I thought this might be of interest to people here. I originally posted it to a couple of other forums that are oriented more towards the M1A and M14 pattern rifles.
I have seen questions in several forums about loads in .308 Winchester using Hodgdon Varget that approach the maximum charge listed in the manuals. I have been curious about this myself so I decided to load up a couple of bracketed lots and test some near maximum loads. Hodgdon #27 and Nosler Fifth Edition list a maximum charge of 46.0g using a 168g bullet, Lyman #48 lists a maximum of 45.7g for a 168g bullet. The 168g Nosler J4 Match and the 168 Sierra Match King have performed the same for me in my rifles so I used the Nosler in these loads. I loaded up 100 rounds in two lots. The first lot of 50 rounds is loaded in fireformed RWS cases that have already been shot a few times in this rifle. The second lot is loaded in fireformed Lapua cases shot once in this rifle. The rifle is a Sako AII in a tactical/varminter configuration. The rifle is a factory rifle that I had pillar bedded and fine tuned couple of years ago.
Sunday August 1 was a fine day for shooting. The temperature in the Sacramento valley had dropped below 90° and a nice breeze was helping keep things cool. This
first target started out with a below average group on the top left. I focused my concentration better when shooting the next group on the bottom right. Moving up to the top right and then the bottom left I shot a slightly stiffer load. Aside from the first group I cannot see a lot of difference in overall size.
After a cease fire and patching the rifle out with some solvent I shot this
second target following the same top left. bottom right, top right and bottom left sequence as before. The first group started out very nicely but I screwed it up on the fourth shot. The edge to edge size of the four shots measures .555". The two loads shot on this target merit further testing in my bolt guns. I was very pleased with the ten rounds of Hirtenberger ball ammo I shot as well. I have not seen any ball ammo that shoots as well and I wish it were more widely available.
After another cease fire and some more cleaning I shot two groups into the
last target. My concentration lapsed once again but I recovered it for the last group. It was getting pretty late in the day so I shot another ten rounds of Hirt and packed up.
I do not have a chronograph so I have to inspect the case heads for signs of pressure. The cases all extracted easily enough but did require more force rearward force to extract than the new Lapua cases did when I fireformed them. At no time was it difficult to turn the bolt. I have noticed in the past that previously fireformed cases sometimes require a bit more force to pull them from the chamber. The Hirtenberger cases extracted with no difficulty at all. Careful inspection of the RWS cases showed some faint signs of extrusion into the bolt face. These marks were difficult to see without a loupe or reflecting light off the head of the and may have already been present. Examiniation of the case heads with a 10x loupe showed that the bolt face impressions were comparable to what this rifle has made before in the same batch of cases. The primers showed no signs of cratering or extruding around the firing pin.
While I consider these loads fine for my bolt action rifles I would be
very cautious of shooting such loads in a gas operated rifle such as an M14 pattern without extensive testing. Varget is among the slowest powders suitable for the M14 pattern and therfore places higher pressure on the gas port.
Returning to the range the following weekend I find that these loads and this rifle are performing beyond my expectations. I wish I were up to the same level of performance. The range this weekend was like an oven. The temperature hovered right at 100° on Saturday and hit 102° on Sunday with humidity between 15-23%. At least it's dry heat in the Sacramento Valley.
The
first target shot on Saturday shows me that these loads are consistant in both RWS and Lapua cases. The
second target just reinforced these thoughts. I've now tested the load on the
third target four times and it is not as consistant as two of the slightly milder loads. I'll try it one more time along with another two tenths increment in charge weight. I was hot and tired by the time I shot the fourth target. The load was consistant but I was jerking things up, down right and left so every group has at least one flyer. Considering the accuracy problems I had with this rifle before the pillar bedding it's a bit ironic that I am now disappointed with one inch groups. It would probably help if I skipped espresso when heading to the range.
Sunday I didn't have as much time to shoot because the range was crowded. The one box a year pseudo deer hunters have infested the range. Watching some of these dingbats is like watching a rerun of Gilligans Island. Imagine the skipper shooting and Thurston Howell on the spotting scope. I shot this
continued test but was a bit distracted by some 300 Win Magnum muzzle blast coming from the bench next to me. After these guys left I shoot my last few rounds and ended the day shooting a
.262" Group. I think this rifle could do this every time as long as I am up to the task and it's a good example of what a well tuned factory bolt action rifle can do.
I think I'll keep it.
