I'm using 31.0 gr of 3031 and 170 gr Interlocks for a book estimated 2150 FPS at the muzzle.
I'm something of a fanboy with respect to the results of large sample size testing as reported by Hornady on their podcast. Their primary findings are:
1) Group size is primarily dependent on a bullet and powder your barrel likes.
2) Group size does NOT depend on small changes in powder load. In particular, they have not found any evidence of velocity or accuracy nodes with small powder charge changes when looking at large (35 shots or more) samples.
3) Generally speaking, accuracy gets worse with increasing velocity.
4) Generally speaking, stick powders are more accurate than ball powders.
The bottom line then is to chose a good bullet and well proven powder for the round and then use the lightest safe charge needed to get the down range performance you need.
I hunt the woods in Vermont and want through and through shots for a blood trail at relatively short distances. Hornady reports that the Interlock is tougher and less prone to coming apart than the FTX and needs 1800 FPS on target for reliable expansion. 2150 FPS at the muzzles give me (by the book) 1800 FPS at 115 yds and 1750 out at 130.
So, I consider this to be a 130 yd load, maybe a bit further if I have a clean broadside shot.
In terms of accuracy, I no longer trust 3 or 5 shot groups. This load has given me a 3 shot group of 3/4" which sound awesome. But when taking a series of 7 3 shot groups - each with a cold barrel - for an aggregate of 21 shots, that group has opened up to a whopping 5" at 100 yds. Using a group analysis tool gives me a mean radius from the group center of 1.5, which means the vast majority of shots will fall inside a circle of 6".
That's good enough for a 130 yd gun IMO.
Last edited by Pinnah; 02/15/24.
