The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

Does anyone have a view on a start jump for the 123 Amax? This is for the 6,5-284 and right now I am around 40 thou off the lands with little hope of getting much closer...

I only have experience with the 6,5x47 Lapua using this bullet. I've used my Scenar's and A-Max with less than 10 thou jump with excellent results. The base to ogive measurement in my rifle where bullets touch the lands is around 2.118" (measured with the fantastic Shooting Shed gage ) using the trial and error method of removing the firing pin spring and "feeling" when bullets of different overall lengths contact the rifling when closing the bolt.

I've used A-maxes with BTO lengths of 2.115" to 2.100" with good results. I tried jamming at 2.120" but accuracy was terrible so it doesn't like to be jammed. See pictures below, my notes state the BTO length.

I did some load development at 2.682" OAL (2.110" BTO) and 39.7gr to 40.1gr of RS60 gave some really good groups so I know that the bullet likes this much jump. Velocity was not recorded at the time of those groups but it was in the region of 2,900 +/- 50fps when I shot those rounds the next time (I don't have my notes with me so can't recall exact numbers).

A note: my 6,5x47 Lapua has a very short throat so my results may not be good for others.

Hope this is useful for you.

2.110" BTO (around 0.008" jump) 2.120" BTO (around 0.002" jam) 2.110" BTO, different powder charge to above