doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Holland & Holland video

Ah, my ignorance of the trade is not far beneath the surface, but I'm under no illusion of men swinging hammers!

I'm trying to understand the different barrel manufacturing methods. For instance barrels forged around a mandrel versus barrels that are drilled and honed. In the case of the latter, how are the chamber, forcing cone and choke achieved?

Reamers or broaches.

In the case of a (cold) hammer-forged rifle barrel, a barrel blank with an oversize bore is actually hammered radially inward against a mandrel that is the "negative" of the bore, thus producing the lands and grooves at the proper diameter.

I'm unaware of any shotgun barrels that are made with this method.

Shotgun barrels, whether bar stock or a forging, are first drilled, then reamed and honed to final bore size. The chamber and forcing cone are cut with reamers made for the purpose. If the barrel will have a fixed choke then the bore is drilled, but not reamed for its full length, leaving a portion near the muzzle a smaller diameter. This is finished with reamer and hone to a diameter that establishes the choke.

In the list of steps to finish the Holland .500 3", 2 hours for "Balance, Plug, and Chequer". Then later, 3 more hours to "Recut Chequer". Interesting that the checkering is recut, evidently more painstakingly, after finishing the wood with oil.

SRH

Here's another interesting video.

http://vimeo.com/109802386

While it is a distinction that no shotgun barrels were cold hammer forged, but for years, Ithaca "Roto-Forged" shotgun barrels for M37 pumps over a steel mandrel. The mandrel was inserted into a heated tubular billet and the billet was auto-hammered with 4 hammers roughly the size of flat irons with the force of 132 tons until the metal extended over the mandrel the desired length. The hammer marks were removed by a lathe.
(paraphrased from Walt Snyder's book, Ithaca Featherlight Repeaters).

Here's Mr. Snyder's Shotgunworld post on the topic:

"A mandrel was inserted in a 10 inch round stock piece. That went into the forging unit where it was heated red hot by induction coils. Several hammers than rotated around the blank stretching it into a 30 plus inch barrel. The hammer marks were ground off via a lathe operation, and then on to the rest of the barrel making operations. I tried to cover all this with photos in my book on the M-37."

It's been my understanding that Remington barrels, such as those on the 870 and 1100 are/were cold hammer forged. From Remington's website:

"5) Are all Remington barrels hammer forged?

No. Most of our production rifles and shotgun barrels are hammer forged, though we do use various barrel manufacturing techniques to suit the unique needs of various weapons and systems.

6) Does Remington make all of its own barrels?

No. While most of our barrels are made in-house on our state-of-the-art cold hammer forging equipment, we do source barrels from various industry leaders based on the requirements of our customers."

Does anyone know what brand of abrasive paper they are using in the Holland and Holland video? The abrasive they use on the metal work, is pinkish/red in color, and appears to be made from a woven material or is cloth backed.

I would love to try some, it seems like it would not load up nearly as fast, and last longer than regular paper backed abrasives. If any of our British friends (or anyone else for that matter) recognizes that particular abrasive, please let me know.