Stepped barrel vibration

jaegermister

Heavy barrels/stiff fluted barrels/free floated and evenly bedded barrels have proven themselves as accuracy improvements. Recently studies have revealed molecular wave vibration that travels thru the barrel steel at over 6000fps as the bullet travels down the tube. My question: I noticed German Mausers and large artillery barrels are stepped is this in response to this vibration? To eliminate or tune the vibration? A photo of the Bismark shows barrels stepped in exact proportion to 98 barrels. Is it possible to tune the vibration (upward vibration) to cause a bullet to rise the line of bore as it exits the muzzle?

Mobuck

In most cases the stepped barrel is the result of manufacturing. It is much easier/cheaper to reduce the barrel diameter in steps rather than a gradual taper. It also facilitates installation of sights, barrel bands, or whatever.

jonk

The stepped barrel also was a function of expansion- when it heats up under rapid fire it expands ever so slightly (the steel). The thicker, harder to heat steel is at the rear where the combustion is hottest, where the 'barrel whip' would be greatest; plus the steps promote less binding as it expands.

Probably also a lesson learned from the GEW 88- early ones had no 'beefed up' breech, just a long constant taper barrel- and a few chambers blew out.

MIKE WISKEY

I have read that the weapons designers did use the 'stepped' barrel to dampen vibration while keeping the weight down. The same effect as barrel 'tuners' do today. I have also read that almost all the 'vibrations' are in the vertical plain (up/down, no sideways).

jaegermister

I have built several scout mausers, all retaining the original stepped barrels. In each case the guns shoot at point of aim over a greater distance than similar mausers with sporting tapered barrels. Both types having the same bore line to scope line of sight line, the stepped barrels will shoot dead on at 20ft and out to 100 yd, whereas the sporter barrels will shoot low at 20ft and gradually rise to dead on at 100yd. This obvious being due to the scope height and line of bore below line of sight.

Hawk Carse

I saw a picture of a Mauser with handguard off. The stock inletting has clearance cuts in front of the steps. For heat expansion, they were planning on RAPID fire.

v35

My understanding is that each section, having a separate vibration frequency wont allow the barrel to whip sinusoidally when fired.
I've also heard recontouring these barrels defeats accuracy built into these barrels.

ENBLOC

I have a few Mausers. I always liked the look of the steps in the barrel. Vibrations or not; there is the coolness factor going on here. I notice too that on my Argentine Mauser Sporter the barrel appears to be rather thick once shortened. Somewhere between taper & bull don't you think?[8D]

v35

Note the stepped barrel on the German Leopold railway gun in Mike Whiskey's post.
They carried the principle to serious long range artillery.

sandwarrior

jaegermister,

The stepped barrel is a compromise between accuracy and weight. As noted the thicker barrel at the chamber end helps dampen vibrations. Since putting a heavy barrel all the way out to the end isn't feasible they had to compromise the best they could. The compromise, IMO, is better than putting a thinner, high quality barrel on there and hoping it shoots better. Stepping gives the thickness where needed. And, provided the steel is of good quality, the end of the barrel isn't going to whip if the front end of the barrel doesn't cause it.