The Firing Line Forums - View Single Post

garryc · May 24, 2006, 10:33 AM

I finally finished my load development with my CZ 527 7.62x39
First I tried Olympic ammo and found two things. its dispertion was a 7inch verticle string, straight up. When I tried to resize the cases there was a ring left at the bottom of the web. I also found, upon pulling some bullets, that the crimping severly distorted the bullet. Save those for ratteling in the AK.
Then I tried winchester white box FMJ's, they had a .311 bullet. 2.75inch group. Then winchester SP's, 2.25 group. I was beginning to think something was wrong with the gun. No problem resizing the cases.
Then I loaded Sierra 110gr .308 HP's with 26.5 grains of R7. 2 inch wide x 3 inch high group. When shooting at a water filled milk jug at 100yrds it showed no sign of expansion. (Neither did any other bullet)
I tried Hornady 123gr .310 with 25.5 grains of R7. It gave a round 2 inch group.
I then loaded Sierra .311 SP bullets with 25.5 grains of R7. Groups ran 1 to 1.25 inch. Now I was getting somewhere.
I loaded Sierra 150gr .311 bullets with 24.8 grains of R7. The first group went into one .75 inch hole!! Of 6 groups the largest was 1.25 inch.
Now the question,
The 150 arrives at 150yrds with more KE than the 125, like 175ft pounds more. But will the bullet expand at the 1750 aprox (calculated) velocity? Would the 125, having less energy and near the same velocity, expand better?

May 24, 2006, 10:33 AM	#1
garryc Senior Member Join Date: November 12, 2005 Posts: 2,536	7.62x39 CZ 527 I finally finished my load development with my CZ 527 7.62x39 First I tried Olympic ammo and found two things. its dispertion was a 7inch verticle string, straight up. When I tried to resize the cases there was a ring left at the bottom of the web. I also found, upon pulling some bullets, that the crimping severly distorted the bullet. Save those for ratteling in the AK. Then I tried winchester white box FMJ's, they had a .311 bullet. 2.75inch group. Then winchester SP's, 2.25 group. I was beginning to think something was wrong with the gun. No problem resizing the cases. Then I loaded Sierra 110gr .308 HP's with 26.5 grains of R7. 2 inch wide x 3 inch high group. When shooting at a water filled milk jug at 100yrds it showed no sign of expansion. (Neither did any other bullet) I tried Hornady 123gr .310 with 25.5 grains of R7. It gave a round 2 inch group. I then loaded Sierra .311 SP bullets with 25.5 grains of R7. Groups ran 1 to 1.25 inch. Now I was getting somewhere. I loaded Sierra 150gr .311 bullets with 24.8 grains of R7. The first group went into one .75 inch hole!! Of 6 groups the largest was 1.25 inch. Now the question, The 150 arrives at 150yrds with more KE than the 125, like 175ft pounds more. But will the bullet expand at the 1750 aprox (calculated) velocity? Would the 125, having less energy and near the same velocity, expand better?