68 or 69 grain .223 recipies with 748.

[Lovesbeer99]

I've been loading 52 match and 55 grain rounds with Winchester 748 powder with some good results. I recently tested some Blackhills 69 grain match rounds that my buddy gave me and now I need to try my own 68 or 69 grain loads but can't find much info on it. I see that some recommend 24.5 grains and others say 25.5 but that's it?

Anyone else loading these. I bought a box of 68 gr Match bthp's to test.

Thanks -
Lovesbeer99

 

[GunTech]

Here's a ladder chart for 68gn Hornady and W748 at SAAMI pressures in commercial cases. Please note this is calculated, and you should work up carefully:

Cartridge          : .223 Rem. (SAAMI)
Bullet             : .224, 68, Hornady BTHP M 2278
Cartridge O.A.L. L6: 2.260 inch or 57.40 mm
Barrel Length      : 22.0 inch or 558.8 mm
Powder             : Winchester 748

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.943% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-09.4   90    21.74   2666    1073   39391   7033     93.8    1.170
-08.5   91    21.96   2694    1096   40651   7110     94.3    1.154
-07.5   92    22.19   2722    1119   41957   7184     94.7    1.137
-06.6   93    22.42   2750    1142   43306   7256     95.2    1.121
-05.7   93    22.64   2779    1166   44705   7325     95.6    1.106
-04.7   94    22.87   2807    1189   46151   7392     96.0    1.090
-03.8   95    23.09   2835    1213   47649   7457     96.4    1.075  ! Near Maximum !
-02.8   96    23.32   2863    1237   49202   7519     96.8    1.060  ! Near Maximum !
-01.9   97    23.55   2891    1262   50810   7578     97.1    1.045  ! Near Maximum !
-00.9   98    23.77   2919    1286   52478   7635     97.5    1.031  ! Near Maximum !
+00.0   99    24.00   2947    1311   54205   7688     97.8    1.016  ! Near Maximum !
+00.9  100    24.23   2975    1336   55999   7739     98.1    1.003  !DANGEROUS LOAD-DO NOT USE!
+01.9  101    24.45   3003    1362   57856   7787     98.4    0.989  !DANGEROUS LOAD-DO NOT USE!
+02.8  102    24.68   3031    1387   59786   7832     98.6    0.975  !DANGEROUS LOAD-DO NOT USE!
+03.8  103    24.91   3059    1413   61788   7874     98.8    0.962  !DANGEROUS LOAD-DO NOT USE!
+04.7  104    25.13   3087    1438   63870   7913     99.1    0.949  !DANGEROUS LOAD-DO NOT USE!

 

[Lovesbeer99]

ping

 

[Byron]

Give Hornady and Sierra a call. They have developed good data for their respective bullets. Byron

 

[jmorris]

Hornady's 4th edition shows 25.8 grains (max) of 748 with the #2278 68grain BTHP with a COL of 2.250. My 1-7 ar liked 25grains of 748 with the above oal. 23.4 grains is what they show as a starting point.