Gunsmithing Rifle Chamber With a “Forcing Cone”

[Edsel]

Once, I briefly read that a certain big - name European manufacturer had a freebore which seemed to mimic a revolver’s forcing cone.

Not sure if it was Steyr.

Anybody know of this?

 

[want2learn]

i recall reading something like that....can't recall if it concerned Weatherby or Sako? I've got to do a little search.

I just found this tool to measure the forcing cone in rifles.....https://www.triebel-guntools.de/en/chamber-gauges-for-rifle-calibers.html
so it must exist?

 

[RTH1800]

Weatherby as famous(infamous) for very long freebore. Could be a terminology issue.
They did it for several reasons. One of which was that they could overload ammo and claim their actions were the only ones strong enough to handle the hot Weatherby ammo. Accuracy suffered of course.

 

[Yote Klr]

Weatherby's freebore is long, BUT the freebore diameter is only a few of ten thousandths wider than caliber.

Compared to most all other cartridges which is much more than a thousandth larger than caliber.

The reason for Weatherby's design is to build more velocity without the initial high pressure spikes. And guides the bullet squarely into the lands.

 

[Edsel]

i recall reading something like that....can't recall if it concerned Weatherby or Sako? I've got to do a little search.

I just found this tool to measure the forcing cone in rifles.....https://www.triebel-guntools.de/en/chamber-gauges-for-rifle-calibers.html
so it must exist?

Know what, it might have been Sako.

Those look like some kind of case gauge, though.

Weatherby as famous(infamous) for very long freebore. Could be a terminology issue. They did it for several reasons. One of which was that they could overload ammo and claim their actions were the only ones strong enough to handle the hot Weatherby ammo. Accuracy suffered of course.

Mitigates the pressure spike, I would guess...

 

[Crang]

Weatherby as famous(infamous) for very long freebore. Could be a terminology issue.
They did it for several reasons. One of which was that they could overload ammo and claim their actions were the only ones strong enough to handle the hot Weatherby ammo. Accuracy suffered of course.

This althought the accuracy really isnt that bad on my MKV but it does make it tougher to find a load it likes as tuning can only be done by adjusting charge or powder type. Zero chance of loading anywhere close to the lands if you want it to fit the magazine (although that would defeat the point). On the 7mm Wby Mag I have I can get a Barnes 160gr to clock 3035 and print .65 MOA consistently but it took a lot of work to find that load.

 

[Edsel]

The reason for Weatherby's design is to build more velocity without the initial high pressure spikes. And guides the bullet squarely into the lands.

Ok...

 

[Edsel]

Found a post referencing it.

Might just be hearsay, it seems...

 

[Edsel]

Kiss the lands vs Freebore

Seems strange that both can be so accurate. How does that work? Some guys are so adament that freebore cannot shoot, but my Sako's easily shoot MOA with a variety of bullets loaded to SAAMI. Of course most rifles out there are not Freebore so people have a lot more experience with measuring...

www.go2gbo.com

Really not sure.

Personally don’t have the background to comment on such.

 

[Edds]

A lot of cartridges have a tapered, instead of a parallel, freebore.

For starters, look at the SAAMI specs for Winchester cartridges. A 243, 264 Mag, 270, 284, 300 Mag, 338 Mag, all have a tapered entrance into the barrel. There are other too, including the 30-06.