English Mike sent me a few .277 130gr Fox bullets to test. These are manufactured in Europe and we don't see them much (if at all) in the US. The are a monolithic brass bullet.
The only other brass bullet I have tested is the 6.8mm Controlled Chaos (CC) which did not have positive results. The CC shed bits of brass from the ogive but did not expand nor did it shorten enough to remain stable. Thus it tumbled and penetrated tail first through my bullet trap and plywood backstop.
I did an initial test at 100 yards with the 130gr Fox. The ogive disintegrated into tiny bits of brass but the bullet shortened enough to stay stable (nose first) so the bullet shank over-penetrated but remained in the bullet trap. It looked like a remake of the CC so passed on to English Mike the initial (not positive) results and promised to finish tests at greater distance.
Yesterday I was out at the range with the .270 so tried another test at 275 yards (max range distance). To my surprise, I pulled a perfect mushroomed bullet out of the bullet trap with excellent penetration. Expansion was driven to the bottom of the expansion cavity with is non-typical for monolithic bullet. They usually fully expand at a higher velocity/closer range like 100 yards.
Based on the 275 yard results, I decided to test at 200 yards. In this situation, the bullet shank was found deep in the bullet trap again but it had fully mushroomed but the pedals broke off and penetrated independently. The bullet shed it petals almost immediately as there were 3 offset holes in the back of the water jug where the pieces had spiraled out. Only one piece is shown. I actually recovered two pieces but lost one after leaving the range. They averaged 10 grains which is sufficient to sustain internal damage.
I was able to derive the Fox bullet's BC which was 0.277 (G1) with the LabRadar. Not surprising as this is not as streamlined as the 130 GMX or 129 LRX (BC approx 0.414). BTW, bullet accuracy seem good with two bullets within an inch of each other at 275 yards.
I looks like this bullet has been optimized for impact velocities below 2300 fps (less than .270 velocities). Higher velocity impacts are still lethal and had energetic reactions with the water jug. I have one bullet remaining and will conduct a low velocity test around 1800 fps.