For starters, I am new at reloading. I have done a ton of research on subsonic load data. Which powders are best. Which primers, etc. I ended up starting a load using Berry's 220 grain with CFE BLK and CCI #400 SRP.
Here's my question plus explanation for the group (and it might be long winded):
Every load manual i have seen, seems like 16" barrel is understood barrel length for the data. I am loading for an 8" barreled AR with a 1:8 twist. So that being said l, I have searched for info on forums to see what others are doing and I have found some data on 220's with CFE.
So I started load development using the grain weight recommendation from Sierra since they publish for free and they have a 220 grain bullet (although not same exact shape). They said 11.8 grains of CFE yields 1050 and 13.4 yields 1250. Again I'm assuming this is for 16".
So I started at 11.1 grains and got 761FPS avg. I guesstimated that 1 grain is about 75-100 FPS and bumped up the load to 13.0 grains. Then I got 914 FPS avg. So I added another grain to 14.1 total and got 954 FPS avg.
Here is the interesting part, it was a dime sized group at 33yds. I couldn't believe it. If my 308 bolt gun shot that group I would have been impressed.
I already had 5 rounds of 14.3 grains loaded so I shot those and the avg was 1048 but the group opened up to 1.5"-2.0".
So all that being said for the back story, I think these grain loads are very high. Does this make since to someone that has loaded 220 grain with CFE BlK?? I have seen others post data of 10.5-11.5 grains CFE BLK giving them 1000-1050 FPS in an 8" barrel. What am I missing and what's going on? The only thing that I can't measure scientifically is the crimp. I am wondering if I am not crimping enough/properly/or at all. If my crimp was too light or nonexistent, would this be the reason I need 2.5-3.0 more grains of powder???
More info: I'm using the Hornandy full length resizing die, that is supposed to be crimping. I set it up exactly like their YouTube tutorial showed. And I watched it 10x, but still don't get the feeling that it is working properly. I'm also not sure if the Caldwell G2 chronograph is 100%. During the testing I had many Error messages throughout the day. I played with it until I brought it closer to the gun and started getting consistent readings.
Any advice on the subject would be appreciated. And I didn't say it before but all loads had positive bolt lock back and zero feeding issues. I also seated to 2.20 OAL. Thanks.
Here's my question plus explanation for the group (and it might be long winded):
Every load manual i have seen, seems like 16" barrel is understood barrel length for the data. I am loading for an 8" barreled AR with a 1:8 twist. So that being said l, I have searched for info on forums to see what others are doing and I have found some data on 220's with CFE.
So I started load development using the grain weight recommendation from Sierra since they publish for free and they have a 220 grain bullet (although not same exact shape). They said 11.8 grains of CFE yields 1050 and 13.4 yields 1250. Again I'm assuming this is for 16".
So I started at 11.1 grains and got 761FPS avg. I guesstimated that 1 grain is about 75-100 FPS and bumped up the load to 13.0 grains. Then I got 914 FPS avg. So I added another grain to 14.1 total and got 954 FPS avg.
Here is the interesting part, it was a dime sized group at 33yds. I couldn't believe it. If my 308 bolt gun shot that group I would have been impressed.
I already had 5 rounds of 14.3 grains loaded so I shot those and the avg was 1048 but the group opened up to 1.5"-2.0".
So all that being said for the back story, I think these grain loads are very high. Does this make since to someone that has loaded 220 grain with CFE BlK?? I have seen others post data of 10.5-11.5 grains CFE BLK giving them 1000-1050 FPS in an 8" barrel. What am I missing and what's going on? The only thing that I can't measure scientifically is the crimp. I am wondering if I am not crimping enough/properly/or at all. If my crimp was too light or nonexistent, would this be the reason I need 2.5-3.0 more grains of powder???
More info: I'm using the Hornandy full length resizing die, that is supposed to be crimping. I set it up exactly like their YouTube tutorial showed. And I watched it 10x, but still don't get the feeling that it is working properly. I'm also not sure if the Caldwell G2 chronograph is 100%. During the testing I had many Error messages throughout the day. I played with it until I brought it closer to the gun and started getting consistent readings.
Any advice on the subject would be appreciated. And I didn't say it before but all loads had positive bolt lock back and zero feeding issues. I also seated to 2.20 OAL. Thanks.