Coned Bolt

[Richard Coody]

Hey Guys bare with me. I am old and just getting into this accurate shooting thing again after a 30+ year layoff.

Can someone explain what a coned bolt is and why it would be useful in a single shot benchrest rifle.

 

[expiper]

Richard,,,good question ,,,,if you have never used a rifle with cone breaching you have treat coming,,,Ralph Stolle came up with this improvement bak in the 60's when every bench rifle was a 222/222 1/2 ,,etc,,,,the small dia. ctg/case would lay on the feed ramp and the difference between its c/l and the c/l of the chamber was so great that the nose of the bullet would run into the face of the bbl tennon (even on a Rem 722) and upset your shooting rhythm,,,,,it helps with the .440/.478. ctgs also ,,,the cone breach (shaped like a funnel) and the resultant cone bolt nose solved the problem,,,,now most other action manufactures have followed suit,,,,its one of those things that you dont know unless you struggled/fought with it in the early days of "B"enchrest,,,,Roger

 

[Hal]

Early model 70's and I think Springfield rifles have coned bolts.

Hal

 

[snert]

The cone sure helps when single loading for groundhogs. I cuss and mutter every time I load my 722, and smile every time I load my Hart action.

 

[Ned Ludd]

Picture of a coned boltface:

Simplest answer to your question is that a coned bolt/breech facilitates single feeding, especially with long, sharply pointed bullets. At the same time, it helps prevent damage to the bullet nose.

 

[dkhunt14]

Snert and expiper have it right. It let's the round feed without catching on that square edge. The funnel shape helps the pointy bullet not catch when feeding. Matt

 

[NorCalMikie]

You won't be doing that to a Savage bolt head.

 

[lpreddick]

Hey Guys bare with me. I am old and just getting into this accurate shooting thing again after a 30+ year layoff.

Can someone explain what a coned bolt is and why it would be useful in a single shot benchrest rifle.

I bought a Stiller Predator V single shot coned bolt for a varmint build and was blown away! I cursed about every time I tried to chamber my 223 AI. A coned bolt is fantastic. My next build was also a cone bolt. Thank you to the designer!

 

[mikecr]

If you're observing your bullets, pointy or othewise, contacting outside the chamber with feeding, you've put together a real mess..

 

[dkhunt14]

If you're observing your bullets, pointy or othewise, contacting outside the chamber with feeding, you've put together a real mess..

Mike, tell me about this when you are trying to shoot 10 shots in 30 seconds and shooting a Remington. Just throwing shells in and working bolt. There is no comparison between a coned bolt and regular. Matt

 

[Richard Coody]

Picture of a coned boltface:

Simplest answer to your question is that a coned bolt/breech facilitates single feeding, especially with long, sharply pointed bullets. At the same time, it helps prevent damage to the bullet nose.

So the action is also milled out to match the bolt face? You can't use a coned bolt without an action built for it?

But no change to barrel chambering?

I have seen a thread on here about 700 actions from PT&G with coned bolts. Am i to assume the action will be milled to accept it?

 

[expiper]

Richard,,,,the rear of the bolt lugs are what contact the action ,,,,the front being coned requires that the bbl tennon be coned to match it (with ~.010" clearance as with any bolt )....you can put a coned bolt in a 700 action but the new bbl must be machined to match,,,,I hope this helps,,,Roger

 

[mikecr]

Mike, tell me about this when you are trying to shoot 10 shots in 30 seconds and shooting a Remington.

I know of no rational reason for any of that. But I do know that an action built for the cartridge intended does not require breech coning assistance for correct feeding. Savage WSM action, for WSM cases, comes to mind.

I like a coned breech for extended web support. Other supposed benefits are dubious in my view.
I believe a test between flat/coned breeches from a correctly machined action(for the cartridge), would show zero benefit one way or the other as far as feeding. It's also difficult to accept that competitive BR shooters(actually) would assemble & use poorly feeding configurations(mismatched components) today.

 

[Richard Coody]

Richard,,,,the rear of the bolt lugs are what contact the action ,,,,the front being coned requires that the bbl tennon be coned to match it (with ~.010" clearance as with any bolt )....you can put a coned bolt in a 700 action but the new bbl must be machined to match,,,,I hope this helps,,,Roger

That answers my question very clearly. When the barrel is chambered it must be coned to match the bolt.

Kind of eliminates the stock remage barrels

 

[swd]

I know of no rational reason for any of that.

To get off as many shots of your string as possible before the condition changes.
If you don't shoot competively it may never apply to you. But for those of us that do it's a big deal.

 

[Fast14riot]

My 1917 (built Oct. 1918) has a coned breech.

 

[BoydAllen]

I had an old Shilen DGA with a flat faced bolt, chambered in 6PPC. I never had a problem with loaded rounds, but if I wanted to chamber an empty case, I had to feed it into the chamber. I have had numerous Remingtons, and never had much of a problem feeding .222 or .223., and a push feed model 70 in .222 that seems to work fine. I have a Viper that is coned, and the PPC bolt head for my bighorn single shot is is coned, so I have experience with both. If you are working with a single shot custom action there is no reason not to use a coned bolt. With magazines I have a habit of pushing a round into the mag. When I use a single shot adapter I make sure that it has the correct feed divot appropriate to the caliber.

 

[hogan]

No action modification. Barrel has to be mated to the coned boltnose. Bolt lugs are square where fit against the receiver recess, in the rear.