GRIZ: I'm sure you're aware that chronographing and pressure testing are two totally different things. You don't know what powder FEDERAL used in the load, or even if it was truly above +P other than basing this purely on velocity. Do you know what the pressure rating for that +P+ load is? The SAAMI maximum average pressure for .38 Special +P is 18,500 PSI with +P+ running slightly higher, IF IN FACT, it is designating anything more than a higher velocity rating. It is not simply a slightly downloaded .357.
For everyone concerned: In the SPEER #11 which shows data that was around for a good many years without risk of people using dangerous loads, the pressure rating of .38 Special +P was 22,400 CUP. FOR .38 SPECIAL REVOLVERS. Noirfan's question asked about using .38 Special cases for loads in a .357 MAGNUM. The CUP rating uses a different pressure measurement, but in terms of PSI, it's higher than the current rating for +P+ and at a time when pressure for the .357 Magnum ran 46,000 CUP.
Some of you guys are casting an assumption that potentially dangerous advice is being dispensed here. And some of you are doing it while your facts could be a whole lot straighter. What is more dangerous for a new reloader? Explaining the correct method for building a higher performing load, or giving them misinformation?
Let's look at some of the advice so far. 1. Build these types of loads in full length cases. How about telling these guys how much unused case capacity their likely to encounter with propellants like Unique or something even faster burning? How many revolvers have been exploded because of a double charge of fast burning powder used in full length magnum cases.
If we're going to be blunt. I'll just state it exactly how I feel. Using Unique in a .357 Magnum case is about as useless as tits on a boar, IMO. Pressure will be unnecessarily high for the performance achieved and I've yet to see a Unique load at high pressure in a .357 Magnum case that couldn't easily be bettered in accuracy by using a more appropriate powder that gives better case fill and operates at much lower pressure.
VELOCITY DOES NOT EQUAL PRESSURE. But if you feel justified in recommending a powder that is likely to create maximum pressure in this case, it's kind of obvious that you're not aware that lower pressure can be achieved with an appropriate slower burning powder. The fact that some of you may not know how to go about this is obvious. But yet, you're dispensing advice that a new reloader may assume is expert advice.
As far as what's getting old to me is a guy that thinks he's established credibility with his knowledge of reloading based on his post count!