23 June 2004, 03:49
JameisterNew barrel: How much of breech end to leave on?
If the goal is to make a light rifle, how much of the fat end of the barrel must be left on for a 3006 size case? From the barrel makers, this end seems to come in 1.2, 1.25, and 1.1 inch diameters, and are about 2.5-3.5 inches long before the taper. For pressure purposes, how much is needed to leave before the taper? Is any needed, since the threaded portion is smaller to start with? Isn't peak pressure measured about 5-6 inches down the barrel anyway? For support of barrel harmonics, etc, how much metal thickness is needed or does it make a difference?
Is it customary for a rebarrel job to leave on the factory proof markings from the barrel stamped on the end, or is this just to make the barrel as long as possible to use the full monty, as it were?
If this is asked before, please direct to thread.
Jameister
23 June 2004, 05:20
<Guest>take a look at a Winchester featherweight in 30-o6 and that will give you a good idea.
Blue
23 June 2004, 05:23
free_minertake a look at a winchester featherweight contour. I don't know the dimensions, but Winchester didn't feel you need much of a barrel shank ahead of the receiver, and I've never heard of one blowing up or swelling.
Check out
http://benchrest.com/douglas/dimensions.htmlthey show a featherweight contour which is probably very close or a copy of the Winchester
Original military Mauser barrels barely measured 1" just ahead of the receiver ring.
23 June 2004, 05:46
J WisnerThe Winchester M70 Featherwieght contour is fine for the 30-06 size cases.
I have used the Featherwieght contour up to 35 Whelen with no problems.
However BSA used it on one of their rifles, the standard calibers worked fine.
The real problem was the 7mm Rem Mag and 300 Win Mag, the front of the chamber walls are so thin the barrel would strech and then the now oversize front section of chamber would cause the case to not relax. Thus you now have an fired case stuck in the chamber.
The only way to fix it is to rebarrel with an heavier breech.
Jim Wisner
Custom Metalsmith
Jim, Thanks for that insight about the magnums. I've argued with people that rechambering old Military barrels (Mausers) to accept magnum cases was not a good idea in my opinion. This is just another GOOD reason not to IMO.