Question Regarding Hodgdon Reloading Data for the .40 S&W

[BinRat]

I checked the Hodgdon Reloading website for information regarding loading some X-Treme plated 180 gr round shoulder flat nose .40 S&W bullets I just received, using W231 powder. They only list data for the Berry Bullet and the Hornady XTP bullet in that weight, which is no issue. it showed:

180 gr BERB FP 4.4gr 872fps 26400psi 5.1gr 984fps 33500psi
180 gr HDY XTP 4.1gr 797fps 23800psi 5.0gr 947fps 32900psi

It seemed odd to me that the data for the plated Berry bullet had a range of higher weights of W231 than the data for the jacketed Hornady. I understood that plated bullets should be loaded with higher lead data or lower to mid-range jacketed data.

Can anyone clarify this for me? I don't know whether I'm just not seeing something obvious or whether all those birthdays have clouded my reasoning. Thanks.

 

[Wreck-n-Crew]

I can confirm that the Berry's data is legit and did a thread on it at TFL http://thefiringline.com/forums/showthread.php?t=542969

Since then I have received 500 Extremes in 180 Gr RNFP I have seated them with the same OAL and charge of Autocomp with pretty much the same results.

What I think your seeing and referring to is the difference in bullet lengths. Though OAL is the same if one bullet is longer, it seats deeper and may use less powder. Also depending on the powder. Seating a bullet deeper is the same as shortening OAL in effect and some powders may react differently in pressure than others when seated deeper. The reason that some of the other powders do call or a tad more powder, though seated deeper.

 

[tightgroup tiger]

I understood that plated bullets should be loaded with higher lead data or lower to mid-range jacketed data.

The jackets on the Hornady XTP bullets are much harder than the plating on the plated bullets. The Hornady XTP will have much more friction when hitting the riflings than the lead or plated so the XTP will build more pressure quicker than the plated so the plated can take a little more powder to equal the same pressure as the jacketed. This happens alot with the slower moving, softer, plated bullets and faster powders when the speed of the bullet is below the threshold of what a plated bullet can take.

The pressure rating of the load is the overall limiting factor and when the pressure of the XTP is higher due to the extra friction of the harder jacket the plated bullet can be loaded a little hotter because the pressure isn't as high as the jacketed.

 

[gamestalker]

I agree with your analogy Tightgroup Tiger, but this particular published load does seem rather contradicting when compared to the other plated/jacketed loads and data. In most instances I've seen, jacketed data is almost always higher than recommended plated data, stranger things have happened though.

I would still use the published data, but I still think it's unusual.

GS