Loading 300 Win Mag

rlphvac

solid fixture here in the forum
Grumpy I'm getting ready to load some 300 Win Mag loads so I looked up IMR 4350 & there is such a difference in starting loads . The bullets are Hornaday SST 165 gr. What I found is Hornaday calling for 58.1 Gr. IMR 4350 to Pet Loads calling for 73.5 Gr. IMR 4350 others are 71.0 Gr.Nosler 70.0 Speer 67.0 Lyman I am leary to load theese because thats a big difference between weights
 
the first few chapters in most quality reloading manuals go into some detail on the process of working up safe reloads,and most provide a section well worth reading through carefully.
first youll have to realize the, manuals, data sheets are generated all using totally different barrels, and in most cases different bullet manufactures , Ive generally found that you can buy three to five better known manuals and average the starter loads, then you work up loads to nearly duplicate, but not too exceed, the factory pressure levels.

http://www.midwayusa.com/product/57...tridge-reloading-9th-edition-reloading-manual
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http://www.midwayusa.com/product/1064217655/lyman-reloading-handbook-49th-edition-reloading-manual
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http://www.midwayusa.com/product/537267/speer-reloading-manual-14
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http://www.midwayusa.com/product/158738/nosler-reloading-guide-8-reloading-manual
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http://www.midsouthshooterssupply.c...-Reloading-Manual-2nd-Edition-by-Richard-Lee-
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http://www.midsouthshooterssupply.c...cluding-Supplements-Number-1-24-By-Ken-Waters
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youll need an accurate , micrometer to measure the expanded diameter of the fired case in your rifles chamber then you know the max expanded case diam. by measuring the expanded fired case just in front of the rear belt
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http://www.harborfreight.com/0-to-1-inch-range-digital-micrometer-895.html
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once youve found the pressure limits you can start accuracy testing, youll generally find the powders that most completely fills the case will be more accurate and in some cases magnum primers like the 215 FEDERAL give a more consistent result.
ID stronly suggest starting at least 6 grains under the listed max loads AVERAGE of the three to five manuals you choose to use and work up in 1 grain steps MAX

http://www.handloads.com/articles/default.asp?id=39

http://www.chuckhawks.com/developing_hunting_loads.htm

http://www.sportingshootermag.com.au/news/best-rifle-hand-load-development

http://www.nosler.com/blog/news-and-articles/2013/6/4/beyond-the-basics-developing-your-own-loads

read this on manuals,
http://garage.grumpysperformance.com/index.php?threads/new-reloading-manuals.2379/#post-56752

LOOK THIS OVER
http://handloads.com/loaddata/default.asp?Caliber=300 Winchester Magnum&Weight=All&type=Rifle&Order=Powder&Source=

A micrometer is a measuring gauge operated by a screw with 40 threads per inch. This means that one complete revolution of the screw advances one thread or one-fortieth of an inch. 1/40˝ equals 25 thousandths of an inch or 0.025˝ (40 x .025˝ = 1˝). The beveled edge of the thimble is divided into 25 equal parts. Each line of the micrometer's thimbles equals 1/25 of .025” or .001˝ (one thousandth of an inch). One complete revolution of the thimble therefore equals .025˝ or one line on the barrel scale. With that in mind, here's a quick quiz: What is the reading shown in Figure 1?
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How do you think you did? Did you come up with .385˝? If not, look at the drawing again. Each of the lines on the barrel represents .025 of an inch. Each of the longer lines (the ones with the numbers above them) equals .1˝ (4 x .025”). So, we’re showing 3 full lines (.300) and 3 of the small lines (.075). We’re up to .375˝. The last .010 is indicated by the reading on the thimble. Add that to the .375˝ and you have a reading of .385˝. Sounds a little confusing I know, but trust me, you’ll get the hang of it the more you do it. Heck, even my wife can read a micrometer now and I still can't boil water.

If you need more precise measurements, which is quite common in machining, you can achieve readings in ten-thousandths of an inch by using a Vernier scale (optional on some micrometers). The vernier scale, marked on the barrel, has ten divisions, each equaling 1/10 of 1/10,000”. The difference between a thimble division and a vernier division is 1/10,000 of an inch. Therefore, when the zero lines of the vernier exactly coincide with thimble lines (Figure 2), the number on the vernier lines is the difference between the vernier line and the next thimble line in ten-thousandths of an inch. Thus when the fifth line on the vernier coincides with a thimble line, the thimble has moved 5/10,000 of an inch.
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Example:

First determine the number of thousandths, as with an ordinary micrometer. Then find a line on the vernier that exactly coincides with a thimble line. By adding the vernier reading to the thousandths reading the actual reading in ten-thousandths of an inch is obtained. The reading shown in Figure 2 is .260˝ plus .0005˝ or .2605˝.

Hopefully, you haven’t run screaming after all of that. It sounds confusing, but take your time and keep at it. It will make sense.
 
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