Anybody ever test "swamped" barrel profiles on centerfire rifles? Just turning the middle part of the barrel skinny, then leaving it thicker tapering back out to the muzzle. Seems like it might force the node of vibration to the muzzle (i.e. bullets might exit at same place). Kind of like a built in muzzle weight/ barrel tuner. Plus you'd have a lighter rifle overall, but with a little bit of muzzle heaviness to aid offhand shooting and tracking. Any thoughts?

Every conceivable contour you can dream of has been tested and retested by the military, bench rest shooters and every dog and pony in between. The most common variant of what you describe is one of many running boar contours. They seem to offer no advantage what-so-ever to accuracy. Their purpose is to move the weight of the barrel forward without increasing the weight of the gun over the legal limits allowed by the game. The idea behind doing this is to make it forward heavy to settle the gun down when shooting off hand. It also makes the gun swing smoother. It's generally accomplished by removing weight from the middle of the contour or having a slimmer straight contour and then having a weighted area at the muzzle machined into it. Increasing the felt weight of the gun by means of a simple fulcrum.

The Germans did a lot of experimentation with node points in an effort to increase accuracy and it is a commonly held thought that the steps in the Mauser barrels coincide to the node points in the barrel. The fact that manufacturers and bench rest shooters do not use such things pretty much shows that there are no gains to be had from it.

You can mess with it if you want, but I personally wouldn't put any money into such a test.

Common to use swamped barrels for flint locks, but centerfires? Only if you really want one but don't expect any change in accuracy.
Now, it is a proven fact (by me) that the Mauser steps do contribute to accuracy. Which is why I only sell stepped barrels.

quote:

Originally posted by dpcd:
Now, it is a proven fact (by me) that the Mauser steps do contribute to accuracy. Which is why I only sell stepped barrels.

Well naturally.

But of course your accuracy guaranty with the steps is null and void if the customer chooses to use a bullet weight, or a velocity other than that which the barrel was specifically tuned to.

That's just a given of course.

Actually Tom.
There is the reoccurring story as to how the Germans located the node points in the barrels. They first screwed the barrel of known steel propery and hardness into a rigidly held receiver and put a series of steel rings on the barrel where they anticipated the node points should be. They then began firing the gun until the rings found the zero points and settled down during firing. Then they began turning the barrels down, retesting between cuts to the changing node points as the diameter decreased. When the barrel finally made weight the steps were all located at the zero points. As long as they stayed with the correct steel recipe, hardness, bullet weight and velocity they could whack out as many as they wanted and the node points would all be pretty damned close to the steps.

This of course is just a story that I have heard over and over again over the years. I don't actually know if there is any truth to it and I have never locked a receiver into a vise to try to duplicate the experiment. But it is a good story!

I believe it.

I am a strong believer in stepped barrels .
thats all I use , unless it's uncontoured , just the same dia. Chamber to muzzle .

I always thought that the Germans stepped their barrels in the M98 for better accuracy --with the military ammo !!

Swamped barrels are there for better looks with those very long barrels.
All I know is what CST taught me !

Mauser Sporter barrels are all stepped as well; so the theory works with hunting ammo too.
Which is why I sell stepped sporter barrels only.

I think I'll just wait over here with my gentle curves and tapers and just watch you guys trip over your funny little gwerschtoppen gwerbotton steps. LOL

Like this?

http://www.lothar-walther.com/282.php

Ski 1...why don't you just do it and report on the results. I think you could achieve the same goal by leaving the first 6" or so at the muzzle straight cylinder, then bring taper back further, without calling attention to a rather strange "flintlock" contour

Addendum to the above: Got a critical call re "strange" flint,ock contour... (Gotta ber careful) Not strange for a flintlock, fact is those old guns seemed like the muzzle was hanging by an air hook..just meant might look strange on a sporter bolt gun

I should clarify . I'm a firm believer in stepped and reverse stepped barrels THAT HAVENT BEEN PROPERLY STRESS RELIEVED .
Now , ask how I come to that conclusion!

standard M4 rifle barrel profile -- i know it's NOT what you meant, but it is being done, a couple million, in fact

The barrel on a "Running Boar" rifle is small in the middle and heavy at the muzzle.
Done to improve offhand shooting at a moving target.

M

I have handled a couple bolt action rifles that Mark Silver has done with swamped barrels yet I think you would have never noticed the swamped effect unless you could handle the barreled action out the stock. Mark and a few other guys I think had a barrel maker make up a swamped profile pattern for them some 25 plus years ago.

The other thing to remember is if Mark was given a plank off a picnic table to use as stock for topper single shot shotgun the completed project would be elegant in every respect and very tastefully done. Mark should be classified as a National Treasure.

Darcy,

Did Mark Silvers do the swamped profile on a round barrel or an octagonal barrel?

Thanks,
Steve

quote:

Now , ask how I come to that conclusion!

Gary,
I am asking; how did you come to that conclusion sir?

Buy many of the same barrels , chamber and shoot fast , chech poi shift . Then I realized I could set the barrel up in a test stand for measuring , freeze the barrel and chech shift . Both ways didn't change when using MOST high end barrels . When using middle of the road barrels is where the needle starts moving .
I don't know if it's scientific enough but it seems to be verified by the shift .so what does this have to do with bore Id and tapered barrels , a stress relieved barrel shouldn't have its bore enlarge as the material is removed from the contouring process . So after my using a stepped barrel or reverse stepped barrel the accuracy and repeatable accuracy was as good with the middle of the road barrels as the high end .

both were round

I have shot reversed taper barrels on a BR rifle. It always required a tuner to squeeze the accuracy out of them. Not worth the time and trouble.

Thanks!