The neighbor is using my loading setup to find a good load for his 243. It’s a Savage Model 10. The projectiles are 100 gr Nosler Partitions. So far, Varget isn’t showing us much, though we’ll raise the loads a bit in the morning. He’s using my powders and will replace what he uses, so the other on-hand options in a reasonable burn range are R17, H4831sc, IMR 4064, IMR 3031.

Suggestions? I don’t have a 243, so I have no load history with the caliber.

IMR 4831 worked well with the 100 Partition when I was loading for .243 during the Obama shortages and H4831 was nowhere to be found. So might be worth trying the H4831. The sweet spot was around 2950 fps or a slight bit higher. That was with an early R700 with 1:9.5” twist and 24” barrel.

I had good luck with 4350 in 243. Would definitely give the 4831 a go.

With that bullet and powders I would be trying H4831sc. R17 might be good also but I have not used it. Looked at a box here from days gone by that used H4831 with 100gr partition and 42gr that shot well out of my old Remington Mohawk

Just looked at Nosler data and they show RL17 to be the most accurate powder and at max listed load. Probably worth a try working up to it. https://load-data.nosler.com/load-data/243-winchester/

H4831 will be tried in the morning. Thanks.

4350 is the go to with 100 grain bullets. I'd try the RL17 and see whether your rifle likes it.

I'm a long-time fan of IMR 4350, but 4831 is also good for this bullet weight in a .243; 3031 may be a bit fast for good velocity.

Don't know if you have any on hand, but I got great accuracy with both 100 grain Partitions and 100 grain Speer Grand Slams using IMR4320. I realize that it isn't one that is typically shown for the heavier bullets but it worked great in my Tikka before it was rebarreled and it still works very well in my Ruger American Pred. Speeds are right around 2850 for the load I am using.

H-4350

4831 should work great..... Partitions for me have been at best 1 MOA but have only tried them in a few calibers

40 grains of IMR 4350 shot really well in my savage 243 with partitions pro hunters and hornady btsp. All 100 grain.

R17/R19

IMR 4350 with 100 gr. soild base noslers is all I used in two .243's.

i use 4831 with 100g sierra gamekings and its deadly at 42.2. Get just over 2800fps and the accuracy is killer

Found the magic at 42 gr of H4831sc. Thanks to you guys for suggestions.

Congratulations. Almost exactly my load, which was 42.3

I prefer IMR4350 but use what works best in your rifle.

Don't over look Hybrid 100v. I'm using it and running 105 amax at 2980 out of a savage model 10.