.243 measurement jam/jump - help

Ottawacats

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Hello,
Please be kind, newbie to reloading and perhaps reading into this way to much or just misreading completely.

Rifle - Savage 11 .243

So I have read that the "coal" length is 2.710 for the .243
I purchased the Hornady Lock-N-Load OAL Gauge Straight along with there modified .243 case. When I measure my rifle with Amax 105 I get 2.762 and when I use vmax 65 I get 2.655. So my big question is what should I be seating the bullet depth at? Or did I miss a step or completely confuse my self with the Hornady oal gauge?
 
Hello,
This is a pretty hard question to answer with the information you have provided... but here is my take on it.

Firstly, since you are planning on loading multiple bullets for your .243, i would recommend picking up a bullet comparator kit (hornady). This will allow you to measure the distance from the case base to the bullet ogive (diameter of bullet that matches the diameter of your rifling). Measuring to the ogive will give you a repeatable seating depth you can use with any bullet, for that particular rifle/cartridge.
I have a savage 10 .243 and i think off the top of my head the coal-to-ogive is 2.442.

The main reason for varying seating depths of a particular bullet is to find the coal that works the best in your particular rifle.

I am going to assume that you are going to do some target shooting with the AMAX and hunting with the VMAX.

Target shooters will likely conduct a ladder test by building multiple sets identical cartridges and varying the seating depths. They would likely start by building a set of cartridges with the bullets way off the lands (rifling) and gradually increase the cartridge length with each set. For example purpose, they may build 6 bullets at a length where the bullet is 0.110 off the lands
-6 bullets 0.70 off the lands
-6 bullets 0.30 off the lands
-6 bullets 0.10 into (jam) the lands

Shooting these sets of bullets under similar conditions would tell them witch seating depth is more accurate in their rifle and give them a point in which to further narrow down to the most accurate coal.

You can do the same thing with the VMAX, but if you are using it for hunting purposes you will not want to jam the bullet into the lands as you can potentially have the bullet stick in the rifling when you extract a live cartridge.

The VMAX's shape will generally make it less sensitive to accuracy differences based on seating depths and you may not see as dramatic changes in accuracy.
I made some nosler varmeggedan clones a few years ago by measuring a live factory round for it's coal, then following the nosler reloading guide for powder charges.

Please note that similar cartridges with differing coals may have very different pressure curves (especially jammed rounds) and as with anything in reloading, all experimenting should be done wisely and carefully. Make sure you have a few good reloading manuals and read them carefully before beginning any reloading- berger manual is pretty good imo,

I didn't answer you original question-
Hope this helps
 
Like guntario said. Get the comparator tool and measure to the ogive, then coal doesn't matter. If I didn't have the comparator tool I would think it's safe to take each one back .030" to .040" or so from the measurement of each bullet. As long as you can make sure they're not touching the rifling.
 
I always make a dummy round to find the lands. Insert dummy round with gentle neck tension and then close the bolt. Try this several times. I then use the Hornady comparitor to measure/check the length of loaded rounds at the ogive.

I have 2 unopened boxes of 100 105 grain Amax I might be willing to part with. I drive to Kanata regularly so if you find they shoot outa your Savage and you want to make me an offer let me know. But wait until you see how they shoot in your gun.
 
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