Barrel Repairs / Alterations

Unless you are very lucky, or very careful, at some time you will need to have some work done to the barrels of your gun.

Barrels, these days, are made from steel containing a mixture of chrome and nickel. They are very strong and flexible to accommodate the explosion of the propellant. Some older guns have Damascus barrels. Steel barrels, when made, are blacked or blued (best quality barrels take on a blue sheen when polished and finished by an expert). Damascus barrels are browned as they are made of iron and steel which is twisted together then soldered around a central mandrel. This is what gives the distinctive swirl pattern in the metal. Depending on the number of rods of iron and steel used, the pattern also changes. The more rods, the finer the pattern and the higher the quality.

barrel blueing - Greenwood Gunsmiths Tern Hill, Shropshire, UK

Which ever type of barrels you own, refinishing them is a job for an expert. We are very lucky to be associated with one of the best barrel finishers I have ever found. His best English blue is superb; none of my pictures do justice to.

He is also very good at a number of other jobs that require a masters hand, including relaying the ribs of the barrels if they become loose, polishing the bores if they are damaged or pitted.

I have seen him take some huge dents out of barrels and restore them to pristine condition.

The photograph to the left is an example of the barrel finisher’s art. Note the bluish tinge to the barrels.

Shotguns, as most of you know, I am sure, have a restriction in the muzzle end of the barrel, called the choke. This is measured in thousandths of an inch.

A cylinder choke has no restriction, where as a full choke has a 40 thou restrictions.

cylinder= 0 restriction

Therefore:-

¼ choke=10 thou

½ choke=20 thou

¾ choke=30 thou

Full =40 thou

An additional 5 thou to each of the above is usually expressed as improved.ie improved ¼ =15 thou.

However, the Americans call a ½ choke modified, and the ¾ choke improved modified, so it can all get quite confusing.!!!!!

Therefore, it is always best to speak in thousandths of an inch, if you are asking for your chokes to be altered, or buying an additional choke for your multichoke shotgun.

Chokes are altered by lapping the choke area to reduce the amount of restriction. To explain lapping, a plug of lead if formed around a thinner steel rod. The lead plug is a tight fit in the choke area and is then covered in fine carbrundum grit. It is then spun slowly, moving backwards and forwards, to polish out the metal thousandths of an inch at a time. Once again, if it is carried out properly, as well, as increasing the size of the shot pattern, the distribution of the pellets can be improved, giving better kills.

A browning multichoke in a very poor state - Greenwood Gunsmiths Tern Hill, Shropshire, UK
A browning multichoke in a very poor state

Some shotguns are fitted with “Multichokes”. This is where the muzzle of the gun is overbored, and then threaded to accept a screw in restriction or “Choke”.

These can be very useful, as they change the spread of the shot or pattern, enabling the shooter to use the same gun for different disciplines. I.e.: Skeet, cyl and cyl, or sporting perhaps ¼ and ½.

However, I would like to point out that, in my opinion, chokes have less effect on the pattern than they used to, due to most modern cartridges using plastic cup wads. These tend to hold the shot together more than felt or fibre wadded cartridges. I feel, today, choke has more effect in the mind, than on the pattern.

But, if you own a gun with multichokes, or you feel the need to have your gun retro fitted with them, do take them out and clean them properly.

If you do not clean them properly, they may not seat properly, and allow gases in behind, lifting the back edge of the choke and effectively blocking the barrel. The next shot could have the following effect:

Part of the shot and gases blown out the side of the barrel - Greenwood Gunsmiths Tern Hill, Shropshire, UK
Part of the shot and gases blown out the side of the barrel
Internal view. Notice how the top portion of the choke wall is missing
Internal view. Notice how the top portion of the choke wall is missing
Part of the shot and gases blown out the side of the barrel - Greenwood Gunsmiths Tern Hill, Shropshire, UK
Internal view. Notice how the top portion of the choke wall is missing

I recently found this barrel in the back of my “odds and sods” cupboard and thought you might like to see it. It is the barrel of a 325 12b Browning, which was put in the boot of someone’s car. His friend then went to put his gun in, forgetting it was loaded. It went off, and this was the result!!!!

It goes to show the destructive power of a shotgun at close range, and what could happen if we don’t pay attention. 28 grams of lead emerging from the muzzle at approx 1500ft/sec is frightening.

These pictures are of an old English boxlock whose ribs have parted company with the rest of the barrel. On a newer gun, ribs can become loose because they were not soldered correctly when the gun was made.

On older guns, as above, vibration and heat, coupled with degradation of an older, poorer type of solder leads to “pin holes” along the rib to barrel joint. Moisture can then penetrate, giving the above effect. Yes, that is rust and old flux!

Part of the shot and gases blown out the side of the barrel - Greenwood Gunsmiths Tern Hill, Shropshire, UK
Internal view. Notice how the top portion of the choke wall is missing
Part of the shot and gases blown out the side of the barrel - Greenwood Gunsmiths Tern Hill, Shropshire, UK

As you can see, though, in the hands of our master barrel maker, nothing is beyond redemption. As usual, I wish my photography was up to the standard of his work and blueing.