clip slot and thumb cut relief

[Johnny_V]

I’d like to begin by expressing my appreciation for this community and its wealth of knowledge. The detailed discussions here have significantly broadened my understanding of the Vietnam-era M40 rifle.

At present, I am in the process of assembling a Replica M40. I intend to send my six-digit receiver to LRI for the thumb cut and clip slot and would value the community’s feedback regarding the quality and authenticity of their machining—specifically their clip slotting and thumb reliefs as they pertain to the M40. Most of the necessary components have been sourced, and I’d prefer to have this work completed prior to barreling.

Thank you in advance for your expertise and recommendations.

 

[John L]

Read Chads description of this service on his website very carefully. I don't think he does the clip slotting like the M40 had, I believe it is more like the slotting done on the M40A1. It would be best to check with him directly and make sure he is willing/able to do the M40 style. If he is you will find nobody better to do the job.

 

[HarryBC]

Find Raven Rifles, Raven6 I think. He has his personal M40a5 listed for sale, should be able to search for him that way. His M40 series builds are highly recommended…

 

[DFOOSKING]

I'm pretty sure Chad can cut smiley faces in your reciever if you want them.

At the end of the day, the task of clip slotting is probably almost child's play for a CNC machinist of his level. He just needs the specs. The Vietnam era M40 and the later M40A1 probably have some variations.

 

[Johnny_V]

Years ago, I had LRI flute a couple of bolts for me, and the quality was excellent. Of course, that was a straightforward cylindrical piece. I spoke with the machinist who performs the clip slot and thumb cut, and he explained that before proceeding with the cuts, he would contact me to review the entire process and confirm any modifications required in his CNC program.

 

[ruqikr454]

Find Raven Rifles, Raven6 I think. He has his personal M40a5 listed for sale, should be able to search for him that way. His M40 series builds are highly recommended…

I reached out to Raven a year ago to do an M40 build and said he didn’t renew his FFL was wasn’t building them any longer
I hope this has changed my build is still in pieces!

 

[HarryBC]

Try Raven again… I hear he has a FFL now and is accepting work.

 

[packratt]

Please post if he is back in business. May finally be ready to start mine.

 

[Jrb572]

I'm pretty sure Chad can cut smiley faces in your reciever if you want them.

At the end of the day, the task of clip slotting is probably almost child's play for a CNC machinist of his level. He just needs the specs. The Vietnam era M40 and the later M40A1 probably have some variations.

There is so many different ways to clip slot. But there is a certain way the M40 stuff is done to make it clone correct
If I remember correctly Chad knows the correct way to do it to make it clone correct. But I think he has his way and for it to be different you have to request it. I’d call Tuesday and ask or @LRI maybe will answer here

 

[ruqikr454]

Try Raven again… I hear he has a FFL now and is accepting work.

That’s fantastic news
I will reach out to him

 

[Random Guy]

At present, I am in the process of assembling a Replica M40. I intend to send my six-digit receiver to LRI for the thumb cut and clip slot and would value the community’s feedback regarding the quality and authenticity of their machining—specifically their clip slotting and thumb reliefs as they pertain to the M40.

I’m not a machinest and thus I am not an expert, but since you are openly asking for opinions, here’s mine. Below is my vintage Remington 40-X repeater with a factory clip slot that was reportedly made in the 1969-70 era based on its serial number. Please note the two small “semi-circular” cuts that facilitate holding the old 5-rd stripper clip into the clip slot for rapid fire reloading during a rifle match. The two little semi-circular cuts are what is seen on the original 6-digit M40 rifles made from 1967-69. I call this a “true” clip-slot design:

…in contrast, below is my C-prefix M40A1 replica that was made by a retired 2112 at PWS many years ago. It’s lacks the semi-circular cuts, and is what I will call a “lug slot” cut. It allows the rear lug of the Unertl scope mount to fit tightly into the “lug slot”, but it’s not going to work well with the old 5-rd stripper clip as it lacks the two small semi-circular cuts to hold the stripper clip in a vertical position. That’s my opinion of the nuanced difference between a true M40 era “clip slot” versus the later “lug slot” used on the M40A1/A3/A5s.

Below picture shows the front and rear lugs of a reproduction M40A1 scope mount that illustrate the purpose of hand-filing the scope rail to fit very tightly (basically zero tolerance) within lug slots machined on the M40A1/A3/A5 receivers.

Lastly, I will also note that once the M40 or M40A1 scope rail is installed, it is visually IMPOSSIBLE to see if the machining on the receiver has the small semi-circular cuts for the stripper clip or not - so it’s purely an OCD thing when it comes to machining that area.

My 2cts as a non-machinest, and good luck with your project. (Below is my replica M40 project based on that old 40-X clip-slotted receiver).