Is your seating die micrometer accurate, not repeatable/consistent, accurate? When you move the micrometer .003 does it move the bullet depth .003?
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Is your seating die micrometer accurate
- Thread starter AllenOne1
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Yup ... pretty darn accurate ... I use the Redding Competition Micrometer Seating Dies for 6.5-CM, 300-WM, 300-PRC, 300-NM, and 338-LM. The thing that's not so repeatable is when I come back to them after days or weeks for a new batch. I always tune back a hundredth or two and retest to find the exact seating depth I'm looking for. But once there, it works through the whole session and adjustments are very accurately. I dial a 2/1000th's change, reseat, and I get 2/1000th's deeper measurement on my comparator.
My Wilson seating dies are very accurate. But, you know, a lot a variance can be induced with the neck tension isn't consistent or the seating is quite tight. Since I anneal my cases after every firing, I get very consistent/repeatable seating with my die adjustments, and the adjustments are accurate.
I do anneal after every firing and set neck tension with a bushing die to control neck tension the necks are also lubed with graphite. I do get pretty consistent seating depths after I get the die adjusted which isn't hard just a little fine tuning to get it right.
The issue I had is related to doing a bullet seating test. I wanted to extend the die out about .040 so I dialed in .050 assuming I would dial it back down to get my starting point, well it only moved about half of that amount so I dialed another .020 to get it out there and then started working it back. Scratches head but oh well.
Then as I'm running the test it is going good moving very close to .003 with each .003 adjustment until about the 6th move then I moved .003
and it only moved .002. It repeated that for the next 3 moves. It seemed to help if I tapped on the top of the die lightly after making the adjustment.
I've had this die apart before but I don't remember any floating parts in there that might be sticking. After I get this test done I'll likely take this die down again and see what I can determine.
The Wilson dies do seem like the hot ticket for repeatable accuracy.
Wilson dies have an adjustable seater stem. The setscrew that keeps it from spinning sometimes comes loose and then the micrometer spins but the seater stem doesn’t move. Maybe that’s the issue.
People love to hack on Hornady products but I think their is more value in their dies than most people would like to admit, same goes for Lee.
My Hornady 300 PRC seating die disagrees with you. Shoulder bump was inconsistent, slightly over-sized in the body. I got it when that's all you could get, and it got replaced as soon as Whidden made one.
I'm sure you meant size die rather than seating if you had shoulder bump issues. Don't get me started on the sizing die that came with this Redding seating die I'm playing with now.
You may not buy another Hornady die but I will not be purchasing another Redding die ever. Customer service never responded either so double nil on that one.
Yes on sizing vs. seating - long day. As for die brands, I've had mediocre luck with all the common brands. I use Whidden for my sizing and like them. For seating I use LE Wilson Micrometer Seaters with an arbor press when possible.
I disagree. Their CS had been superb in my experience.
it's not the die, it's the brass. I use Redding, Wilson and Forster all with micrometer screws. All are extremely accurate. The reason I can get unconsistent seating depth (I mean by that more than one thau variation) is brass. If there is deifferent hardness in the brass you will see it while formating (you will get a difference in headspace). If I assume there will be difference in neck tension as well I anticipate that and seat my bullets long and than adjust with the micrometer. I will still have difference in neck tension but at least I will have consistent seating depth.
Don't forget about slight variations in bullet to bullet ogive profile variations. This will also lead to "inconsistent" COAL/COH dimensions. There just isn't a hell of a lot you can do about It.
I use Wilson Micros exclusively with an arbor press and am very happy with them. I get +/- .001" or .0015" variation, but I'm not seeing that it's affecting anything negatively.
I use Wilson Micros exclusively with an arbor press and am very happy with them. I get +/- .001" or .0015" variation, but I'm not seeing that it's affecting anything negatively.
That's a very good point and why I sort my bullets from the bullets base to the seating pin contact point on the ogive instead of the ogive point just above the bearing surface. This way I get very consistent seating depths, though the jump distance will vary a little. And that works great since that amount of jump distance difference makes no significant difference in performance. Seating depth differences are way more important.
I use the Redding micrometer seating die and it works pretty damn accurately.....003" dialed gives me .003" of depth. I pitched the sizing die that came with the set in the trash....they are apparently not vented and dent brass unless you play games and fuss about lube.
VooDoo
VooDoo
I was thinking along those same lines as I was playing with this die. Why aren't we seating the bullet from the same place on the ojive that we are measuring on the ojive? Does anyone make a seating die that does that?
It is the natural manufacturing variations of the bullets themselves. No die can compensate for that. As mentioned above, you can sort bullets by length (Ogive to Base). Or, you could sort by weight. I've tried both in the past. I didn't find that there was enough benefit in doing either (for me) so I quit doing it. YMMV.
Granted, the variations are slight, but they do exist. I concluded a long time ago that there was nothing I could do to compensate/correct for those variables and that I should just go shoot.
Personally, my belief is that seating dies are actually pretty simple devices and in this day and age, it's difficult to make a shitty one. Oh, they're out there, but the shitty ones are usually the result of carelessness and/or indifference during the manufacturing process. Poor QC is usually the root cause.
Nothing is perfect. I use Wilson dies exclusively because of the high level of consistency in their quality and as importantly, their usability. Although, I did get a .308W seater from them that I had to rework because the chamber was so loose. Other than that, I've never had any problems with them.
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You can shape your seating stem to whatever profile you like for it to contact your bullet wherever you want. I shape all my seating stems with a sacrifical bullet and lapping compound
My point was that you have a variance in the bullet between the spot you measure on the ojive and the place that you seat from on the tip area. Even if the ojive relationship was perfect between two bullets the variance between the ojive and the tip could be moving the measured seating depth because the tips have a variance between the two bullets. By measuring at the ojive and seating at the ojive you would remove one variable.
The ogive is the entire curved surface from where the bearing surface ends to where the meplat begins.
If you want to sort by the difference between your seater contact and the comparator contact then you can use the bob green comparator to do so. It measures this “critical distance”
I have lapped my seating stem as well but it still isn't going to contact the bullet on the ojive comparator contact point. I guess you could get a comparator that would measure from the seating stem contact point, that may be the easiest way to maintain consistent contact points.
I'll have to look into that a little more I don't think he is doing what I'm trying to describe but the BGC is purely for comparative measure of ogive radius variances.
I want to measure and seat from the exact same spot on the ojive. That only leaves the variation in that one spot on the ojive as the determining factor in seating depth. Aside from neck tension, lube, seating speed, etc.
Altering the internal profile of the seater stem to mitigate bullet damage from excessive seating pressure is not a good idea, especially when you’re using seater dies like Wilson or similar with extremely tight tolerances.
If you keep seating pressure below 70 PSI the bullet won’t swage inside the seater stem and your seating depth will be uniform.
If you keep seating pressure below 70 PSI the bullet won’t swage inside the seater stem and your seating depth will be uniform.
The way I see it, BTO is simply not important. It's the CBTO than can be important for those who want to seat their bullets into the lands. And of course, it's important for a CBTO when one is first deciding a just where one wants their jump starting point (the mag length being an issue), then working the seating depth for tuning the load. (BTW. many newbies are confused by the the difference between BTO and CBTO as these are often used interchangeably in thread discussions)
Since seating depth, is so important (like reloaders will adjust in .003 increments to tune the load), having the base of the bullet seated at the same depth in the case goes a long way in making the load consistent since that's what effects volume in the case for the particular powder charge. If one is only measuring BTO, then that "critical distance" can produce significant differences (like .003 or more) depending on the quality the bullet manufacturer has for them or that of the particular lots.
In measuring different bullets, I was surprised by the large amount of variance between the seating stem contact points and the Meplats, which play a major roll in the bullet's OAL and the COAL measurements. Apparently, the molding or tipping process, however that's done during manufacturing, induces a lot of variance there. Of course, the OAL is just a net measurement of all the sections of a bullet as shown in your picture.
lol . . . well, I can go on about other measured differences I'v looked at, like the effects of variations in bearing surface lengths, but it's been a long week and I feel like my very old brain cells are fried.
It is the die. And the brass. But we can control dies better than brass.
The problem with the inconsistent brass is that we, the ordinary people, can't get the brass so perfect that there will be no difference in the sizing and seating proces.
So the main point is that we must assure that the dies will be the same all the time.
So what this means?
This means that ALL our dies MUST firmly contact our shellholder, to maintain dimensions constant, because our brass hardness is not always the same.
This goes for the sizing proces, so for this task Redding is selling their competition shellholders. So we can press our dies hardly to our shellholder. I there is more space between die and shellholder, you must put washer between die and shellholder.
And this goes for the seating bullet process ALSO. But manufacturers of the dies write wrong manuals, because they say that we shouldnt contact seating die body to the shellholder, just internal sleeve should contact shellhoder. And this is WRONG. Very very wrong!
You must contact die body to shellholder very hard to get repeatable results. If not, your cartridge length will vary. And that's why people get repeatable results with Wilson dies, because in Wilson die you contact metal to metal very hard and there is no gap between. So with this aproach you eliminate variations from the brass hardness.
Just press hard every die to your shellholder and you will control your dimensions (but with consistent brass hardness you will get even better results
.And having sturdy non-flex press helps A LOT (mine RCBS Summit sux...)
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This is making a lot of sense to me, you have to take out any clearances that may be present in the die/press/shell holder assembly and then let the seating stem take over and seat the bullet. I'm going to look at my setup and see if this can be applied.
For me, when it comes to my Forster die (https://www.forsterproducts.com/product/bench-rest-ultra-micrometer-seater-dies/), one line = .0005", always (meaning: as long as I haven't messed anything else up along the way lol). EDIT: even though according to Forster: one line should/is supposed to = .001" (and FWIW, this is with 6mm/.243" bullets).
Seating-depth tests are no drama as long as I count my turns properly and end up being within ~ +/- .001" of what I hoped they'd end up at when checked with calipers.
I like seater dies that contact the shell plate with a "sheath" that wraps up the whole cartridge before the bullet seats, I had used a Hornady Match Grade micrometer die for a long time that made great ammo, but it was not as consistent and/or predictable/repeatable when talking thousandths...
FWIW, I borrowed/tried using a Wilson in-line micrometer seater and arbor press for a while to seat bullets (to compare the against the Forester) and it was a wash for me, the Wilson/Arbor method was just slower and more annoying. YMMV.
Seating-depth tests are no drama as long as I count my turns properly and end up being within ~ +/- .001" of what I hoped they'd end up at when checked with calipers.
I like seater dies that contact the shell plate with a "sheath" that wraps up the whole cartridge before the bullet seats, I had used a Hornady Match Grade micrometer die for a long time that made great ammo, but it was not as consistent and/or predictable/repeatable when talking thousandths...
FWIW, I borrowed/tried using a Wilson in-line micrometer seater and arbor press for a while to seat bullets (to compare the against the Forester) and it was a wash for me, the Wilson/Arbor method was just slower and more annoying. YMMV.
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