Home Forums Reloading Big Game Rifles 243 100 Grain and 4064 Powder

I've been working up some loads for a 243 I've finally got around to shooting, and since it's going to be primarily a deer rifle, I'm trying various loads mostly with 90 and 95 BT's, but also with home 100 grain SP's I have.

I've got several different manual's, mostly out of date, and many pages of data I've printed off Hogdon's site, along with a number of others. One site gave a load of 40.5 grains of IMR 4064 with a 100 grain bullet. According to every thing else I have, that's 4 grains over the listed max.

I'm not going to try the load obviously, but curious as to any experience any others may have had with 4064 and 100 grain SP's, along any data you'd like to share.

I have also use H4350, H4895, H4831, even 3031 with good results

40.5g is going to be a serious hot load and I would not fire that kind of load.

41.0g of either 4350 will be a great load, start at 40.0 and work up in three shot groups, keep the copper out of the barrel, kiss the lands if you can.

My go to powder in that caliber and bullet weight is H4831. YMMV

My go-to load in a 243, and it's worked fantastic in the 5 that I've had and reloaded for, is a Sierra 85 grain HPBT bullet, and 45 grains of W760 powder. It will shoot sub MOA any day, all day long. I've killed a bunch of coyotes, and a few deer with it, but I prefer a better bullet for deer. so that's why I've been trying the BT's and the 100 grain SP's.

I shot the rifle today, and I'm going to toss the 100 grainers, as they don't shoot good in it, and go with the 90 grain Noslers BT's with 760 powder. I worked that load up for another 243, and it shoots good in the new one. The new rifle, a M7 Predator, also shoots the 85 Sierras sub MOA at 100 yards.

My original post here was to hopefully figure out where in the devil that 40.5 grain load for a 100 grain bullet came from, as I know it's way over max. I'm guessing I got it from some "expert" reloader's internet data.

As far as powders go, a lot of them will work well in a 243, and I've used a number, but always seem to come back to two.....W760 and IMR4350, although I have used 4064 to work up some loads for a Youth rifle.

I've ran 38 grains of 4064 with a 100 grainer in the 243 for as long as I have been reloading for it....

I run a lot of 4064 in the 243 from 65 grain V Maxes, up to the 100 grain Sierras and Hornadys..

most of it I got off of the old IMR Brown Load Data Pamphlets, which are who knows how old nowadays...

its always worked for me.... IMR 4895 and 3031 are two more good powders for the 243s...

37-38 grains of 4064

We used to shoot 39 grains of IMR-4064 with 100 grain Sierra Gamekings. Always shot fantastic for us.

There are other powders that will give more velocity and maybe more accuracy but it will work fine.

4064 is a hard powder to beat in a wide range of cartridges. I have used it in 223, 22-250, 220 Swift, 243, 25-06, 270 and 30-06.

I found my .243 shot the 100 gr Sierra Pro hunter, flat base bullets with a modest jump to lands better than boat tails

[ The new rifle, a M7 Predator, also shoots the 85 Sierras sub MOA at 100 yards.

No hijack, but does the Predator have a long throat or a "normal" throat? And does that camo dip film really protect the metal?

I had a MK II Ruger in 270 that shot more of a pattern with a boattail bullet but was a 1/2" gun with flatbased bullets.

My 6mm BDL shoots okay with boattails but shines with a flat based bullet. Actually shoots Partitions better than any boattail I have tried.

I’ve always used IMR 4350 in the 243 with Bullets heavier than 85 grains. I also found you could substitute H 414 for 4350.
H 414 being the same as 760. Hasbeen

Haven't measured this one, but I'm going to say normal, based on what limited seating I've tried so far.

I bought one of the first Predators that came out in 223, and the finish on the metal still looks great after 10 years or there about. The finish on the stock however has rubbed off where I carried it slung over my shoulder, and it rubbed on that side. I have them in 223, 22-250, and 243.

My m7 Predator won’t shoot the 105 hpbt or the 105 amax. With 100gr and down it’s been very accurate.

100 Sierra
95 nbt
87 vmax
87 hpbt
80 gmx
80 ttsx
Several different 80 sp
70 Sierra


The 87 vmax, 95 Nosler and 80 Barnes get the most work. I use 4350 for all of them.

re- 26 is best now for 100 grainers . Imr 4064 will work especially with 85 sierra bthp.

I am using R26 and the 95BT and it has been excellent. Once you use up your current powders I would go to R23, R16, 4451 or some of the newer temperature stable powders. I would also see which ones seem to be more consistently available and/or buy in larger lots. I am not sure if I would call the 243 an inherently accurate cartridge but it has been very easy for me to find a good load. I think this is partly due to popularity and the abundance of good published loads.