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N140 Loads with 174 gr SMK
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britrifles View Drop Down
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    Posted: July 11 2025 at 1:08pm
My supply of Varget is dwindling down, so I’m in search of another match load. I’ve got lots of N140 so chose that to work with. 

I’m shooting these loads out of the No.4 T that I just rebarrelled with a Lothar Walther 4 groove RH twist barrel. Now at 155 total rounds after these tests. 

Basic Load Data:

PPU Case Annealed and Neck Sized
WLR Primer
VV N140, 40.0, 40.5, 41.0, and 41.5 gr. 
174 gr Sierra MatchKing
3.070” OAL

It was evident after the first group of 40.0 gr N140 that I would not shoot the 41.0 and 41.5 loads as velocities were higher than I expected. Also, the 40.5 gr N140 load, the group blew out. 

Data is for 10 shot groups fired at 600 yards off the bench. 

Also showing is the control group, my standard Varget Match Load.  

MV = Mean Velocity
ES = Extreme Spread
SD= Standard Deviation



I’m going to drop the N140 loads back and try 39.0 and 39.5 gr. Would like to get the velocities about the same as my Varget load, that way the rifle will regulate to the No. 32 scope elevation settings and accuracy will probably be very good as well. N140 is a slightly slower burning powder and giving higher velocities than Varget at the same charge weight. 

I’ll provide an update here on the results of 39.0 and 39.5 gr. 
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Strangely Brown View Drop Down
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Geoff,

I think I've mentioned on here before that 41.8grs of N140 has a long held belief here in the UK that it replicates the MkVII load of 2440fps ?? 
I wonder if that is popular (UK) shooting myth, or are your results possibly temperature related? 

  


  
Mick
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britrifles View Drop Down
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Good question Mick.

I neglected to give the weather conditions. It was not all that hot, 85 deg F at the time of shooting the N140 loads.  N140 is supposed to be quite temperature stable.  

Vihtavuori website gives the following for N140 with 174 SMK seated to 3.070”:

Min  38.4 gr at 2379 fps
Max 41.7 gr at 2566 fps

Based on my tests, I suspect that is about right. 

 I’m rather suspect of the claim that 41.8 gr duplicates Mk 7 ball muzzle velocities. Or, Vihtavuori has changed their powder formulation since then.  I’m thinking it’s more like 39.8 gr. 
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Strangely Brown View Drop Down
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Food for thought Geoff! 
I wonder if I need to re-look at my loads which did at the time include a 900 yard shoot which I am now (slowly) experimenting with a 190gr bullet and N150.

The forecast for tomorrows shoot at Bisley is 93f, assuming I manage to shoot my three details in that heat! 
Mick
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93 deg F in the UK?? 

That’s 10 deg hotter than the forecast for NE Georgia tomorrow.  But it’s the 70-80% RH for tomorrow’s match that I’m more worried about.   

Shooting a 80 round Service Rifle match, four stages of 20 rounds each + 2 sighter shots per stage. 
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Originally posted by britrifles britrifles wrote:

N140 is supposed to be quite temperature stable. 

Geoff, I've had this temperature stability chart saved on my hard drive which shows the expected velocity gain per degree rise in temperature.  Unfortunately the baseline isn't shown nor the low and high temps that the chart can be expected to be reliable but it is useful as a tool to know which powders are the least affected by heat.  I have no idea who developed this chart nor can I speak to its accuracy.
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Originally posted by britrifles britrifles wrote:

93 deg F in the UK?? 

Geoff we're in the middle of a heat wave after the wettest winter I can recall; drove back from Bisley today and the car recorded 32.5c or 90.5f in old money as call it over here. 

Hot weather is not conducive to good shooting!
Mick
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Originally posted by Strangely Brown Strangely Brown wrote:

Originally posted by britrifles britrifles wrote:

93 deg F in the UK?? 

Geoff we're in the middle of a heat wave after the wettest winter I can recall; drove back from Bisley today and the car recorded 32.5c or 90.5f in old money as call it over here. 

Hot weather is not conducive to good shooting!

We're having a bit of a cool down here in Texas Mick, it's only going to be 93 f. today.  ;>)  The only way we can shoot on a really hot day when it's north of 100 is shoot in the shade and have large fans blowing.
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Thanks Derek, I’ve seen that table before, but not sure where. 0.4 fps per deg F is quite good (stable). That suggests only a very small increase shooting at 85 deg F vs 70 deg F (6 fps). 

I’ve done my own tests with Varget, and found it very stable, as others have.  I’ve not noticed any appreciable change in MV with Varget from 40 deg to 85 deg F which encompasses about 80% of the conditions I shoot in. 

Speaking of heat, I shot in a match yesterday, as did Mick on the other side of the pond, and it was miserable on both sides!  By the time of the last stage of the match at 600 yards in slow fire prone it was around 1230 with full sun right above us.  We had just had a light shower and that sun drove the humidity up to around 80% RH.

Yesterday I was shooting a 80 shot Service Rifle Match with the AR.  My 600 yd stage load is 23.5 gr N140 with the 80 gr SMK. I did not see any change in elevation setting from my last match when it was quite a bit cooler. 

From winter to summer, I’ve not detected more than 1/2 MOA difference at 600 yards with N140 from 40 to 85 deg F.  I get much more change in elevation (and measured velocity) after I clean the bore with JB and completely remove the carbon ring that builds up right in front of the case, as much as 100 fps difference. 
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I've done some poking around on the net and did find out that the previous formulation of N140 was not all that temp stable, more like 1.4 fps/deg F vs 0.4 that is shown on the table that Derek (Sapper) posted.  But, the newer formulation with the decoppering agent is supposedly much more temp stable.  

I think I have the newer formulation, I will check when I get home tonight.  

Next step is to test 38.5, 39.0 and 39.5 and that will complete the range of loads from 38.5 to 40.5 gr at which I should be able to interpolate on 2370-2400 MV that I'm looking for; providing it also gives good accuracy at 600 yds.  
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New load tables incoming I hope!
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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I now wonder if the VihtaVuori formulation change also resulted in a change in the load data.  My results (so far) seem to agree with the load data that VV currently has on-line with a MAX charge of 41.7 gr at a muzzle velocity of 2566 fps.    

I rarely ever go back to the hardcopy book data, unless I know that the power I have is from that time period; otherwise I pull up the current data from the power manufacturer.  
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Good move
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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I checked the jug of N140 I have opened, it is the more recent formulation with the decoppering agent and “temperature-stable” statement. 
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That's good news!
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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Got out to the range today to finish with the N140 loads in the No. 4 T. 

Wx was warm and humid again today, similar to last weeks tests (40.0 and 40.5 gr N140).  Getting tired of this, looking forward to fall.  Winds were switchy today, so shot these at 300 yds, last weeks were at 600 yds.

Again, basic load data is:

PPU Case neck sized
WLR Primer
Vihtavuori N140 Powder, all charges weighed
174 gr Sierra MatchKing
3.07” Cartridge Overall Length

These are all 10 shot groups fired off the bench. Garmin XERO Chrono. Group size is center to center extreme spread in minutes of angle. Temp: 85 deg F. 



To duplicate Mk VII velocity specification (2440 fps),  40.3 to 40.4 gr N140 with 174 SMK

To duplicate my 40.3 gr Varget Match Load, 39.2 to 39.3 gr N140. 

Velocity spreads today were larger than last weeks loads, this may indicate that spreads tighten up with N140 at the higher velocities. 
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