update on the 220 beggs

R

Richard

Member
I am sure many of have had the "clicky bolt" issue upon extraction with this round. I finally hand kiff grind me a reamer that is .442 at the base ( measured .200 ahead of the bolt face. And also changed the body-shoulder to .401 This took care of the problem, I got sick of "polishing out the back a couple of thou" This is a .250 nk reamer and the print # is 17487.
Just thought I would pass this along.

Richard Brensing.

The thing shot good anyway, ask Gene Beggs , we shot against each other at the rattle snake last year
 
Richard said:
I am sure many of have had the "clicky bolt" issue upon extraction with this round. I finally hand kiff grind me a reamer that is .442 at the base ( measured .200 ahead of the bolt face. And also changed the body-shoulder to .401 This took care of the problem, I got sick of "polishing out the back a couple of thou" This is a .250 nk reamer and the print # is 17487.
Just thought I would pass this along.

Richard Brensing.

The thing shot good anyway, ask Gene Beggs , we shot against each other at the rattle snake last year
Click to expand...



Richard, glad to hear you are having good results with the new reamer.

Gene Beggs
 
That would have worked also

but Gene has the dies made from Hornady. For me it was easier to fit the reamer to the die. The Hornady die works just perfect and "fine tuneing" the reamer was easier to get done. I have a 6mm begs reamer also and I will have kiff do the same for it also.

Richard Brensing
 
I agree with Richard Brensing; in most cases, it's easier to fine tune a reamer to an existing sizing die than vice versa.

When I spec'd out the initial reamer design for the 220 Beggs cartridge, I chose to retain the same dimensions at the base and shoulder as the original 220 Russian. The cartridge worked out well and I decided to go ahead and authorize Hornady to make the sizing dies.

Dave Kiff makes the reamers for Hornady. Lonnie Hummel heads up the custom die shop and Ben Searing does the CAD drawings and other engineering. The four of us agreed; the sizing die should be .0030 smaller than the chamber, i.e., .0030 squeeze. All was well and good except for one little detail we overlooked. :eek:

The Lapua 220 Russian case as it comes from the box measures .440 at the base. It chambers fine in a .4400 chamber but leaves no room for expansion in the critical area where the solid head transitions into the case body, sometimes referred to as the pressure ring. Obviously, you cannot have a sizing die that measures .4370 at the base, because you would then be gouging into the solid case head. So,,,,, the reamers had to be reground to .4400 at the base, the same as the chamber reamer; hence, no sizing. :mad:

As it comes from the chamber, the fired case measures .4003 at the shoulder and .4400 at the base. The Hornady die reduces the shoulder to .4010, which some regard as excessive but it does reduce the base at all. In spite of these supposed 'problems', the dies have served well; case life is excellent and both the 220 and 6mm Beggs cartridges have proven as accurate as anything on the line including the legendary 6PPC. The 6mm Beggs presently holds the NBRSA Unlimited record for 5 shots at 300 yards, .3550 fired by Jim McGowin at St Louis.

What I have done and most experienced BR gunsmiths know this, is to polish out the aft end of the chamber to .4420 with 320 grit paper on a split dowel. Only takes about five minutes if you do it while the barrel is still set up in the lathe. But as Richard Brensing said, it would be nice if you did not have to do this. It's a simple matter and not expensive to send your reamer to PTG or JGS and have them regrind it to the new dimensions.

Hopes this helps explain what is going on. By the way, if you ever get the urge to drive yourself crazy, try designing your own cartridge, dies and reamers. :p

Later

Gene Beggs
 
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Gene

I must be missing something here but how do you regrind a reamer to cut a slightly larger chamber from a smaller chamber dimension?

The example you gave grinding a reamer from .4400 chamber to a .4420. I would say that you would have to order a new reamer because where do you get the metal to regrind from? The reamer needs to be slightly larger to remove the extra metal from the chamber.

Like I said something does not jive forme.

Calvin
 
CYanchycki said:
I must be missing something here but how do you regrind a reamer to cut a slightly larger chamber from a smaller chamber dimension?

The example you gave grinding a reamer from .4400 chamber to a .4420. I would say that you would have to order a new reamer because where do you get the metal to regrind from? The reamer needs to be slightly larger to remove the extra metal from the chamber.

Like I said something does not jive forme.

Calvin
Click to expand...



Calvin, the reamer is tapered and long enough to set everything back and get into an area where the flutes are larger diameter. There are some cases where the reamer would have to be replaced but not this one.

Gene Beggs
 
Thanks Gene....

I was starting to wonder if our cooler than normal summer was affecting my brain more than it normally does........:rolleyes:

Calvin
 
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