cone breach chamber

[Westex]

I never tried Cone breach chamber until a I had a buddy that had a used barrel for 40x with cone breach . it was damaged from someone filing on it and dry firing so I just recut headspaced . I really liked it . just have to be careful and not dry fire . I liked it so much I grabbed a Shilen Ratchet I had and cut cone on it . It performs great .

 

[TRSR8]

A cone, in and of itself has zero to do with the quality of the chamber. The majority of them are there because guys don’t or can’t cut extractor slots. Years back guys did it to index barrels but not done to any extent these days.
IMO far too easy to ding them.

 

[flatlander]

For a while, Vudoo cut semi-coned breech tenons on the barrels they fitted & chambered. There were two versions - one that left less metal at the breech face, the other one left considerably more. The reason they did it wasn't to get away without cutting extractor slots, but to provide space for crud falling out of suppressors when guys would set the rifles in racks muzzle-up so it wouldn't bind up the bolt. I think a lot of guys who're serious about accuracy above all else have stopped shooting suppressed in matches, so don't know if Vudoo is still using the semi-coned breech design.

 

[VLNBYR]

Or if you have a 100 different barrels with a cone breech and the shoulders set back a few .001 and some precision shims they will all fit your actions.

 

[kevin nevius]

Just opinion here............

Cone breeches are a compromise, you need as much material backing the rim as possible for good ignition, but just enough rim protrusion for extractor purchase. Deformation from dry firing is also more of an issue because there just isn't much material to resist it if there is contact.

Also, cone breeches are only really an option when actions have a great extraction system (Anschutz is one of the best, and the extractors are radiused to fit the conical cone surface well). The Swindlehurst is another that handles a cone really well. I would never use a cone breech for any 2500 / Trident / Nitro action.

They also avoid the tedious timing of the extractor cuts, which from a smiths perspective is really nice (again IMHO).

If done correctly, there is absolutely no accuracy potential difference between the two (cone or slots).

Happy Thanksgiving!

kev

 

[Walt Krafft]

A coned barrel is all about easy feeding of a round dropped onto the feed tray or out of a magazine. If you have a pre-64 Model 70 winchester you can see what a coned breech and bolt looks like.

Thread is discussing rimfire cones not centerfire.

 

[FNSafari]

Deleted mine.

 

[kevin nevius]

Thread is discussing rimfire cones not centerfire.

Just an example (I know you are aware, just for those who don't know what one looks like I guess)

 

[1Merlin]

Kevin what are we looking - the above action?

 

[jfp]

maby this will help

 

[kevin nevius]

Kevin what are we looking - the above action?

Hi Merlin:

My apologies, this was the first picture I came across in my files.

Its a Copperhead action I did some time ago. Most of the cone breech actions I have done are Anschutz though - I will try to find a picture and post it later. They look just like this one though.

The cones I do are typically 30 degree frustrum cones, .125" deep, with the small diameter at least .2550" (from memory). As I mentioned, that diameter needs to be as large as possible to back the rim (for good ignition), yet thin enough for the extractors to reliably purchase the rim.

Thanks,

kev

 

[DGP4]

What is the advantage of a cone breech, besides indexing the barrel? PLs educate me guys!

 

[HuskerP7M8]

Hi Merlin:

My apologies, this was the first picture I came across in my files.

Its a Copperhead action I did some time ago. Most of the cone breech actions I have done are Anschutz though - I will try to find a picture and post it later. They look just like this one though.

The cones I do are typically 30 degree frustrum cones, .125" deep, with the small diameter at least .2550" (from memory). As I mentioned, that diameter needs to be as large as possible to back the rim (for good ignition), yet thin enough for the extractors to reliably purchase the rim.

Thanks,

kev

Hey Kev,

I thought that was my Copperhead when I first glanced at it, but I think mine is a different serial number.

Landy

 

[grauhanen]

What is the advantage of a cone breech, besides indexing the barrel? PLs educate me guys!

No need for extractor cuts.

 

[TRSR8]

Always wondered about one element of a cone, but have never seen it discussed.
Given the modest reduction in surface supporting the rim, where priming is, can one make any case for some impact on ignition?
I never saw any test of a barrel, with/without in that regard.

 

[WSnyder]

I'll go out on a limb and say it was probably Bill Myers that started using coned RF breeches or at least made them more common place. He did a lot of barrel indexing back then. He made a bunch of his own actions and many were setup for easy indexing. You RF guys can correct me

 

[TRSR8]

I'll go out on a limb and say it was probably Bill Myers that started using coned RF breeches or at least made them more common place. He did a lot of barrel indexing back then. He made a bunch of his own actions and many were setup for easy indexing. You RF guys can correct me

He really didn’t do a ton of indexing.
FWIW Billy did two guns for me, one cone, told me , basically just a lot easier/faster, which kind of surprised me so zero actual benefit I ever saw/heard .
Also, if he supplied barrel, he never did much customer evaluation….you got what you got.

 

[WSnyder]

He really didn’t do a ton of indexing.

Good to know. I just went by what he showed me when I visited. He had several of his Ti actions with clamp bolts up front at that time for indexing. He had different versions of that and in the actions themselves. It was too long ago to remember all the stuff we messed with when I was there. So much to see and take in (and learn). I don't recall him holding back answering anything I asked about. He pretty freely shared. I have his Rockwell lathe that he barreled so many rifles on.

 

[TRSR8]

Good to know. I just went by what he showed me when I visited. He had several of his Ti actions with clamp bolts up front at that time for indexing. He had different versions of that and in the actions themselves. It was too long ago to remember all the stuff we messed with when I was there. So much to see and take in (and learn). I don't recall him holding back answering anything I asked about. He pretty freely shared. I have his Rockwell lathe that he barreled so many rifles on.

Yep, I understand. i know he played around with it when it was a hot topic but I don’t think any big number of customer guns got indexed, we had a few up here and Bill and Inez shot with us several times, the majority taking place before his actions got out the door so he very well could have circled back on that.
he was definitely a master machinist….GE as I recall.

 

[WSnyder]

GE as I recall.

I'm pretty sure you are correct there. He talked about that and I think that the Rockwell might have come out of there? If not it came from one of the places he worked as a machinist. He had so many cool things he made in the shop. He showed me much of it and how it was done. I spent near two days listening and learning with him. I'm grateful and thankful for all he shared. I also have one of his reamer holders and cleaning rods that he made.

Oh and he treated me as an equal even though I was no where near the machinist he was nor had anywhere near the knowledge he had.