Eye opener this morning on my Pardini 32's

I have a Pardini HP from the Larry's days and I have a newer 32 conversion from a few years ago (different from current and Larry's). Both are 32 SWL but they couldn't be more different. The newer barrel's chamber is .0015-.002" larger diameter when I measure my chamber casts. Then I noticed the rifling on the older barrel has lands about half as wide as the newer barrel. The twist rate on the old barrel is significantly faster as well. Looking down both when held side by side is shocking. I just never looked down the 2 at the same time or paid attention but my pursuit of better groups with my cast and powder coated HBWC bullets has driven me to this. The newer bolt is flat on the topo rear while the older one is rounded for the entire length of its top. I have never fired a round through the newer barrel. I bought the conversion from a friend who doesn't reload (or shoot all that well anymore). I also got about 3K once fired brass cases which is all that this barrel has ever seen. 
Now I'm contemplating using the newer barrel and bolt with the larger chamber and slower twist and wider lands on the older frame. Everything appears to fit together well.
I don't know that I have any specific questions but would appreciate input from anyone who has knowledge of these issues. My HBWC is 98-100 gr. depending on my alloy. With the older barrel I have several recipes that produce 1" 5 shot groups at 25 yards off sandbags  at 670-730 fps. New Fiocchi wadcutters chrono at 610 fps from this barrel and shoot patterns rather than groups.

Greetings,

I have seen Pardini HP in four model changes.

The rifling twist has been consistent.

The groove diameter had varied from 0.311" to the current 0.3135".

If your barrel has a "faster twist", I suspect it has a non-Pardini barrel installed.

I know the bolts have changed slightly; but, I am not well versed on them.

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With the Pardini factory barrels, a well formed 0.314" HBWC of 98-100 grains shoot easily in the ten-ring at 50 yards.

I have been using 1.70 (one point seven oh) grains of Bullseye in Lapua cases.

The above load also shoots well in the faster twist barrels.

I have no experience with powder coated bullets.

Cheers,

Dave