Talyn
Emissary
Note: This article also describes why the "Classic" BHP can barely handle the .40 S&W. And the BHP in the article is a Mk.III which was built to barely handle it.
Now the high points...
gundigest.com
FN—thorough engineering prowess has always been their strength— In the classic BHP, or Hi-Power, is a steel frame where more than 80 percent of the steel is machined away from the forging.
Another gun writer described it once as being made from the “best grade of Velveeta-class steel,” and he wasn’t far off. It didn’t need exotic alloys or high-strength steels; it worked and worked for a lifetime in 9mm.
But chambered in .40, the test guns died a quick and ugly death. Barrels, slides and frames all expired in different ways and at different round-count intervals, but they all died. So, the engineers rolled up their sleeves and got to work.
The .40 BHP differs from the 9mm in three major ways, besides the breech-face and bore. First, the .40-caliber barrel has three locking lugs instead of two. This spreads out the case-thrust load over 50 percent more steel. The slide is heavier, even though it’s the same length as the 9mm. This, combined with a heavier recoil spring, reduced slide velocity, which was just killing slides and frames. And, lastly, the frames were made of steel castings.
With the machining greatly reduced, FN could cast the 40 frames out of a much stronger alloy—an alloy that didn’t even need heat-treatment to make it strong.
The cast frames (Mk.III only) have the bottom of the frame, at the back of the magazine well, serrated in the direction of the bore axis.
Look at the bottom of the pistol frame at the magazine well.
If the surface appears smooth (left), the frame is probably forged.
If it has the longitudinal grooves or “ripples” (right), it is cast.
From Stephen A Camp's Articles...
When Browning started to develop the .40 S&W version of the Hi-Power in the middle 1990s, they quickly discovered that significant changes had to be made on that version in order to stand up to the beating of the .40 S&W cartridge.
These included a thicker (stronger and heavier) slide, additional slide/barrel locking lug, and other items. Also, the strength of some of the materials was improved. The improved steels are now used on both the 9mm and .40 guns. Thus, any .40 Hi-Power should have the stronger steels, and the newer 9mm guns will also have them.
Specifically, the receiver (frame) was changed from forged to cast steel. Although we tend to think of forged parts as being stronger, machining of the part becomes difficult when really strong steel is used. Practically speaking, cast parts are sometimes stronger than forged ones because really good steel can be used in the casting, with only minor machining required.
Now the high points...
A closer look at a very cool Yost Custom Browning Hi-Power SRT model in .40 S&W.
A Yost Hi-Power In .40 S&W: Custom Coolness
We take a closer look at a very cool Yost Custom Browning Hi-Power SRT model in .40 S&W.
gundigest.com
FN—thorough engineering prowess has always been their strength— In the classic BHP, or Hi-Power, is a steel frame where more than 80 percent of the steel is machined away from the forging.
Another gun writer described it once as being made from the “best grade of Velveeta-class steel,” and he wasn’t far off. It didn’t need exotic alloys or high-strength steels; it worked and worked for a lifetime in 9mm.
But chambered in .40, the test guns died a quick and ugly death. Barrels, slides and frames all expired in different ways and at different round-count intervals, but they all died. So, the engineers rolled up their sleeves and got to work.
The .40 BHP differs from the 9mm in three major ways, besides the breech-face and bore. First, the .40-caliber barrel has three locking lugs instead of two. This spreads out the case-thrust load over 50 percent more steel. The slide is heavier, even though it’s the same length as the 9mm. This, combined with a heavier recoil spring, reduced slide velocity, which was just killing slides and frames. And, lastly, the frames were made of steel castings.
With the machining greatly reduced, FN could cast the 40 frames out of a much stronger alloy—an alloy that didn’t even need heat-treatment to make it strong.
The cast frames (Mk.III only) have the bottom of the frame, at the back of the magazine well, serrated in the direction of the bore axis.
Look at the bottom of the pistol frame at the magazine well.
If the surface appears smooth (left), the frame is probably forged.
If it has the longitudinal grooves or “ripples” (right), it is cast.
From Stephen A Camp's Articles...
When Browning started to develop the .40 S&W version of the Hi-Power in the middle 1990s, they quickly discovered that significant changes had to be made on that version in order to stand up to the beating of the .40 S&W cartridge.
These included a thicker (stronger and heavier) slide, additional slide/barrel locking lug, and other items. Also, the strength of some of the materials was improved. The improved steels are now used on both the 9mm and .40 guns. Thus, any .40 Hi-Power should have the stronger steels, and the newer 9mm guns will also have them.
Specifically, the receiver (frame) was changed from forged to cast steel. Although we tend to think of forged parts as being stronger, machining of the part becomes difficult when really strong steel is used. Practically speaking, cast parts are sometimes stronger than forged ones because really good steel can be used in the casting, with only minor machining required.
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