140 grain bullet conundrum

[Againstthegrains]

So I got a few trial packs of .308 cal viper bullets in 165, 150, 140 and 130 grain.

I ran them through GRT and found that in my 26 inch barrel .308 win I can hit nodes at 2615ft/sec for the 165, 2835ft/sec for the 150grain and 3050ft/sec for 130 grain. But those 140's at the same (right) pressure land smack bang between the 130 and 150 grain nodes.

I tried running them at a half node (2900f/s) and they do not group at that speed. There is too much pressure if I try reach the 3050ft/sec node and other than the case fill% and lower pressure, there is not much point in running a 140 grainer, at the same speed as a 150 grainer to get it to group, or am I missing something here?

Is it possible that some bullet weights are just meant to be white elephants in certain calibers?

[Treeman]

Definitely - but more so for certain barrel lengths, take that load of yours and run through QL with a 24 or 26 inch barrel ?

[Againstthegrains]

I don't have Quickload, so I ran it through Gordon's Reloading Tool.

They basically tell the same story. For a 26inch barrel, the nodes are spaced around 200f/s apart at about 3050, 2835, and 2615f/s.

So the only advantage of going from a 150 to 140 grainer is that pressure drops 4% and recoil by 7%.

I guess I keep coming to that conclusion, that the 308 was made for 150gr bullets. I just wish Howa would make them in 1:12 twist instead of 1:10 which would be more suitable.

[Treeman]

I have always loaded the .308 with an 168 gr bullet - never had any reason to question the load, never tried anything else, just tried 168 and it worked totally.

I am of the it seems lessor group of shooters that believe that the 150 gr bullet is absolutely wrong for the .308, less BC - Sd, too much speed not enough behind it.

[Tripodmvr]

Treeman, you now have apples and oranges. All copper bullets need speed to open up and they do not lack penetration. You can therefore lose 15 to 20% in weight but still have a good hunting bullet.

The range of bullets as well as propellants will always have some anomalies. With the 223 and S321 you will find very little speed changes between 50 and 55gr bullets. To reach the next node to the top, the 40gr bullets then achieve 400fps speed gain.