N140 or N150 in 308

[Hunterjohnb]

I normally use N 140 for 165 gr rounds. Recently loaded with some N 540 and was surprised at the accuracy improvement.The load was 44 grs under 165 gr heads, loaded to max length, in a T3.

 

[ChesterP]

Let us know how you get on with the RS50! We use that in our target loads at the target rifle club I shoot at, word really well!

I've just loaded up a series of loads from 39 to 45 grains with RS52 (similar to N150) and 165gr Interbonds. I just need to get down the range now to see which is the best one.

I'll let you know how I get on Stu. I've avoided the 52/62 propellants as they're hotter burning double base powders, so barrel life takes a toll if choosing to use them. RS50 and/or N150 probably will cover my 175gr & 190gr target rounds and also my 150gr hunting rounds.

 

[phaedra]

Used both N140 and N150 with 168gr Nosler Custom Competition, A-Max, Sierra 2155's and 167gr Scenars in my Steyr SSG-04. All give 1/2 moa at 200yds if I do my bit.

 

[Yorric]

I'll let you know how I get on Stu. I've avoided the 52/62 propellants as they're hotter burning double base powders, so barrel life takes a toll if choosing to use them. RS50 and/or N150 probably will cover my 175gr & 190gr target rounds and also my 150gr hunting rounds.[/QUOTE

Useful info ChesterP - thanks. Where can I find details of values for burning temperatures of different powders? It would be nice to have such info to aid in powder selection. Is it hidden somewhere in the mass of information included in Quickload?

I've used lots of N140 & Alliant Reloder 15 for 308 loads. Always managed to shoot excellent groups with bullets from 125 through 180 grains.

 

[AN DU RU FOX]

Heres an updated chart but ,notice different powder makers may produce slightly different charts ,,only a guide. http://bulletin.accurateshooter.com/2016/01/updated-hodgdon-and-imr-relative-burn-rate-chart/

 

[old man]

I use N150 at 45.7gns with Sierra 150gn Gamekings. Col 2.795"

Gives an average of 2740fps over the chrono.

Have used N150 at 46.0gns with 150gn Gamekings Col 2.810" to good effect too.

Another burn rate chart.....http://www.t2ammo.com/data/_uploaded/file/Techniek/Powder Burn Rate Chart.pdf

 

[Yorric]

Thanks guys -- but I was asking about burn temperature data - not burn rate. LOL

Ian

 

[AN DU RU FOX]

Thanks guys -- but I was asking about burn temperature data - not burn rate. LOL

Ian

Powder Temp Stability: Hodgdon Extreme vs. IMR Enduron - PrecisionRifleBlog.com Winchester 140 Grain Match Ammo - Page 3 theres two.

 

[Yorric]

Powder Temp Stability: Hodgdon Extreme vs. IMR Enduron - PrecisionRifleBlog.com Winchester 140 Grain Match Ammo - Page 3 theres two.

Hmmm- Thanks again, but again that is not what I'm asking for. I want to be able to compare powders by the temperatures that they will each generate when burnt at the same temperature start point. The aim is to decide which powders will cause least barrel damage.

Ian

 

[tarponhead]

44.7g of N140 behind 150g Nosler BT's or Partitions

 

[kennyc]

Hmmm- Thanks again, but again that is not what I'm asking for. I want to be able to compare powders by the temperatures that they will each generate when burnt at the same temperature start point. The aim is to decide which powders will cause least barrel damage.

Ian

on a .308? is it even possible to shoot a .308 barrel out with sporting use?

 

[Yorric]

Firstly apologies to the OP for taking this thread off to the side a bit. Maybe I should open up a new one.

Kenny - Agreed it is hard to shoot out a 308 with just sporting use - I am thinking more in general terms for other more agressive chamberings & also for target shooting. Some of us do a bit of both & I as an engineer like to make my machinery last as long as possible.

Ian

 

[Laurie]

AFAIK, there is no flame temperature data available on smallarms propellants. All that is available is specific energy ratings. Viht N140 and N150 are rated at 3,720 and 3,780 KJ / Kg respectively. As the latter's maximum charge weights are usually a bit heavier than those of N140, the energy input is therefore a bit higher. On the other hand, at moderate loadings, pressures will be lower. As it is the combination of temperature and pressure that wears barrel throats, there is likely nothing much between either combination, and certainly over many thousands of rounds of 308 Win using both, I've never seen any difference.

Both can kill 308 Win barrels in 2,000-2,500 rounds when pressures are high enough as is regularly the case in FTR competition, especially with heavier bullets. N150 is the powder of choice for long-freebore chambers and heavy 185gn Berger LR BT 'Juggernaut' FTR loadings and 2,500 rounds barrel life maximum is the norm.

For 150s, N140 would be my first choice; for 155 match bullets and heavier, I'll use N150 for preference. Reload Swiss RS50 (which is TR140) is a very good substitute for N140, hence the unofficial name it was given here in its early days. It's a marginally 'warmer' powder at 3,815 KJ / Kg specific energy rating, but as all are single-based types they're relatively barrel-friendly.

 

[Yorric]

Thanks for the info Laurie - I was hoping you might chip in. I'd looked & not found an idiots guide LOL.
I will do a bit of studying of the specific energy ratings & see if I can get my little grey cells lined up!

Ian

 

[25 Sharps]

on a .308? is it even possible to shoot a .308 barrel out with sporting use?

If I ever get around to sorting that 110 v-max load in my old girl I might!!

 

[Roedeer 1962]

Could you use the n140 for 243 and 308 ???????

 

[phaedra]

Could you use the n140 for 243 and 308 ???????

10 seconds on the Viht reloading guide would tell you all you need to know,

http://www.vihtavuori.com/en/reloading-data/rifle-reloading/-243-winchester.html

http://www.vihtavuori.com/en/reloading-data/rifle-reloading/-308-winchester.html

 

[ChesterP]

Firstly apologies to the OP for taking this thread off to the side a bit. Maybe I should open up a new one.

Kenny - Agreed it is hard to shoot out a 308 with just sporting use - I am thinking more in general terms for other more agressive chamberings & also for target shooting. Some of us do a bit of both & I as an engineer like to make my machinery last as long as possible.

Ian

Sorry....just come back to this after being away for a while.

Mea Culpa Yorric. I needed to be more specific from the start, but Laurie's informative post hits the mark. I meant specific energy of course, and in relation to barrel life, like you, I use my rifles for target as well as hunting, so want some extended life from them. As I shoot 190gr as well as lighter bullets from the 308, I'd rather rely on that bullet's trans sonic stability than drive it hard for higher velocities, to try and eek out a bit more barrel life. Using double base in a sporting rifle of course shouldn't show drastically reduced barrel life especially with the lighter bullets and lower MVs compared with, say, 1000yd target requirements. I'll be using RS50 behind some 175 smk's and also be using it for my 150gr SGK hunting loads. Using the N140 for a few years now has shown me that whilst it's a great choice for accurate 150gr hunting loads, when used for target to achieve higher MV's, it has to be pushed too close to max pressures in shorter barrels to get the MVs needed. Using the Chrony, I've mapped velocities (both 155 SMK and 190 MKs) and the curve is rather steep towards the higher end of the pressure scale. I was advised by my supplier to try RS50 as it had a more linear pressure V's velocity curve, so it might be the better bet to generate the velocities needed at lower pressures. I have yet to try it but will. N150 would be the better choice for the 190's but I haven't used it yet.

 

[Yorric]

Nada de culpa ChesterP.
What you say is reflecting my thinking & as I'm running out of the Alliant Reloder 15 that I have used in 308 for years, Now is a good time to get things tuned better. I want to decide on the best powder before buying a good sized quantity.

My recent experience has pointed me towards using slower powders than previously, & as I learn more from playing the permutations in Quickload I'm starting to understand better.

Another consideration is to use powders with copper fouling inhibitors in them. - It sounds like a good idea to me. -- Just another filter in the data flow!!

I now use HBN to drop barrel pressures by coating bullets & bore with it. So far it seems to be working as predicted - i.e. slower build up of fouling & almost no copper build up, much easier cleaning, no fouling shots are needed after cleaning & treating the barrel. (first shot is right in the group). Accuracy / grouping hasn't changed.
I get a warm feeling knowing that I am reducing friction & hence (hopefully) barrel wear. I do need to up the powder charges to get the velocity back up to my barrel sweet spot. The pressure doesn't increase as fast as the velocity & I end up running faster without getting pressure signs.
I expect to be moving into compressed loads more due to this & using the slower powders.

Ian

 

[ChesterP]

Thanks for the useful feedback Yorric. I haven't come across HBN...where is it available from, and is it just a case of patching through the barrel once cleaned with it? It sounds promising. I have tried various de-coppering and coating chamicals in the past, but have seen no real reductions in fouling (from the 308, it's not a problem until I've fired between 80 and 100 rounds; less from the .223). I have obtained some useful velocities from the 190's using N140 (2500 fps) but that's marginal on pressure, so I don't feel that comfortable with it. Looking forward to trying the RS50. Will also be switching to the 175 gr MK as I haven;t tried that one yet.

On deer, it makes little odds. I load lowish at 43.1gr N140 and use 150gr SGKs. Slowish load but seems to do the trick and is bob-on accurate.