Share your homemade tips on measuring seating depth

I take a case and just start to push a bullet into it. Slowly chamber it into the gun and extract, and when the bullet contacts the lands it will push it into the case. Measure with calipers. Push the bullet in a little further (however large you want your jump to the lands to be) and crimp in place. Use this dummy round to set up your dies for that bullet and seating depth.
 
^^^ I use the press to seat it a bit deeper every time, but same idea.
Once you have the depth you are happy with, take the seating stem out of another calibre's die, and measure the overall length of the cartridge and seater stem, and record the measurement. This will eliminate strange measurements caused by any variations in the bullets' tips.
 
I use the magazine on my .338LM Remington 700P, and the magazine is too short for me to contact the lands with the factory barrel.

I seat them as long as I can while still ensuring that I have reliable feed in my magazine, and use bullets that are good with jump, such as 300 SMK's.


For guns that do not have magazines, or they are single fed only, the tips above are good.

A good tip for determining how much jam into the rifling you have, is to make up a dummy round and smoke the bullet using a lighter, chamber it, and use your calipers to determine how much the lands rubbed off the the smoking, adjust as needed.
 
I have a Stoney Point tool with modified cases for most chamberings I use.
However, If I have no case for the tool, this is how I find the throat length.

#### the rifle, and drop a cleaning rod down the bore from the muzzle. [I usually put a wrap of masking tape on the rod at the muzzle length.]
Take a fine ballpoint pen and draw a line on the tape right at the muzzle.
Then remove the rod, open the action, and drop a bullet, point first down the chamber.

Then drop a sized case down behind it. While holding the bolt against the case, [to hold the bullet in the throat]
Drop your cleaning rod down the bore and make another line on it at the muzzle.

The distance between the two lines is the length to the lands of your rifle with THAT bullet only.
Subtract .015 - .020" from that measurement, and you have the seating depth for that bullet.

Regards, Eagleye.
 
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