flechero wrote: ↑Wed Dec 04, 2019 8:32 pm
Good info, thank you.
I agree with you on length. I always load a new bullet by taking a dummy and seat it down a few thou at a time until it plunks and rotates freely and then a few more until it feeds smoothly. I load to the longest length
my shortest bbl can handle in a caliber. ( but for rifle I load for a specific gun).
I don't have access to the Sierra manual but my online search suggests the Sierra data may be 6.1gr. of Silhouette. Accurate/Ramshot manual list max of Silhouette with the Sierra 125 JHP as 5.1gr. with other 124 gr. projectiles going 5.4gr to 5.9 gr..
The variance between bullet and powder manufacturer's data always intrigues me.
Yep, plunk and spin. One of my suggestions for those who are looking for a good reloading manual is to get one with pressure rated data. It's a must if you want to know a powder's characteristics for a given caliber. One reason that those who provide burn-rate charts advise that placement on a burn-rate chart can not be used as an indicator of a powder's charge-weight, because burn-rate charts come from closed bomb testing. A vessel of the same size. Powders can definitely vary by caliber.
I'm familiar with all of Western's data going back to 2001, when I first started using them. It reminds me of some things I saw with Vihta Vuori powders that I was using before then. Some powder manufacturers/suppliers who provide data, don't exactly tell us everything about how the data was collected. There are recent changes that would require a thread of its own to explain, so here's my take. So far as I know, up until 2015, SAAMI had specs for the 9mm, in particular, that allowed a tolerance range as far as cartridge and chamber dimensions. That, unfortunately, allows the data provider to work at any given dimension they care to use, so long as it's in the tolerance range. If you want to show the highest pressure possible for liability concerns, the data may have been collected from barrels that were at the minimum of the tolerance range. Shorter chambers and tighter bores for example.
The best way I know to make this point without causing offense to the guys in the Western Ballistic's lab comes from a simple question regarding the +P data they list. Just take it as my opinion that I know their powders. I have used both True Blue and Silhouette extensively for making higher velocity 124 gr. JHP loads in 9 x 19mm. No 7 is one of a kind for 147 gr. JHP loads as I've probably mentioned and it's been almost two decades since I last loaded a 115 gr, JHP. No 5 is somewhat similar to True Blue but lacks the pressure stability and ballistic uniformity. So knowing that, my question is why would they show +P data for inappropriate powders that burn too fast for even a slight advantage in velocity? Another thread on the subject of "The Point of Diminishing Returns."
Also consider that while SIERRA and SPEER do not show pressure data, which I prefer, that certainly does not mean that the loads are not pressure tested. About as clear as mud, right? I used to say quite often that every handloader should have at least one Lyman manual. The reason being that the data is pressure tested in most cases. It's not the answer to all questions, but some things are left for the handloader to decide based on the information available. As a result, I don't typically use Western's data for the 9 x 19mm. I do not believe that the component makers who provide handload data, even if not pressure rated data, as in the case of SIERRA, SPEER, Nosler and Hornady, ever exceed the Maximum Average Pressure rating for the cartridge. If the highest charge comes from the SIERRA manual, I trust that they know the pressure rating. And while Lyman data is pressure rated, they test in Copper Units of Pressure, CUP, as Hodgdon does also in some cases. Lyman does not always load to MAP, which for 9 x 19mm is 33,000 CUP, 35,000 PSI per SAAMI.
Anything that can be corrupted by man; will be corrupted.
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