This is a discussion on Hornady Reloading Manual within the Ammunition forums, part of the M14 M1A Forum category; If this has been mentioned in this forum already I missed it. Tried a search. the loading information for .308 service rifle in the Hornady ...
If this has been mentioned in this forum already I missed it. Tried a search. the loading information for .308 service rifle in the Hornady 8th edition seems to be on the low side for IMR 4895. Maxing out at 41.4 grains with the 168 grain bullets. I've seen other loading info up to 43 grains. I'm going to start at 40.5 grains with a 168 gr SMK. Is anybody else out here loading much beyond this?
I too have wondered the same question, I have the Hornady manual and the new Sierra. The Sierra shows a max load of 41.3g of IMR 4895 @2600 with a 168 SMK at 2.80 OAL.
I load the 168 SMK to 2.80 OAL, with CCI#34 primers and 40.6grs of IMR 4895 in Lake City brass with roughly .002 neck tension, across my chrono that yields a nice 2525 fps avg velocity for 20 rounds. I stick with 2500 fps is plenty fast for me, I never shoot beyond 300yds..just dont need the extra 100 fps or so. Also by staying with 40.6 grains...just in case my Dillon powder measure is sloppy and I get a .1 or .2 more powder, I not on the bleeding edge of safety, I have almost a full 1.0 grain powder of safety margin.
I also wonder about the people I heard so many people say 41.5 is "standard" loading for me 41.5 is not necessary. Again my target velocity is 2500 fps. Some people may need the extra 100 fps... your results may vary.
Start at 40 grains and work up slowly to find your sweet spot. I'm sure you realize that military brass has less case volume and this definitely effects my loads. Commerical cases can have slightly more volume.
Thank-you for the info. I'm still pretty new at this. I've been shooting DAG in my backyard at 200 yards and have been more than happy with it. Recently made friends with a farmer with a huge pasture and will be able to stretch out to 800 yards and more. Thats as far as my rangefinder will go. Want to see what my rifle and I am capable of doing without pushing the pressure limits.
...I've seen other loading info up to 43 grains...
Read their information carefully, what rifle or barrel did they develop their data with? Most other manuals are using 24" bolt rifles for their .308 load data and those type of actions can and do usually use more powder since they handle the chamber pressures better.
All that being said, the volume of the brass is what makes the difference. When I use a 168gr Amax bullet and my Lapua brass then I usually end up using about 42 grains of IMR 4895. On the other hand, if I use a case with less volume (like just about any other brand since my Lapua brass has the most volume of the brands of brass I use) then I drop down to about 41 grains of IMR 4895. These charge weights give me muzzle velocities in the 2550 - 2600 fps range which is my personal goal. Now for pure accuracy lighter loads seem to work best for me. 40 - 41 grains of IMR 4895 in a standard commercial case and the 168gr Amax will make some pretty nice groups at 100 yards.
When the bug gets you then you will drive yourself nuts with all the intricacies of reloading and rifle operation but until then just experiment with a load using 40 - 41 grains of IMR 4895, a good 168gr target style bullet (my favorite is the Hornady A-Max but an awful lot of people like the Sierra Match Kings), and the cases and primers you have and I think you will be impressed with the results.
You are working with heavy for cartridge bullets at the 168 gr. level and you have to take extra care to ensure all of the conditions and variables regarding reloading 308 Win ammo are taken into account. I would recommend keeping to the conservative level and working up slowly until you have identified the load that works best with your components and rifle. Hornady manual has to keep loads within established safety ranges for a range of rifle types. My M1A requires a different approach to reload compared to my PSS.
While 38.7 grains seems to work for some rifles remember that there is a minimum port pressure required to make the gas piston move with enough force to reliably operate the rifle. I like the lighter loads for the fact that they don't beat the rifle up and the throats will last longer and they usually group tighter, at least at 100 yards. But a new reloader needs to be aware that too light of a load can cause issues too, in fact a lot of reloading manuals warn against loading anything below their minimum loads, which is significantly below the 38.7gr load mentioned.
In my experience, 41.0-41.5 gr IMR4895 in NATO brass is the sweet spot for a 168 SMK. Chronograph verifies this out of two NM and a SM rifle. Spot on around 2600 FPS. This projectile performs well in that particular velocity envelope out of the M1A.
I would start at 39.5 minimum and work up to 41.5 gr. Look for flattened primer condition and recoil report. A chrono sure helps. Depends on brass volume and that's where these $100 chronographs really help save in the long run.
I've noticed that the main load I use, .308 SSTs over 42.5 gr of IMR 4895, I'm already getting high pressure. So high the headstamp was imprinted on my M1A. I also noticed that Hornady ammo is loaded hot. I like their products, but I really hope they test their loads with each powder and not do mathematical guess work.
Mustang - I'm using Winchester brass, CCI #34 primers, Hodgdon 4895 and 168gr SMK bullets in 18.5" barrel M-14 type rifles. NOT the same powder as yours, but I've noticed chronograph muzzle velocities well below what the Hornady "Service Rifle" section indicates. Like almost 200 fps of muzzle velocity. Same holds true for VV N-135 as well as the H-4895. The shorter barrel(s) contribute to the lower velocity, but not all of it. IIRC the Hornady test specs also say something about military brass (in addition to the 22" barrel).
This is just an educated guess at this point, but perhaps Winchester .308 cases have more interior volume than some other types of brass do. I've worked slowly up to Hornady's "maximum" loads for both VV N-135 and H-4895. No pressure signs of any kind.
I find that the Speer manual has hotter info and my results mirror the Speer book. I use 43.5grs to 44.0 grs of IMR-4895 in commercial Winchester cases with WLR primers and 168's. This gets me around 2600 to 2650fps. If I use Sierra's info, my loads are a little slow in the low 2500fps range.
Thank-you all for your input. I had already loaded 15 rounds at the 40.5 grain level and thought that was being conservative but now I am not so sure. I guess I'll pull these and start over at 39 or 39.5 grains.