.308 Win load development with 150 grain Hornady SST and Vihtavuori N140

I decided to give reloading a go. After reading about it, all pros and cons, I was convinced it is a good idea.

However, I did not want to spend hundreds on equipment only to find out later I do not like it. I asked a few questions on hunting forums and ordered Lee Classic Loader in .308 Win caliber plus a few extra bits and pieces to help with case preparation, and Lee Powder Measure Kit to play with different loads.

Lee Classic Loader seems to be ideal for a first timer as it contains pretty much all is needed, however it comes with just one powder scoop. As  my aim was to develop a load for my .308 Winchester, I wanted to vary powder weight, hence Lee Powder Measure Kit. It is enough for my purposes and much cheaper than any decent powder scales.

I had been advised to buy a few bits and pieces for case preparation and that list included:

• Lee case trimmer and lock stud
• Lee case gauge and shellholder
• Lee chamfer tool
• Lee primer pocket cleaner

I also bought Lee Modern Reloading 2nd edition book and read it all to have an idea what it is all about. After analysing loading data for 150gr bullets, Hogdon’s H4895 and Vihtavuori’s N140 become my top two options.
There was not a great choice of powder and bullets in my local gun shop so I eventually bought a tub of N140 powder, Hornady #30302 150gr SST bullets and CCI N200 large rifle primers.
Reloading manuals differ regarding starting and maximum loads so I averaged them and it looked like starting load should be around 40gr and max 47gr. Lee manual tells you to increase powder weight from min to max in at least 5 steps. So ideally it would be like that:

However, having no access to powder scale I had to use Lee dippers. They are very easy to use and cheap, but according to Lee 1gr of N140 powder is 0.07317cc. But the smallest scoop available is 0.3cc. Using all the combinations of Lee dippers it is only possible to vary powder by 0.1cc, which is about 1.3gr of N140. So no way I could vary powder weight by 1gr, not to mention 0.1gr… So will need scales at some point eventually… However, it should be enough in a decent size .308 case but would not recommend it for .222 and smaller cases where finer weight adjustments are required. Unless you are lucky and find your load quickly…
I decided to prepare 5 loads:

I slightly neck sized one case to the point when bullet goes in using little force and chambered it in my rifle in order to measure bullets overall length. I repeated this exercise a couple of times with different cases and bullets, averaged results and it looked like the SST bullet in my rifle gives maximum overall length of 2.870″ when touching lands. After reading all about it is the best to have rounds almost touching lands, I decided to load all rounds to the length of 2.855″, which is 0.015″ off the lands. It should be close enough for good accuracy and also not touching lands, which according to Lee should not be used in hunting rifles.
I shot 5 shots using 150gr Sako, my usual factory load just to have a benchmark to evaluate my loads against.

The first shot on the left was from a clean barrel so the group was not great at about 2.4″, but it usually was about 1.5″ for 5 consecutive shots.
I made 20 rounds, 5 different loads as planned, 4 rounds each powder weight, same OAL.

The first group loaded with 39.5gr of Vit N140 was 1.6″ and slightly low.

The second group loaded with 42.3gr was 1.5″.

The third group loaded with 43.6gr of N140 opened up again to 2″.

The fourth one at 45gr produced 1.7″ group.

The last one was the best at 0.95″ and loaded with 46.4gr which is close to maximum load.

I was really pleased with the last group as using only 20 rounds I achieved better accuracy than Sako factory ammunition.
I decided to work around 46.4gr load and do not change powder weight anymore, but vary overall length.
SAAMI spec gives 2.800″ for .308 Win so I decided to vary length between 2.855″ which is close to lands on my rifle and recommended SAAMI length.
I again loaded 20 rounds, 5 differ OALs, 4 rounds each.

So I had 2.840″, 2.830″, 2.820″,  2.810 and 2.800″

This group opened up in comparison to my original 2.855″ group.

The next group shrank again to under 1″.

This was a shock for me as I could not believe I was able to shoot such a group.

This group grew again.

Here are the results.

I think the group shot under 0.5″ was the best group ever shot by me. I was not 100% convinced about all advantages of home loading, I am now. It is also much cheaper than buying factory ammunition, good fun and gives you a lot of confidence in your abilities and your rifle.

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