How do you know what breech length to get.

[BillG]

I am wanting to build a .338 rifle and I have been looking at barrel blanks. While looking I have noticed different breech lengths on the blanks. What length breech will I need or should I get for .338 RUM chambering.

 

[Dusty Stevens]

I would ask your gunsmith who will be chambering it what he wants. he will know exactly what he would want to use for a RUM

 

[BillG]

I think I know but what exactly is the breech on a barrel. Is it the part of the barrel where the chamber is.

 

[swd]

It’s not critical other than how much the blank weighs and how it fits a stock.

 

[gunsandgunsmithing]

It's mostly about weight and gun balance. It also has value as a heat sink area. Peak pressures occur about 2"-3" in front of the chamber. With that said, look at a factory Remington or most any factory hunting rifle contour. They aren't very big there.
There "may" be some value in regards to expansion under pressure and clickers developing over some time with hot loads but the threaded portion, the actual tenon, is the smallest and weakest area of the shank end of the barrel and is likely a big part of why brass often becomes tight in the web area.

 

[BillG]

Thanks guys this helps a lot. Would I becorrect then in assuming a 2.85 inch cartridge might be aided by a 5 inch breech. As some of the heavier breech area would be in the area where pressure is highest. This would also aide in balancing a long heavy barrel that I am looking for.