Originally Posted by Unclenick
It won't necessarily. In handgun cartridges it mainly depends on whether the space in the case can take the pressure of the extra gas made by a magnum primer without it unseating the bullet before the powder burn gets underway. Sometimes, when there is a lot of empty space in the case and the magnum primers are not unseating the bullets, they are actually better for accuracy by increasing start pressure. That's explained in the article I linked to in my earlier post.
Also, don't just change to a different primer without knocking the charge weight down another 5% and working back up. Ironically, under some circumstances a standard primer can cause higher pressure than a magnum primer does. This is mainly when the magnum primer is unseating the bullet but the standard one is not, so the powder fired by the standard primer starts building pressure in a smaller space.
Ok, well in this case scenario, there is alot of available space. The projectile is quite large though, thats the main reason why I use Titegroup, because it takes up minimal space in the casing and I know there is a nice gap between powder and projectile. Thats not why I chose the primer though, I just had 100 laying around that I bought awhile ago and figured Id make a load using them and if they work out, Ill stick with them. So far they have not shown any signs of affecting accuracy at all but the charge seemed to clearly be on the high side. So, the current charge is toned down 10 & 5 percent respectively. I havent had any range time yet though and probably wont until Sunday or Monday though because I gotta work, but ill keep you posted and im curious what develops and what you have to say.. Thank You.