March 13, 2012, 04:43 AM
So I picked up some MG fired LC Brass and M2 bullet pulls (147gr) from gibrass, basically to make some plinking ammo. I sat down and reloading a few just to try the next time I go to the range, I think I have about 8 reloaded. The case was trimmed to 2.010" and the bullet crimped on the cannelure. I loaded 43gr of IMR3031.
Now here is my concern, I understand that Mil surplus brass can have thicker walls and therefore increase case pressure. Should I be worried with these rounds? 43gr is under maximum for a 150gr bullet (.308 Load data); however now I'm concerned due to the case thickness. Anybody have first hand experience with this? Thoughts?
March 13, 2012, 05:46 AM
Yes, LC 30-06 and 7.62 Nato brass is a little heavier than some commercial brass. the GI brass is worth a grain or two less powder for sure. Winchester seems to be the lightest. So, what brass did your data book use during testing? The Speer I was looking at used IMI brass which is pretty close to LC brass. Also always start at the starting load and then work up.
March 13, 2012, 07:11 AM
First, if the bullets you have weigh 147gr and are boattail bullets, they are M80 pulls, not M2. Yes, 7.62x51 brass is heavier and has less case capacity than most commercial .308 brass, so reduce your charge weights accordingly. I load quite a bit of the M80 pulls in LC brass, and I use 43.0gr of IMR4895. Since IMR3031 is a faster powder, personally, I would reduce your charge weight by at least a half a grain. Just MHO.
March 13, 2012, 08:03 AM
That was a typo on the 147gr, they are 152gr. I'd heard the M2s were slightly more accurate than the M80 pulls so I spent the extra $25/1000.
I'm probably going to pull these bullets since it's such a small number of them and knock back the load. I have 4 reloading manuals, Speer, Lyman 49, Sierra, and Lee. For this load I used the Sierra which I believe has 43.5gr listed as max for IMR3031.
Don, do you feel that 43 with the M80s is as high as you will go? Or is it just a comfortable load?
March 13, 2012, 08:13 AM
That's as high as I will go with IMR4895 and M80 pulls. If I was loading M2 pulls like you are doing with IMR3031, I would drop down to 42.0, due to their longer bearing surface.
March 13, 2012, 08:29 AM
Great. Many thanks on the advice. I've got some IMR4895 as well which is why I was wondering.
Looks like I'll pull & drop down to 42.0. I've got a Chrono too so I can see how the load is performing which will be nice.
March 13, 2012, 08:55 AM
I've got a Chrono too so I can see how the load is performing which will be nice.
+1. That's the best way to approach load development.