I’m looking for some load info for my newly rebarreled .338LM. I used to use Retumbo, but that’s not been available up in Canada for over 2 years In the quantity I desire (or the prices). So, I’ve chosen VV N570. I see on their site that the max charge weight for the 300gr SMK is 91.3gr. I consulted locally with a fellow shooter of the same bullet and N570, and he tells me that he has found a node with his 26“ barrel with 93.0-93.5gr. I talked with another fellow shooter, and he has found a node with his 30” barrel at 94.2gr.
Is the consensus to load beyond VV’s maximum posted weight? Or is that just the lawyers advice? My goal is around 2900fps with my new 31” barrel. My former 26” pipe got a velocity average of 2880fps with 93.6gr of Retumbo. Yes… a stout load. Bolt lift was moderate, and I always got ejector marks on the case head. The reason I continued with this very accurate load was that it worked very well to a mile and all the way out to 1900 metres. Brass life didn’t seem to suffer either. I annealed every firing and got an average of 14 cycles before case separation occurred.
I‘m about to roll up some rounds for load tests this weekend. Here’s what I’m thinking: 90.0, 90.5, 91.0, 91.5, and 92.0 for my first outing. For those of you (I know there are a lot using N570) loading a 300gr class bullet, am I going in the right direction? I will using my LabRadar to check speeds.
I guess the most pressing thing on my mind is the fact that shooters are loading over VV’s maximums (and in some cases by a lot). I guess I will pay close attention to bolt lift and other signs. But I’m curious to what everyone thinks.
Andy 6MT
Is the consensus to load beyond VV’s maximum posted weight? Or is that just the lawyers advice? My goal is around 2900fps with my new 31” barrel. My former 26” pipe got a velocity average of 2880fps with 93.6gr of Retumbo. Yes… a stout load. Bolt lift was moderate, and I always got ejector marks on the case head. The reason I continued with this very accurate load was that it worked very well to a mile and all the way out to 1900 metres. Brass life didn’t seem to suffer either. I annealed every firing and got an average of 14 cycles before case separation occurred.
I‘m about to roll up some rounds for load tests this weekend. Here’s what I’m thinking: 90.0, 90.5, 91.0, 91.5, and 92.0 for my first outing. For those of you (I know there are a lot using N570) loading a 300gr class bullet, am I going in the right direction? I will using my LabRadar to check speeds.
I guess the most pressing thing on my mind is the fact that shooters are loading over VV’s maximums (and in some cases by a lot). I guess I will pay close attention to bolt lift and other signs. But I’m curious to what everyone thinks.
Andy 6MT
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