chambers when fired.

 

[Ledd Slinger]

You guys also have to understand that I only bedded the stem on a standard Redding seater die. It's just an attempt to make a standard die a little better when using it to seat VLD bullets. I dont do this with my custom chambered Wilson micrometer dies and other match grade seating dies. For those I just use a VLD stem that is already made for them.

If you already have a good match grade VLD seater for a given cartridge, I don't know that bedding the stem is going to make it any better.

 

[Ledd Slinger]

Ok, I have some results...

Keep in mind that this is just a standard Redding seater I am trying to improve. Bullets were not measured or weighed in any way. Pulled straight from the box with only quick visual inspections for abnormalities. 4 different loads of 4 rounds. 16 rounds total. Also loaded sighter/foulers but did not measure them.

My goal with this stem bedding test was to stay within one thou seating depth and one thou runout. Judge the results below for yourself. The one seating depth a hair out of spec on #12 had to have been the bullet, not the die. Ran the case in the seater 3 more times while turning it 90 degrees each time. Measurement remained exactly the same. Anyhow, I'm going to call this a successful mission....for now. Next test will be to see how much shrinkage I get from the JB over time. If seating depths change due to shrinkage, I plan on rebedding the stem with Marine Tex. (Probably should have used Marine Tex in the first place...)

Cartridge: 338-375 Ruger, custom hunting rifle. Trued SS 700, Brux barrel, custom reamer, etc...

Bullets: Berger 250gr Elite Hunter VLD

Brass: Hornady (multiple firings), with the holy hell prepped out of it as best I could. Freshly annealed before sizing. Hate Hornady brass, but its my only option for this cartridge.

 

[Ledd Slinger]

For those of you who are also getting seater stem pressure rings on your bullets, bedding the stem will eliminate that.

First photo is a bullet I pulled a while back (inertia puller) and re-seated today in a fouler/sighter round. This bullet was seated with the stem as it comes from the factory. Notice the distinct ring mark way up high on the ogive. Also a testament to how tiny of an area the original standard stem was contacting the VLD ogive.


New bullet seated with the bedded stem. No markings on the ogive whatsoever. Can't even tell it's been touched.

 

[Dusty Stevens]

you reckon the next box of bullets you open you'll have to rebed that stem? I think you'll find that changes more than that little bit of jb weld shrinking.

 

[222 rem]

i believe a better question would be "what seating die doesn't seat by contacting the bullet somewhere along the ogive".

Wad cutter seating dies

 

[Ledd Slinger]

you reckon the next box of bullets you open you'll have to rebed that stem? I think you'll find that changes more than that little bit of jb weld shrinking.

Don't know. Will just have to see. Pretty easy task if I need to drill it out and do it again. Only takes a very small amount of compound. If I sorted the bullets, the numbers would probably have been even better. I think it's worth the consistency I am seeing so far. Just have to see how it shows up on paper. Scope ring bedding is curing right now. Hopefully shoot tomorrow.

I know ogives will vary a tiny bit from lot to lot, but as long as I can maintain good concentricity and "consistent" seating depth, I don't see a reason to re-bed

 

[Bart B.]

Bullets were not measured or weighed in any way. Pulled straight from the box with only quick visual inspections for abnormalities. 4 different loads of 4 rounds.

Thanks for that incremental seating data.

Have you ever done a test starting with the bullet seated about .050" into the case then increments about .005" deeper until bullet heel is at the neck-shoulder juncture?

 

[Ledd Slinger]

Thanks for that incremental seating data.

Have you ever done a test starting with the bullet seated about .050" into the case then increments about .005" deeper until bullet heel is at the neck-shoulder juncture?

No I havent. My seating depths are only based off lands touch point. Jam on this rifle is .012" from touch. So long as the bullet bearing surface is forward of the neck shoulder junction, I'm happy. I'll usually start with a mid point jam then work to the touch. On this rifle my starting seating depth is 2.890"...touch is 2.884", full jam is 2.896" Somewhere in the touch to .004" jam is usually where I find good accuracy. I say "usually" because I have had a couple rifles that shot best with a big 0.040" jump to the lands with the Bergers.

Now those numbers aren't "exact" actual seating depth measurements in reference to the lands because my comparator doesn't quite touch the actual lands contact point on the bullet. They are just numbers for reference using a different point on the ogive. Match grade bullets are pretty consistent and I can always locate touch with a new lot if I have to.

 

[Bart B.]

I've always thought "seating depth" was how deep bullets were seated in case necks. Learned that from a SAAMI rep decades ago.

 

[Ledd Slinger]

I've always thought "seating depth" was how deep bullets were seated in case necks. Learned that from a SAAMI rep decades ago.

I dont know. I only ever measure from base to ogive and reference the lands. dont really care how far down in the neck I am just so long as there is sufficient neck to bearing surface contact and the bearing surface is not threatened by the formation of a donut. I just hold up a bullet to one seated in the case and eyeball it to make sure Im good. You don't find your lands by knowing how deep in the neck a bullet is seated. You find the lands by chambering and seating a round many times in small increments until there is no touch. That measurement is case base to lands contact on the ogive

I couldnt even tell you what my COAL is. Never measure it. My COAL measuring goes something like this: "Does it fit in my magazine? Yep, ok, good" . No reason at all to check COAL for single shot rifles.

 

[Bart B.]

You don't find your lands by knowing how deep in the neck a bullet is seated.

I agree, but according to SAAMI, "seating depth" means how deep in the necks a bullet is seated