190 grain Hornady Sub-X in .300 BO results

[Lennyjoe]

Finally finished building a sufficient load with this bullet and 1680 for my 10” barreled.300 Blackout and AAC Cyclone suppressor. Below are the results.

.300 Blackout
10” barrel
AAC Cyclone suppressor
Blackout brass made from LC 5.56 brass, resized with RCBS die
1680 Powder
CCI Small Rifle Primers
Hornady 190 grain Sub-X
O.A.L set at 2.065”
5 shot strings indoor range
72 degrees, 978 above sea level

10.5 grains:
891
911
876
918
886

11 grains:
932
919
937
946
924

11.5 grains:
1011
1000
1019
992
998

12 grains:
1080
1056
1054
1064
1076

12.5 grains:
1098
1108
1111
1116
1115

I didn’t go above 12.5 because I didn’t think it would stay subsonic and from what the numbers reflected is that it’s too close to the limit for my liking.

I didn’t get a picture of the 12 and 12.5 grain grouping but I’ve attached the groupings I did capture. Top left is a 208 grain Hornady BTHP over 10.5 grains of 1680 from same rifle in same conditions doing 1040 FPS. The rest are as marked. Once I pick my load (most likely 12 gr) I’ll readjust the red dot.

 

[mcb]

The 11 and 11.5 groups look good. What range? If it was me I would come down a 1/10 or two off the 12 gr load for the best velocity assuming the accuracy is as good. I like my subsonic at or just below 1050 fps. How much are you paying for those Sub-X?

 

[Lennyjoe]

The 11 and 11.5 groups look good. What range? If it was me I would come down a 1/10 or two off the 12 gr load for the best velocity assuming the accuracy is as good. I like my subsonic at or just below 1050 fps. How much are you paying for those Sub-X?

Was @25 yds (limited to indoor range) but will take the 12 grain load to the outdoor range possibly this weekend.

Midsouth Shooters supply has them in stock for $33 per hundred. Midway USA had them earlier for a few $ cheaper but now have them for $33 as well.

 

[Lennyjoe]

MidwayUSA