Seems there had to be a reason at that time as I'd think it added to the mfg's machining and stock inletting expense. Was Mauser the only rifle that had this?

I read somewhere once that it was easier to manufacture and actually made a more accurate barrel. I couldn't tell you if it was true or not, but I can say I had a step barreled FR-8 that really shot well.

When it gets really hot a tapered barrel makes it harder to ensure that it will not impinge on something when it lengthens. A stepped straight diameter is easier to inlet for and deal with fittings around the barrel and stock. Or so I have read.....

Only guessing but am assuming that it might have to do with all the hand guards and barrel bands on military rifles - as the sporters did not have them.

I have a Polish rifle that is stepped up.

I believe it had to do with barrel harmonics

Now it would make sense for the Moisin-Nagants to be "steppe-d".

And to allow of installation of sights to allow for proper regulation of sights given the barrel length.

These rifles were designed to be used with bayonets thus a lot of stress.....at least that's my 2 cents!

a knowledgeable machinist told me that is easier to step it than it is to taper it on the older machines

coulda swore i read somewhere it had to do with barrel harmonics......IIRC the Germans did alot of testing on just where to put the steps to improve accuracy....

To add,I have a "Army Hunting" rifle,which is a sporter.This is also called a Type "C".It has a stepped barrel,like a K98,clip slots,came in two calibers 8x57 and .30/06 for export.No provsions for bayonets or any military equipment.
Mine was built in the early 30's,but may have seen service as a "sniper" rifle during WWII,since a scope,claw mounts and "Greener" style safely have been installed,then later(1940) German Army marks added.In my studies of the Mauser,the stepped barrel was used as a way to maintain accurcy without weight.

It was for machining both the barrel and the wood. The
harmonics mostly occur after the bullet has exited.

The way it was explained to me by a rather well read scholar of the bolt action rifle, was that the stepping was:

1: makes a stiffer barrel without the weight thus increasing accuracy and resistance to bending when used with a bayonet.

2: made the machining and fitting faster and easier to increase production abillities.

3: made the swapping of parts much easier as matching "flat" surfaces is much easier than matching "tapered" surfaces.

Per Olsons book on Mausers, Mr. Paul Mauser found that a barrel lenghtened when hot, so a flat surface prevented elevation shift compaired to a bedded tapered one.

My last Mauser project (early war BRNO) started out with the intent of re-barreling. I made the classic mistake of 'shooting the donor' and the original stepped barrel with minty bore shot so well I would blush if I told you how small the groups were. So, I built the gun around that barrel, steps and all. It seemed somehow out of place in a custom walnut burl stock, G&H side mount, Lyman receiver sight, double set triggers, etc., but my faith was restored during the first range session with the completed rifle.

Exactly, a 1909 in 7.65 that we have, has it`s original barrel. Outstanding accuracy with Sierra match bullets, to name one.

A wide variety of answers here, so I'll add my opinion.

Machining a uniform tapered barrel is more difficult than manufacturing a straight "no-taper" barrel - it's just a cylindrical cut. This was probably truer before CNC machining than it is today and probably required a more complex lathe (with some sort of a cam to govern the machining).

You need the most steel in the chamber area as this is where the most pressure if generated; as you move toward the muzzle , pressure falls off and less metal is needed. To make the barrel lighter, it can be reduced in diameter and since straight parallel cuts are easier and required less complicated lathes, it is logical that a series of straight no-taper cuts are made. A simple rounding cut at each step completes the task.

So, my answer is manufacturing simplicity and less cost.

In the musty archives of my feeble memory is the faint recollection that barrel harmonics was the reason for the steps.

Some custom barrels have been made with steps also. A Mauser 257 with Henriksen on the barrel has a single step in it. This barrel is tapered before and after the step. I have no idea who made the barrel, but it does shoot very well, even with me behind the trigger.

I'd bet lunch money that "harmonics" were among the last considerations for wartime rifles. If they were improved, it would have been a serendipitous gift - and probably discovered long after.

Ease of machining plus ease of fitting parts and stocks would have been the primary driving reasons.

ofcourse but the stepped barrel was designed outside of wartime.....yes it is easier to produce but they spent a hell of alot of time testing various things during peace time.....most of Mausers and the others designed thier rifles between the wars, and IIRC the stepped barrel came out during this time, not as a time saving measure during war time production....

Yinz figure the Krauts also stepped this'un, for ease of machineing and fitting?



Then, there's this tidbit from Olson:


Paul Mauser found that rifle barrels have 3 distinct vibration points. He also found that the continuous firing of magazine after magazine of ammo would cause the barrel to expand longitudinally. By putting steps in a barrel, the vibration was reduced. Stepped barrel Mauser rifles require a small amount of clearance between the front of the step and the recess in the stock to allow for the longitudinal expansion during rapid firing. The clearance allows the barrel to expand without jamming into the wood. Often, dried grease, grit or a combination of both will have worked their way into the clearances. Carefully scrape it out. If a stock has been swapped, the clearance may not exist at all. If that is the case, use a Dremel tool or scrappers and relieve the stock. (Source: �Mauser Bolt Rifles� 7th Ed, Ludwig Olson, F. Brownell & Son, Montezuma, Iowa, 1976)




Logged

I guess all this begs the question then - why aren't todays target and benchrest barrels stepped?

Because a heavier barrel dampens vibrations better than a lighter barrel, and thus, minimizes the error when bullets leave the barrel at different points in that barrel's 3-dimensional vibration pattern.

And, lighter weight is of lesser interest to a benchrest shooter than to an Army (infantryman) who has to carry his rifle, ammo, water, some food, grenades, shovel, etc. while marching up to 20 miles a day.

Barrel harmonics certainly do affect accuracy but this was probably not the main reason. Military rifles of the era were generally considered sufficiently accurate to pass the test if they could group into 4" at 100 meters. Most troops could not hit a man at 400 meters anyway, especially if he was moving, hence the universal use of machine guns (many bullets on target) for ranging fire.

Certainly if anyone has a Model 96 Swede in 6.5, in vey good condition,they will see that accuracy was importnat in the earlier years. Those rifles will shoot right alongside,if not better than most of todays out of the box rifles.

Cause their freefloated...much harder to do in old timey mil. stuff.
Look at todays AR barrels...more cuts in the barrel than you can shake a stick at, but float it from the receiver, bedding problems then don`t exist.

Does it or does it not make a barrel more accurate ?

I migt be wrong, but I believe I read some where that a tapered barrel whips the entire length in one harmonic mode each time.The steps,disrupt that whipping.

My memeory is not 100% any more and I could be wrong,as always.

The original congiguration of the 6.5 Swede Military Model 96 or the shorter carbine ( Model 37 ?)was not free floated and stil gave astonishing accuracy. When I sportorized mine,I cut the barrel at the 1st step back from the frint sight. Probably still one of the most accurate rifles I have, although I'm not into punching tiny groups in paper

I have 4 Swede Model 96's - 1 stock, 1 with Elite target sights, and 2 Kimber conversions. All shoot well - impressive for military rifles 100+ years old.

Those rifles will shoot right alongside,if not better than most of todays out of the box rifles.

+1..... That goes for my three Mod. 96's also; two originals and one Kimber conversion. All shoot very well, which is probably why I wound up owning three of 'em. Somebody obviously knew what they were doing when those things were designed and built.

I have a stepped barrel but the sections that are supposed to be straight have a slight taper.

Had an old wise man tell me once it was due to the barrels being superheated during battle, the thicker rear portions of the barrels held there shape's better when hot, and the fronts were able to cool a bit quicker, thus kinda balancing out the make-up.

Gunner

Everybody who posted accuracy as a result of barrel stiffness and "harmonics" (the barrels modal shape or operating deflection shape) are correct. Each length of the barrels three differing diameters has a tapered profile.

Then why don't they still step the barrels of benchrest and target rifles today?

I also tend to wonder what perceptible difference it would make in an infantry rifle with a full-length stock and open sights.

Maybe a difference in accuracy could be seen in scoped sniper rifles.

Phil is correct other wise all bench rest barrels would be stepped and they are not

If I were guessing the reason for the steps I would guess ease of manufacture or compatibility with other parts of the rifle before I would guess accuracy. The Mauser mil. guns were made in the millions to outfit troops; not made in the thousands to outfit hunters.

the sights had to have a flat surface and so did the band and forend at the end. so maybe it was just for ease of fitting?

+1...........

I'll just add that just because a stepped-barrel Mauser shoots very accurately doesn't mean the accuracy is due to the steps. I''ve had the same experience, but have also had old 1903 Springdfields, 1917 Enfields, Swiss M31's that shot extremely well, and all had typical tapered barrels.

In fact I own a nicely "sporterized" M98 done by some unknown customer maker. It has the original military barrel with the steps turned off--and shoots VERY well.

All of which makes me guess the secret to accuracy isn't stepped barrels but good barrels.

And as plenty of folks have pointed out many of the older barrels were very good.
I bought a number of stepped 30-06 Mauser barrels when Numrich was selling them new/surplus. They were built by FN and every one I have used could usually be coaxed into shooting MOA with proper loads.

I did that trick once, and though admittedly a sample of one, had abysmal results. I turned the barrel into a straight taper that just barely cleaned the steps (very lightweight- about like a Ruger featherweight contour). It turned a barrel that was an honest 2MOA producer into one that would put the first shot out of a cold barrel deadnuts on center. The second shot would go about 2" higher. The third 2" above that, and so on until the 5th shot was clean off the paper. Nice group- about �" wide and 10" tall. Repeatedly. If I waited 20-30 minutes between shots it was a dinger. Still, I hunted with it. After all, after a second shot at a deer it's not likely to still be patiently giving you a third chance. I traded it off and as far as I know its still being hunted. (I often threatened to take it antelope hunting, and if I missed with the first shot, and the animal ran directly away from me, I could keep shooting as the gun would be automatically compensating for the rapidly increasing distance! )

Undoubtedly I released some hidden stresses in the barrel when I turned it. (And the action was bedded and barrel free floated in the channel. Pressure point experiments in the barrel channel did nothing to improve it.)

A gunsmith friend did an experiment with a stepped M38 6.5 Swede barrel on which he milled the rear-most diameter into an octagon, then turned the remainder of the barrel into a taper to cleanup the remaining step. It is quite elegant looking. It gives nice accuracy- 1-1�" and made up into a dandy trim custom rifle to boot.

Very interesting thread. I find it especially interesting that there seems to be no discovered documentation as to why the barrels were stepped. It could not have been a casual decision. Maybe no one wrote it down back then.

I can't remember how long ago, but "Precision Shooting" or " The Accurate Rifle" had an article on this subject. IIRC, it was an interview and I believe it had something to do with the bore expanding from heat. Just can't remember like I use to!

gnoahh,

I actually performed a similar conversion to your gunsmith friends on the stepped barrel of an FN-actioned South American military Mauser in .30-06--except I did it by hand, with files. I converted the rear section to octagon, then draw-filed away the step in the front section of the barrel. It shot just the same as it had before.

They used their rifle barrels like a kabob for cooking meat in the field.

The steps were put in so your grub wouldn't slide down the barrel and burn your hand.

It also prevented iron mites from climbing down the barrel and eating the sights off.

Just say "no" to bath salts JM....

Just like you said no to taking a bath?

Well sure, but it was a custom afterwards and likely quite unique to boot. ;O)

Guessing it was probably an FN Columbian Army rifle in 30-06?

Picked one of those up many years ago, for the action. Cost me around $60 at the time. Never had the "don't shoot the donor" problem, as the bore/muzzle crown were both extremely poor and it couldn't keep three within 3", rested @ 100 yards.

Eventually became the basis for my trusty econo-thumper, with a slightly used 24" Douglass SS that was already threaded/chambered in 25-06. Still have it.

That rifle has accounted for a fair pile of dead deer over the past 25 years, couple of 'em taken beyond 400 yards.

I figured Paul Mauser would know why the barrels had steps, so I checked with him.

He says they are for consistent stock fitting when the barrels expanded, for ease of fitting sights, and simpler headspace adjustment.

Read about it in his patent:



More here:

Mauser stepped barrel patent

Bruce

Kinda implies it enhances accuracy for one thing, seems to me, as several of us stated earlier

It enhances accuracy only in relation to how the stock and bands maintain a consistent fit as the barrel expands. It makes the military rifle more accurate, not the barrel alone.

For a free-floating barrel or non-rapid-fire barrel, it wouldn't matter.

Bruce

Yeah, the dampening of vibration nodes is conspicuously absent. The system also specifically includes the full-length stock design.

Must not have worked that well. Does anyone still do the steps?

The Swedes always were noted for quality (materials and machining). When they ordered their first Mausers, they were made in Germany, but the Swedes insisted that Swedish steel be used. It was considered superior to German steel.

That shows how little Mauser knew. He also thought that the
"Thumb Cut" was made to allow gas to escape.

A 40 LB bench barrel does not need stepped. but nobody wants to carry a bench barrel in the field.