Hi,
I bought the 185gr HBRN bullets to get a safe, but higher velocity bullet from the 45 ACP, at normal pressures. I doubt that the low pressure of the 45 ACP would obturate the base of the Berry bullet, as it is very thick and plated. This principle works in pure lead bullets and where the base sides of the bullet is very tapered, i.e. thin at the base and thicker towards the inside of the bullet.
Before purchasing the 185gr Berry HBRN I believed these bullets would offer the same basic advantage as the "THV" bullets, but not as markedly, meaning the hollow base increases the combustion space of the case. This allows the reloader to increase the powder charge above normal (I DO NOT USE fast powders as with the THV) for a solid, flat base bullet. Using slower powder (Unique, Auto Comp and Blue Dot) than what is popular with the light bullets in 45 ACP, I got what I was looking for. Because the question asked was about Unique, I shall share the following: My starting load of 7.9gr (Speer #14 lists 8.2gr as maximum) did not even cycle the slide on my 6" Springfield Longslide, but did cycle the slide of a 5" Norinco and my Ruger SR1911. I have used more powder than Speer's max load with this 185gr HBRN bullet, and still found it to be milder than 230gr factory loads. Because these loads are more than the manufacturers max, I shall not share them, only the principle involved.
As an aside, the inverted 185gr Berry HBRN bullets make very impressive HP bullets for my 480 Ruger, when using a 45 ACP case as a jacket for making the bullets (I shoot away all my small pistol primed 45 ACP cases). I add lead pellets to then get to any desired bullet weight I want, from 275gr up to 400gr. Accuracy is good enough to play with out to 50 yards with the 2x magnification scope on my 480 Ruger. Cases of the 45 GAP work better, but are much more expensive.
RSA1