Case head separation?

LoneTraveler

Well-Known Member
Joined
Feb 7, 2014
Messages
782
Being a Rimmed case the Head space would be by the rim. From drawings of the 460 S&W the rim thickness is .059.

The previous post on using a fired primer would give you a good idea if the head space is excessive.

I have made shims from an aluminum beverage can to find excessive head space.

The 7X61 Sharp and Hart cartridge in the Schultz & Larson Rifle with its back of bolt lugs was notorious for head separation of cases because of Action stretch.

Some years ago a company imported a 357 Mag. Lever Action rifle from I believe it was Brazil that had a soft bolt or soft action. At that time we carried a 357 Mag. side arm. Several officers bought these 357 lever rifles for a work gun to carry and use the same ammo as the pistol carried. After about 50 rounds of duty ammo the headspace went out of specs. and they had trouble with cases loaded 2 or 3 times would separate in the rifle chamber.
I was ready to get one of these rifles when problems arose. Heck No.

When the pressure builds in the chamber the case walls swells tight against the chamber if the head of the case then gives the brass will thin and separate.

If the head space is to much could cause this problem. Or the action is stretching to allow the case to separate.

If you do the math. 460 S&W case head diameter .520 and published pressure at 65000 PSI. may cause enough stress on the action to stretch it on firing.

Good Luck in finding the problem and a solution.
 

engineer40

Well-Known Member
Joined
May 5, 2015
Messages
977
Location
Rockford, MI
High pressure ‘sticks’ the more forward portion of the case wall to the chamber wall all whilst blowing the case head rearward ‘til slowed by collision with the T/C’s firing pin bushing but continues on rearward a bit more as the rearward thrust causes the T’C’s frame to stretch, adding that much more to the stretching of the case body and so there’s even more thinning of the case wall just forward of the case head. Mr. Bellm’s firing pin bushing shims can rid that particular T/C frame & barrel combination of its excessive head space.

Thanks again for everyone's responses! I ordered Bellm's shims. I got them a couple days ago but haven't had the time to install and test yet.

I will report back with any findings!


So far this TC Pro Hunter in 460 S&W Mag has been finicky. For a few weeks I was wondering if I should sell it. Then I let my cousin shoot it at the range last week and I also shot it a few times. We were both smiling from ear to ear. Everyone that has ever shot it, falls in love with the super lightweight, compact size, and it makes such a big boom! I can't sell a firearm that makes me (and everyone else) smile every time I shoot it. So I plan to mess with it a bit more. It's worth the effort. This rifle actually weighs less than the 10" revolver that shoots the same cartridge.
 
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