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View Full Version : H-4350 vs H4831 SC for 6.5x284



JasonYuke
12-31-2008, 04:51 PM
My load development has been completed for my F-class rifle with SMK 142s, I have developed 2 loads well, that shoot close but H4350 wins out over H4831 SC, not by much but it shoots .3s-4s vs .5s-.6s.
A good shooter gave me some advice because of the different burn rates I would be better to go with H-4831SC due to throat errosion life.

How much quicker will 4350 bugger a throat vs 4831.. I am not sure I see a reason why it would, but I woudl like to know if someone could give me the skinny on throat errosion issues with the 6.5x284, how to prevent, or slow down and how to clean the throat and not the whoel barrel.

My 2 F-class barrels, and guns are new -100 rounds on one and 5 round on the second, and would love to start out on the right foot! I just shot 5 to confirm the load of the first and bingo!!!


I am used to 6 ppc rifles, and this is my first target barrel burner.

Any advice Please!

JasonYuke
12-31-2008, 05:00 PM
I guess this is more than just one question!

Sorry...

LarryBartholome
12-31-2008, 05:38 PM
In F-Class elevation is the name of the game. The 10 ring, much less the X ring are quite small. The smaller your groups are the better your score is likely to be. If you want long barrel life shoot a smaller case. “3s-4s vs .5s-.6s” is a no brainer, use the H-4350. With a 0.6 moa group you only have 0.2 moa from the edge of your perfectly centered group to the 9 ring. Any wind or elevation change at all and you lose a point. A 0.4 moa group gives you another 1” on either side at 1k. A 0.3 moa gives you another ˝”. FWIW most of my US Team mates use H-4350. I can’t answer your erosion question. I found the same thing you did with the two powders and haven’t shot out a barrel. I take them off before they are shot out.

milanuk
01-01-2009, 04:36 PM
Larry,

Thanks for your input... very interesting, BTW. I have a 12 F-Class rifle in 6.5-284 that I tinker with every now and again. Originally had it shooting w/ H4350, then had some scope issues, then starting fussing around w/ H4831SC because of some similar warnings about H4350 cooking the throat early. At this point, I think I just wasted a small chunk of my useful barrel life trying to get it to shoot as good w/ H4831SC as it was with H4350, and I've pretty much decided that H4350 is what I'm going to stick with for now.

Monte

TonyR
01-04-2009, 08:41 AM
I have wondered about these sorts of things as well and I have found a spreadsheet program on one of the Forums, either here or 6mmBR, that sheds some light on the trade-off. If you do a search on "ACCURATE BARREL LIFE", it will probably turn up.

Anyway, you put in Bullet diameter, Loaded Grains of Powder, Powder Heat Potential, Pressure, and Yes/No for Moly, and it gives back expected accurate barrel life. I guess those are the key factors.

So, after finding max loads for H4350 and H4831SC in QuickLoad, the inputs are;

H4350

Bullet Dia .264
Powder 50.9grains
Powder Heat Potential 3990
Pressure 59200
No Moly
Total 1479 accurate barrel life


H4831SC

Bullet Dia .264
Powder 55.2grains
Powder Heat Potential 3870
Pressure 59341
No Moly
Total 1434 accurate barrel life


Since these numbers are pretty consistent with what I have been seeing in my 6.5, I find this formula useful at least for planning and comparisons.

The estimated barrel life is so close for both powders that I would say there is no significant difference. There just seems to be a trade-off of a hotter burning powder offset by fewer grains for about the same barrel life at max pressure.

However, my gun gives me the best accuracy well below max pressure. 51.6 grains of H4831SC is giving me about 2975 fps with 139gr Scenars just touching the lands, and that seems to be the sweet spot for my gun. The formula says I should get accuate barrel life close to 1700 rounds with that load.

Bob Raymond
01-04-2009, 03:07 PM
Thanks for that Tony, very interesting.

Jason and I had talked about this as we both shoot the 6.5 x 284.

The 4350 has also been my experience that it is a little more accurate at 100 by .1, which on a 1/2 MOA at 1000 is huge.

Thanks again for the info.

david dumas
01-12-2009, 05:42 PM
my 6.5 x 284 kinda likes Hodgdon Retumbo too,,,,,,,,,,,,,,,,,,(140MatchKings or berger 140VLD's)

the wind is my friend,,,,,,,,,,,

DD

dubya
01-13-2009, 04:10 PM
I have wondered about these sorts of things as well and I have found a spreadsheet program on one of the Forums, either here or 6mmBR, that sheds some light on the trade-off. If you do a search on "ACCURATE BARREL LIFE", it will probably turn up.

Anyway, you put in Bullet diameter, Loaded Grains of Powder, Powder Heat Potential, Pressure, and Yes/No for Moly, and it gives back expected accurate barrel life. I guess those are the key factors.

So, after finding max loads for H4350 and H4831SC in QuickLoad, the inputs are;

H4350

Bullet Dia .264
Powder 50.9grains
Powder Heat Potential 3990
Pressure 59200
No Moly
Total 1479 accurate barrel life


H4831SC

Bullet Dia .264
Powder 55.2grains
Powder Heat Potential 3870
Pressure 59341
No Moly
Total 1434 accurate barrel life


Since these numbers are pretty consistent with what I have been seeing in my 6.5, I find this formula useful at least for planning and comparisons.

The estimated barrel life is so close for both powders that I would say there is no significant difference. There just seems to be a trade-off of a hotter burning powder offset by fewer grains for about the same barrel life at max pressure.

However, my gun gives me the best accuracy well below max pressure. 51.6 grains of H4831SC is giving me about 2975 fps with 139gr Scenars just touching the lands, and that seems to be the sweet spot for my gun. The formula says I should get accuate barrel life close to 1700 rounds with that load.

Seems to me that those loads are a little hot! What was FPS on those?
Most, including myself run around 48.0 to 49.0 w/H4350 and 51.0 to 52.0 on
H4831sc.
Gary.

TonyR
01-13-2009, 08:34 PM
Hi Gary.
Those loads are probably on the hot side. My accuracy load with H4831SC is 51.6gr which keeps me in the 2950 to 3000fps range depending on the day. The loads I used for the comparison above are just estimates that QuickLoad gives at maximum CIP pressure. Jason's question was about throat erosion, and I was trying to illustrate the use of a formula and show a comparison under a worst case of heat and pressure. I was not recommending those loads to Jason, Bob or anyone else, but thanks for bringing it up if I didn't make that point clearly enough.
Tony

JasonYuke
01-14-2009, 08:14 AM
That is great info Tony, my gun loves H 4350 right at 48.0 and shoots amazing with it.

TonyR
01-14-2009, 09:00 AM
Hi Jason
I ran the 48.0gr of H4350 you are using through QuickLoad and the Barrel Life Formula using my seating depth for the Lapua 139gr Scenar. QuickLoad estimates the velocity at 2965fps from a 31 inch barrel at 50458psi peak pressure (CIP Max is 59465psi per QuickLoad) and the barrel life formula estimates 1963 rounds which is on the long end of what people seem to be expecting from match barrels. Estimating in QuickLoad with H4831SC for the same muzzle velocity gives 1896 rounds. Again, probably a toss-up for barrel life given the lack of precision of a formula like this. For what it's worth, I bought my gun used from a friend right after it was rebarreled. He had used H4350 and told me to expect about 1500 rounds. Of course, most of the top shooters seem to recommend changing the barrel conservatively so that one doesn't go bad in an important match. I haven't asked him, but he probably took it off before it stopped shooting well. In any event, the 6.5x284 seems to burn out barrels a lot faster than my other gun which is a 6mm BR. I do a lot of experimenting with that gun, but I decided to stay with the first good load I found for the 6.5x284 because I couldn't see the point of burning out a barrel trying to find something a little better.
Hope this helps.
Tony

michaelb
01-14-2009, 01:07 PM
Just as David Dumas mentions with Retumbo, don't overlook the really slow overbore powders.

I fill up the case with vvn-170. RL25 works too, as with any rifle no two are alike and you find what works.

Much of the Williamsport crew run H4350 in 6.5/284, If memory is right I believe around 48 gr. I never went after the faster powders only because I prefer to fill the brass as much as possible.

Bob Raymond
01-17-2009, 04:04 PM
Hi Gary.
Those loads are probably on the hot side. My accuracy load with H4831SC is 51.6gr which keeps me in the 2950 to 3000fps range depending on the day. The loads I used for the comparison above are just estimates that QuickLoad gives at maximum CIP pressure. Jason's question was about throat erosion, and I was trying to illustrate the use of a formula and show a comparison under a worst case of heat and pressure. I was not recommending those loads to Jason, Bob or anyone else, but thanks for bringing it up if I didn't make that point clearly enough.
Tony

Thanks Tony, Jason and I got it. We run similar loads to the rest of the folks here that have posted.