N140 v N540

[PaulC]

Does anyone have any real life experiance with barrel life expectancy with the two powders in .308 with a 155 grain bullet thanks in advance.

paul

[alpha1]

I have all ways used N140 wih the 155grain Hornady A max in my Steyr SSG P1 it still shoots realy well I have no idea of round count but its a lot.

[Laurie]

In the early days of FTR, a number of us 'killed' quality barrels (ie Bartleins) in 1,300-1,500 rounds with the 155gn Scenar and N540. These were 'hot' loads, but then there is no sense in using an N500 series powder if you're not chasing MV.

 

So far as N140 + 150-165s go, every second handloader in the UK has experience of this from club plinking shooters, through deerstalkers, and a lot of TR competitors for whom a 155gn match bullet + N140 is the only combination they know. Barrel life is almost directly related to loadings / pressures from maybe 2,500-3,000 at the hot load end to TR shooters with 7,000 rounds and upwards who see increased long-range elevations but which still fit in the 2-MOA five-ring. 5,000-6,000 would be the figure to plan on though for a mild to lukewarm load used in slowfire competition.

 

The reason is pretty straightforward. N140 is a relatively cool burner rated at 3,720 Kj / Kg (Kilo-Joule per Kilogram) specific energy whilst N540 is the 'hottest' canister powder on the market rated at 4,100 Kj / Kg.

 

IMHO, N150 is a superior powder for the 308 even with the relatively light 155gn class of bullet compared to either 140 based grade, and generally so far as one can see with the tiny barrel number samples involved, gives better barrel life too with sensible loads at the cost of only marginally lower MVs. (That doesn't apply to heavy FTR N150 loads in Palma brass under the 185gn Berger Juggernaut where 2,500 rounds is potentially all you'll see before precision starts to fall off.)

[The Gun Pimp]

Does anyone have any real life experiance with barrel life expectancy with the two powders in .308 with a 155 grain bullet thanks in advance.

paul

A couple of us - seeking the extremes of 308 velocity in our FTR rifles with N540 - had barrels burn out in around 1000 rounds. Yes, it surprised me as well!

 

You won't get the velocity with N140 but you will get a lot more barrel-life.

[ezmobile]

I will absolutely agree with everything Laurie & The Gun Pimp say. If you're looking to use 540 in a stalking rifle where you're only taking a couple of shots a day, then I guess its fine. But, if its for a target rifle where you may take several "strings" of shots per outing, then steer away from it.

I think if you are still wanting to wring a bit more speed out of a 155 maybe you could try RS52, its still a high energy powder, but a little kinder to barrels so I believe, but willing to be told otherwise. I used it for a couple of seasons of T/R where 46 grains would drive a sierra 155 MK to 3000 fps through a 32" tube.