Primers & imr 4350

B

bluealtered

New member
Since getting this .243, i am of course looking at different loading data. While looking at sierra i see that they have magnum primers listed in at least one of their loads, since i have a fair ammount of mag primers i have to ask, have you used them for your .243 loads, and how did it work?

I am also wondering how far down grain wise, (65-70?) have you used 4350 for your .243? Thanks, blue
 
Mag primers are used for ball powders to improve ignition. You wouldn't need them for IMR 4350 and other stick powders.
 
Quote:

I am also wondering how far down grain wise, (65-70?) have you used 4350 for your .243? Thanks, blue



I hope you don't plan on using 65-70 grains of 4350 in a 243 case. I doubt you could pack that much powder in there.

I've used H4350 with good success in 243. I've heard that the guys in really cold areas like Alaska will use Mag primers to guarantee ignition under extreme cold conditions, but I wouldn't know about that being a desert rat.
Mag primers are not necessary for 4350. Since you mentioned that you have lots of mag primers, I wouldn't be afraid to develop your loads using them. Mag primers burn longer than std primers. Just watch for pressure as you normally would and stop when you show signs of excess pressure.
 
I have been using win large rifle with no problems 40.0 grains and the 70 gr speer TNT my 243 loves it nice little groups ( haven put it on fur of any kind yet ) Look in the lyman manual it lists this load for the 70 gr pill it is the starting load ( shot so well I didn't bother with any more for this powder bullet combo ) good luck
 
Quote:
Quote:

I am also wondering how far down grain wise, (65-70?) have you used 4350 for your .243? Thanks, blue



I hope you don't plan on using 65-70 grains of 4350 in a 243 case. I doubt you could pack that much powder in there.



I think maybe he was talking 65-70% of case capasity. If you have a supply of magnum primers that you want to use I think I would start with the listed starting loads and go from there,watching for pressure signs. I have used IMR-4350 with good results in a .243 Handi Rifle, but I was using just the CCI 200 large rifle primers.
 
Magnum primers aren't needed for IMR-4350 in the .243 Winchester. I use either Winchester Large Rifle or Federal Gold Metal Match primers in my .243 loads. Either one works fine even below freezing temperatures. Can you use Mag primers if you have a large stock and want to use them "just because"? Sure, begin with the starting load and work up as you normally would. Problem is the magnum primer "may" make pressure, velocity, and accuracy a little inconsistent versus the standard primer. A chronograph will tell you that information.
 
Actually, I think he meant 65-70 grain bullets, and if there's any experience with 4350 and the lighter bullets.

I do not, but I do use mag primers for most of my .243 loading. If I were you, I'd use them, but you need to work up the load again to make sure it's safe.
 
Back
Top