vhitavouri n150 burn rate?
- Thread starter Archer79
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memilanuk
Gold $$ Contributor
When Obama got elected, and Varget and H4895 became unobtainium, I switched to N150 on the advice of some Candadian friends. Behind a B155.5BT in .308 Win or a B82BT in .223 Rem it was nearly interchangeable with Varget as far as charge weights - literally within a tenth, across multiple barrels.
I haven't played with it as much with the heavier .30 cal bullets; I've heard some good reports from people I trust, so I may have to dust off the 5 jugs or so I still have under the bench
I haven't played with it as much with the heavier .30 cal bullets; I've heard some good reports from people I trust, so I may have to dust off the 5 jugs or so I still have under the bench
I think you are right on the money.. I have found that even though the burn rate chart as well as Viht literature, states N150 as near H4350, I don't think so.. I have used it extensively and I find it FASTER than VV N540! It may be up to 0.20grs slower than Varget>>>but no more than that! But it is an awesome powder, albeit a bit on the temp sensitive side>>>but not too bad!When Obama got elected, and Varget and H4895 became unobtainium, I switched to N150 on the advice of some Candadian friends. Behind a B155.5BT in .308 Win or a B82BT in .223 Rem it was nearly interchangeable with Varget as far as charge weights - literally within a tenth, across multiple barrels.
I haven't played with it as much with the heavier .30 cal bullets; I've heard some good reports from people I trust, so I may have to dust off the 5 jugs or so I still have under the bench
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N150 is definitely faster burning in practice, or is at least so in common applications, than IMR/H4350 and similar. It's very widely used in the UK for heavy bullets (185 Juggernaut / 200.20X etc Bergers) in 308 using Lapua Palma small primer brass, but I've used it very successfully with 155gn bullets too, and saw an example last year of the 155.5 Berger BT being given well over 3,100 fps with it in a long-freebore FTR rifle and using a heavily compressed charge in Palma brass.
Thanks to lengthy VarGet / H4895 shortages, N150 has also become the 'go to' powder in the UK for the 6mm BR with 105-108gn bullets and will match VarGet for MVs using maybe a single grain weight more powder. If it conformed to its nominal burning rate position, this wouldn't work very well - or at any rate might work while producing sub-standard MVs. However, these are very good.
In cartridges that do need a step slower burning powders - the 6.5mm trio of 6.5X47L, 6.5mm Creedmoor, and 260 Rem, this grade often shows signs of being a bit too fast burning, at least in the Creedmoor and 260. In the 6.5X47L my experience with the cartridge and 123-130gn weight bullets is that some rifles seem to prefer VarGet or Re15, but others won't perform at all well with them, but do so with N150. In the two larger capacity cartridges, N150 will perform OK with the 120-123gn bullets but even here seems to move into over-pressure very quickly indeed when charges approach usable maxima - N550 is a better Viht grade for this application, but the 'high-energy' (colloquially 'double-base') formulation puts me off it these days. For 136-142gn, I'll use N160 instead of N150 any day. (Another Viht powder that often acts faster burning than the Viht burning rate table would suggest.)
So, in practical terms, N150 seems in some cartridges at any rate to actually lie between VarGet and H4350, but nearer the former. My other conclusion in 20 years plus of using these powders is that whilst the N100 and 500 variants of each grade have nominally identical burning rates according to Viht, they are anything but in practice - N530, 540, 550, and 560 are very much slower burning than the single-based equivalents. N550 probably is somewhere close to the 4350s in practical terms.
The question as to where it lies in relation to N140 is an interesting one. Very close I'd say. A potentially big plus of the Viht range is that the very large numbers of grades provides products whose performance and behaviours are close to each other allowing overlaps in usage to suit individual rifles, chambers, barrel etc set-ups. So N140 and N150 are practical alternatives in 308 Win match use over a wide range of bullets, and recent usage suggests a considerably wider weight range than I would have once credited - Bryan Litz and his Team Michigan teammates using N140 up to the 200.20X bullet if I've got hold of the right end of this particular stick for instance. I would have said until recently that the balance tilted towards N150 at around 185gn bullet weight, but maybe not. Certainly at some lighter weight point in the bullet weight spectrum, N140 will be superior (probably 150gn in 308) and at the other heavier bullet end, N150 is a better choice (certainly with 210s, and I'll still say 200s as a personal preference). The usable charge weights for those bullets in between (168-185gn) will be pretty close probably, only a grain or so apart.
You do see this in a few other powder ranges - Hodgdon's IMR-8208 XBR and H4895 seem to be very close in practice, and in some applications in turn, H4895 and VarGet don't have much between them.
Thanks to lengthy VarGet / H4895 shortages, N150 has also become the 'go to' powder in the UK for the 6mm BR with 105-108gn bullets and will match VarGet for MVs using maybe a single grain weight more powder. If it conformed to its nominal burning rate position, this wouldn't work very well - or at any rate might work while producing sub-standard MVs. However, these are very good.
In cartridges that do need a step slower burning powders - the 6.5mm trio of 6.5X47L, 6.5mm Creedmoor, and 260 Rem, this grade often shows signs of being a bit too fast burning, at least in the Creedmoor and 260. In the 6.5X47L my experience with the cartridge and 123-130gn weight bullets is that some rifles seem to prefer VarGet or Re15, but others won't perform at all well with them, but do so with N150. In the two larger capacity cartridges, N150 will perform OK with the 120-123gn bullets but even here seems to move into over-pressure very quickly indeed when charges approach usable maxima - N550 is a better Viht grade for this application, but the 'high-energy' (colloquially 'double-base') formulation puts me off it these days. For 136-142gn, I'll use N160 instead of N150 any day. (Another Viht powder that often acts faster burning than the Viht burning rate table would suggest.)
So, in practical terms, N150 seems in some cartridges at any rate to actually lie between VarGet and H4350, but nearer the former. My other conclusion in 20 years plus of using these powders is that whilst the N100 and 500 variants of each grade have nominally identical burning rates according to Viht, they are anything but in practice - N530, 540, 550, and 560 are very much slower burning than the single-based equivalents. N550 probably is somewhere close to the 4350s in practical terms.
The question as to where it lies in relation to N140 is an interesting one. Very close I'd say. A potentially big plus of the Viht range is that the very large numbers of grades provides products whose performance and behaviours are close to each other allowing overlaps in usage to suit individual rifles, chambers, barrel etc set-ups. So N140 and N150 are practical alternatives in 308 Win match use over a wide range of bullets, and recent usage suggests a considerably wider weight range than I would have once credited - Bryan Litz and his Team Michigan teammates using N140 up to the 200.20X bullet if I've got hold of the right end of this particular stick for instance. I would have said until recently that the balance tilted towards N150 at around 185gn bullet weight, but maybe not. Certainly at some lighter weight point in the bullet weight spectrum, N140 will be superior (probably 150gn in 308) and at the other heavier bullet end, N150 is a better choice (certainly with 210s, and I'll still say 200s as a personal preference). The usable charge weights for those bullets in between (168-185gn) will be pretty close probably, only a grain or so apart.
You do see this in a few other powder ranges - Hodgdon's IMR-8208 XBR and H4895 seem to be very close in practice, and in some applications in turn, H4895 and VarGet don't have much between them.
So is N160 actually closer to h4350?
Also thanks for the info Laurie
Subjectively I'd say N160 falls somewhere between IMR-4350 and 4831, but nearer 4350, so maybe a little slower burning than the H-version. (I'm looking into .300 RSAUM loads right now for a new build and in printed data from Lyman, N160 uses 2.0 to 2.5gn higher charges than IMR-4350 for similar pressures but slightly higher velocities. 2gn isn't a huge amount when you're talking 62-65gn, but suggests that in this cartridge it's definitely a bit slower.)
However, all this jogged my memory about a very interesting alternative form of burning rate chart in an old (2004 print date) Norma reloading manual that I have. The approach here was to use a single charge weight in a single cartridge / bullet with nearly 100 different powders. The cartridge was 308 Win loaded with 43.2gn of each powder under a 143gn FMJ bullet. IMR-4350's pressure and MV were taken as the baseline and allocated 100 points in each, the other 97 or so powders (quickest Viht N350 revolver powder; slowest Viht N170 rifle powder) indexed against IMR-4350.
Starting with H4895 as the fastest burner of the bunch we're interested in, pressures against the IMR-4350 100 base are (rounded to the nearest whole figure - Norma goes to one decimal place).
H4895 .......... 174
IMR-3031 ...... 171
Norma 201 .... 171
IMR-4320 ...... 163
Viht N135 ...... 161
Viht N140 ...... 157
IMR-4895 ...... 153
IMR-4064 ...... 148
Viht N540 ...... 137
Norma 202 .... 136
Allt. Re15 ...... 134
Norma 203B ...134
Viht N150 ...... 118
Viht N550 ...... 113
Viht N160 ...... 108
IMR-4350 ...... 100
Norma 204 ..... 99
H4350 ........... 95
IMR-4831 ...... 93
Allt Re19 ....... 91
AA-XMR4350 . 84
Viht N560 ...... 83
Allt. Re22 .......82
Norma MRP .... 80
IMR-7828 ...... 78
H4831 ........... 77
Remember this was printed in 2004 and Norma doesn't say when the testing was done. For instance there is no H. VarGet in the list. It could be that the Hodgdon extrudeds were Scottish manufactured by ICI-Nobel before it closed and the current manufacturer, ADI took over. Others may have changed in around 20 or so years. (XMR-4350 would have been the old Czech version, still available but now called Lovex SO70 and different from today's Accurate-4350 which is made by the same people who make IMR extruded powders in Canada.)
And there are some strange results, likely due to the use of the single cartridge/bullet with many powders being unsuitable for it and well out of their efficient pressure range. Few would put IMR-7828 and H4831 together in effective burning speed. N140 looks far too fast burning in this chart, and N160 seems to be very fast being quicker than all of the 4350s.
Still .......... interesting!
Down South
FTR Junkie
Very close to Varget as everyone mentioned. It was within .5 gr with the lot i had of N-150 & Varget.
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