303 British, IMR 4227, 150 gr lead

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PolarFBear

New member
I have a good load for a Lee 180 gr lead round. 20.4 grains of IMR 4227. I use the same load in my Moisin Nagant carbine. NOW: I want to use a 150 lead LEE but can find no load data. Can I still use the 20.4 grains of IMR 4227? I only "kill" paper and steel. Not looking for a hunting load or real precision shooting. I have checked the Lyman, Lee, and Hornady books; no luck.
 
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Unclenick

Staff
The 150-grain bullet is going to leave more empty space in the case. As a general rule, you don't want powder to fill less than about 60% of the empty space under the bullet, or erratic pressures can arise. You are already below 50%, so you would do well to put a little tissue paper or a tuft of polyester pillow stuffing over the powder to keep it against the flash hole to prevent the pressure excursion problem, though this powder may be fast enough not to have it. Irregular velocities measured by a chronograph would tell you.

In QuickLOAD, if I seat the bullets to the same COL, it looks like you will need to add about 1.2 grains of powder to maintain pressure with the lighter bullet.
 
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