Gunsmithing Clip slotting the M700

[LRI]

After a fair amount of research its come to my attention that there's some artistic interpretation on this process. Prints are scarce and even after tracking down some old salts from PWS there's still some rather vague/grey areas that were often left to the whims of the person doing the work.

I'm not a historian on the M40 by any means. I generally take my cues on this stuff from a neighbor who's forgotten more about it than I'll ever know. After speaking with him at length yesterday, here's what I came up with.

The question I had is based off the print I was given. There are missing dimensions. Specifically the pair of tangent radius features where the bridge transitions back to the OEM port length. Same goes for the opposite side. The drawing clearly shows the facets on the side opposite of the port continuing back to the bridge, despite the lack of dimension callouts.

When I confronted Al, he smirked and simply replied, "there's no hard rule on this. Everyone was doing these things back in the day..." He went on to comment about how the port elongation varies between two different types as well. The double radius that I did and the single large radius. Both are correct, just a matter of who did it.

So, I wing'd it. Came out perty nice I think. I did this one completely by hand on the Bridgeport. If I get more I'll prolly fixture it up in the 4th axis and automate the process.


I elected to run the port radius features all the way down to the ejection port floor as the receiver wasn't quite square here and I had a funny edge initially where the tool exited the part. continuing it down to the port floor corner radius made for a convenient transition point that once finished should make for a nice looking piece.

Base holes on this action were spot on. The owner sourced this receiver and he did a great job. All the holes were within .002" of the raceway centerline. Made my job much, much easier.

All that's left is a little engraving on the action and barrel.

Neat stuff!


C.

 

[pmclaine]

tag

 

[29aholic]

Why the run on the left side of the action?

 

[Jkob60]

You might want to make a cut along the left side of the top rail. It will facilitate feeding by allowing the thumb to push the cartridges all the way down into the magazine. Just my .02

 

[RedBull6]

Very nice

 

[nashlaw]

Just something about the look of professionally cut gunmetal. Call me a sentimentalist, if you like.

 

[LRI]

You might want to make a cut along the left side of the top rail. It will facilitate feeding by allowing the thumb to push the cartridges all the way down into the magazine. Just my .02

Kinda hard to load em this way with an optic base and optic installed isn't it?

 

[LRI]

Why the run on the left side of the action?

The print actually shows it. Just doesn't provide for dimensions. Factory M700 SA port length is a nominal of 2.375

Look at the print. Port length is called to a value of 2.58. Now look at the facets opposite of the port. Those features are drawn right up to the revised port length. They'd be .205 short normally. The top of the port is widened as well. Drawing clearly shows the magazine feed lips which are normally hidden when viewed from straight down.

From my original post:

The question I had is based off the print I was given. There are missing dimensions. Specifically the pair of tangent radius features where the bridge transitions back to the OEM port length. Same goes for the opposite side. The drawing clearly shows the facets on the side opposite of the port continuing back to the bridge, despite the lack of dimension callouts.

When I confronted Al, he smirked and simply replied, "there's no hard rule on this. Everyone was doing these things back in the day..." He went on to comment about how the port elongation varies between two different types as well. The double radius that I did and the single large radius. Both are correct, just a matter of who did it.

 

[gewehr]

You never cease to amaze

 

[eddieharren]

How much do you charge for this service?

 

[Brushout]

Tag for future

 

[Boltfluter]

Chad,

You are having way to much fun. Awesome as usual.

Regards, Paul

 

[29aholic]

Pretty cool, I am assuming someone is building an M40 clone?

 

[LRI]

How much do you charge for this service?

$200

 

[LRI]

Pretty cool, I am assuming someone is building an M40 clone?

Correct. We were commissioned to hang the barrel and machine the receiver. The rest is being handled elsewhere. I devoted an hour to hunting down You Tube vids that show legit M40's. Best resource I found was footage taken at the USMC and NRA Museums. One would have to assume those rifles are period correct. This made sorting out the crown choice much easier. The M40 build guide here on The Hide has some versions that deviate from what the video's illustrate. Specifically the radius transition from the crown's face to the barrel OD contour. Like I said, there's some variety due to how it was produced. It's a tall order to simply state that one is "right" and another isn't. That said, it's tough to argue with a documented museum piece so that's why I went that route.

 

[eddieharren]

$200.00 is a very reasonable price. We've been doing them for $250.00 but we re-blue the action afterwards.

 

[Jkob60]

Kinda hard to load em this way with an optic base and optic installed isn't it?

Then why in the hell the clip slot? You can't charge the mag with a clip with a base and optic installed either. I was referring to when you are charging the mag using a five round clip!X WTF. Is it just for looks?

 

[LRI]

It's for the scope base. Back in the day the Marine Corps had a special base that keyed into the existing clip slot. An additional lug surface was added to the front also.

the idea being that the base is physically locked to the action and the screws just hold it together.

 

[pmclaine]

And if anyone is interested TwoManAttack is selling replicas of the lugged scope base and Lazy21 is taking orders for USO MST100's which are replicas of the Unertl scope that most often was found mounted on an M40A1.

So buy a base, scope, send your action to LongRifles Inc. shazzam you have an M40A1.

 

[LRI]

We're making bases as well. In fact if this is who i think it is we might be making them for him.

i also made a variant for winchesters. It's debut was the Hide Cup rifle for this year.

)

 

[pmclaine]

We're making bases as well. In fact if this is who i think it is we might be making them for him.

i also made a variant for winchesters. It's debut was the Hide Cup rifle for this year.

)

Great sir! Im not aware of your manufacturing of the bases and hope my intrusion does not harm you.

Im just trying to reach people that want an MST100 in hopes I can get mine sooner. Going to your sight now to educate myself on your products.

I really enjoy your gunsmithing posts. Thank you for showcasing your skills.

 

[Deleted member 10043]

Then why in the hell the clip slot? You can't charge the mag with a clip with a base and optic installed either. I was referring to when you are charging the mag using a five round clip!X WTF. Is it just for looks?

The original M40/M700 had the clip slot. The Marines put a Redfield base on it that rendered the clip slot useless in Vietnam. But this is desired for someone building an M40 clone. Don't know about the M40A1 in general.

 

[TWOMANATTACK]

I recently donated an M40A1 Unertl scope mount to the NRA museum. If you watch the you tube video you will notice that the M40A1 in that video has the wrong mount. I believe that mount to be a DDROSS prototype mount. I saw it and couldnt stand it (OCD), so I donated an Orignal USMC issued Unertl mount to the museum. Reason I bring this up is, the NRA does a FANTASTIC job but they are not working with unlimited number of parts. They only have what they have and get donated. Doug Wicklund was very grateful. So you may see stuff that isnt truely spec as in the case of the M40A1 mount. Best of luck
Respectfully
TMA

Correct. We were commissioned to hang the barrel and machine the receiver. The rest is being handled elsewhere. I devoted an hour to hunting down You Tube vids that show legit M40's. Best resource I found was footage taken at the USMC and NRA Museums. One would have to assume those rifles are period correct. This made sorting out the crown choice much easier. The M40 build guide here on The Hide has some versions that deviate from what the video's illustrate. Specifically the radius transition from the crown's face to the barrel OD contour. Like I said, there's some variety due to how it was produced. It's a tall order to simply state that one is "right" and another isn't. That said, it's tough to argue with a documented museum piece so that's why I went that route.

 

[Mortarman0341]

Tag


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