.308 Win load development with Speer 180gr SPBT bullets over Vihtavuori N140 powder

When I bought my .308 Win rifle I got 2 boxes of Sako 150gr SP ammo with it and shot a few roe with it. I think majority of deer dropped on the spot with a few making 10-40 yards tops. I was quite happy with it but the bullet clipping shoulder usually resulted in excessive damage to the front or even worse burst rumen. When I got into reloading first bullet I tried was Hornady 150gr SST which was not too bad. I still have a few reloads and it was also very effective, much more accurate but very similar to Sako SP resulting in some meat damage on roe. Following my experience with .30-06 I also use that behave a bit better with heavier bullets I decided to try new bullets. I wanted either something heavier or not as quickly expanding as the SST. I got a few bullets in mind, but as always the bullet choice in local shops verified everything… For some reasons Scots do not like bigger calibers and heavier bullets and for .30 cal there is usually a choice of 150gr and 123gr ūüėĮ¬†, but little 180-220gr.

Speer 180gr SPBT

I had a choice of Hornady and Speer SPBT 180gr so I just got Speer to try something different… I decided to use the same powder I used for 150gr SSTs – Vihtavuori N140 and large rifle CCI 200 primers. This time I used once fired RWS brass I got cheap, but I had to full size it before using. So this time I could not use my Lee Classic Loader kit.

Lee Hand Press

As I have limited space at home when I came across second hand Lee hand press with a few extras I bought it. I also got used RCBS dies. I needed a full length sizing die as RWS brass was fired, but not in my rifle so it needed full sized. I used RCBS lube and small Hornady pad which comes with a convenient loading tray for 50 rounds. Lee hand press is another good Lee product I recommend. It takes very little space and even using full sizing dies it is not too tiring to use. You have to find comfortable position and rest one arm of the press on your leg (I know it looks like I am struggling on video, but only because it was not a comfortable position, just wanted to film it the best I could). I used Lee trimmer and chamfer together with Lee primer pocket cleaner to prepare sized cases.

Finding right load

I looked at loading manuals and found recommended starting load to be 38gr of Vihtavuori N140 and 44gr maximum load. I again wanted to use Lee dippers to speed up the process. Both min and max loads where quite close with volume to Lee dippers I could use. So I used 2.8-3.2cc in five 0.1cc steps.

Volume 2.8cc 2.9cc 3.0cc 3.1cc 3.2cc
Weight 38.2gr 39.6gr 40.9gr 42.3gr 43.7gr
Dippers 2.8cc 1.9cc+1cc 2.5cc+0.5cc 3.1cc 2×1.6cc

I made 20 rounds in total, 4 of each powder load with the same COAL and went to try them out. First one 38.2gr group was 1.4″, the same as the second load 39.6gr. The third group was slightly better at 1.2″ and I knew I a bit pulled one of the shots… The fourth group (42.3gr of N-140) grew again to 1.4″ and the last one was best at 1″.

Too Hot

Even though the last group was best, it was close to maximum load and a bit too hot with some rounds resulting in a “sticky” bolt difficult to open and some extractor marks on the brass. So, I decided to work around 40.9gr load as it was safe and most promising. You can see extractor impressions on the photo, these are small circles on the bottom of the brass.

Finding right COAL

COAL 2.790″ 2.800″ 2.810″ 2.820″ 2.830″
Group 0.4″ 1.2″ 1.4″ 0.6″ 1.1″

As my SST load was not grouping well close to lands I made up 5 different loads with COAL ranging from 2.790″ to 2.830″ where the longest one was about 0.015″ off the lands.

The first load I tried was around 2.790″. I say around as with Speer bullets being soft point they differ quite a bit and I do not have any fancy tool to measure to ogive. I simply measure the whole cartridge and know how long they are on average. The SSTs were much more consistent being plastic tip type. The first group was really good at 0.4″. The second group with COAL of 2.88″ was 1.2″ with the third one (2.810″) at 1.4″. The fourth group was a bit more than 0.6″, but a strange thing happened and one of the bullets was not on the target. I think I got one of the small branches that or grass and the bullet fragmented and hit low below the target… The last group (2.830″) was 1.1″.

I think I will settle on the 40.9gr of N140 and 2.790″ COAL as I do not think I can shoot any better that 0.4″ at 100m. I will make a few more rounds just to see if it is consistent and am planning to test this load on roe and roe deer this coming season.

When I was shooting a few round landed in wet grass and heather that is acting a bit like ballistic gel and I managed to recover some of the bullets. They are not bonded as jacket and lead separated so will see how they work on deer. I hope they are not too quickly expanding but time will tell.

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One comment

  1. Very interestig reading again. We use 6,5×55 Norma, Oryx when we hunt moose and for training Jaktmatch Norma. When we hunt roes with our dogs from 1st Oct we use our shoot guns caliber 12. We can shoot roe buck from 16 th Aug but only stalking and with rifle, same as we hunt moose with.
    We consider to buy bigger caliber guns if we going to hung hogs…there we need more power.

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