12 Twist 22-250/69g SMK h/t Michael Courtney

[benchracer]

38.2 grains of RL-17 produced an average of 3615 fps for ten shots.

I gave the new Tipped Matchkings a try. They all hit the target sideways, so it looks like I will be staying with the standard 69 SMK's.

69 SMK/38.2 RL-17

AVG 3618
ES 47
SD 13


I have attached the QL predictions. Note the large discrepancy between predicted and actual powder charges for the measured velocity.

The relevant OBT nodes are predicted to fall at .978ms and 1.110ms. This particular load did not fall on an OBT-predicted node, coming in around 1.050ms. When the projected powder charges are corrected vs actual, it appears the 37.3 grain powder charge would fall close to the predicted OBT node at 1.110ms.

I intend to chrono the 37.3 grain load to see what ES and SD numbers look like. However, with SD running at .36% for the 38.2 grain load, I am not sure it will be worth it to sacrifice approximately 100 fps for a questionable gain in accuracy over an already excellent load. It will be interesting to see what actual shooting results have to say on the matter.

 

[Iron Worker]

That's fascinating, I have a T/C predator it has a 12" twist I'll have to try out those 69gr smk

 

[benchracer]

That's fascinating, I have a T/C predator it has a 12" twist I'll have to try out those 69gr smk

I would be interested in your results when you do. The Berger twist calculator says these bullets lose a lot of bc from a 12 twist, but they could still be pretty useful to lay the smackdown on a critter in situations where a more frangible bullet may not be desireable.

 

[benchracer]

I gave the new Tipped Matchkings a try. They all hit the target sideways, so it looks like I will be staying with the standard 69 SMK's.

This was the result when I tried the 69 grain Tipped Matchkings from my rifle. Kinda looks like I am playing Battleship in this picture...