.243 advice

[Stinger]

Recently loaded .243 with good success, but am still working up in the powder charge department to find the perfect load.

I am using IMR 4064, Sierra 85g HPBT.

I worked up from 36-38 in half grain increments. I currently have 38, 38.5, and 39 grains loaded up.

My oal is 2.620 (Lyman gave 2.615 with the exact bullet). However, Sierra data has the oal at 2.650. Do I have a problem here? The other loads all shot fine with zero pressure problems. Why I seated them at 2.620 is beyond me. I knew that I would eventually experiment with longer oals, but chose one that was a little longer than listed in the Lyman to begin my workup.

Your advice would be appreciated,

Stinger

 

[dakotasin]

your oal will be fine. i usually seat as long as possible (longer than what you are, and longer than load manuals... i jam the rifleing to start), and work my way shorter if i have to. that way, there's only 1 direction to go for fine tuning a load.

 

[Grumulkin]

If you measure several loaded rounds, you will find the cartridge OAL will vary by several thousandths of an inch since the bullets are not of precisely the same length. The most important thing is to have the bullet near the lands where the rifling starts (at least in many guns) but not actually engaging the lands. Set your seater die up so the bullet is seated just off the lands if possible and don't be concerned about overall length. Several other considerations:

1. Some guns (Weatherbys for instance) have so much freebore you will never be able to seat a bullet near the lands.
2. Enough of the bullet has to be seated to hold it securely in the case.
3. The length has to be such that the cartridge will feed from the magazine of the gun.
4. If it's a heavy recoiling round, you will need to roll crimp in the cannelure which will then determine your overall length. The exception would be a nonbelted, rimless, straight walled cartridge where a taper crimp rather than a roll crimp should be used.