Little help in the right direction plz.

MK77

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I am working on some load in a long throated 300 win mag. I can seat the bullets out .200 over saimi spec and still cycle thru my mag well. Curious if there is a way to calculate the difference in case capacity in how it relates to case fill/ density with that much difference. I am careful and do work my loads up, and I know pressure signs are probably more important. But with this covid business on, I'm finding extra time on my hands, and my half a brain does like to understand what is going on when I change my load up. Thank you.
 
I would guess that you can mark how much of the bullet is in the case with a caliper. Then fill the case with the powder you use until that mark, then check how many grains of powder you have under the bullet. Then math to see the difference in %.
Not scientific but could give you an idea.

You are right, load density is not important - rely on verified load data and creep up on max slowly.
.200 over is a lot. Does it chamber ? You should hit the land loaded this long..

Loading long is usually to try to find the sweet spot were you get the best accuracy for a given bullet after having find you best ( powder ) load. If you use that rifle for hunting, stay within spec, there is no need for it or to hot rod it with more powder than is called for.

Keep in mind, than loading long - jammed into the lands will raise pressure.

Since you have free time - here is some reading on the subject:
https://www.shootingsoftware.com/loadens.htm
 
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With the scirrocco 2 180gr i was still getting a .050 jump. Thank you for the link, that was an interesting read. It also touched on my other issue of a short barrel. I. While I am not looking to kiss the lands I have some concerns over to much jump ,as well it would be ashame to not make some use of the room. I am also switching to accubonds as they have been much more forgiving in building accurate loads in a couple other rifles I have. Software and a Chrono are coming in the near future I believe.
 
Weatherby rifles have a long lead, they still shoot lights out, so I would chase the accuracy rather then chase the lands, regardless of the make of rifle your shooting.

Is this a new rifle? or new to you? is it possible someone had it throated out for a long heavy bullet?
 
Can you give more details on what you mean by long throated? Does the rifle just happen to have a long throat or did someone make it that way on purpose?
 
It is an L61r Sako, and I would be surprised if It had seen a box of ammo before I bought it. I have heard that weatherbys have a lot of freebore, other then this rifle I've never had to deal with it. Start at saimi spec and chase accuracy? Add an extra .100 to length and chase accuracy? Haven't had alot of time to tinker with it before, until now. Ditching the scirrocco is a good start lol, I couldn't get them to group worth nothing.
 
Forget SAAMI specs. If you can load to 20 thou off the lands, go for it. (Make sure it will fit the mag).

Different makers use different throats in their chambers.

Start low and work up looking for accuracy and pressure.
 
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