Contrary to the writings of a quack, the holy grail of powder burning is a flat pressure curve. The vihtavuori n500 series is advertised to do just that and produce 150 fps higher velocity than conventional propellants.
Generally speaking, a flat pressure curve would result in greater throat wear, as max pressure + temp occurs for a longer period. According to the vihtavuori adverts, this factor is mitigated by [ QUOTE ]
<font color="purple"> Although these new powders have a higher energy content, they do not cause greater wear to the gun. This is because the surface of the powder has been treated with an agent designed to reduce barrel wear. </font>
[/ QUOTE ]
The N500 series powders cost more for 2 lbs than WC872 in 8 lbs jugs. If I could really get an additional 150 fps with no greater wear, it would be a bargain.
comments? Any experience?
Run Forrest, run!
N550 did give me good velo, about 150 fps more than an equivalent charge of w760, but it fried my three groove Pac-Nor in about 900 rounds! That gun was in a caliber that should have easily made it to 2000 rounds before being set back a thread and rechambered.
I have read VV's disclaimer before and their deterrent coating garbage is a load of marketing bullpucky. 5 series made the first 3 inches of my throat look like a dry lake bed when viewed through my gunsmith's Hawkeye.
I might also mention that this barrel was properly broke in, was cleaned rigorously every 30-50 rounds, and all 900 bullets shot through it were moly-coated to help reduce barrel wear (if you believe in that sort of thing).
Since my experience with the nasty 550, I have talked to many long range varmint hunters via email and they all have had similiar experiences. I would stay 100 miles away from the closest bottle of any 5 series VV powder. As I have said before, VV 1 series are some of my most favorite powders and VV 5 series are my least favorite!
Hope this helps.
I shoot it in one of my 308's exclusivly with 175gr SMK bullets. This barrel is a Rem heavy varmint conture by Hart its finished at 25" the velocitys I get with this load are above what i have ever experianced 2760fps with a load of 47grs of VV-550. I have over 1000 rounds with this powder in this gun and have seen no affects on accuracy at all , the gun cleans just as well as it ever did and doesen't seem to feel and rougher. Another note this powder doesen't seem to be temp sensitive as O worked this load up in 50 deg temps and shoot it now in the mid 90's with no noticable signs of pressure increase.
So far I love it , doesen't foul bad gives more speed.
NOW , I haven't looked at the bore with a scope so it could be cooked but unless the accuracy falls off soo , I don't have a problem with it.
GoodGrouper, Interesting to hear about the abrasiveness of N550 in your rifle, and that others have experienced similar problems. I have only fired about 100 shots with this powder during accuracy testing and chronographing in my .17/222 mag imp with the 25 and 30 grain bullets, so am unable to determine whether it did cause any significant erosion on the throat of my barrel. Velocity wise, it appears to give up to 100 fps more than W760 and H414, however, I noticed that accuracy was ordinary while working up to maximum pressure, then suddenly at maximum pressure the group size reduced dramatically.
I have used N560 in a variety of cases including .17/222mag imp, 224 Clark, 22/250AI, 25/06AI, and in no instance has it delivered highest velocity or best accuracy. I found that like N550 good accuracy was only achieved at maximum pressure, which certainly restricts its usefullness.
So far I have found that N165 to be an excellent powder with the heavier bullets, and have just started testing N170 in the 25/06 AI with the 130 and 142 grain Wildcat bullets.
Despite the cost of about $105 Australian, I would probably buy more N165 and N170, but am most unlikely to buy anymore of the N500 series powders.