OK so the Peregrine are Bore Riders like the Hydros. Bore Rider = The diameter of the bullet is that of the lands or very close to. The raised section/driving bands are grove or close to grove diameter. The Barnes are grove diameter with groves cut into them. So the Hydros can be seated with the front section of the bullet sitting in the rifling and the first band just off. Barnes type only the ogive can do this. Theoretically the Barnes type will produce a higher pressure?

Does this mean that bore riders can be used in thin barrels or doubles or older guns? I do not know but would expect they could be.

The designer/developer of the Hydro claims he tested many grades on copper/zinc alloy to find one that was not too hard or soft and produce pressures similar to soft nose bullets. Got that from the Woodleigh reloading manual.

Now my observations and thinking. I have load developed for 300 grain 375 H&H and 400 grain 416 Rigby. I will discount the 375 loads as I had to use a different powder to the cup & core type bullets. In the Rigby using the same powder loads I get 100FPS faster with the Hydros then 400 and 410 grain soft nose. No detectable increase in felt recoil, subjective and not precise I know.

What I put the extra velocity down to is lower pressure due to lower friction allowing a faster Excelleration. Yes plenty of holes in this logic, however when I use Woodleigh 410 grain solids- these are slightly undersize, and same powder load I can detect a difference in the felt recoil. I might add these loads are not far off my recoil tolerance. This maybe why I can pick the difference as a little increase becomes noticeable.

People may or may not agree with me and that is fine as this is an extremely narrow sample.