.243 Winchester loads using RCBS 243-095-SP mold

[hockeynick39]

I have heard that the @43 Winchester is a finicky feller with cast bullets. I am finding that to be true even though I shot 15 loads of my first run of tests. The best group I mustered was 1 1/2" using 23.5 gr H4895 with Dacron filler @ 2.600" COAL. I know the 243 Win likes to be pushed with jacketed and this may be part of the problem with shooting it in cast. I may try a string up and one down to see where we get with it. I am using heat treated wws, that drop at 245 and 101 gr (425F in a convection oven for 1hour), and have measured them up to 25 BHN on my Crabtree tester, so pushing them a little faster won't be much of an issue. Bore slugged around .2425" and I am sizing on Lyman 4500 using a 244 sizer. If anyone can make any suggestions as to a decent load or what they have found to work in their rifles, I am all ears at this point. Thank you.

[GabbyM]

Personally never achieved high velocity loads with anything like accuracy from my 243. My rifle is a 26” barrel varmint rig with an Ackley Improved chamber. With .245” boolits I turn necks to qualify any old fattened necks for a .002” release clearance. Have a Lyman #245496 in 84 grain and Saeco 87 grain. Also a NOE Egan style 85gr I’ve not shot as yet. What I ended up with is settling for around 1,850 fps. Run it over 11.0 grains of Unique so it burns clean and doesn’t heat the barrel up. Sub MOA at 100 yards very consistent and good for 200 yard paper shooting on a clam day. Load makes enough pressure to seal case neck for a clean gun. My 270 Win is another caliber where I just gave up on high velocity and settle for an accurate load with shotgun powder at under 1,900 fps. I run my 222 Rem at over 2,400 fps and never had to work at it.

I had loads using Rx7 that would yield single digit SD over a Chrony. But would not stay on paper at 200 yards. Velocity is recorded in my book as 2,040 fps. One inch groups with occasional fliers at 100 yards but they failed to stay on printer paper at 200 yards. That was 17.2 grains Rx7 with no filler. Oven Heat treated 2:6 alloy at around BHN #20. If your stated 1 ½” groups are consistent ten shot strings then you already exceeded my go fast efforts. So congrats on that.

That 100 gain bullet may do well over something like 2400 powder. At any rate I’ll guess you could get excellent accuracy with a shotgun powder load at 1,700 to 1,800 fps. I enjoy them a lot. Ten shot strings don’t even overheat the barrel and ammo disappears fast. This barrel should last a very long time with the cool load.

This winter I plan to cast up a batch of the Egan bullets from a copper enhanced alloy then try them over some AA 5744.

[MT Gianni]

Run a search then try that RCBS boolit over 2400, start at 11.5 gr and work up to 13 or when accuracy says I'm done.

[rhill]

I am shooting Lyman 245496 also. 15.5gr. of IMR4227 shows some promise, I still have a few tricks to try to hopefully improve this load.

[Maven]

I am shooting Lyman 245496 also. 15.5gr. of IMR4227 shows some promise, I still have a few tricks to try to hopefully improve this load.


Also try 14 - 15 gr. IMR 4198 or 13 - 14 gr. AA 5744 with Ly. 245496.

[rhill]

Thanks for the suggestion Maven, but I have tried 4198, its a no-go in my rifle, I was hoping for good results as I have a few pounds of it to use up.

[quilbilly]

11 gr. of Unique are exceedingly accurate in my wife's Mossberg 243 and an 89 gr. CB

[str8shot426]

I have good 50 yard accuracy with 11 gr. Of imr 7625. H&R handi rifle.