GJgo
Member
Hey All,
So I've been fighting this Weatherby Vanguard Sub-MOA 270 WSM I bought last year trying to find a handload that the thing will shoot well. To make a long story short, my quest led me to Reloder 17 (the new stuff) and 130gr Accubonds. In my gun, 63 grains puts 'em out of the barrel around 3400 fps and they group real well.
I had the bright idea that I'd pick up some 130 grain Ballistic Tips to practice with since they are the same profile- right? Wrong. Here are the things that I discovered.
First, the ogive is not the same. When I tested the COAL at the lands between the two, the Accubond cartridge is longer by .010". Next, when I load a cartridge at .015" off the lands with the Accubond, when I load a Ballistic Tip without touching my dies, the Accubond COAL is longer by .005". The end result, while not a huge difference, is that the BT is .010" off the lands at the same die setting.
Second, it takes a different amount of powder to run the same speed. In my gun I have to run 64 grains to make the Ballistic Tip run the same 3400fps that the Accubond runs at 63. I did a little searching and it seems that the bonding process in the Accubond anneals the copper a little, effectively making it softer. This makes sense to me with what I'm seeing, but it is not obvious nor is it reported (that I'm aware of) in the loading manual information.
Third, the BT just doesn't group like the AB does in my rifle. that sucks, because I like to practice and the AB is quite a bit more expensive!
So, has anyone else had a similar experience?
On a side note, with both I can run them up to about 3500fps before I start to see the slightest pressure signs. While I haven't bothered to go higher since the groups open up, there is some headroom. What's a 270 Weatherby Magnum again???
So I've been fighting this Weatherby Vanguard Sub-MOA 270 WSM I bought last year trying to find a handload that the thing will shoot well. To make a long story short, my quest led me to Reloder 17 (the new stuff) and 130gr Accubonds. In my gun, 63 grains puts 'em out of the barrel around 3400 fps and they group real well.
I had the bright idea that I'd pick up some 130 grain Ballistic Tips to practice with since they are the same profile- right? Wrong. Here are the things that I discovered.
First, the ogive is not the same. When I tested the COAL at the lands between the two, the Accubond cartridge is longer by .010". Next, when I load a cartridge at .015" off the lands with the Accubond, when I load a Ballistic Tip without touching my dies, the Accubond COAL is longer by .005". The end result, while not a huge difference, is that the BT is .010" off the lands at the same die setting.
Second, it takes a different amount of powder to run the same speed. In my gun I have to run 64 grains to make the Ballistic Tip run the same 3400fps that the Accubond runs at 63. I did a little searching and it seems that the bonding process in the Accubond anneals the copper a little, effectively making it softer. This makes sense to me with what I'm seeing, but it is not obvious nor is it reported (that I'm aware of) in the loading manual information.
Third, the BT just doesn't group like the AB does in my rifle. that sucks, because I like to practice and the AB is quite a bit more expensive!
So, has anyone else had a similar experience?
On a side note, with both I can run them up to about 3500fps before I start to see the slightest pressure signs. While I haven't bothered to go higher since the groups open up, there is some headroom. What's a 270 Weatherby Magnum again???
