I started a similar post under bigbores and thought I might get more response here.

I'm in the proscess of building a lighter weight 411cal rifle. Something close to the old mauser type B others have told me. Case is basically a 400Whelen built from a 280 case with the shoulder moved forward. I have an older version in 416 but the barrel is heavier than I want to use on this one.

I believe the #5 was the one I used on the 416. In measuring some of my barrels total metal thickness (both sides added). In my 308Norma I have .214 in my 358N it is .254 and I believe the 458&375 Whitworths used the same contour that would give a 458 with .224.

If I start with a 26" #4 which is .650" at the muzzle I would have .239" about half way between the 458 and my 358N but since I want a 24" when I shorten it I get .256" or equal to or greater than the 1/4".

Anyone have any barrel info on the big bore type B?

All thought would be appreciated.

I am not a gunsmith. the .239" divided by two leaves the barrel thickness at .119". My concern about that dimension would be safety and accuracy. That thin might make the rifle a little whippy if the barrel is beyond 22". I want to think that Fred Zeglin once told me that as a minimum .250" + bore diameter is needed before he would rebore a rifle. Just my 2 cents, like I said I am no gunsmith.

muzzle diameter of my 416 barrel (Douglas #5 contour) is close to .70....leaving something like a .140 wall.....I'm not sure you can get thinner than that!

quote:

am not a gunsmith. the .239" divided by two leaves the barrel thickness at .119".

I've heard from .2 to .25 for a rebore. I agree .239 is to the thin side. That is why I liked a 24" which would give me .256".

Vapodog since we are most often on the same page curious why you feel the .7 is your limit? Wish someone could measure a 458Whitworth. I'm under the impression that the taper is the same for both the 458 & 375. Which would then have .672" at the muzzle.

I used the #5 for my 416( if my memory is working)when I cut it back to 24" the countour was even heavier. That weight barrel would really be front heavy with a light countour stock. My case will burn around 65grs of powder not the 100+ of some of the magnums.

the .458 and .375 Whitworths did use the same contour.

Most folks have a lot more steel than is needed for safety and proper functioning. You can easily go under .100" wall tickness no worries about catastrophic failure.

When you say "416" I am assuming you mean ".416," as in caliber. 416 SS is not as strong as the CM barrel steels, such as 4340, 4140 or whatever. If you are going with 416SS, then personally I wold use a contour with minimum wall thickness of at least .125, and mo' steel would be mo' better!

I think .400 Whelens are one of the coolest round chambered these days. Have you read Petrov's writings on it? He gives you the real deal and explains the problems with chambers and brass used by some in the old days that gave the .400 Whelen an undeserved bad name. A friend was working at G&H and helped Petrov get good historical data on the round.

Another thing is that any of the premium barrel makers will turn you just about any custom contour you request. The set up charge is usually very low.

So fill us in on details of your project. Sounds like cool with the little teaser of info you gave us!

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I think .400 Whelens are one of the coolest round chambered these days. Have you read Petrov's writings on it?

Yep I use it often when I get into discussions as to the shoulder dia of the 400.

My case is not that much of an improvement over the Whelen. I just happen to have the reamer and several others made from it. It started as a 280rem case shoulder moved forward to 2.17" blown out to .458 and 40deg. When I decided to make the 416 version I had access to a barrel and 416 bullets were easier to get. Darn thing was heavy and set in my safe. Then my buddy got transferred to Alaska and asked to borrow it(about 8-9yrs ago) So I decided now to build a lighter 400 version. While the original design called for a .458" shoulder all of my formed and resized brass comes in at .46-.461 (fl resized with custom dies) So here is what it will look like using .46"
.

Due to the parent I usually set the chamber for 2.54 but blowing out that far leaves the case just below 2.5" Leaving room to grow. I've tried longer brass but actually lose net capacity compared to Norma 280. To make Boom Stick happy I might make this 2.6 and try the cylinder brass and see if it cost me much velocity. Sure much easier to form.
The 416 version gave me these results. I would think the 400 would be close.

Is is what I got from the 416 version when I had it. Loads are IMR4895
Bullet Charge Velocity
350Speer
68 2400
67 2385 Most Accurate
66 2365
65 2350

300 Hawk
70 2570 Accurate
69 2555
68 2525

400Hawk
67 2205
66 2190
65 2160 Accurate

My buddy is using only 340s and the load data he gave me is:
340 Woodleigh IMR 4064
68.5 2435
68 2430 MOA
67 2410
66 2395
65 2375
64 2360
63 2340

I have several rifles with #3 .375 barrels, .625 at muzzle leaving .125 wall. I can't imagine that the .12 wall on your #4 .411 would be of any consequence. I agree that the lighter the better for a "small" bigbore that one actually wants to carry and hunt with...

quote:

Vapodog since we are most often on the same page curious why you feel the .7 is your limit? Wish someone could measure a 458Whitworth. I'm under the impression that the taper is the same for both the 458 & 375. Which would then have .672" at the muzzle.

I looked for thinner barrels but the Douglas was the thinnest I found.....Obviously I didn't look hard enough!