Today was my second attempt with this load. The first time out it was apparent I did not have the taper crimp tight enough. As per forum member Siringo's load data posted in the knowledge base I am loading the Barnes 275 grain XPB .451(460 SW) over 34.5 grains of Lil'Gun. I used new Hornady 450 BM brass. The only prep to the brass was a slight chamfer on the case mouth. With this last 6 bullets I had left from the box I put a very heavy taper crimp on them.
With the first loads I did, the crimp was not visible. This time it was. The very end of the case mouth had a smoothed look. I checked them with my calipers set to .475 and to be honest I think they were very slightly under but it just kind of depended how I held the two together... it was close. Next I gave them the "thunk test" and got a nice "thunk" so I figured I'd give them a try.
I set my target at 75 yards. I fired these from a concrete bench. I was not as steady as I should have been because my chroney was not lined up exactly so I could only rest the rifle on the front bag. Instead of resting the butt on the rear bag I had to pull it into my shoulder to have proper alinement with the chroney.
So here is the first 3 shot group. Two went into the same hole. The next 3 shot group was a clover leaf but off the target because I changed my aim point to a dot at the top of another target. This load shoots about 4 inches higher than the Hornady 250FTX. Average velocity for the six shots was 1962fps. According to the Barnes manual the 275 grain XPB expands reliably at 1400 fps. The ballistic tables put it at just over 1400fps at 150 yards with a mv of 1900fps so expansion should be really good in the 100 to 150 yard range. Fifty yard vel. would be just over 1700 so it might shear petals at 50. I am pretty pleased with the results so I will buy another box and shoot some 100 groups.
450 BM 3 shot group by
Shadow Dog, on Flickr