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Drilling "near" a chamber?

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04 August 2013, 08:17
gk1
Drilling "near" a chamber?
I have a previously sporterised m96 mauser fitted with the original millitary stepped barrel.
I am considering fitting a pair of Talley bases onto to the barrel so that l can fit a scout scope.

My options are fitting one base onto the chamber step and one on the barrel step. Is it ok to drill near the chamber of a barrel. By my calcs l should have about 226 thou left after tapping for the screws (125 thou protruding).

Alternatively if l move forward 5/8" to the first barrel step and use the same screws, l can mount both onthis and l will have about 127 thou left.

What's the convention for drilling near the chamber?

My plan b is to mount these on a tube and just drill some shallow locating and grub screws and secure everthing without drilling significantly into the barrel.
04 August 2013, 19:52
M Pursell
I don't know what the "minimum" from the bottom of the hole to the chamber should be, but I'd be very comfortable with .226.


Mark Pursell
04 August 2013, 22:58
dpcd
Those old barrels are not as strong as modern chrome moly, but leaving .226 wall thickness will be fine. It's not so much the hole, it is the fact that you are making a stress point in the steel. You could drill holes in the chamber all day and not affect it, other than having your brass have a hole in the side of it. (and a jet of hot gas would not be good) Remember, that is how chamber pressure used to be measured (radial copper crusher method). As for barrel wall thickness, Hatcher turned an 03 Springfield chamber down to .125 wall thickness and nothing happened until he used proof loads; then it cracked.
04 August 2013, 23:19
N E 450 No2
Random thought.

I find I like a small red dot sight better than a scout scope.

Why not drill the front reciever ring for a Picitanny rail, and install a Mini red dot like a Docter Optic, Trijicon TMR, or a Burris Fast Fire???

Again just a thought... Smiler


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05 August 2013, 05:42
Toomany Tools
I had a sporterized '96 with original barrel in the shop a couple years ago for a new barrel. Found whoever driied and tapped for scope base, forward hole was drilled through to the chamber. Owner claimed he hunted with the rifle for many years and never had noticed anything wrong. So, I'm quite sure .226 is more than enough.


John Farner

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05 August 2013, 18:26
gk1
Thank you all for yor replies.

NE 450 No.2,
I have a Docter sight and an older Aimpoint 2000. I find these to be excellent for snap shooting or low light but the size of the dot (even a 2 moa one) covers too much of the target. If find the edges of the red dot a bit fuzzy and this limits the range to about 150m.
A scout scope on the otherhand allows me to be accurate to 300m because the reticle is small.
06 August 2013, 11:07
eagle27
quote:
Originally posted by gk1:
Thank you all for yor replies.

NE 450 No.2,
I have a Docter sight and an older Aimpoint 2000. I find these to be excellent for snap shooting or low light but the size of the dot (even a 2 moa one) covers too much of the target. If find the edges of the red dot a bit fuzzy and this limits the range to about 150m.
A scout scope on the otherhand allows me to be accurate to 300m because the reticle is small.


I would agree that a scout scope in lieu of a dot type sight provides magnification and a finer reticule for more precis bullet placement especially as the range grows. If you have a rear iron sight on the barrel why not look at using a bridge mount from the receiver ring to the iron sight. A scout scope does not have to sit right along the barrel to work. I replaced a green dot single point sight with a 2x Leupold using the above mounting method on my Mauser 404 and this set up is great.
07 August 2013, 20:01
Tapper2
I made a scout rifle out of a Rem. 742. I used the rear site dovetail and welded a mount on the barrel. I wanted the scope to not be attached to the receiver. It works great and cut the group size in half......Tom


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