jef2015 said:
If I know what it takes (powder loading) to reliably cycle 230 gr fmj, is it probable it will take the same using 230 gr plated? Are there other factors I am not thinking about?
Yes and yes.
Most plated bullets sized same as jacketed bullets will cycle the slide with the same powder charge.
Berry's website lists 45ACP plated bullets as sized larger at .452" compared to .451" for jacketed bullets. Because of the larger sizing, Berry's bullets will generally provide tighter bullet-to-barrel fit, especially for oversized factory barrels and produce higher chamber pressures (reason why Berry's recommends you use start-to-mid range jacketed load data). I typically use lead load data with Berry's bullets and get reliable slide cycling/spent case extraction and very good accuracy.
Berry's also sells Hollow Base (HB) bullets in 45ACP and the hollow base expands better (obturate) to produce more consistent chamber pressures and greater accuracy. My experience with HB bullets has been that I can use same lead load data or slightly less to produce the same level of accuracy (probably due to less high pressure gas leakage during powder ignition).
As to others needing to use more than 5.0 gr of W231/HP-38 in their pistols to reliably cycle the slide, I am guessing that they are experiencing more high pressure gas leakage due to larger than .451" groove diameter barrel, longer leade (space the bullet jumps from the case neck/chamber to the start of rifling) and the use of shorter OAL that allows more high pressure gas to leak around the bullet, which all reduce the chamber pressures and would require more powder charge. As Walkalong posted, the use of longer 1.265" OAL will allow the bullet's bearing surface to engage the rifling sooner and build chamber pressure faster, which would seal the bullet to the barrel sooner and leak less gas ... hence why 5.0 gr powder charge works for so many pistols/barrels.
I have used 5.0 gr of W231/HP-38 with various 230 gr RN (jacketed/plated/moly coated/lead) at 1.25"-1.265" OAL (depending on leade length) and it has worked well in various pistols with very good accuracy. Some shooters I know have to use 5.2-5.5 gr due to difference in reloading variables.
To get least amount of high pressure gas leakage and greater accuracy with less powder charge, determine the Max OAL using the barrel out of the pistol (bullet should drop in freely and spin without hitting the rifling) then determine the Ideal OAL by function check testing from magazine to feed/chamber by manually releasing the slide without riding the slide with your hand.
