Generally speaking what is considered the minimum thickness for a barrel wall? I'm thinking more of the muzzle end rather than the chamber end.

Reason I ask is that i'm contemplating a .44 (.430") with a muzzle diameter of .660" by my calculations that leaves a wall thickness of .115".

Another reason is that I have a rifle that I want to install a front sight on but am concerned that once I drill and tap it I may be close to the "minimum".

Thanks,

Mike

In an article in Rifle or Handloader some years ago, John Barness gave a 'rule of thumb' of approx .10" muzzle wall thickness. I used his advice on a .35 Whelen(.358") when I used a barrel with .600" muzzle diameter.

I remember Barsness saying that. I generally don't want less than .120", however, for me, I truly dislike heavy rifles and am always amazed at the heavy contours folks put on hunting rifles!

BA

That Whelen sounds nice!

Brad, yes, the Whelen is nice. I went with a Douglas #2 profile barrel because I, like you, don't see a need for heavy barrels on hunting rifles. We carry them more than we shoot them. Also, I used a laminated stock of my own creation and it's weight more than offset the light barrel. I don't have a problem holding for off-hand shots at reasonable ranges(not over 100 yds).

Here's a picture.

http://www.hunting-pictures.com/members/paulharper/35whelen.jpg

98,
Did you lay the laminate up yourself, or were you talking stock shape? If it's a homemade, how did you compress the layers? I have always liked laminates, but I really like light guns so have stayed away so far. Nice looking setup tho.
Doug

Doug>

No, I didn't lay-up the laminate. It's a Remington surplus blank I got from Numrich Gun Parts Inc. They cost about $35.00US.

No question - laminate is definately heavier than walnut, all other things been equal. I drilled some large holes in the butt and routered a groove in the barrel channel and it is still heavy. I like the looks of the laminate but I might go back to walnut.

Another thing I found with laminate. It splits easily. When I built the stock, I glass bedded around the recoil lug including the entire barrel channel and around the rear tang. I relieved the wood behind the rear tang. I also bedded the bottom metal with clearance around the magazine box.

So I was rather annoyed when the stock split behind the lug, behind the magazine and into the top of the pistol grip. Fortuately, I was able to repair the split by installing two cross-bolts and injecting epoxy into the splits.

The split was along a layer of wood which is the weak link. Apparently the wood used is birch or some sort of soft hardwood. The glue is stronger than the wood.

Pac-Nor Barreling says .125" is minimum for barrel wall thickness.

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Phil- Life Member NRA & SCI

98: Yes, that is good-looking!

Nice job,

Brad

z1r,
Phil R gives good advice. I have been around the block a few times, and this is my preferred rule: 0.125" wall thickness at the muzzle. This is the O.D. of the barrel minus the bullet diameter/groove dimeter and then this difference divided by 2.

O.100" is a bare minimum if you want to flirt with inadequacy. Some rifles do.

I have a #3 Douglas that is 0.625" at the muzzle in .375 H&H. That is 0.125" muzzle wall thickness. It shoots 3/4 MOA and the rifle with iron sight weighs under seven pounds empty. A 1 pound Brown Precision stock balances perfectly with this light barrel.

The CZ 550 in 416 Rigby that I have has a 0.666" muzzle O.D. Again, this is 0.125" wall thickness at the muzzle.

The CZ 550 in 458 Win.Mag. that I measured was 0.670" at the muzzle. This is 0.106" wall thickness. That is a little too thin for me, but it works with a barrel band front sight base.

If you want a sveldt and rugged 404 J, go with a 0.680" or larger muzzle and a sporter contour. 0.675" would be my bare minimum for your gun. You have every right to try a 0.660" muzzle if it turns your crank.

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RAB

[This message has been edited by DaggaRon (edited 04-16-2002).]

I have a factory original (tang safety) Ruger M77 35 Whelen with a 22" barrel that measures .560". Also, a J.P. Sauer pre-war Mauser 35 Whelen that measures .555"

Thanks for all the replies.

I think for cartridges in the 50,000 psi range I'll stick to a thickness of near .125". For this project I may consider going as low as .100" since the cartridge is a low pressure round (42,000 psi). I'll turn the barrel down to .680" first and check the weight/balance then I can always work down.

Thanks,

Mike

Mike,
I was thinking more of loss of accuracy with the thin walled barrel being more whippy. They can be accurate with forend tip pressure, but usually not as good as the heavier barrel when free floated, and definitely harder to get to shoot well if too thin.

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RAB

DaggaRon,

Thanks for the clarification. This is a good point you bring up. I was thinking in terms of safety when trying to determine a minimum but there's no sense in building an inaccurate rifle either.

-M

When I discussed manufacturing a large bore anti-materiel rifle with Christensen Arms many years ago, they revealed that the barrel is actually made of steel, overwrapped by carbon fiber. The steel carries all the pressure loads, the carbon fiber being necessary to get the stiffness back. I point this out because the steel barrel liner on these graphite barrels is incredibly thin. When I was researching the design guidelines for barrels it became clear that most barrels are considerably stronger than is necessary, but that the thickness is more a necessity for adequate stiffness (which drives accuracy). The apparent safety factor for the typical barrel is only about 1.2, but this is not the whole story because the steels used exhibit very high strength increases with strain rate, which means that under dynamic loading they are probably at least twice as strong as their static yield stress numbers would otherwise suggest. This gives a real safety factor of roughly 2.4 - 2.5. An ultralight featherwight barrel would perhaps have a safety factor of 1.8 to 2 (just a guess). Also, the pressure at the muzzle end is typically about 20% of the peak chamber pressure at exit for long arms.