cone bolt face

[matthias]

i saw a post in the gunsmithing section about bolt face clearance on a cone? bolt.

1- what is a cone face bolt
2- why would one have this built ( advantages )
3- any draw backs?


thanks for your time educating me.

 

[shortgrass]

"Coned bolts" go along with "cone breeching". The angle on the bolt matches the angle cut into the end of the barrel. The cone/angle in the barrel acts like a feed ramp.The pre-'64 Win. 70 and the '03 series of U.S. Govt. Springfield Rifles were designed this way. An aid in feeding for a controlled round feed rifle, supposedly. The Mauser '98 is CRF but is not breeched in this manner.

 

[queen_stick]

this is a coned bolt:
http://www.bordenrifles.com/images/gsborden01.jpg

and this is how the barrel must be 'coned' to accept the coned bolt:
http://i15.photobucket.com/albums/a375/kgunz11/FGW%20Rifle%20Builds/conedbolt.jpg

 

[matthias]

ok that makes sense. its like my smith and wesson 625. only there is a bolt that has to match up behind it. thanks guys.

i learn something every time i log in it seems

 

[holstil]

You won't see many coned bolts on repeaters.



Jim

 

[Scott Harris]

You won't see many coned bolts on repeaters. You need an edge to catch the next round in the mag.
Jim

+1 Single shot is the best application for a coned bolt. This is kind o amusing if you think about it, because a repeater needs reliable feeding and we just said a standard bolt is best. But, feeding reliability is touted as a benefit of a coned bolt/barrel. My take is it is completely "nice-to-have" My coned single shot works great...and so do all my standard bolts. A few years back, I asked German about this and his comment was "sprinkles on the donut" completely unnecessary, but an option for a single shot.

 

[Ing. Michael W. Mayerl]

You won't see many coned bolts on repeaters. You need an edge to catch the next round in the mag.
Jim

+1 Single shot is the best application for a coned bolt. This is kind o amusing if you think about it, because a repeater needs reliable feeding and we just said a standard bolt is best. But, feeding reliability is touted as a benefit of a coned bolt/barrel. My take is it is completely "nice-to-have" My coned single shot works great...and so do all my standard bolts. A few years back, I asked German about this and his comment was "sprinkles on the donut" completely unnecessary, but an option for a single shot.

A tip for all standard bolts: a cone on the rear side of the barrel chamber (where the cartridges comes into the chamber) with a flat angular of 25° - high polished - rise up the reliability dramaticaly.
Most guns only have a very small 45° edge or a small radius there but a flat 25° angular brings more area and cartridges with flat bullet tips find the way much better into the chamber.

 

[riverwolf1]

While there's probably not a bunch of guys using them, there are several coned bolt repeating, actions available! Try looking at Kelblys Kodiak action! I have one and it works to perfection!

 

[Hammer47]

Kinda seems like everything that Kelbly builds is like that.

 

[Robert]

You won't see many coned bolts on repeaters. You need an edge to catch the next round in the mag.
Jim

+1 Single shot is the best application for a coned bolt. This is kind o amusing if you think about it, because a repeater needs reliable feeding and we just said a standard bolt is best. But, feeding reliability is touted as a benefit of a coned bolt/barrel. My take is it is completely "nice-to-have" My coned single shot works great...and so do all my standard bolts. A few years back, I asked German about this and his comment was "sprinkles on the donut" completely unnecessary, but an option for a single shot.

A tip for all standard bolts: a cone on the rear side of the barrel chamber (where the cartridges comes into the chamber) with a flat angular of 25° - high polished - rise up the reliability dramaticaly.
Most guns only have a very small 45° edge or a small radius there but a flat 25° angular brings more area and cartridges with flat bullet tips find the way much better into the chamber.

A cone bolt head is not an obstacle for repeaters. It is easy to design the bolt head to perfectly catch the round to be fed.
I think the major argument against cone breechs comes from the fact it need extra work, sjill and care when rebarelling
R.G.C

 

[Robert]

While there's probably not a bunch of guys using them, there are several coned bolt repeating, actions available! Try looking at Kelblys Kodiak action! I have one and it works to perfection!

Yes, but this also increase the gao barrel/bolthead and the unsupported part of te case rear.
R.G.C

 

[roundknob]

In the case of case head seperation wouldnt this cone multiply the amount of blowback, and would this type use any special porting?
Steve