40X vs Rem 700 Diameter

[Bob3700]

Gents,

I have run across something that puzzles me. Recently I removed a Rem. 40X action that was pillar and Devcon bedded into a factory 40x target stock.

Went to install a Rem 700 and much to my surprise, it wouldn't fit at all. Not even close. The Rem 700 is much larger in diameter than the Rem 40X. The action screw locations are the same but that is about it.

I always thought that the 40X and the 700 were the same action, just minor differences for the single shot feature of the 40X.

Now I will tell you that the 40X is an action of mid to late 60s vintage and the 700 is from the 80s.

There is a whole lot of bedding and wood removal to install the Rem 700 where the 40X was. I have not run into this before.

Bob

 

[rayjay]

Get your calipers out and measure both receivers. I thought they were all 1.3XX .

I think they are all warped to varying degrees and this will affect the fit for sure.

Ray

 

[TRECustom]

Bob, 40Xbr receivers are surface ground all the way around the O.D. It's part of the factory "blueprinting" for those rifles. I don't know if 40X match rifles are or not. Since this one is a single shot, it might be a 40Xbr. Also, all the match rifles have clip slotted bridges and magazine wells.

700's are only partially ground across the bottom. That must be the difference. Rayjay is right. caliper the O.D.'s and compare them. I wouldn't think that they would be more than maybe .010" smaller, but in a good bedding job, that would stop an action from dropping in.

Let us know what you find. Also if your action is a 40Xbr.,No clip slot and no magazine cutout). Good info.

I'll watch this thread,

Thanks, Tom

 

[Bob3700]

Tom and Ray,

The Rem is a 40 XB. It is a single shot, so no clip slot and no repeater.

I have not had a chance to put a caliper on it yet but will this evening.

The stock was bedded using billet al pillers and Devcon F1 for the base and F2 for the final skim coat. The fit to the 40XB action was pretty snug.

As you said, .010" when things are bedded tight is significant.

Will get back to this thread this evening with some dimensions.

Bob

 

[Bob3700]

The Remington 40XB action measures 1.388" in diameter.

I don't have the 700 in my shop anymore so don't know what it's diameter is. Just that it is larger than the 40 XB.

The 700 is one of the newer versions that have the anti-bind rail down the left side.

40XB is older and has none of that.

RGDS

Bob

 

[rayjay]

I looked at some notes and I put down 1.355 for my 40x dia. I just measured a 700 rec and got 1.351 to 1.355 depending on where you measure. It's definitely not round.

 

[Bob3700]

Ray and Tom,

Did some further investigating.

First off I measured my 40XB action wrong. The diameter at the receiver ring is 1.358. Had my brother measure the 700 action and it was 1.356. Now we are asking ourselves why the 700 is sitting so high in the 40XB stock.

Answer, the 700 action is a later version and it has that anti-bind slot in the bolt and the guide down the right side of the action. The 700 action loading port is actually .140" higher on the outside lug side than the older 40XB action. The rest of the dimensions are the same, the new action just LOOKS like it rides higher in the stock because of the loading port dimensional difference.

Mystery solved.

Bob

 

[rayjay]

I made an internal action wrench for my older 40x. I got in a newer 700 last week and went to insert the action wrench and guess what ???!?!? Anti bind slot. I get to cut a slot in the action wrench the next time I am making chips with the milling machine.

 

[Bob3700]

Ray,

I just got finished doing exactly the same thing. My wrench is for the older actions without the anti-bind feature.

Not hard, just another thing to add to the "To Do" list.

Bob

 

[TRECustom]

Bob, I have bedded a couple of 700's with and without the anti-bind, but I never swapped them out, and never caught the port height difference!

Thanks for the heads-up, Tom

 

[rayjay]

I just added the slot in my action wrench. While messing with the wrench I discovered that tolerance stack had caused one surface [ now the upper surface since the addition of the slot ] was not bearing against the lug raceways in my 700 action [ I will have to check the 40x the next time I go to remove the bbl ]. I probably made the shaft a bit too big [ at least for this 700 ] and the head must be offset a few thou from the shaft centerline.

I carefully filed the 'high' side until I had good contact on all 4 surfaces.

 

[fredcw4]

the locking lungs on 40x's in 22lr are midway on bolt and receivers as was on rem 37's. 40x's center fire locking lungs, 721,722,700 short or long actions are up forward at the chamber.

 

[Sniperhandle]

Zombie thread response crew #2

By now the kid's are all grown and have moved out.