Go Back   CMP Forums > CMP Sales > CMP Bolt Action Rifles
Register FAQ Members List Calendar Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 01-03-2012, 09:46 PM
wellfedirishman wellfedirishman is offline
 
Join Date: Dec 2011
Posts: 24
Question 1903A3 - Need help identifying a scope mount hole pattern please

Folks,

Thank you all for your help with a recent 1903 sight question. I need to draw on your collective wisdom again in identifying a hole pattern on a 1903A3.

This is a Smith Corona 1903A3 that some thoughtful individual drilled and tapped (and left a scar on the receiver too over the M of Model). The rifle is in overall reasonable conditon (bore is good), with a few dings and dents on the stock and a chip out of the front handguard, and rust freckling on the barrel bands.

Since it is already tapped for screws, I was considering putting a scope mount on it. What I need is to identify what base would fit this.

There is a pair of holes at the front (by the number/manufacturer), with a spacing of approx 0.5". These holes have been neatly plugged. About 4.43" or maybe 4.45" behind the front rearmost hole, there appears to be a third hole under the rear sight. It looks like a screw was cut off and remains inside. It may be removeable, not sure how to get it out without messing up the threads.

Since there were two holes at the front and one at the back, I think it is a Leupold mount but I have no way to check if the spacing is correct. I believe there was also a style of Redfield mount that dovetailed on the rear and had 2 holes on front.

Can anyone tell me what type of mount will fit this? Your input would be greatly appreciated.

ETA: The stock has a Circle-P and FJA stamp, and a V143 large stamp on the right hand side (unit or Veterans organization?)












Last edited by wellfedirishman; 01-03-2012 at 10:12 PM.
Reply With Quote
  #2  
Old 01-04-2012, 08:03 AM
S99VG S99VG is offline
 
Join Date: Jun 2010
Location: Northern California
Posts: 780
Default

Redfield Jr. mounts take one hole in the rear bridge (like yours) and one hole in the front ring (unlike yours). Leupold bases for a rotary dovetail mount take two holes in the front ring. Keep in mind there have been a lot of scope and base manufacturers over the years with many now forgotten about. I'd check to see if your hole pattern lines up with a Leopold base (which is identical to the Redfield with the exception of the front hole pattern). You too may be able to fit a Redfield base, but it will need another hole drilled in the front ring as both yours look to be placed too far forward. The dimple over the M looks just about where a hole would need to be drilled for the Redfield base. Hope this helps.

Last edited by S99VG; 01-04-2012 at 05:13 PM.
Reply With Quote
  #3  
Old 01-04-2012, 11:22 AM
3StrikesNC 3StrikesNC is offline
 
Join Date: Oct 2009
Location: in a house
Posts: 2,039
Default

I had a similar issue with an A3/A4 build. I used a Redfield Jr. mount. The rear screw lined up perfect in the dovetail, but the front screws did not. Since it's a lot easier to modify the scope base versus modifying the receiver, I chose to modify the base with some cold re-blue.

It's much easier to have a machine shop/smith plug the Redfield Jr. base and re-drill/counterbore it to match your tapped receiver. Prior to doing so, you want to make sure the (3) tapped holes are in-line positionally so you don't start off with an offset set of rings/mount.

Also - looks like your receiver was spot drilled to locate another hole, right on the "M" of Model. I wouldn't bother nor be concerned. It'll be covered up.

As a note, I had some "significant' filing/sanding to do to the "Made in China" Redfield scope base. The one I had would "rock" between the front and rear. Took me quite a few hours to hand fit it perfect, but I'm anal about stuff like that and it fit perfect when I was done. I didn't want any undue stress on the screws/mount/rings/scope tube.

Last edited by 3StrikesNC; 01-04-2012 at 11:25 AM.
Reply With Quote
  #4  
Old 01-04-2012, 11:30 AM
3StrikesNC 3StrikesNC is offline
 
Join Date: Oct 2009
Location: in a house
Posts: 2,039
Default

Also - I noticed you have a straight stock. If you plan on using this rifle in CMP Sniper competition, you'll need a scant or a "C" stock. The straight stock is not legal/as-issued for the match.

Seems to me I read SC's were not made in A4 configurations either, but I don't believe the CMP rules would prohibit you from using it. Maybe someone else can chime in on this.
Reply With Quote
  #5  
Old 01-04-2012, 05:29 PM
S99VG S99VG is offline
 
Join Date: Jun 2010
Location: Northern California
Posts: 780
Default

3StrikesNC makes a good point. Make the base fit your rifle - heck all you need is one screw in the front ring anyway.

Last edited by S99VG; 01-04-2012 at 05:34 PM.
Reply With Quote
  #6  
Old 01-04-2012, 08:37 PM
wellfedirishman wellfedirishman is offline
 
Join Date: Dec 2011
Posts: 24
Default

Thanks folks, I really appreciate the good advice.

I ended up finding an older USA-made Leupold 1903a3 base that I can modify to fit the existing hole pattern on the rifle. Measure twice, drill once and all that.

Turns out that the rear screw hole (under the A3 sight) is drilled straight through so it should be fairly straightforward to tap into and turn it so it drops out.
Reply With Quote
  #7  
Old 01-04-2012, 08:43 PM
3StrikesNC 3StrikesNC is offline
 
Join Date: Oct 2009
Location: in a house
Posts: 2,039
Default

They make left hand fluted drill bits. they often work for drilling out broken screws as the bit "grabs" and can back the screw out. Just buy one and run your drill in reverse.

If your good, you might be able to back the screw out using an awl and very light tapping from a hammer.
Reply With Quote
  #8  
Old 01-06-2012, 11:24 AM
lapriester lapriester is online now
 
Join Date: Oct 2009
Location: Cobb, N California
Posts: 10,707
Default

Quote:
Originally Posted by wellfedirishman View Post
Thanks folks, I really appreciate the good advice.

I ended up finding an older USA-made Leupold 1903a3 base that I can modify to fit the existing hole pattern on the rifle. Measure twice, drill once and all that.

Turns out that the rear screw hole (under the A3 sight) is drilled straight through so it should be fairly straightforward to tap into and turn it so it drops out.
Hopefully red Loktite wasn't used when it was put in to make it a "permanent" fix. That might complicate matters some.

Larry
Reply With Quote
  #9  
Old 01-06-2012, 08:50 PM
wellfedirishman wellfedirishman is offline
 
Join Date: Dec 2011
Posts: 24
Default

I picked up an old-style USA made Leupold base for the 1903A3 and the frontmost hole and rear hole (mounts on the 1903A3 sight base) match up, as do the screw threads. Looks like I am in business Thanks for the advice, much appreciated.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 09:21 AM.