Second trip to the range with my GSR and I must say, I like it even better.
This time I took it to the big range as I was confident that I'd be on paper. I have not made any adjustments to the sights and this rifle is pretty much zero'd at 50 meters with most loads I put through it.
Jacketed bullet loads:165 grain Hornady SP Interlock over Varget (two grains below max). Varget has been a good powder for me but I didn't expect it to do as well in this short barreled rifle. Book for this powder at MAX estimates 2773 fps out of a 24" barrel. I'm over 2400 fps with 2 grains left to go. This load is also proving to be very accurate.
50 meters, iron sights, three shots, ~ 1/2" c-t-c
The same bullet with IMR 3031 did ok but averaged about 50 fps slower with a load a bit closer to the published Max.
150 grain FMJ, pulled surplus bullets with IMR 3031, 1.5 grains below published max approached 2600 fps and showed very promising accuracy.
It doesn't appear this rifle is either bullet weight or powder sensitive with jacketed bullets. Yet another unexpected upside.
Cast bullets:120 grain Lyman 311008 plain base. Last time out this bullet did not impress. This time it produced the second best groups of the day. I'm driving it a little over 1250 fps with Bullseye powder. Better still this load prints nearly identically to the jacketed bullet loads at 50 yards.
The Lee C309-113 F again showed promise. I'll adjust the charges to try to get it subsonic and try a different powder to push it up over 1600 fps and see how it does.
The 173 grain Lyman 311041 improved this time out too. 5 grains of Bullseye pushes this bullet 903 fps (avg) and it 1" accurate at 50 yards with the iron sights. The POI is between 1-2" lower than POA with the Jacketed Bullet 50 yard zero. I shot this plain based (no gas check) and seated it deeper than the Lyman Manual suggests. OAL = 2.550" At that length it seems to feed a little better.
Another load using Unique drove this bullet (with a gas check) to almost 1400 fps shot close to point of aim of the Jacketed loads at 50 yards but the group size approached 2". The next trip out I think I'll try to drive it faster and see if it improves.
All and all a good trip and the GSR exceeded my expectations. Plenty to build on and tweak. I'm getting more familiar with it and the sights which helps too. I REALLY like that the cast loads and the Jacketed loads print close at 50 yards with the same zero. This will make it much more useful in the field. My plan is to tweak the loads and visit the range once again before taking it out in the woods for some field testing. So far I'm VERY happy.