Stepped vs. tapered barrel

O

Orita

Member
- I recently got a K98k barrel and I asked about the meaning of the markings
stamped on my barrel (please see my topic "K98k barrel markings"). The K98k barrel is stepped and I asked myself the reason the Germans had made the barrel stepped and not uniform tapered. Why ????
I assume must be many reasons and for the moment I can think of only three of them:
a) Easier to manufacture;
b) For easier fitting (stock fitting);
c) Reduced vibration for a better accuracy.
Any more reasons ???? Thanks in advance for any answers.
Orita 09/18/16
 
The stepped barrel adds a lot of cost/time and material loss to the manufacturing process. Stepped barrels require different tooling and inspection/gauging for each step on both the barrel and stock inletting to maintain a consistent product.

My guess is the steps aid in stiffness (more material) and more surface area for cooling.

A straight tapered barrel, like that found on a Kar98a, would be much easier/cheaper to produce in volume; that would only require a single lathe with a taper attachment or a tailstock with a known offset. The stepped barrel would likely require a series of lathes set up for each step of the barrel, and a separate gauge/inspection for each step.

You might have to add up the sum of all previous German service rifle barrel profiles previous to the 98k to find the answer, and the real reasoning behind it may be lost to history.
 
Orita,
* To amplify on your observation of barrel vibration as a rationale for stepped barrel design, Colin Webster, in his remarkable book titled Argentine Mauser Rifles, 1871-1959, Pg.62 discusses the Model 1891 Mauser development in detail. I quote an excerpt of this 2003 Schiffer published book as follows:

"These barrels were the first to incorporate a stepped exterior profile. Paul Mauser realized that when hot, the barrels stretch quite considerably and could crowd and upset their bedding. To allow for this movement, he replaced the previous tapered barrel with a sectioned barrel that can expand up to 5mm into clearance cuts made in the stock, remain bedded and pass through the barrel rings without obstruction. This had not been an issue with the Belgium sleeved barrels but emerged when the Argentine and Turkish Commissions eliminated the sleeve in 1890. Unlike the the early designed tapered barrel, the stepped design ensures at least 95% of the exterior surface remains bedded at all times thus reducing vibration and improving accuracy."


* Trust this adds insight to your query.

Respectfully,
Bob
 
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