CaneCorso85
Member
Hey guys,
I'm having a bit of trouble getting my 308 ammunition to register anywhere near the load data velocity using the prescribed loads. Here's what i'm using:
Lake City brass
168 SMK
IMR-4895
Win LR Primers
Fired from an M1A Socom
Data from the Sierra and Lee manuals
The data in the lee manual calls for a starting load of 41gr of H4895 (they don't list data for IMR) working up to 43.5gr, which should produce 2703 fps.
The Sierra manual calls for 42.1gr of IMR4895 to only get to 2600fps (does not list data beyond that speed)
Here's what I loaded, and the speeds it chrono'd at:
(yes, I started lower previously and the speeds were in the 2300's)
43gr
#1 - 2415fps
#2 - 2487fps
44gr
#1 - 2525fps
#2 - 2539fps
(note I'm now exceeding data from both books and still not even close to the listed velocities. No signs of overpressure on the casings)
45gr
#1 - 2534fps
#2 - 2530fps
#3 - 2544fps
46gr
#1 - 2614fps
My target velocity is 2660
Question is, despite being pretty high above the max loads for each manual, I'm still not at the prescribed velocities; should I go to 27gr to try to hit 2660? I can take some pictures of the brass for each load if that would help, however, I had a couple of experienced reloaders take a look at them and they didn't see any signs of overpressure. I don't imagine Sierra and Lee got that data using a gas operated rifle like the M1A. It's probably safe to assume a lot of that pressure is lost operating the action, which would tell me I'm probably safe to keep going. I'm just curious what the experts at THR have to say about it.
I'm having a bit of trouble getting my 308 ammunition to register anywhere near the load data velocity using the prescribed loads. Here's what i'm using:
Lake City brass
168 SMK
IMR-4895
Win LR Primers
Fired from an M1A Socom
Data from the Sierra and Lee manuals
The data in the lee manual calls for a starting load of 41gr of H4895 (they don't list data for IMR) working up to 43.5gr, which should produce 2703 fps.
The Sierra manual calls for 42.1gr of IMR4895 to only get to 2600fps (does not list data beyond that speed)
Here's what I loaded, and the speeds it chrono'd at:
(yes, I started lower previously and the speeds were in the 2300's)
43gr
#1 - 2415fps
#2 - 2487fps
44gr
#1 - 2525fps
#2 - 2539fps
(note I'm now exceeding data from both books and still not even close to the listed velocities. No signs of overpressure on the casings)
45gr
#1 - 2534fps
#2 - 2530fps
#3 - 2544fps
46gr
#1 - 2614fps
My target velocity is 2660
Question is, despite being pretty high above the max loads for each manual, I'm still not at the prescribed velocities; should I go to 27gr to try to hit 2660? I can take some pictures of the brass for each load if that would help, however, I had a couple of experienced reloaders take a look at them and they didn't see any signs of overpressure. I don't imagine Sierra and Lee got that data using a gas operated rifle like the M1A. It's probably safe to assume a lot of that pressure is lost operating the action, which would tell me I'm probably safe to keep going. I'm just curious what the experts at THR have to say about it.