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When working up a load(rifle) find your OAL here.
http://www.thefirearmsforum.com/showthread.php?t=97328&highlight=coal

Then select your powder of choice. Start Low and work up looking for accuracy and pressure.

Once you are satisfied with a bullet/powder charge combo, then you can adjust OAL to fine tune for accuracy. Just remember, increasing OAL (longer round) will also increase pressure and decreasing OAL(shorter round) will decrease pressure. So, it's best to start your Load development with the longest OAL you plan to use and fine tuning by seating deeper.

Reason: Powder and powder charge usually has a greater affect on accuracy than OAL.
 

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I never use my powder measure/thrower (wasted couple hundred bucks for me); prefer to weigh each load on beam scale,(don't use my elec scale either) but I'm only doing a limited amount of hunting rounds. My redding powder measure varies from load to load anyway. I'd get an assortment of of those small power measure spoons and use a beam scale. I actually like the whole process.

I also wouldn't get too involved with all the technical tools and gadgets at first; concentrate on the basics. Thats where I wasted too much money. They'll sell ya anything you have money for if you bite. I find most my bullets like .015-.020 off anyway for starters. A few more like .050 but none like factory ammo which I find to be .080 off with my 30-378.

As far a primer seater, you can't beat that Sinclair tool. I wasted money myself on things that didn't work well for me.
 

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I find my OAL for pistols by making dummy rounds, and that is always my first step when I am loading a new bullet or for a new gun (or new caliber). I then start working up my powder load, usually starting in the low to medium range, unless the OAL is significantly shorter than loads I find in my manuals. Once this baseline is established, then I can adjust both parameters to try to achieve whatever my objective for that round and that gun might be. For revolvers, I am less concerned about OAL for jacketed bullets, since that is often determined by the bullet cannelure.
 

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Just remember, increasing OAL (longer round) will also increase pressure and decreasing OAL(shorter round) will decrease pressure.
I thought it was the other way around. Wouldn't increasing the round decrease pressure due to more room for internal explosion? And decreasing the round increase pressure due to less space and faster build up of pressure?
 

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No 76highboy, not the coal. I'm talking about the pressure thing steve4102 was talking about. Reread his reply. What do ya think?
 

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I thought it was the other way around. Wouldn't increasing the round decrease pressure due to more room for internal explosion? And decreasing the round increase pressure due to less space and faster build up of pressure?
Yes and No.

Yes for straight walled pistol rounds.

No for bottle necked rifle rounds.

In a bottle necked rifle round the farther the jump to the lands the less the pressure. Case capacity has little or nothing to do with pressure with slow burning rifle powders. Just the opposite is true with straight walled rounds and fast burning powders.

This is from John Barsness of Rifle and Handloader Magazines.

It decreases peak pressure, for two reasons. The longer "jump" of the bullet to the rifling results in a lower peak pressure, since the bullet engraves more easily the faster it's going when it hits the rifling.

Also involved is the "progressive" burning of almost all modern rifle powders. This means the pressure increases relatively slowly from the time of ignition. Thus peak pressure occurs when the bullet beyond the barrel throat, with very slow-burning powders as much as 3-4 inches.

Handgun powders are much faster-burning, and even regressive, meaning pressure peaks when they're first ignited. Thus seating them deeper allows more time for initial pressure to build.

This effect is slightly exaggerated in revolvers. The initial, quick pressure rise is relieved somewhat when the bullet passes the cylinder gap, allowing some gas to escape. When bullets are seated deeper it takes them longer to pass the cylinder gap, giving pressure more time to ri
se.

Here are a couple charts that may help explain.



 

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Ok did not know that with rifle rounds, thought it was the same for both. Thanks Steve4201.
 
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