My two little helpers, Landen and KB showing Daddy which 243 WSSM 95g Nosler Partition three shot group is the best. The only difference in the three loads is different seating depths of the bullet and the firing order.
I have been working on a 95g Nosler Partition load for my 243 WSSM A-Bolt Stainless Varmint Laminate for the past couple of months. After some tweaks with the COAL I am finally satisfied with the load and its accuracy.
I started working on loads based around Accurate MagPro powder. I soon found that I had to back off the amount of powder that the case could hold by a considerable amount to keep my bolt from being stiff when I open the bolt. MagPro is my bread and butter when it comes to powder but for this load I needed something with an even slower burn rate.
Once again I am finding that at least in my 243 WSSM rifles the powder burn rates of the powders, that are recommended in the powder and bullet manufacturer's load data are often too fast to get full case capacity without excessive pressures. Maybe it's a superstition but I like my handloads to have charges of powder that fill the case enough to the point that they are compressed or at least I can't hear any powder rattling around if I shake a cartridge next to my ear. I believe that I get better accuracy and speed with a powder that has the right burning speed to give me a full case of powder.
243 WSSM 95g Nosler Partition Three Shot Group with Hodgdon Retumbo Powder.
For this bullet Hodgdon's Retumbo was my ticket and believe it or not, it's not quite slow enough to give a compressed load as I figured I would be able to do. There aren't many powders much slower than Retumbo (you can see powder burn rates on reloadingbench.com)... maybe 50 BMG powder is the ticket. ;)
During this couple month process of loading up a few rounds to shoot each week I broke the decapping shaft when it decided not to go down the center of the cartridge. Not sure why that happened? The new tapered expander's diameter on the shaft is 0.243 inches and the old one was 0.242 inches. So far the point of impact has been the same with the one load I shot before and after the change but the chronograph is now saying 3165 fps compared to 3250 fps. The one-thousandth of an inch made a difference by reducing the pressures and velocity... I could probably move back up a grain of powder but the load is shooting just fine for me right now so I'll leave it alone.
The load I am going with I was hoping for a one-hole group and ended up with a half-inch group. The three shots were the fourth, fifth and sixth in a string of nine shots. Shots four and five make a single hole with the sixth shot flying a little high. I could probably get a little better accuracy if I played a little more with the COL but I feel really good about this load being sub MOA which is plenty good enough for me to hit anything I plan on shooting.
- You can view this 243 WSSM 95g Nosler Partition handload on the handload page: 243 WSSM Handloads