doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com chopper/lump barrels?

Most of my life I have shot pump shotguns, only recently getting into O/U shotguns. Therefore, I am not familiar with the terms "lump" or "chopper" as it refers to typs of double barrels.

Could one of you shed some light on this for me?

http://www.hallowellco.com/abbrevia.htm


Chopper-lump barrels (also called Demi-bloc barrels) - A method of joining the two separate tubes of a set of barrels where the right-hand half of the pair of lumps under the barrels are forged integrally with the right barrel and the left-hand half of the pair of lumps under the barrels are forged integrally with the left barrel. Chopper-lump barrels can be recognized by the fine joint-line running longitudinally down the center of each lump. This method of jointing barrels is the best because: 1. It is the strongest in relation to its weight, and 2. Because it allows the two barrels to be mounted closest to each other at the breech end, reducing problems regulating the points of aim of the two separate barrels.

All the methods of barrel joining shown at the Hallowell's site have been used successfully. The care and precision of work is more important than the method. Chopperlump barrels did become very fashionable and a high quality gun is likely to have them. However, their presence is not a guarantee of a high quality gun; they also show up on cheaper gun.

OK thanks.

can you discribe the other methods of joining the barrels together?

I have a feeling that some of the O/Us are just tubes that are inserted into a machined block of steel that makes up the rearward portion of the barrels and into which the locking recesses are machined, as well as the cuts for the extrators. Is this correct?

Correct. Called "Monobloc(k)". Used on SxS as well.

I count at least three methods which allow the bbls to be set as close as the chopper lump.
1-conventional; 2-dovetail lump; & 3-shoe lump.
Closness on any of these is limited only by the amount necessary for regulation or the strength of the matl, whichever comes first, same with the chopper-lump.

devrep and 2-piper:
I think you are both correct. Chopper lumps are generally considered "Best" for reasons devrep stated, and 2-piper I dont think devrep is implying other methods will not get barrels as close, just that they will not get them any "closer"

OK boys, thanks for the information.

In looking at my O/U shotguns the monoblock looks to me to be a pretty good way to make a shotgun and I can see where it might be cheaper to manufacture it that way.

Is the monoblock considered down scale in terms of producing a quality O/U?

thanks for the credit but my post was just a cut and paste from the Hallowell site.

Monoblocking is a "modern" way, although the process is actually old. A barrel set made via monoblock should be just as good as any other, care and skill of work being equal. If the monoblock is welded, then the seam becomes basically invisible. Choppers will likely command extra respect because the fashion is well set at this time.

If the issue was excellence of construction, then one piece barrels would be the top-o-the-heap. Guns are no longer just tools - they are pieces of art and craft. So, fad and fashion must apply.