How Did Long Branch rifle their barrels?

[browningautorifle]

Some info from our past threads here... I don't think anyone mentions the manufacture of the machines or type.

http://www.milsurps.com/showthread.php?t=1682

https://www.milsurps.com/showthread.php?t=45997

Information

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[Rick]

Some info from our past threads here... I don't think anyone mentions the manufacture of the machines or type.

Thanks Jim. About all I can take from that is the answers suggested the rifling was broach cut. Given the horrendous looking (through a borescope, mind you) striations running the length of the grooves after all that lapping, I think I could confidently guess they weren't button rifled. They sure don't look anything like what you see when you look into one of the barrels we button rifled.

That makes me mildly curious as well. Looking at how quickly a barrel blank can be button rifled, and how smooth the result is, I wonder what the productivity/quality advantage was for wartime production, choosing any method of cut rifling over button rifling?

The rifling machines on site at what was previously Montana Rifle Company/Remington were designed and fabricated right there. They look about as technologically advanced as a club - but at one point those two machines were rifling about 20,000 barrels a month. The guys we brought back said they were most reliable machines in the shop, and the new guys (after they'd graduated from the barrel lapping benches) were put on the riflers because they were the most simple and easiest to run.





After working with those 1930's Pratt & Whitney machines for nine months, it leaves me with a bit of professional curiosity about the machines and methods used to deep hole drill and ream Long Branch's.