777 Load Question
 

I switched to 777 today and I am not gtting a good group. I am using a load of 100 grains with 209 winchester primers. I use the hornady XTP's 240 gr. At 100 yds, out of six shots, all were in the kill zone, but no relative groups. It seemed as if all shots were within 3 inches each way of the bulls. Basically, no better than a 6 inch group. I was using a rest and also dry patched between shots. After the fourth shot, I cleaned with solvent and shot two more times. Any suggestions would be helpful. I may try moving down to 90 grains. Would too heavy of a load cause what I have witnessed?

Gun: Thompson Center Black Diamond

Are they .430 XTP's? I had good accuracy with 80gr Triple 7 2f and a .430 XTP in a green CR sabot years ago in a CVA Magbolt 150. Try Sabotloaders technique of patching between shots for accuracy.

They are the 50/44 XTP's with the black CR and I am using FFF triple 7. Im thinking if I go down to 90 grains that should be about 1840 FPS. Back to the range tomorrow. Hopefully I will have better results. Im afraid to drop too much when it comes to grains because I dont want to lose range, but then again, if I cant get a group at 100 yds, long range wont matter anyways. I would love to be able to shoot at least 150 or 175. 200 would be great!!!

I think you have the wrong bullet for that type of range.

Black CR sabots are for .45 caliber bullets.

Good observation Omega 45, That not a valid sabot/bullet combination. Also, with my black diamond 80 to 85 grains worked best.

This 100yd group was shot Friday with 100gr volume of Triple 7 3f using 300grain Harvester PT's in a Harvester smooth sabot out of my Pro Hunter with Encore Bergara barrel. I believe 90 grains was a tighter group but I cannot find my notes from a few months ago. :confused0024:

Shot 1: 1736 fps
Shot 2: 1748 fps
Shot 3: 1769 fps

Sorry!!! I just checked and they are the .45/240 with the black CR. I am heading to the range now. Im going to start with a low grain load and move up from there. Hopefully I get a group and at least get a starting point. Thanks for the information. I will let you know how I do today.

Blast away. :fighting0007:

I am thinking 80-90 grains with that combo.

My first question would be - do you need the Crush Rib sabot? If the bore is not that tight and in a Black Diamond it should not be but that does not mean it isn't, I would really try a different sabot. Older Crush ribs can leak pressure around the outside unless they are crushed tight. I would bet you would have better accuracy with a standard black Harvester, either the sort black or the long black. The other option is the MMP HPH-24 which comes standard with TC bullets.

One other thing I think that Harvester has changed the design of the crush rib sabot to help it retain pressure by putting the ribs on in a diagonal patern vs the normal striaght up and down pattern. The diagonal pattern would help the sabot seat in the lands and grooves better IMO.

Do you have any smooth sabots.... if you do maybe remove your BP and push a couple down through and see what you think...

One other thing check your barrel to stock channel - is the barrel getting caught in the channel in anyway....

I shoot most often 110 grains in a simular gun but I do use a different and a bit longer bullet most often.