H4831SC to H4831

Would substituting H4831SC for H4831 be beneficial to get a better case fill? Better case fill helps with consistency. Just a thought since my case is only filled 90% with H4831SC. H4831 will fill it more close to 100% for the 6.5 x 284

Not necessarily. The sc packs tighter or more consistent the regular will not be as even but a drop tube would help.

I would say that if you've got room left over using the SC version, and you want a fuller case, the regular H4831 will fill the case a little better.

The non SC does take up more room in the case. So it would increase your case fill with the same powder charge. But, you are changing powders and lots, so you will need to start over on the load. If you have a working load with the SC, just run it. It will work fine. 90% case fill is fine.

If you are running your 6.5x284 on a short action, the 4831 SC is a good powder. If you are running it on a long action, I would switch to a much slower burning powder to get your speeds up. I never was able to get any speed out of a 6.5x284 with 4831, but it did shoot good.

Asking out of ignorance - how does the short vs. long action have an impact on this?

The 6.5x284 was originally made as a short action round (308 Win, 243 Win, 260 Rem length). It's a short, fat case, with a rebated rim (308 Win case head). When you want to shoot the heavy, high BC bullets, like a 140 grain Berger VLD or Hybrid, the bullet is seated very deep in the case for it to feed out of a short action magazine. That's about at 2.800" to 2.860" in COAL loaded length. Loaded as a short action caliber and the 140 bullets seated deep, you impede on the available powder volume, and can not get a lot of powder in the case. Loaded like this, you may get 48 to 50 grains of 4831SC in the case. Speeds will run about 2800 to 2850, 2900 if you are lucky. There have been numerous shooters upset after buying a short action 6.5x284 rifle because they "read on the internet" that they can push a 140 grain 2950+ fps. You can not get this in a short action due to the reduced case volume capacity and the bullet seated deep in a short action. I had one customer really up set about this when all I could get was 2850 fps at max pressure, and the accuracy node shot best at ~2820 fps. He said he might as well shoot a 260 Rem, and I agreed. I have tried with multiple 6.5x284 rifles built on a short action to hot rod it to get the speeds up, and none of them went faster than 2850 fps. (You can get them faster than this with a double base ball powder, but then you run into the temp sensitivity issues, which I won't mess with).

To make the 6.5x284 shine and get the higher speeds, a lot of shooters build this round on a long action and chamber the rifle with a long throat. This allows you to seat the bullet out long around 3.200" to 3.400". This gets the 140 grain bullet out of the case more, and increases your case volume significantly. You can now run a stiff load of H1000 or Retumbo (about 56-59 grains) and get the speeds up to around 2950 or more. With a longer barrel, I've seen 3000+ fps, which is a freakin' awesome round to shoot.

My 6.5 x 284 is a 9 twist with a 27 inch Shilen Match barrel, so I won't be able to stabilize the 140's, but currently using the 123 Sierras Match, last experiment I was pushing barely 3100 fps with 53.5 grains H4831SC but was shooting nicely with 50.2 grains but its slow.

Do you think it will stabilize the 130 Hybrids if I were to switch? Does pushing it faster help in spin to stabilize? This Rem 700 action came off a 6 mm that I bought from an old friend. It's a short throat with 3.340 with a comparator. I can probably try a drop tube to see how much powder I can squeeze out of a Retumbo.

Chad, I am running a 140 Hybrid at about 2975 with H4831SC out of my long action 6.5-284 with a 26" 8 twist Bartlein. I have clocked speeds over 3000 with this combo but backed off a little because of pressure signs. I tried Retumbo, but the loads were really compressed before I got the speeds I wanted.

How much powder are you using?

A 1:9" twist will stabilize a 140 VLD. If you look at the Berger calculator (link below), it will stabilize just fine with a 1.3 stability factor (SF). The 130 VLD/Hybrid will also stabilize with a 1.43 SF. I'd lean to the 130 VLD, but if you want to run the 140, it will work. Yes, pushing it faster allows more RPM's, which increase stability some. Drop tubes work well to cram more powder in a case. You will need to be able to seat the bullet out LONG to run Retumbo. Is your rifle a short or long action? and do you know what your seating depth is where the bullet touches the lands on a 130 or 140 Berger?

http://www.bergerbullets.com/twist-rate-calculator/

Yes, you can get the higher speeds in the long action with most powders, including 4831 with a longer barrel. Retumbo has shown to get more speed than 4831 in the long action rifles I've played with, and they shot very well, also. The key is the long action and seating the bullet out far.

Thanks; that makes sense

The rifle used to be a 6mm, so its a short action? I checked the 130 VLD OAL with a comparator and it measures 3.415. I measured the action from the front to the back without the bolt and it measures 6 and 1/4 inches and with the bolt its 7 and 1/4 inches.

6mm what? If it was a 6mm Rem, then yes, it should be a short action. What's the COAL from base to bullet tip where it hits the lands?

With the dial caliper alone without a comparator its 3.117. and yes its a 6mm Rem

3.117" won't fit in the magazine, will it? If not, what is your max mag length?

Forgot to add that its a single shot, no magazine. It's actually a benchrest rifle.

Oh, well there you go. Seat the bullet as long as you can where it just touches the rifling (you don't feel tension when chambering the round when closing the bolt, but the rifling may leave slight rifling marks on the bullet). Make sure it doesn't jam into the rifling (I'm not a fan of this method). With the bullet seated out long, you can increase your max powder charge by a few grains. This will help get your speeds up and increase your case fill.

Thanks Chad, side note, how much powder of H4831 SC is max? If you know. I'll try H4831Sc and H4350 and see how they both work.

thanks Chad for the twist rate calculator tip, I use a black marker on the bullet to see when its touching the lands.

It depends on which bullet you are shooting. I'd use the reloading manuals and bullet mfg reloading data for more exact data. But you should be a grain or two over their max if you seat the bullet out far, like stated. The main thing is finding max pressure for YOUR set up, and know not where to go over.

Yes, the black Sharpie works well.

Manuals have different data, but I know that I need to work up till pressure and back off. I was just asking if you had a number to throw. Thanks Chad

Stan, I use 51.5 gr of H4831SC in a Cooper which is a long action 1:9 24 inch barrel, for a real nice accuracy load in my rifle. COAL 3.18 @ 52.5 I started getting pressure signs but accuracy is fantastic at the 51.5 in my rifle.