Warning: Long report, lots of content, and an attempt to find a substitute practice load for the 174gr Lehigh Defense CF bullet
So today I finally went and shot my 174gr Lehigh Defense CF bullets and I was pleased. I only loaded up 2 loads in my ladder as the price of the bullets is too great to be popping them off like nothing. How would I ever figure my load out then? Good question
Goal: Have a suitable substitute load for my 174gr Lehigh Defense CF round and find the best subsonic speed for the round w/out shooting up too many expensive bullets.
So in order to save money I bought 100 of the 175gr Grafs HPBT bullets for a much cheaper price $27.99
http://www.grafs.com/retail/catalog/pro ... ctId/26343
I then proceeded to load both bullets so that the same amount of bullet resided in case. Now I came to discover that the Grafs bullet is way shorter than the 174gr Lehigh Defense CF bullet so I could not load the Lehigh Defense CF bullet to the recommended COAL which is 2.200" and be able to load the 175gr Grafs while keeping approximately the same amount of bullet in case for both loads. The Grafs bullet is so much shorter that another .020 would have been so deep I was uncomfortable with if/how the crimp was going to work. I decided to get as close as I felt comfortable with and landed on 2.180" for the Lehigh round.
Now I created a 5 load ladder with the Grafs bullet and I took the lower end and higher end of the powder charge spectrum to create a 2 load ladder for my 174gr Lehigh Defense CF (LDCF). This worked out magically as the loads shot almost identically!!!!
The following image is of both my LDCF and Grafs loads/bullets with 10.7gr A1680. The speeds were going to be too fast for me to hunt with but still both managed to stay subsonic with my suppressor on out of my 16.5" 1:8twist BFG barrel 300BLK Savage Axis conversion from .223.
I settled on the following LDCF load at COAL 2.180" for further accuracy and AR15 functionality testing as the following shots were done quickly and were done with the Magnetospeed chrony attached to the barrel. I am quiet sure I can tighten up the group by just taking my time to shoot instead of rushing the shots to get through my 13 development loads and to move on to some subsonic turret adjustment practice shooting I had planned.
16.5" 1:8twist bolt gun
174gr LDCF
COAL: 2.180"
10.3gr A1680
Primer: CCI 400
Brass: LC, annealed, 1/2 turn LFC light crimp
Magnetospeed V1
MX: 1045fps
MN: 1003fps
Avg: 1021fps
I did notice that my equivalent 175gr Grafs loads shot about 70fps faster with the same powder charge but printed very close to one another as you can see from the one image I took.
For example the Grafs load at 10.3gr A1680:
175gr Grafs HPBT
COAL: 1.889"
Primer: CCI 400
Brass: LC annealed, 1/2 turn LFC light crimp
Magnetospeed V1
MX: 1124fps
MN: 1062fps
Avg: 1094fps
I didn't shoot the 10.3 gr LDFC and Grafs in my AR to see about function but the 10.7gr loads function perfectly in my AR, I just didn't record speeds. They must have both barely been subsonic as they did not go super with my suppressor on.
I hope this helps folks out