7MM 163.5 gr VLD Bullet

[BOBC]

Would like to hear from the forum regarding this. A friend of mine asked if I could make him some lighter 7mm bullets for his 284 Shehane. So we decided on a 163 gr. So I made up a few for him to try. He has been using 180's. So he increased his 180 gr powder charge one grain for the 163 and changed nothing else. He tested both bullets at 1000 yds on a pretty calm day. He used his 180 zero for both bullets. He shot two groups back to back the 180 & 163.5. The 163's printed 11" higher than the 180 and the windage zero was the same for both. The 163's however, shot a much smaller group than the 180's and the recoil was noticeably lighter. He said he could kick up the powder charge on the 163's because they showed no signs of excessive pressure. The 180 clocked at 2833 fps. and the 163 at 2950 fps. A very small powder charge increase should be able to increase the 163's MV to 3000 fps. The 163 bullet OAL is 1.425" almost the same as his 180 bullet, maybe the 180 is .050" longer. Would the velocity increase of the 163 along with it's tighter grouping and reduction in recoil give it an edge over a 180, or would it be a push? The forum's views as always would be appreciated.

 

[Terry]

For Benchrest Accuracy always wins.

 

[Toolbreaker]

Would the velocity increase of the 163 along with it's tighter grouping and reduction in recoil give it an edge over a 180, or would it be a push? The forum's views as always would be appreciated.

Maybe . I would say for him to go ahead & work up his load for your 163's, then test them head-to-head with the 180's again, but on a less than desirable day: switching & gusting winds. That's the only way (that I'm aware of) to be absolutely sure.

 

[BOBC]

Thanks, that sounds like a good idea.

 

[4xforfun]

The "163's printed 11 higher" comment has absolutely no meaning unless they both had the same close range zero.

On the other hand, "the 163's shot a much smaller group than the 180's" comment says a lot...provided it was more than a one group test!!