Thinking of reloading,

Will they be covering annealing?

Not sure. They are sending out the pre-course literature this week.

Although I have been re-loading for about six or seven years, I started out with a 1-1 course from a local RFD.

My first cartridges (I kid you not) were 577-450 Martini Henrys.

About a couple of years ago, I also spent a day with Yewtree (Richard) on non-lead load development. That was an education, and time well spent with a very decent, and very knowledgable chap.

Last year the NRA required all 'home loaders' to sign a document which implies that the shooter knows what re-loading is all about, and if the wheel comes off at Bisley (it has twice to my knowledge), it's down to you. The writing is on the wall.

I saw the NRA advert for the course and thought I would sign up and see what they have to offer.

What's the worst that could happen...

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So I've just measured some 6.5 bullets for accuracy of o/a length:-

Accubond with a polymer tip, max variation over 10 bullets of .0025"
Yew Tree with an aluminium (I assume) tip, max variation over 10 bullets of .0005"

From the quick drawing I've done to approximate a 6mm Nosler BT, with an eccentric bullet of only .002", means a contact variation at the ogive of .013"

Loading with decent kit, RCBS and good brass, Norma, using good bullets, Nosler, I found that eccentricity up to .003" or even .005" was common. I concluded that when the bullet leaves the case and moves down a degree of free bore, eccentricity of these dimensions are irrelevant with the bullet eased into the rifling in a short distance and then travelling down a long barrel. Eccentricity measured at ogive will always produce bullets further from the land than planned, therefore you could say safer as athough the bullets I measured for o/a length are quality and therefore accurate, maybe there are bullets out there that are not so good.

This was the reasoning that although I have a precision mic for measuring to the ogive, I no longer bother as hunting ammo is more than capable of being produced by measuring the arguable more accurate o/a length. The OP I believe was interesting in loading within a budget and hence the reason I do not believe he needs to invest in precision micrometers.
Interesting.

I routinely measure the bullets I use after sorting them for weight, the difference was less than a thou of variation in going from tip measurement to ogive measurement, and that ties up with your Yew Tree figures (0.5 thou). In the sort process between one in ten and one in 50 bullets get removed, and the rest usually form a few groups which I separate rather than the clean theory of a single peak normal distribution. The "less than a thou" figure is per group: I have not done it for worst bullet to average.

On your drawing where you go from the 0.5 thou difference between COAL and OAL-to-ogive, + 2 thou eccentricity, to give the 13 thou of contact variation, it is not eccentricity of the bullet but poor seating. The die should control the seating centralisation, with the shoulder as the reference, with the neck deforming to put the bullet in it centrally to that. I will do some measurements, and see what the figures are, for the neck to tip offset variation, using a watchmaker's lathe to hold the case, and post pictures tomorrow.

(For Tixkat1x observing the discussion, ignore this side discussion as these are micrometer measurements as good verniers (Mitutoyu, Sylvac, M-Sure) are accurate to only +/-0.7 thou and a Lidl/Aldi vernier is often +/-7 thou. A micrometer is 10x better than a good vernier but they only measure a limited range. Due to the range for checking bullets and COAL, one needs 3 micrometers to do this sort of thing: 0 to an 1 inch, 1 to 2 inch and 2 inch to 3 inch or 2 inch to 4 inch depending on who makes the micrometer. Don't worry about it, just check your die to keep your COAL or OAL constant.)
 
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Interesting.

I routinely measure the bullets I use after sorting them for weight, the difference was less than a thou of variation in going from tip measurement to ogive measurement, and that ties up with your Yew Tree figures (0.5 thou). In the sort process between one in ten and one in 50 bullets get removed, and the rest usually form a few groups which I separate rather than the clean theory of a single peak normal distribution. The "less than a thou" figure is per group: I have not done it for worst bullet to average.

On your drawing where you go from the 0.5 thou difference between COAL and OAL-to-ogive, + 2 thou eccentricity, to give the 13 thou of contact variation, it is not eccentricity of the bullet but poor seating. The die should control the seating centralisation, with the shoulder as the reference, with the neck deforming to put the bullet in it centrally to that. I will do some measurements, and see what the figures are, for the neck to tip variation, using a watchmaker's lathe to hold the case, and post pictures tomorrow.

(For Tixkat1x observing the discussion, ignore this side discussion as these are micrometer measurements as good verniers are accurate to only +/-0.7 thou. Due to the range for checking bullets and COAL, one needs 3 micrometers to do this sort of thing: 0 to an 1 inch, 1 to 2 inch and 2 inch to 3 inch or 2 inch to 4 inch depending on who makes the micrometer. Don't worry about it, just check your die to keep your COAL or OAL constant.)
You can't shoot to that degree of 0.005" as 0.5" is half an inch lol
 
You can't shoot to that degree of 0.005" as 0.5" is half an inch lol
0.5 thou = 0.0005 inch = 0.5''' = 5 ten thousandths of an inch, which is the variation of length to ogive or variation in total length of bullets from a decent manufacturer. Which is why I said they were made to an amazingly small tolerance so it does not matter whether you measure COAL or OAL to ogive.

Deermanagement's point is a good one, as tiny variations in how the bullet enters the freebore then rifling makes a big difference in group size. Try it: just change the COAL and see your groups go all over the place, or change the seating concentricity by a much smaller mount, and see the same.
 
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0.5 thou = 0.0005 inch = 0.5''' = 5 ten thousandths of an inch, which is the variation of length to ogive or variation in total length of bullets from a decent manufacturer. Which is why I said they were amazingly small tolerance so it does not matter whether you measure COAL or OAL to ogive.

Deermanagement's point is a good one, as tiny variations in how the bullet enters the freebore then rifling makes a big difference in group size. Try it: just change the COAL and see your groups go all over the place, or change the seating concentricity by a much smaller mount, and see the same.
No it does not lol that is why drawings state in the top or lower right hand corner +/- 0.004" not 0.5" or in Metric it would be
0.12mm Guess you started your apprentship in 76 being 1 year older than me.. :tiphat:
@Fox Tales
 
this sound like what i need, and a head space kit, or head space bushing if it will work with the comaparator body £130:doh:
were only here the once👍

do i actually need a head space gauge??
 
No it does not lol that is why drawings state in the top or lower right hand corner +/- 0.004" not 0.5" or in Metric it would be
0.12mm Guess you started your apprentship in 76 being 1 year older than me.. :tiphat:
@Fox Tales
I have not posted a drawing. I only referred to Deerhunter's drawing.
He gives two numbers, 0.32mm, which is 12.6 thou, which he rounded correctly to 13 thou, and 0.05mm which is 1.97 thou and he rounded it to 2 thou.
Not seen where your +/-0.004" figure comes from, but that is 4 thou, which is 0.1mm. Can you explain further, as clearly two different wavelengths are in play here?
I started my apprenticeship in 76.

do i actually need a head space gauge??
Not really. You can find the length it jams easily enough, and work from there to tell you what headspace you have for your FLS.
If you want to be really clever, there are a couple of very low melting point alloys, that you pour into a chamber with a rag pushed into the rifling, then pop it out and measure every aspect of the chamber. Wood's metal is handy stuff: melts in boiling water.
 
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I have not posted a drawing. I assume you refer to Deerhunter's drawing.
He gives two numbers, 0.32mm, which is 12.6 thou, which he rounded correctly to 13 thou, and 0.05mm which is 1.97 thou and he rounded it to 2 thou.
I started my apprenticeship in 76.


Not really. You can find the length it jams easily enough, and work from there to tell you what headspace you have for your load.
No I was referring to the drawings we both scratched out heads as young lads.. +/- 0.004"
mine was 77. :tiphat:
 
I have not posted a drawing. I only referred to Deerhunter's drawing.
He gives two numbers, 0.32mm, which is 12.6 thou, which he rounded correctly to 13 thou, and 0.05mm which is 1.97 thou and he rounded it to 2 thou.
Not seen where your +/-0.004" figure comes from, but that is 4 thou, which is 0.1mm. Can you explain further, as clearly two different wavelengths are in play here?
I started my apprenticeship in 76.


Not really. You can find the length it jams easily enough, and work from there to tell you what headspace you have for your FLS.
If you want to be really clever, there are a couple of very low melting point alloys, that you pour into a chamber with a rag pushed into the rifling, then pop it out and measure every aspect of the chamber. Wood's metal is handy stuff: melts in boiling water.
not feeling clever, or brave enough to be poring anything into my chamber:)
i will just order the OAL gauge and bullet comparator then, watched a few youtube videos on them, i recon i can make good use of them, thinking of buying the flat anvil too to make the measure easier, only £20👍
 
"not eccentricity of the bullet but poor seating"
Yes is not the bullet that's eccentric, it's the seating. As I said, using decent RCBS dies, and consumables, with a jig I made when I was still toolmaking, I'd get as much as 0.005" movement (that's +/- 0.0025") on a DTI running on the ogive in the same sort of area my precision mic contacted which gives a bigger bullet to lands variation than using the bullet oal. I really don't think it means a great deal having a less than perfect bullet alignment, I've managed to find very good groups with minimal ammo. And this is coming from someone who used to work to tighter than a thou on occassion so I like to see things straight and aligned. Not having thought that much about it before but after using the old fashioned method of measuring bullet contact to lands with a bullet inserted into a case and either blued or marked up with whiteboard marker rather than smoked with a candle, I have likely ended up with underestimated amount of space due to having bullets not perfectly seated.

Last loads have been Yew Tree about 100 thou off the lands that produces something like 1/4 moa, admitedly 3 shot groups but enough of them and the last 22/250 I had bullets sat about 1/4" off the lands and that still shot less than 1/2" all day.
 
not feeling clever, or brave enough to be poring anything into my chamber:)
i will just order the OAL gauge and bullet comparator then, watched a few youtube videos on them, i recon i can make good use of them, thinking of buying the flat anvil too to make the measure easier, only £20👍
To make sense of you're measurements the anvil is essential, but you don't need to buy the full bullet and case comparators if you are only loading for one chambering.
 
yes only my 223, but when i looked at the prices for the body and 1 insert and a new OAL gauge and the modified case it all came to the same price, so it was new kit for £80 of hardly used for more kit, granted, none of which i will ever use, but im sure in the future i will get a larger calibre and end up needing it 👍
 
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