Barrel tappers

[Fire8523]

Question: when tapering a barrel and threading the barrel shank is there a minimum amount of metal that has to be behind the barrel shoulder?
For example a 28 inch barrel threaded for a Remington 700 with a oversized recoil lug in a 338 rum. Behind the barrel shoulder where the recoil lug sets for 3 inches goes from 1.20-1.17 and continues to tapper down to .900. I have searched all over and made a few phone calls and no one can give me a answer. Another barrel that is threaded for a Weatherby vanguard from the shoulder to 3 inches down goes from 1.12-1.08 these are after the shank is fitted and threaded. Is there a rule of thumb for how much metal (diameter) it has to be after the shoulder on the barrel?

 

[Kp321]

Even Remington cuts their barrels too small IMHO. By the way, the area you are asking about is called the chamber reinforce and I like to extend it to the end of the chamber, minimum. That is probably an overkill but better safe than sorry. To be absolutely sure, have an engineer run a hoop stress calculation on your barrel at the shoulder of the chamber. I am on vacation without my books and computer or I would run it for you.

 

[Fire8523]

Thank you for your response I cannot find any information on this at all. I'm assuming that 1.17 inches is enough metal but better safe than sorry.

 

[rcmodel]

Maybe something like this would be helpful??

https://kriegerbarrels.com/contours

http://www.shilen.com/contours.html

http://www.ershawbarrels.com/scb-contours-and-weights.php

http://riflebarrels.com/barrel-contour-data/

http://pac-nor.com/contours/

https://www.mcgowenbarrel.com/contouring/

rc

 

[Fire8523]

Ok I found a calculator online for the hopp. I put in .534 for the cartridge and subtracting that from 1.17 and adding in 65k psi gave me 77475 my barrel is stainless 126,000 so do I dived that number if I do it gave me 1.6 which would be over the safety factor of 1.5? Never done this before so I'm asking

 

[Kp321]

I found the same one on line and plugged the numbers in and got around 62000 psi.for a safety factor of 2. When I get home I will recalculate using the one I used at work for years.

 

[Fire8523]

Ok thank you I'm not sure how to calculate it and have been trying too. I called the barrel manufacture and they said should work but wouldn't give me any details. Beings that they sell savage pre fit barrels at 1.06 so idk

 

[Fire8523]

Also I'm reading mixed strengths from 88k to 110k it's 416r