Reaming existing 262 nk chamber to no turn diameter - advisable?

S

SmallBoreBuyer

New member
Hello,

I am wondering if is is advisable to ream an existing 262 nk chamber to no turn diameter - can the finished chamber match the print?

TIA.
 
SmallBoreBuyer said:
Hello,

I am wondering if is is advisable to ream an existing 262 nk chamber to no turn diameter - can the finished chamber match the print?

TIA.
Click to expand...

Order a chucking reamer from MSC, etc of the diameter you want. (about $15-20). With careful application on a chamber that is closely dialed in the chucking reamer should follow the existing hole. Be careful though on controlling the finish depth on the reream.


.
 
SmallBoreBuyer said:
Hello,

I am wondering if is is advisable to ream an existing 262 nk chamber to no turn diameter - can the finished chamber match the print?

TIA.
Click to expand...

Last year, I decided to try a no neck turn, and converted my .269 necks to .274. That was perfect for a 220 Russian neck up.

I got a chuckinge reamer, trued a barrel up, and gently run the reamer in, turning the chuck by hand. I did make a guide bushing that fit the large end of the chamber and the reamer to help guide it in the original chamber.

The reamer was held with a small T handle. The reamer will follow the original neck, and the guide bushing keeps it straight. You will be taking a little more out, as you are going from .262.

As Jerry said, be careful to stop exactly where the original neck ended.

By the way, it shot very well. But I panicked and went back to the .269 and started turning necks again.
http://benchrest.com/attachment.php?attachmentid=19179&stc=1&d=1488976020

Just for info, a .269 works great with the no neck turn Norma 6PPC brass.
 

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I buy piloted neck reamers from ptg they can be made in any size you will want and can be had with or without a throating reamer made on it, (I buy separate throating reamers). I use deltronic pins for gauges and measure the distance the .262 gauge protrudes from the breach and then as I ream I will check my depth with an equal length deltronic pin in the diameter that fits the new neck diameter.
I don't mind making the neck a few thousands longer than it was originally and I always cast the chamber when I'm finished just to be certain I didn't stop short.
 
I also use piloted neck reamers and hold them with a tap wrench pushing the rear of the reamer with a dead center in the lathe. If you zero the tailstock where the neck reamer is just starting to cut, you can figure out how far you need to cut from a chamber print. Go slow and gauge your progress with a bore scope. But, you can pretty well tell when you get to the end of the neck as you can feel it start to cut differently as slightly more resistance on the tap wrench when you get to the end of the neck. A decimal chucking reamer is about a quarter of the cost of a neck reamer and will follow the hole and would be the cheaper way to go for a one off project. If you are going to do it routinely, I'd go with a neck reamer or better yet a finish reamer with the neck diameter and freebore you want built into the finish reamer. I opened up 6.5-.284 chambers with .290" tight necks to .296" necks for years before getting a finish reamer throated for 142 gr bullets and a no turn neck. Of course, then after getting the reamer, I've used it maybe once. You just can't ever tell in what the demand is going to be for a reamer.
 
When you open up the neck with a chucking reamer, you will loose the radius at the neck-shoulder junction, depending on how much you enlarge the neck.
 
jackie schmidt said:
Last year, I decided to try a no neck turn, and converted my .269 necks to .274. That was perfect for a 220 Russian neck up.

I got a chuckinge reamer, trued a barrel up, and gently run the reamer in, turning the chuck by hand. I did make a guide bushing that fit the large end of the chamber and the reamer to help guide it in the original chamber.

The reamer was held with a small T handle. The reamer will follow the original neck, and the guide bushing keeps it straight. You will be taking a little more out, as you are going from .262.

As Jerry said, be careful to stop exactly where the original neck ended.

By the way, it shot very well. But I panicked and went back to the .269 and started turning necks again.
http://benchrest.com/attachment.php?attachmentid=19179&stc=1&d=1488976020

Just for info, a .269 works great with the no neck turn Norma 6PPC brass.
Click to expand...

I was expanding a bunch of 6BR to 30 this week & found the necks quite consistent with my mitutoyo ball mike.
This made me wonder if a no turn 30BR would work.
Nominally, an 8.5mm chucking reamer is .3346", which should do the job.
Just estimating, (.335-.308)/2= 0135", enough room for .012 necks.
Has this been tried?
Regards,
Ron
 
RJM said:
I was expanding a bunch of 6BR to 30 this week & found the necks quite consistent with my mitutoyo ball mike.
This made me wonder if a no turn 30BR would work.
Nominally, an 8.5mm chucking reamer is .3346", which should do the job.
Just estimating, (.335-.308)/2= 0135", enough room for .012 necks.
Has this been tried?
Regards,
Ron
Click to expand...

With the latest 6BR Lapua, I am seeing less than .001 variation in neck wall thickness.

If you can live with that, then a no neck turn would probably work fine with .012 necks.
 
I have a new Krieger barrel that I'm fitting to my Stiller drop port.
So I'm thinking of making the older barrel a no turn, just to try it.
The worst case is that I end up shortening the barrel & rechambering with the .330 neck reamer.
Regards,
Ron
 
jay
i like your method as i have used it myself. i dont cast a chamber though. if i am a little short i can see it with my bore scope. Jays method works extremely well. jay has tough me several little tricks over the last couple years. he might not relise it but i am always listening. Lee
 
skeetlee said:
jay
i like your method as i have used it myself. i dont cast a chamber though. if i am a little short i can see it with my bore scope. Jays method works extremely well. jay has tough me several little tricks over the last couple years. he might not relise it but i am always listening. Lee
Click to expand...

Nicest thing anyone's ever said here about me.?
 
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