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I have always wondered why Mod. 21s have dovetailed instead of chopperlumps. Anyone know? Chops

Model 21 barrels are of chopperlump construction. The lumps are then machined so they can be dovetailed together, then soldered rather than brazed which does not destroy the heat treatment of the barrels. This is a totally different system than British dovetailed barrels where the entire lunp is dovetailed to the barrels. I hope this makes sense.....it used to confuse me too.

Buzz,
Did you mean to say, the British braze the entire lump to the barrels instead of dovetailing ,or do I not understand.?

I didn't look it up but I believe Schwing wrote that is was so they could solder them at a lower temperature and retain the steel's properties. The Model 21 dovetail is vertical. There are dovetails that run parallel with the axis of the barrels.

I probably wasted your time. I bet Don Moody will pipe in here with a definitive answer in a little bit.

Best,

Mike

I believe the British dovetail the lumps themselves to the barrel flats then braze. With dovetailed you can usually see a faint braze line lateral to the lumps on the barrel flats whereas with chopperlump you will see a faint line running down the middle of the two lumps where they are usually brazed together. A Winchester 21 is soldered rather than brazed. So, with chopperlump, the lumps are made as an integral part of the barrel and with dovetail, in the british sense, the lumps are made separate from the barrels as an individual and then dovetailed to the barrel flats, then brazed. A picture is worth a thousand words; someone will hopefully post some diagrams to better explain this.

I do not think anyone heat treated the barrels. I don't think that anyone could put them to red heat without messing up the thinner tubes. Years ago I passed on a M-21 @ $1400. It was a 20 bore, splinter and straight stock. Beeb kicking myself ever since. I am just a blue-collar fan. Chops

Chopperlump: I looked this up in 'Winchester's Finest The Model 21': Page 59, "The idea behind Burton"s patent was to develop a new system of joining the barrels together that would be strong enough to withstand recoil forces and heat buildup due to rapid firing, while at the same time be inherently sturdy enough to be soldered instead of brazed, thus not destroying the heat treatment of the barrels.". What I think this means is the original heat treatment in producing Winchester Proof Steel and they felt brazing could anneal the steel due to the higher heat, but this is only a guess on my part as to the literal meaning of the above statement.

This description may sound familiar: "The parts may be further locked together by a screw . . . passing through the halves of the lump, and, as an additional security, the parts may be soft soldered." That's from a British patent, dated 1911. The system was eventually used on the BSA doubles, which appeared about 10 years later--and about 10 years before the Model 21.

To my knowledge, barrels are never heat treated in the sense of hardening. I don't particularly know about Winchester Proof Steel, but many of the higher alloyed steels are a bit ouchy for warping at elevated temperature. That may be what is meant. More likely, IMO, is that the machining of the vertical dovetail and solder assembly was cheaper in the plant than the brazing assembly process. Once tooling is in place, machining is cheap compared to hand work.

I think there may be another view. I think the steel blank prior to being bored and machined was heat treated to a particular hardness and strength. That strength is better than the same steel in its annealed state. However that increased strength was still machinable. By converting to a soldering process instead of a brazing process Winchester was able to preserve that original treatment rather than reduce it further through a brazing process that further lowered its overall strength through additional heat.