magnum primers for .243

[tvc15]

   My speer manual suggests using magnum primers with the 100 grain bullet 4350 or 4831 powders. I also notice they back off the powder quite q bit compared to the other manuals who don't suggest magnum primers. Is the theory less powder and hotter primer=more powder and regular primer?

   Has anybody used the magnum primers with the hornady 100 btsp 4350 or 4831 combo?   TVC15

 

[Luckyducker]

I used to load the 100 grain bullets, I believe the Green Core-lokt and flat based hornady, with 40 grains IMR 4350 and a Winchester LRP standard rifle primer.  I tried some boattail bullets in it but it scattered them.  The best accuracy was with the Core-lokts.  I shot a five shot group at 100 yds  once that looked like one bullet passed through the target but couldn't repeat it.  I see no need for a magnum primer with the powders you mentioned, but if you were going to use a ball powder then mag primers would probably be beneficial. 

[jhalcott]

  I'd get a couple more manuals and compare their recipes. I've used both 4350 and 4831 with standard and mag primers in several calibers. It does make a difference in the accuracy I get with a 7-08 and .260 DEPENDING on the bullet. I'd try them both ways and go with the most accurate. I see Nosler and Sierra both use Rem 9 1/2's and Hornady uses Fed 210's. Most guys are reluctant to stray from the manuals. The first rule of reloading is SAFETY FIRST,THEN SAFETY AND FOLLOWED BY SAFETY.

[wncchester]

I've used both magnum and standard primers in my .243/100 gr loads with H-4831.   Didn't see any real difference between them but best accuracy occured at different charges.   I DID NOT swap the primers without dropping back and only moved up because no pressure problems showed.  Never try to follow a rule of thumb in reloading, you may get your thumb blown off.

[Siskiyou]

I have loaded a lot of H4831 into .243 Win., 270 Win., and 7MM Remington Magnum over the years, the only one that I use magnum primers with is the 7MM Remington Mag.

I use Winchester primers when loading ball powders, and again magnum primers for the 7MM Mag. when loading ball powders.  My “belief” is that Winchester loads it’s factory rounds with ball powder, and list their standard large rifle primer with most of their published loads, and therefore I match the primer to the powder.

I am happy with the paper accuracy of my loads, which exceed the paper accuracy of most factory ammunition I have purchased.  If I were loading for competition I would try the magnum primers and do a side-by-side comparison of the loads over the Chrony and on paper.

My experience when loading H4831 in the .270 Win. using standard primers and firing over the Chrony is that I am obtaining expected velocity.  In my pre-Chrony days I did load a couple hundred rounds using magnum primers and did not see any measurable difference on paper. 

I have used IMR4350, H414 (ball), WW785 (ball), and H4831 when loading the 243 Winchester.  This rife seems to be inherently accurate.  I used CCI200 standard large rifle primers with all loads except with H414.  I used Winchester Large Rifle primers with the H414.  If I was to load the cartridge again using WW785 I would switch to Winchester large rifle. 

The question that comes to mind is if a standard primer ignites 60-grains of H4831successfully in a large .270 case, should it not successfully ignite 45-grains of H4831 or 41-grains of IMR4350 in a medium .243 case?

When cleaning my rifles I find no indication of unburn powder on the patch.  Or another comparison is that my barrel is no dirtier with my standard primer loads then it is when firing factory ammunition.

[Dave in WV]

I'd recommend Winchester large rifle standard primers. They're hotter than most standard primers. Winchester didn't even make a magnum primer until a few years ago and used their standard primers in magnum ammo for many years.

[tvc15]

   I guess speer thinks a a magnum primer has a better chance to burn all the powder. I shot lots of reloads with the 4350 and had a some soot on the case and very dirty  barrell, maybe thats why.   I'll give it a try with a few rounds and watch very closely and see what gives.    TVC15

[huntswithdogs]

I've been using H4831 in my 243 for quite a while and use WLR primers. No problems here. I've used mag primers in it before ,but I'd backed off on the powder and worked my way back up. Accurracy has always been with the LR primers so that's what I stick with. I was loading H414 for a while but stayed with standard primers.


HWD

[steve4102]

I'd recommend Winchester large rifle standard primers. They're hotter than most standard primers. Winchester didn't even make a magnum primer until a few years ago and used their standard primers in magnum ammo for many years.