Hello all, I'm new to reloading and to the Armory. I curious to know if I use a magnum primer for .308, should I use the recommended powder off of the bottle, or should I lower the amount 4-5 grns? I can't seem to find any large rifle primers, but the place I do business with has lots of magnum primers. I'm currently using Accurate powder #2495, 45 grns, 150 gr projectile.

Back off 1-1.5gr and check for signs of presure. I loaded 100's of rounds with mag primers before I was aware of the back off rule and never had any problems, but I never max out loads anyway. I usually start midway between min & max and work up til I get the best groups.
Welcome to the forum and be careful reloading, pay extreme attention to detail and you'll be OK

Thanks for the reply. 45gr is the midway point, but I'll start with lower and work my way up until I achieve my desired results. Just out of curiosity, do you keep a log of all your loads, are just go off the reload data? Probably a dumb question, but just wanted to know. Thanks!

I would start out at the STARTING level on the loading data as there is a pretty big cushion built in with the manuals from START to MAX. I use a chrono for all my work ups to let me know if I am in the ball park of published data or am I too high or too low for what is expected.

I keep track of all I load and now keep a book showing the chrono print out along with the actual groups trimmed down and pasted in a 3 ring binder. I use my own Chrono Data Sheet that I designed for tracking various loads for quick comparison. I've shared it with several board members and so far no one has told me I'm FOS about how I do it so I guess it is OK!!

Greg

Whenever I change from a regular primer to magnum, I approach it like its a new load and re-establish my parameters. Sometimes there's no change but sometimes there's a lot of change. Depends on the powder.

Tj

I load my .308 150 gr FMJ's with magnum primers and AA2230. Like the others said, start off low, work up and chrono. They work great with spherical powders.

Yep, I'll even go so far as to say faster spherical is where there's the least amount of difference between primers too. Doing a load like a new load approach, on A2230 and a 55 grain bullet in .223, my load difference was 0.3 grains to achieve the same chrono results. Most powder dispensers can have that much variance. That was going from CCI 400s to CCI 450s. I saw no difference on the same bullet and caliber going from CCI 400 to CCI 41s.

A2230 is just a fast powder which is designed to burn mostly in the case anyway.

Tj

+1 on backing down the load with magnums as a general rule.