What first? Powder or seating depth?

[rscott5028]

Fitch,

I'm sorry. But with all due respect to a fellow enthusiast who indeed may be a better reloader/shooter than me, I have to call BS.

You're seating bullets .020" off the lands because you're afraid the variance in a box might cause one to touch and create a pressure spike... What kind of crappy bullets and seating die are you using? Try sorting them and get a seater that works off the ogive rather than the tip.

Then, you're indicating that measuring COAL to the tip is sufficent when the ogive measurement will most likely be much more consistent given that meplats are rarely uniform. ...yet, it's not the meplat that engages the lands and causes pressure spikes.

Besides... the seater die should be seating your bullets according to the ogive near a datum line that approximates the ID of your lands rather than the working off the meplat. This completely negates any variance in the length of the boat tail and shank. So, they should be pretty consistent to less than .001" relative to the lands provided that your brass fits correctly in the chamber and bolt face.

Well, at least you did qualify all that and say that it's probably not worth splitting hairs over and worrying about. And, to that extent you are totally correct provided that you work up a safe and accurate load in your rifle. In other words, you don't have to have a precise and accurate measurement of any/every bullet. Because the seater will make them consistent enough that you should be able to attain good accuracy.

So I was going to passively sit by until, you said that straightening your cartridge by bending your necks when they come out all caddiewampus would help accuracy. To wit, I say nonsense. There are plenty of threads here by guys that really know their stuff that explain why it doesn't work that way.

Even though there are some here who think it helps, there's no need for it if you create straight cartridges to begin with.

Sorry to sound so harsh. But, I felt I had to make a statement so that Goofycat and others can cogitate on it a little more, research it, and decide for themselves rather than take one person's opinion.

thanks,
richard

 

[Fitch]

Fitch,

Besides... the seater die should be seating your bullets according to the ogive near a datum line that approximates the ID of your lands rather than the working off the meplat.

I understand your point, and I agree that in theory the ring on the surface of the bullet where the lands will first contact should be the best place to both push on the bullet for seating and to use as a reference for measuring seating depth. In fact I said so in my post.

But I don't do it that way because I have found no practical way to do it.

To begin with, where do you find a die like that? One that has a ring of contact diameter approximating the contact diameter of the throat in your rifle chamber?

I just went and examined all my rifle bullet seating dies and not one of them achieves the ideal of pushing on the bullet at the location where the lands would contact the bullet. All have an interior cone that pushes on the ogive well above the ring where the throat would contact it. None push on the meplat or polymer tip at varying distances above the ring which would define lands initial contact. None push on the meplat or polymer tip (if the bullet has one).

I have a Redding competition micrometer adjust seating die for my .22-250 ammo that won't do that - in fact tomorrow I'll take a picture (using my Nikon 990 which is out in the shop at the moment - it can focus at a distance of ~3/4" in macro mode so you can see the marks clearly) of a bullet showing where it contacts the ogive and where the lands would contact the ogive which is ~0.148" farther down the bullet. To be clear, the die contacts the bullet 0.148" closer to the meplat from the contact ring with the lands. I defined the ring of land contact using a Sinclair tool that looks like a smooth bore Hexnut with different caliber throat size holes reamed in the six sides.

My standard Rddding delux seating die (non micrometer) is actually better in this regard only contacting the ogive ~0.070" above the ring of contact.

I have two RCBS micrometer adjust competition seating dies that also don't make contact anyplace close to the location where the throat would contact the ogive. Thinking about it, while there may be some company making them, I've never seen a rifle die (just examined RCBS, Lyman, and REdding that are on my loading bench) that pushes on the bullet for seating in the same contact ring that will first contact the lands. Pushing anyplace else allows ogive variation to affect the ogive to lands gap.

The throat/lands contact ring is way down the bullet almost at the point where it is full diameter (actually to where it is within about ~.004 to .008" of full diameter - right where the bright spots appear if one jams the bullet into the lands and then pulls it back out - or where a tool like the Sinclair hex nut tools or other base of bullet to ogive contact measuring tools contact the bullet).

To have such a seating stem on my .30-06, for example would require that the seating stem be more than 0.308" in OD to avoid a knife edge thin enough to distory with an ID ring contact diameter of ~0.299" to 0.300".

Finally, if I did find such a seating stem I probably wouldn't use it because of the potential for damaging the rather soft exterior surface of the bullet with such a narrow ring of contact on such a shallow slope.

To summarize, I don't use junk dies - at least I've never seen anybody call the dies I use junk, though you might be the exception. None of the seating stems in my rifle dies push on the meplat or touch the tip of tipped bullets. The seating stems all have a cone that pushes on the ogive but nowhere near far enough down the bullet to be touching the ring where the lands will first touch the bullet. And for calibers bigger than .224 they aren't big enough in diameter to make that practically possible even by reaming them.

I shoot Hornady, Nosler, Sierra, Barnes, and Burger bullets. I would hope they aren't junk. I've had good luck with them on game.

On straightening cartridges:

The idea that straight ammo shoots better than ammo with bullet runout isn't new, or even controversial as far as I know. I've never heard of anybody sorting their ammo and picking the cartridges with the most runout as the best ones. If straight ammo shoots better, it is probably because the bullet is better aligned with the throat in the rifle. I doubt it cares how it got to be so aligned.

The effect will probably be most pronounced in rifles with nicely concentric chambers and tight necks that tend to better center the bullet in the throat than the rather loose SAAMI chambers, but I don't have any rifles with tight necks. I also don't have any with unusually eccentric chambers with respect to the bore. I know because I've looked at them (I have access to a Hawkeye borescope anytime I want to use it).

Why does this concern me? While I absolutely agree that making straight ammo is better than straightening crooked ammo, I have not been able to make consistantly straight cartridges for my 7mmMAG. That I can't mystifies me. I'm reasonbly handy. I am able to buy barrel blanks, thread them, chamber them, headspace them, and install them on my rifles - I have a machine shop in my back yard. I rebarreled my wife's sporterized Springfield '03 (a present from her dad when she was in highschool - late 1950's) last winter as a fun project. But for some reason getting 7mmMAG ammo that consistantly has less than 0.002" runout isn't something I've been able to accomplish. I've tried different sizing dies, different seating dies, seperately and in combination, but no joy. I do better with .243, .22-250, and .223, and somewhat better with ,30-06, but terrible with 7mmMAG.

I have sorted the 7mmMAG ammo and find that the ammo that is straight (defined as measuring less than 0.002" runout measured on the Case Master) shoots better than the same load recipie ammo with 0.010" to 0.012" runout using the same easurement. It just does. I picked extremes on purpose to maximize the effect with respect to other variables like shooting the groups with 70 year old eyes (I did use a 32 power scope).

So when I saw the article on straightening cartridges (I'll have to look for it tomorrow to give you a reference to it) using this tool, with some limited data by the author, I thought I'd try it and bought the tool. It was only $25.00 including shipping so I figured what the heck, I'll try it, if it works great, if it doesn't it can gather dust in a drawer. Using the tool it is remarkably easy to end up with all my cartridges having 0.002" or less runout measured on the CaseMaster.

The CaseMaster showed me I had crooked ammo but gave me no way to fix it. Straightening it using the tool seems to work for me. Maybe it's an illusion, but I don't think so.

Anyway, those folks who have proved conclusively that it doesn't work and isn't worth the time obviously shouldn't do it, but it works for me, so I'll continue do it.

Fitch

 

[rscott5028]

Fitch,

You are correct in that seater stems don't make a single contact ring precisely at the datum line. Nonetheless, seat your bullets and measure the OAL to the datum line using a Hornady or Sinclair OAL guage and you'll find that they are very consistent with quality dies and a good press. ...should be less than .001" extreme spread.

While knowing the exact jump isn't necessary, there are methods for measuring to within .001". However, throats errode. So, it's something you should monitor if group size opens up over time.

Sorting bullets won't improve the variabilty in the amount of jump. But, it will improve group size to some small degree.

Most agree that straight ammo shoots better. The disagreement comes from the notion of straightening ammo and what actually happens to the neck when you attempt to bend them back in place.

With good brass, equipment, and methods, you should be able to consistently produce cartridges with .002" TIR or less. Zero TIR is ideal, but you can still get .5 MOA with .003" TIR in a good rifle.

Regardless of any disagreement on the technicalities, folks who are getting good accuracy should carry on. And, those who are having difficulties should study up and methodically go about proving/disproving the theories through practical application.

Best of luck to all,
Richard

 

[Goofycat]

And, as a tip to new reloaders: Don't load 1,000 rounds at one time....especially if you don't have stainless barrels. Throat erosion will make you wish that you had reloaded perhaps only 200 or 250 rounds using one bullet-seating depth, then planning to seat the bullet further and further out as erosion slowly takes place...and it will take place.

 

[Fitch]

Before I address the quote below, I promised a couple of pictures that showed the difference between where my dies contact the ogive and the location of the land contact ring as defined by the Sinclair tool I use to measure it.

This is a 50g Nosler BT. I've annotated the picture to show where the Sinclair tool touched it, and pressed the bullet into the seating stem on my Redding competition Micrometer die with finger pressure while twirling it to make a scuffed area that defines where the die touches it.

This is another bullet from the same box marked by the Sinclair tool to indicate the ogive/land contact ring and rubbed in the stem of the seating die from the standard Redding Delux 3 die set (not competition dies):

The data is exactly as I reported it yesterday.

Fitch,

You are correct in that seater stems don't make a single contact ring precisely at the datum line.

As stated in my previous post and as supported by the pictures above.

[/QUOTE]Nonetheless, seat your bullets and measure the OAL to the datum line using a Hornady or Sinclair OAL guage and you'll find that they are very consistent with quality dies and a good press. ...should be less than .001" extreme spread. [/QUOTE]

So I'm right, your original advice on choice of seating dies is incorrect, but it doesn't matter?

Well, I can check the validity of that statement easily enough. I went to the reloading bench and picked up a couple of slip cases of loaded ammo and see if it is true.

Well, not too surprisingly, neither of the first two slip cases of ammo I picket up came close to 0.001" extreme spread in base to ogive contact ring. I originally posted that it would vary by 5 to 10 mils. That wasn't an opinion, it was an estimate based on having measured it. That estimate turns out to be reasonably good.

First slip case had 7 rounds of 7mmMAG ammo (left over from zeroing the scope for the PA senior doe season that begins Thursday), twice fired Win. brass, sized in a FL die to bump the shoulders ~0.002". 150g Barnes TTSX seated using an RCBS Micrometer adjustable competition seating die in a Redding Boss press. Measured the base to ogive distance using the 7mm hole in a Sinclair hex nut and a digital caliper. Tools shown in this picture:

Got the following pairs of readings for (base to Ogive)/COAL, all are in inches:

2.674/3.313
2.671/3.308
2.674/3.309
2.677/3.315
2.672/3.311 The Target COAL.
2.674/3.314
2.678/3.313

Extreme spread in base to ogive lands contact ring is 0.007" or about 7X your "should" value.

Now, Barnes bullets might be somewhat less precisely formed than say, Hornady, bullets, so I picked up another slip case with 20 rounds of .30-06 ammo that has 150g Hornady SST bullets seated using an RCBS die from the Full Length two die set (part # 14801). Brass was sized to bump the shoulders 0.002". So I measured these using the same tool but sticking the bullet into the .30 caliber hole instead of the 7mm hole, and got these readings for base to ogive distance (base to the ring where the Sinclair tool said the ogive would contact the lands):

2.641
2.640
2.642
2.641
2.636
2.644
2.639
2.645
2.642
2.640
2.644
2.640
2.642
2.642
2.640
2.642
2.641
2.641
2.636
2.641

That is the sequence in which they were measured. The extreme spread is 0.009" which is actually worse than the Barnes bullets ES of 0.007", but if I'd measured 20 of the Barnes bullets I might have gotten a bigger extreme spread.

Bottom line, your 0.001" Extreme Spread measurement doesn't stand up in a very limited experiment. Getting more data may increase the extremem spread, but it sure as little apples won't reduce it.

Whether the tool is perfect or not, it is very close based on the land marks when I push a bullet lightly into the lands. I didn't bother to measure COAL. And the measurements repeat very well.

I think the Redding Boss is a good press. I think the dies I used are good dies. The Hornady and Barnes bullets are name brand bullets from respected manufacturer's. But I exceeded your extreme spread in both cases.

A theory is only valid until the first piece of data contradicts it.

First you gave me the opinion that I should use good dies that pushed on the bullet where the ogive would contact the lands. I offered observations based on examining my dies which demonstrated that isn't practically possible with any commercially available dies I've seen.

So you backed off and in the quote near the beginning of this post basically agreed that doing what you said I "should" do wasn't possible but then offered a second opinion that it wouldn't matter because if I used good bullets and good dies I "should" get no more than 0.001" extreme spread in base to ogive dimension. That second opinion doesn't stand the test of measured data either.

Most folks are probably loading their ammo pretty much like I loaded the cartridges I measured for this post. The other box of .30-06 ammo loaded at the same time yielded this group in my .30-06 on shots 4, 5, and 6 after using 3 rounds to get the scope adjusted.

That's good enough. I didn't measure the base to ogive distance on those three rounds, but they would be expected to be close to the 20 rounds measured because the bullets are from the same box and they were assembled at the same time.

Fitch

 

[rscott5028]

Fitch,

I'm confident in my ability to consistently load to within .001" without having to fiddle with my dies. Others here on LRH report the same observation.

I just grabbed 5 random 25-06 cartridges and they all fell within .001" and the same for 5 random 270's. Those were all seated with standard dies.

My 6.5x284 and 6br will be at least as good. I just don't have any loaded at the moment.

Extreme spread in base to ogive lands contact ring is 0.007" or about 7X your "should" value.

Where do you suppose that .007" came from?

-- Richard

BTW - nice group with the '06

 

[rscott5028]

I use the Hornady inserts for measuring OAL rather than Sinclair. But, the principle is the same.

I just pulled 5 random 142 SMKs and measured from base to ogive using the #26 insert and the bullets varied less than .001".

Then, I repeated the procedure on the same 5 bullets using the #25 followed by the #24 inserts with the same results. The maximum variation in distance between the #26 datum line and the #25 was .001". Same for #26 to #24 variation.

I repeated the process with 105 Bergers and got the same results.

Anyone can do this at home and decide for themselves. Just make sure you've got good instruments and technique.

Given that I have confirmed that my bullets are uniform...

Some possibilities that might cause me to end up with more than .001" ES in OAL after seating these bullets might be: (as measured from case head to the datum line on the ogive approximating the ID of the lands)
- seater resting on bullet tip with irregular meplat rather than contacting ogive
- slop and/or flex in the dies and/or press
- inconsistent press operation
- case or case head not square
- too much or irregular neck tension
- compressed load
- other?

It's that simple.

-- Richard

 

[Fitch]

Fitch,

I'm confident in my ability to consistently load to within .001" without having to fiddle with my dies. Others here on LRH report the same observation.

I just grabbed 5 random 25-06 cartridges and they all fell within .001" and the same for 5 random 270's. Those were all seated with standard dies.

My 6.5x284 and 6br will be at least as good. I just don't have any loaded at the moment.



Where do you suppose that .007" came from?

-- Richard

BTW - nice group with the '06

I don't know where that .007" came from. I just know it's there, I measured it.

I will do some more measuring and see what I can find in the way of data that might suggest an explanation. At the moment I have nothing.

I also don't know why my 7mmMAG ammo tends to have more eccentricity than my -06 ammo, but it definitely does. I also know the 7mmMAG is more accurate than the -06. Go figure?

Target from the 7mmMAG (Savage 112BVSS, re-crowned and bedded) shooting the 150g TTSX bullet in ammo loaded the same as the round in the picture - before I got the straightening tool:

I'm envious of your ability to load with the base to ogive distances having an extreme spread as small as you do. So far I haven't been able to do that. I'm not sure my rifles would shoot any better, but I'd like to give them the chance.

Fitch

 

[rscott5028]

I don't know where that .007" came from. I just know it's there, I measured it.

I will do some more measuring and see what I can find in the way of data that might suggest an explanation. At the moment I have nothing.

I also don't know why my 7mmMAG ammo tends to have more eccentricity than my -06 ammo, but it definitely does.

I'm envious of your ability to load with the base to ogive distances having an extreme spread as small as you do. So far I haven't been able to do that.

Fitch

I apologize if I sounded disrespectful. I've seen your targets. So, I know you can load and shoot. We just have a slight difference of perspective on how it all fits together which doesn't necessarily translate to one's ability to shoot.

I had issues with my 7RM until I switched to Norma brass, and changed from the T-Mag to the Forster press.

-- richard

 

[Fitch]

I apologize if I sounded disrespectful. I've seen your targets. So, I know you can load and shoot. We just have a slight difference of perspective on how it all fits together which doesn't necessarily translate to one's ability to shoot.

I had issues with my 7RM until I switched to Norma brass, and changed from the T-Mag to the Forster press.

-- richard

No problem. You were polite about it, so I figured if I stayed with data and dialog we'd figure it out. We did.

Thanks for the suggestion about Norma Brass. I may give it a try.

Edited to add:

Thanks to your prodding I went back to the reloading bench and started fooling around. Found two things.

First, the seating die wasn't set up quite right. The case holder wasn't firmly engaging the bottom of the die at the top of the stroke as is necessary to take the linkage out of the seating depth determinatin and leave it only to the seating stem in the die. I fixed that, reset the die and ran the 7mmMAG ammo I previously measured back through the die. The COAL is now the same.

That's the good news.

Better news, I measured the base to ogive distance on the 14 bullets I have left in the box of 150g TTSX bullets. They averaged 0.7949", call it 0.795". The extreme spread was 0.006" on just the bullets with the shortest being 0.792 and the longest being 0.798".

Re-measuring the ammo after running it back through the reset seating die, I end up with the extreme spread on the cartridge base to ogive distance being 0.006 which is the same as the bullets in the box.

With that as input, tomorrow I'll load some cartridges with the reset die but using bullets which measure within +/- 0.001" (I have 4 that fit that criteria) and see if the completed cartridge base to ogive dimension settles down. If it does, I'll know what caused the variation with the Barnes bullets in the 7mmMAG ammo.

I need to do some additional investigation on the 150g SST in the .30-06 to see what might be causing the variation I measure there. When I do I'll put it in a different thread.

To the original poster: I'd say figure out the powder charge first, then fine tune with jump unless it's a Berger bullet in which case I'd do as Berger recommends.

Fitch

 

[cabinfever]

The orignal posters question was which variable do you play with first; powder or seating depth. Ten years ago I would have said powder. With the invention of the internet and specifically reloading and hunting forums, we as hunters and avid shooters can compare notes thus reducing the expense of trial and error. My internet research has saved me a lot of time and money over the years and for the most part the information i have gleaned, has resulted in tighter groups in the field. While researching, you will discover that one or two powders will usually dominate as the most accurate powder for the cartridge and bullet weight you have chosen. Start with this powder. Assuming you are doing good case prep, start with .010 back of the lans and do a latter test (.020,.030.040, .050....090) from there. You will notice that one group will be significantly better than the rest. At that point you can play with .005 increments for fine tuning.

 

[ricky b]

Posting reply to save info. Man I want be bored deer hunting this year