Wanted some input from anyone running this stuff. I switched my 308 over since I shoot 185 juggernauts out of a 22" barrel. I was wanting a temp stable powder with some velocity. I have a range right outside my loading room window. At 68° inside I loaded 5 at a charge weight and tested with Magnetospeed 2. Avg was 2735 with an SD of 6. Now it's 26° outside and same load, brass, lot, ect is registering 2689 and SD of 15. Still put down a 3/4" @ 200 yds. Any input?
Viht N540 and stability
- Thread starter Dshooter
- Start date
I have used it in a 6mmBR, 6 Dasher and a 6.5 x 47L. It is a phenomenally accurate powder. However, there are 2 BIG drawbacks. 1.) it IS a bit temp sensitive. You will need a cold weather and a warm weather load. and 2.) it WILL eat your throat up like candy! The heat explosion number shows it to be THEE hottest powder made. The 6 Dasher I had loved it. BUT I only got 1600 or so rounds out of it and the barrel was toast. It is a GREAT powder for accuracy and speed>>>however, it has it's limitations like any thing else..
Since you have experience with it, I'll take your word for it. I did see it had the highest expl number. Someone else fairly knowledgeable said it also had some other kind of coating to prevent premature throat errosion....i don't know. It has the best velocity of all the powders I've tested, and efficient too. Did it with less powder. Does it have a sharp node curve or is it somewhat forgiving; I've only tested 3 charge weights and only being .3 gr apart, 2 of them were crap and one seemed to be pretty good as referenced above.
If you read about their powders in their literature, you will see that they impregnate their N"5" series powders with some additive that is supposed to inhibit throat erosion. Well let me tell you, they need to add A LOT more of it! LOL!! There is NO PROBLEM with the powder if you have a warm weather and a cold weather load.. If they could do what Alliant did and make it more temp stable, I would use it regardless of how it eats up throats>>it's that good. However, combine those two "properties" and it does not make for a good competitive powder.
When the FTR sub-class was introduced (2008? 2009?) and nearly everybody here (the UK) shot 155s in standard Norma and Lapua 308 Brass pre 'Palma' case times, N540 was the powder of choice for UK competitors. 3,100 fps was available from a 30-inch barrel with the 155gn Lapua Scenar, the most widely used bullet initially before Berger's 155.5gn and 185gn BTs (Fullbore and Juggernaut) arrived on the scene.
Barrel life was BAD! Less than 1,500 and in some case only 1,100-1,200 rounds where people had somehow pushed loads to give over 3,100 fps. We stopped using N540 VERY quickly indeed. H4895 and H. VarGet were found to give almost as good MVs with the lighter bullets and N150 is the norm here for 185s - but with rather better barrel lives. (They can still be low by 308 Win standards given the soft steel in custom made barrels - 2,500 rounds isn't unusual for the 185gn Juggernaut / N150 combination in Palma brass and running at the loads and pressures needed to get 2,825-2,850 fps from a 30-incher.)
Remember too that UK Effers don't string shoot (we shoot two or even three on the mound shooting alternately) and summer ambient temperatures are well below those of North America, so our barrels don't run as hot as those of US competitors'.
There is evidence though that running the N500 series powders at 'sensible' loads and pressures doesn't produce ruinous effects. Steve Donaldson, one of our top FTR shooters, has loaded the 210gn Berger BT Long-Range over Viht N550 for as long as I've known him, first in LRP Lapua brass then in the 'Palma' variety from its introduction. He sees 3,500 rounds + barrel life from loadings that give ~2,700 fps in a 32-inch barrel. He also entered every single match in the 2013 US F-Class Nationals / F-Class Worlds at Raton four years ago when temperatures were high especially in week one and the rifle was used by other team members alongside himself in the teams matches. (Can't remember the team name now - it was one of the four-shooter 'Rutland' teams sponsored and managed by 'Biff' Conlon, a joint US/UK effort, Biff being American.) Steve told me he didn't have to reduce his UK load despite a 30-degree ambient temperature rise.)
Barrel life was BAD! Less than 1,500 and in some case only 1,100-1,200 rounds where people had somehow pushed loads to give over 3,100 fps. We stopped using N540 VERY quickly indeed. H4895 and H. VarGet were found to give almost as good MVs with the lighter bullets and N150 is the norm here for 185s - but with rather better barrel lives. (They can still be low by 308 Win standards given the soft steel in custom made barrels - 2,500 rounds isn't unusual for the 185gn Juggernaut / N150 combination in Palma brass and running at the loads and pressures needed to get 2,825-2,850 fps from a 30-incher.)
Remember too that UK Effers don't string shoot (we shoot two or even three on the mound shooting alternately) and summer ambient temperatures are well below those of North America, so our barrels don't run as hot as those of US competitors'.
There is evidence though that running the N500 series powders at 'sensible' loads and pressures doesn't produce ruinous effects. Steve Donaldson, one of our top FTR shooters, has loaded the 210gn Berger BT Long-Range over Viht N550 for as long as I've known him, first in LRP Lapua brass then in the 'Palma' variety from its introduction. He sees 3,500 rounds + barrel life from loadings that give ~2,700 fps in a 32-inch barrel. He also entered every single match in the 2013 US F-Class Nationals / F-Class Worlds at Raton four years ago when temperatures were high especially in week one and the rifle was used by other team members alongside himself in the teams matches. (Can't remember the team name now - it was one of the four-shooter 'Rutland' teams sponsored and managed by 'Biff' Conlon, a joint US/UK effort, Biff being American.) Steve told me he didn't have to reduce his UK load despite a 30-degree ambient temperature rise.)
Laurie, Thank you for your vast wealth of knowledge and sharing your experience. This is why I come to Accurate shooter and have always trusted most of the opinions people here have given me.
The rifle is only a 22" CBI barrel. I was torn between running a slightly faster power given barrel length, and a slower powder due to bullet choice(all baselined/in comparison to Varget). I have tried so many powders; 4166, PP2000, CFE223, RL17, Barger, and probably one or 2 more on my shelf. In the summer(70-85° here) I have great results from several. In the late fall and winter, it goes south, quick(25-40° here). Coming up with a cold weather load I have found to be rather difficult as well. Not only significant velocity loss but SDs well into the teens from single digit. I have tried a lot of different loads and techniques as well. I finally dug into Viht powders and found what I have and the 550 as well.
My only concern is, is N550 too slow for a short barrel? If I was running my 26" barrel or longer, I wouldn't hesitate. I can certainly pick up a pound and give it a whirl....
The rifle is only a 22" CBI barrel. I was torn between running a slightly faster power given barrel length, and a slower powder due to bullet choice(all baselined/in comparison to Varget). I have tried so many powders; 4166, PP2000, CFE223, RL17, Barger, and probably one or 2 more on my shelf. In the summer(70-85° here) I have great results from several. In the late fall and winter, it goes south, quick(25-40° here). Coming up with a cold weather load I have found to be rather difficult as well. Not only significant velocity loss but SDs well into the teens from single digit. I have tried a lot of different loads and techniques as well. I finally dug into Viht powders and found what I have and the 550 as well.
My only concern is, is N550 too slow for a short barrel? If I was running my 26" barrel or longer, I wouldn't hesitate. I can certainly pick up a pound and give it a whirl....
The cold weather deterioration is likely down to 'Palma' brass and the combination of SR primers and the smaller 1.5mm flash-hole diameter. This brass and ignition combination is cold weather affected and becomes powder grade sensitive at somewhere around freezing point. When the 'Palma' case first appeared I did tests in around 3-deg C to see if they still worked at that level. (It is rare for us to see daytime temperatures below that in England given a general warming up of our winters over the last 25 or so years.)
I found that with four or five powders tried all bar one appeared largely unaffected, the exception being Viht N140. There were no apparent misfires or hangfires, but 100 yard groups were poor and ES/SD worse than those from conventional LRP brass 'control loads'. Retesting the Palma brass version some weeks later in the spring at 10-12-deg C saw normal performance restored.
Interestingly, given the conventional view that ball powders are harder to ignite especially in cold conditions, I made up two batches involving heavy bullets and Hodgdon H414 expecting much reduced average MVs and increased ES values. To my surprise, the 'Palma' variety outperformed the LRP brass 'control' in every respect - groups, ES/SD and even in one or two charge weights, MV. However trying out Hodgdon CFE223 in both types of brass with Hornady 155gn Amaxes and 178gn HPBT Match bullets last summer, the 'Palma' loads produced terrible results - 48 ex 50 rounds saw slight hangfires; one with each bullet weight a complete misfire. Pulling the misfired rounds showed the primers had ignited, but there was no sign of the powder granules having been affected in any way that showed up to the naked eye.
So far as N550 plus 185gn Juggernaut in a shorter barrel goes, running it through QuickLOAD suggests around 97% charge burn with a full-case load. (Even 30 inches doesn't quite produce 100% according to the program.) But it also says you get the same MV as a near optimal N540 load for an 8,000 psi PMax reduction. Going a bit heavier on N550 to a mildly compressed load is computed to give a bit more MV for a 4,000-5,000 psi pressure reduction. Although a great tool, QuickLOAD is only a model and gives pointers to results, sometimes amazingly accurately, but not always. Over the years, I've had some odd real life results with Viht N500 series powders in combinations that should have been OK - poor results such as massive muzzle flash / blast in a short barrel 243 Win rifle from N560. So, for you it's suck it and see time!
I found that with four or five powders tried all bar one appeared largely unaffected, the exception being Viht N140. There were no apparent misfires or hangfires, but 100 yard groups were poor and ES/SD worse than those from conventional LRP brass 'control loads'. Retesting the Palma brass version some weeks later in the spring at 10-12-deg C saw normal performance restored.
Interestingly, given the conventional view that ball powders are harder to ignite especially in cold conditions, I made up two batches involving heavy bullets and Hodgdon H414 expecting much reduced average MVs and increased ES values. To my surprise, the 'Palma' variety outperformed the LRP brass 'control' in every respect - groups, ES/SD and even in one or two charge weights, MV. However trying out Hodgdon CFE223 in both types of brass with Hornady 155gn Amaxes and 178gn HPBT Match bullets last summer, the 'Palma' loads produced terrible results - 48 ex 50 rounds saw slight hangfires; one with each bullet weight a complete misfire. Pulling the misfired rounds showed the primers had ignited, but there was no sign of the powder granules having been affected in any way that showed up to the naked eye.
So far as N550 plus 185gn Juggernaut in a shorter barrel goes, running it through QuickLOAD suggests around 97% charge burn with a full-case load. (Even 30 inches doesn't quite produce 100% according to the program.) But it also says you get the same MV as a near optimal N540 load for an 8,000 psi PMax reduction. Going a bit heavier on N550 to a mildly compressed load is computed to give a bit more MV for a 4,000-5,000 psi pressure reduction. Although a great tool, QuickLOAD is only a model and gives pointers to results, sometimes amazingly accurately, but not always. Over the years, I've had some odd real life results with Viht N500 series powders in combinations that should have been OK - poor results such as massive muzzle flash / blast in a short barrel 243 Win rifle from N560. So, for you it's suck it and see time!
Thanks again. I will give it a go. I have plenty of case capacity for the N550. If it is the same density as 540, I'll be fine. By the way, I do have both Palma and LRP Lapua cases. I have been playing with the LRP for fear of small primers in cold weather. I do need to download Quickload; it may reduce my questions of this type on here. Thanks to all. I'm still listening for suggestions, while I give the 550 a shot. More tried and true combinations, the better for me so keep them coming and thanks in advance
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