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Chambering dimensions?


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#1 Jatimatic

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Posted 17 August 2012 - 08:01 AM

Just wondering but why the chamber dimensions are so big compared to a .22LR ammunition? I'm not at the drawing (RG-G) at the moment, but I recall the diameter being 0.3 mm bigger than the casing is and the length of the chambering being 0.8 inches. Isn't the casing usually supported by the chamber walls quite tightly?

And also another question, but I recall seeing a photo of someone actually chamfering the whole circumference of the chamber end instead of cutting the extractor slot in the barrel. Just looking at the drawings makes me think that the counterbore in that case seems kind of unnecessary as the chamfer seems like it would remove so much material that there would be no counterbore left. Am I correct or missing something and does anyone remember where the photo was located on this forum?

Thanks again :)

#2 Cutter

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Posted 17 August 2012 - 04:14 PM

What revision or date is on your print ??

#3 Jatimatic

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Posted 18 August 2012 - 08:54 AM

What revision or date is on your print ??

Date says 9-20-94 and Issue A (hex to the barrel end) is dated 3/7/97.

The bore says .235 x 0.8 inches deep, but a .22LR ammunition has a case diameter of .226, which means a .009 inch diameter difference, which to me sounds a bit large. So, is there an error is this some technical decision that has not been explained in the sheets of paper I have or that I don't know about?

Also would like to hear about the chamfering vs. slot cutting.

#4 nitewatchman

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Posted 18 August 2012 - 06:25 PM

I had looked at the suggestion to bore the chamber also and decided to use my .22LR Chambering Reamer instead. I chamber and headspaced twelve barrels for my gun using the reamer and Go-NoGo gauges. This also insures a good throat and forcing cone in the chamber although this is not as critical for a .22 in this "spray mode" application.

I think this is a safer and wiser approach. A split case is never a good thing anywhere.

Can't help with he slotting verses chamfering, I slotted mine.

nitewatchman

#5 manatee

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Posted 18 August 2012 - 06:49 PM

I also chambered mine using a reamer and gauge. I did the chamfering after talking to Paul. He suggested I do it that way.

#6 Jatimatic

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Posted 19 August 2012 - 07:13 AM

Okay, thank you everyone for your answers :) I think I'm going to either make a reamer or buy one if I can find a cheap source that ships to my country, as the only places that will sell reamers here try charging something like 500 USD for them! Ridiculous, I know and making my own is not that difficult as I have the ability and tools for it, just need to find the dimensions.

Also the gauge dimensions would be nice to find somewhere, as I can make that one also at work.

Does anyone have good sources for these dimensions (go/no-go gauge & reamer)?

#7 nitewatchman

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Posted 19 August 2012 - 04:45 PM

I get my "stuff" from a couple of sources here in the US.

One is Midway.

http://www.midwayusa... ... ugv1551539

http://www.midwayusa... ... long-rifle

http://www.midwayusa... ... e-sporting (Photo is not a Rimfire)

Another is Brownells

http://www.brownells... ... ER-REAMERS

http://www.brownells... ... TS#skugrid

If you are unable to buy, perhaps one of the forum members could assist.

I will also try to look up the dimensions for the reamer and gauge, I have these somewhere.

nitewatchman

#8 bruski

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Posted 19 August 2012 - 04:54 PM

Maybe try ebay.com also.
bruski

#9 shred

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Posted 19 August 2012 - 06:10 PM

Looks into home-made D-bit reamers and chambering .22's with a drill bit as well. Both work, though with the time and effort I put into my RG, I'd rather not half-ass the chambers.




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