Building a heavy buffer!!!!! Sig 716

instructional

#1

I hope this thread finds all the Full30 folks well.
After I started a thread about buffer weights and why there important

@jtallen83 informed me of a sight called
http://heavybuffers.com/716rxh.html
In this sight they had a answer to one of my questions long ago. “Why does my sig 716 kick twice as hard as my other ar-10 rifles” there answer to this problem is a 6.5 oz buffer weight!
So with out further a due let’s go out to the shop!


#2

(Disclaimer: do not do this. It is for entertainment purposes only)

I grabbed a 1” rod 1.124” diameter of 303 stainless and threw it in the lathe.


I’m basically going to copy the dimensions of a stock aluminum buffer housing and make one out of stainless to gain the weight I need to hit 6.5oz.
Use a dial indicator and adjust until you have 0.000 run out.
face off and run a quick pass to get everything true. center drill. 1/2 drill center to depth ~2.600. Diameter of .565 image|666x500 bore to dimension and use a reamer for a smooth bore!
Now check with a buffer weight on a magnet to insure that everything will work.

Start making your cuts. When getting close to final diameter make sure you cool the part to room temp before measuring.

I’m going to not cut a shoulder yet to be sure I have enough weight.

When parting the buffer from the rod stock use a lot of cutting oil and go slow. I was turning at 40 RPMs.
Now to clean up the face of the buffer. Wrap tap around your part to save the finish.

Now to make a buffer bumper.
here is what a pre made bumper looks like. I’m using a chunk of 3/4” polyurethane for the bumper. chucked up a piece of .625 dia steel in the lathe. Faced it and ran a quick cut. center drill. 9/16 drill. .500 depth. ![image|666x500]

now this is razor sharp so be careful. Heat up with heat gun and push polyurethane half way up. cut and remove bottom piece.
For shaping grab a piece of steel and heat it up. heat and roll at an angle till desired shape. now that that is done let’s make the rubber weight spacers. grabbed a chunk of rubber mat. 1/2” I.D. Punch. Make 3 of them.
Trim to proper thickness ~.075”

as much as I want to go over making a roll pin I believe that it’s pretty self explanatory.
Now let’s see what weight we are at with our parts. Remember we are shooting for 6.5oz! the buffer body alone is 3.625oz! with all other parts on the scale we are at 6.625oz!!! This is with 2 steel weights and 1 tungsten weight. Before we go further let’s drill the bumper holes. here is the set up. A little cringe factor with the c-clamp. 1/8” carbide 4flute end mill makes short work of it.
beautiful. Now deber the I.D. And O.D. tape up your buffer and re chuck to cut a shoulder. Re zero out to 0.000 run out. still looks good. to the scale once again! now just the body is at 3.125oz so we lost some good weight. now with all of our parts we are at 6.5oz!!!
according to heavybuffer.com this is our target weight for a sig 716 unsupressed.
Remember be safe and have fun!


9mm AR Build
Buffer weights and why they are important.
9mm AR Build
#3

Killer thread


#4

Man, I need more cool toys in my life like that to play with.


#5

Thank you Brother!


#6

I highly recommend it!


#7

What is a custom buffer with out engraving?

I think this is appropriate!


#8

Keep in mind with this set up you could have all 3 weights be tungsten and have a buffer that weights in at 8.7-9.0oz!!!


#9

Excellent work!! And Double-Excellent coverage of your work!!!

I recently cut a 17-4 s/s buffer, and dropped in a .500 tungsten rod. At only 2.500" long (with bumper) I maxed the weight to 5.8 oz

This prototype buffer is my next phase of planning to run a .338LM on an A5 receiver extension.


#10

Now that is something I want!


#11

You sir, are an artist with machinery. :heart_eyes:


#12

Thank you USMCMahon!


#13

I wish I had all that cool equipment and a shop to put it in…I’m limited to hand tools, a Dremel, and 3ft of tabletop to get all my stuff done.
Nice job sir!


#14

The second you mentioned .338lm in a AR style firearm I got immediate tunnel vision Brother. I also love the buffer you made to be clear!


#15

That’s what I did at first. We all start somewhere.

If you ever get the space to put some equipment start going on Craigslist everyday. Eventually you will find a deal!
That’s how I did it, but now there’s no room in the garage anymore :man_facepalming:t2:


#16

Here is his rifle in action. It does shoot that easy, even if you don’t shoot thousands of rounds a month.


#17

Beautiful isn’t it! I’m just waiting for them to hammer out all the details, and the price.