Berry's plated bullets? Aren't those rated at 1250fps?
I use them for plinking/practice ammo for handguns, but never considered them for a rifle.
Thin plated bullets in general have some speed restrictions.
Berry's lists two speed limits for their bullets - 1,250 fps for their thin plated bullets and 1,500 fps for their "thick" plated bullets.
X-treme has similar suggested limits of 1200 fps and 1500 fps for their regular and heavy plated bullets.
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It's somewhat dependent however on the load and the bore. For example, I use X-treme's 150 grain .308 FP plated bullet on top of a charge of reloader 7 in .30-30.
I get very good accuracy with them in my 30" 1885 High Wall, with 5 shot groups of 1" at 100 yards and 10 shot groups a bit under 1.5" at 100 yards. The velocity is right at 1775 fps, which is well above the 1500 fps limit. However at 1,800 fps I start getting some significant fliers in about 10% of the shots fired and at higher velocities the percentage of fliers sharply increases, and I suspect that is do to damage to the plated jackets at the higher pressure and or velocity of the heavier loads.
Consequently, in a .30-30 you're giving up about 400 fps - but X-treme strikes their cores before plating and then strikes the plated bullet again after plating and the result is a uniform bullet that can produce good accuracy.
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What I would like to see is a heavy plated bullet in .38 caliber in a 158 gr RN or FN configuration. That would allow near full power loads in .357 rifles and carbines.
I'd also like to see a 170 gr FN or RN heavy plated bullet in .308 as it would allow greater efficiency in a .30-30.