DOUBLE & SINGLE BASED POWDERS.

[paulT]

HI, Interested in other reloaders views with which powder choice between high energy double based and single based powers would offer best potentail for 243-308 for 600-1k shooting, I understand the high energy propellents are supposed to be more temp stable whielst offering higher velocitys with lower pressures but many f-class and bencrest shooters seem to prefer the single based powders with their hand loads, Could this be that the single based powders are more forgiving and easier to find a acurate load over the high energy powder, I have found great results with varget and vit n140 for my 308 but cant seem to get same repeatable results with n540-n550, also exellent results with n160 for 243 but not so good results with n560? anyone have experiance with handloads with both powder and able to share findings thanks.

 

[jlmurphy]

I have a 1/8 twist .243 Win and have shot both 107 and 115gr. match bullets at long range. I initially used Re 22 ( double based), but after extensive testing, I now use H 4831, less velocity, but better accuracy and more consistent velocity.

 

[paulT]

Have also found better results with n160 V n560 for my 1 in 8 twist 243 barrel, ES and SD was better with the single based n160 powder, now all i have to do is find a bushing size for correct neck tension with my 105g Lapua molly bullets, My Loaded round with Lapua brass measures 2.72 and i have been using a 2.70 bushing but some shooters feel better results with molly bullets might be gained with more neck tension? guess i will have to try 2.68-2.69 bushing.

 

[flatlander]

In every cartridge I've tried them in, Viht's high energy powders gave best results at the high end of the load spectrum. No question that N540 & N550 were excellent in 223 HP match loads, but look at what's happened to Viht's prices over the past few years since they've stopped packaging them in 2lb. jugs; they're flat too expensive to suit me. Besides, when was the last time Powder Valley had any of these powders in stock? Maybe some of the price increase can be attributed to the drop in value of the US dollar, but I smell price gouging on Viht's part.

 

[Rust]

For whatever reason, single base powders have generally produced more consistant accuracy and lower ES/SD numbers for me. And at long range accuracy and lower ES (for less vertical spread) matter. Extra velocity is meaningless if does not coincide with one of the barrels accuracy nodes with good ES/SD numbers.

 

[AckleymanII]

20% DNT in a powder comes at a cost, throat errosion.

 

[Laurie]

In every cartridge I've tried them in, Viht's high energy powders gave best results at the high end of the load spectrum. No question that N540 & N550 were excellent in 223 HP match loads, ................. flatlander

Denis,

that's our experience in the UK too. They give their best with full-house loadings. Viht N540 is the usual choice here for F/TR with 155s and it'll produce up to 3,100 fps from a 30" barrel with good accuracy and small ES spreads. Seeing how it's rarely really hot here, we don't worry overmuch about temperature effects.

Palma / Target Rifle (Fullbore to US shooters) prefer N140 or N150 as they don't load their cartridges up as much. Some people worry about barrel life, so won't touch double-base powders (although many don't know that all ball types are double-base, irrespective of make and grade).

On temperature, I've heard it said that DB powders are more sensitive ............... or less, depending on who is giving the opinion! One definite advantage of double-base powders is that they keep better in storage, especially in hot, humid environments, so don't degrade, or start to give different performance through changes in their moisture content.

In .308W, although N140 is the most popular powder for it in the UK by far, I've always tended to use N150 in preference for milder loads as I find it gives very good accuracy and often seems to be insensitive to powder charge variations, usable in a wide range of bullet weights from 155-190gn. For F/TR long-range high-velocity loads, I'll use N540 with 155s, and N550 with 185s and heavier.

Although Viht prices have risen a lot here too because of currency changes, US powders have risen even more, and are considerably dearer on a comparable price per lb basis, one reason why Viht powders are very popular.

Laurie,
York, England

 

[flatlander]

Laurie,
I experimented with several powders when I started shooting XC HP in 1998, starting with Ramshot TAC, progressing through N135/N140, Varget, & RL15 before settling on N540/N550 in the 223. I was pretty well satisfied with TAC, but was influenced to switch to single-base powders by the popular bias against double-base types.

Honestly, I feel that TAC is no more temp sensitive than RL15 or N540/N550 - perhaps even less so. Here in Kansas, we shoot in a wide range of temps, from the mid-30s in some of our spring matches,. to 100*F+ in mid-summer, so temp sensitivity is an issue. If I were still shooting 223 in AR15s, I'd probably go back to where I started and load TAC - it gave excellent accuracy & velocity across the course with 69-80gr. bullets.

Interesting that you Brits like N140 in the 308 - I had a Palma rifle built in 2000, and used TAC, N150, & Varget. I'm not getting the velocity with 155s that I'm after with current lots of N150 or TAC, so have used H4895 recently (just got home from the SW LR Nationals in Phoenix). May have to try N140 in the 308 this spring.

 

[Laurie]

Dennis,

as with many 'local' preferences, there is a bit of background to the popularity of N140 here and the pattern of its usage. We got N140 and N160 long before you did in the States, sometime back in the early 1980s - just those two powders though, then N110 for magnum revolvers a little later. For some years there were just those three - and they were very attractively priced. Before Vihtavuori's arrival, most people used home-manufactured ICI Nobel extruded single-base powders, available in three rifle grades if I remember, maybe four, plus four pistol/revolver grades. American powders - Hercules (as was), Hodgdon, Winchester, and IMR were easily obtained in pistol/revolver grades, but much less so in the rifle versions, and were more expensive than Viht or ICI, so their rifle use was pretty limited at that time. Norma powders were also available 20 odd years ago, but were very expensive.

People tried the new Viht powders, liked the small grain format (ICI was very like IMR with long sticks), got good accuracy and velocities, and the fouling seemed easier to remove. So they pretty quickly took the UK market over, which was rather small for rifles at that time. A pattern soon developed that said N140 for .308W and similar cartridges, N160 for .30-06, .243, magnums and like a lot of these things, it's stuck. When other grades appeared, a lot of our TR shooters, especially those who didn't shoot at very long ranges, never tried them. They were happy with N140 and didn't see any reason to change. Even now, many new handloaders or entrants into the sport, are told by the old hands that they should use 155gn Sierras above N140 working up from 44gn to whatever the rifle likes in the 45-46.5gn range. Because of all this, the importer orders a lot of it, and it's held in stock by every British gunshop that keeps rifle reloading gear and components. Add all these together, and you can see why it's so widely used, but I wouldn't say it's necessarily the best 308W powder, and certainly not for all applications in the cartridge.

F/TR is now throwing a lot of things back in the melting pot as there are no bullet weight restrictions here unlike Canada, Australia and New Zealand, and people are looking for a little edge weherever they can find one with 308W ballistics being marginal at 1,000yd, especially as our ranges are mostly low lying and temperatures stay lowish, so you really do need that 3,000 fps plus with a 155 to be sure every bullet is still supersonic at the target.

I've tried VarGet, the US rifleman's favourite with 155s and liked the accuracy, ES spreads and the wide range of charge weights that it does well with, but lost 70-100 fps compared to N540 with this bullet weight. N550 with these bullets peaks at 3,000 fps or just below too from a 30" barrel. Russell Simmonds our top F/TR shooter uses H4895 with the 155.5gn Berger having switched from the 155gn Scenar with VarGet for the 2009 season, but may try heavy bullets this year. His load gives him 3,071 fps, right on the ball for this game.

We had Ramshot powders here very briefly and I gave TAC a go in .308W and .223R, only ever acquiring one tin of it. I liked it, but found it spiked rather quickly in .308W with 155s, but like you had very good results in .223 Rem.

Laurie

 

[paulT]

Thanks for sharing views, some very interesting info there.