BARREL CROWNING

[highlife]

90-Degree Recessed Crown or 11-Degree Target Crown also what reamer for a no-turn 6.5- 284 any input would be helpful
thanks
richard

 

[Preacher]

The crowns are a Ford or Chevy thing, as long as they are concentric to the bore it really makes little difference........
The reamer will depend on the brass your planning on using..
6.5x284 Lapua and necked down 284 Winchester cases are different in neck sizes...
Mike the loaded brass you plan on using and go from there is your best bet..............

 

[TRECustom]

A reamer dimensioned for the Norma 6.5 x .284 chamber will handle the resized neck without turning. Makes a good shooter too.

Good luck, Tom

 

[Rust]

Some experimenter years ago cut a bunch of different types of crown, 11 degree taper, 90 degree recess, 45 degree recess, perfectly flat crown, and even a reverse taper crown. Only thing that made a difference was how precisely the crown was cut cocentric to the bore. Forgot where the article was published.

As far as a reamer goes, the standrdized 6.5 X 284 Norma with a .298' neck would be a decent bet with Lapua brass.

If you buy your brass in bulk, like 500 pieces or so, buy the brass first all out of one lot number and base the no turn neck dimension on that brass. .004' of neck clearance is not too tight, not too loose, while going to .003' or tighter means you have to keep a closer eye on things.

 

[rbertalotto]

Only thing that made a difference was how precisely the crown was cut concentric to the bore.

This is so true, and a 90 degree crown to the bore is the easiest to do. Just about any lathe will cut accurately at 90 degrees. To do anything other than 90 degrees, you must have the bore PERFECTLY dialed in.

 

[Sin_arms]

Only thing that made a difference was how precisely the crown was cut concentric to the bore.

This is so true, and a 90 degree crown to the bore is the easiest to do. Just about any lathe will cut accurately at 90 degrees. To do anything other than 90 degrees, you must have the bore PERFECTLY dialed in.

If you are trying to do accurate barrel work you would be dialing it in as close to perfect anyways. I like to get my barrels dialed into .00025-.0005'

 

[edpmedic]

I agree a 90* is easier to do, but a 11* if done right seems to give a little better accuracy. Again that's just my opinion because I have both on 6.5x284 barrels and see a difference.
Like stated above a 11* you really need to be right on and need to be very care full when using the rifle. Which means don't mess it up because even the littlest chip could make a bad day for you.

 

[msalm]

I'm not fond of a straight 90 degree crown as it's a fairly fragile crown. Doesn't take much of a ding or a cleaning rod jag to rub the edge to mess it up, even if it's slight. Whatever crown I do use, I'll finish it off with a 45 degree chamfer that just goes past the bottom of the grooves. I dial the bore in to less than .0002", and feel this is concentric enough.

 

[Silverfox]

I don't know much about the technical whys and whats, and wherefores, but here's a photo of how I have my gunsmith crown the barrels on my predator and varmint hunting rifles. I do use a nylon brush in my barrels once in a while and the chamfer is supposed to help protect the crown. There's a little lint on the end of the barrel on the chamfer--it's not imprefections!

 

[SRM]

I use a 12 degree myself ( just to be different ).

 

[X Ring Accuracy]

I use a 12 degree myself ( just to be different ).

LOL