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Posted: 6/25/2013 3:18:17 PM EDT
I have been asked quite a bit via IM and post responses to explain just how the heck I mounted an M60 bipod to my AR-15 bumpfire thingy gun. I am not a technical writing master, nor am I a machinist, so please cut me some slack here if I leave out some details. I understand that this is very much WECSOGS, but I had this idea in my head, and needed to make it a reality. It’s not something many people understood or even approved of (due to the bumpfire aspect), so I was on my own

First, here is the gun in question with the bipod mounted.

Anyone who has ever actually tried to put an M60 bipod onto an AR-15 without an adapter knows the issues faced.

---The barrel contour at the end of an M4 profile fits the inside of the M60 yoke pretty much perfectly. The only trouble is, the yoke is about 7/8" at the bottom and the portion of the barrel that is .70" in diameter is about 11/16" long. That leaves ~3/16” of discrepancy to account for.

---Even if the barrel and yoke matched perfectly, the gun would rotate 360 degrees. Something must be made to stop the rotation. I solved that issue by cutting a YHM gas block to be the “stopper”, and it just so happened to workout nearly perfect to become a DIY dissipator length gun. Pretty cool...

1) Assembled views from the side and bottom. This should show where I had to cut and file the clamps of my YHM flip-up gas block to fit the yoke of bipod. Because of the way I used bushings, to transfer the torque of the flash hider to the barrel, the Bipod is actually free-floating. It is able to freely rotate about 5 degrees or so and does not move forward or rearward.




The next thing I did was to go ahead and open up the rear portion of the M60 yoke with a dremel. I would LOVE to have done this with a mill or something, but I don’t have access to one. The rear portion only needed to clear the step-up of .02 of an inch [(.74” - .70”)/2]. Before any of you out there freak out, the bipod already had some damage that I had to fix with the dremel, so at this point, I am not wrecking the thing. The black portion there is paint. I didn’t bother cleaning this up for pics. Oops....



Next pics show the way the spacers work to allow the bipod to be a free float and not spin the FH off the gun. This is probably my favorite part of the whole project.

The crush washer: This actually is the perfect taper to miss the outside of the Yoke and transfer all of the torque to the barrel that is ~1/16” beyond the face of the yoke. I accomplished this with the use of a brass spacer that I had to turn down a bit to slip inside the yoke.

Crush washer


Brass bushing


Exploded view


The final spacer bushing is pictured behind the gas block in the second picture. what that does is bring the gas block face to the area of the barrel that steps up from .70” to .74”; AND allow the handguard cap to hold the rifle length handguards on tightly.

I am sure some of you out there could really do a better job, but this gun has been burning a hole in my brain, so I was determined to make it work with the simple tools I had. I am sure I am leaving out a bunch of stuff like bushing specs and the amount of steel I cut off the barrel clamp. If some of you out there REALLY need that, I can dig out my calipers and get the exact numbers. Until then, this is just a general guideline to how I did it.

Here is the gun in action--enjoy!




Link Posted: 6/25/2013 3:39:54 PM EDT
[#1]
Nice how to. The M60 bipod is a good, strong design, better than the gun itself IMHO. While my idea of a bipod on the AR platform is either a Harris or a grip-pod, that still looks sexy though.

I honestly think you should invest in purchasing a Lightning Link, and get rid of that stock.
Link Posted: 6/25/2013 3:41:33 PM EDT
[#2]
Tagged for home where I can see the pictures.  I'll be using an M5 RAS on my build, so i probably won't use an M60 bipod, but i still want to see it.
 
Link Posted: 6/25/2013 3:42:10 PM EDT
[#3]



Quoted:


Nice how to. The M60 bipod is a good, strong design, better than the gun itself IMHO. While my idea of a bipod on the AR platform is either a Harris or a grip-pod, that still looks sexy though.



I honestly think you should invest in purchasing a Lightning Link, and get rid of that stock.


I think MG's aren't allowed in WA.  Besides, its cheap and works.  



 
Link Posted: 6/25/2013 3:45:19 PM EDT
[#4]
Yep, no MGs in Washington.

Plus, there was an aspect of challenge that I liked about the prone bumpfire stock concept. Could it be made to be accurate and practical? I think so. I am still sort of testing it, and it may take a bit to update considering ammo prices.
Link Posted: 6/25/2013 3:50:06 PM EDT
[#5]
Cool idea. I like it a lot. Going to have to try this out.
Link Posted: 6/25/2013 4:21:51 PM EDT
[#6]
Nice job.
Link Posted: 6/25/2013 5:47:46 PM EDT
[#7]
Tag. Thanks OP.
Link Posted: 6/25/2013 6:59:29 PM EDT
[#8]
Well I thought the bumpfire thingy was kinda dumb until I watched your video....Outstanding!  That thing was rocking!  And it looks really good.
Link Posted: 6/25/2013 8:19:21 PM EDT
[#9]
Quoted:
Well I thought the bumpfire thingy was kinda dumb until I watched your video....Outstanding!  That thing was rocking!  And it looks really good.


Thanks!

Posts like this right here is why I even bothered with a gun like this! Not that I am the only one, but I just saw more potential in these things than others. Perhaps it's because I wanted my own SAW after my time in the USMC and knew this was as close as I was ever getting...
Link Posted: 6/25/2013 8:47:33 PM EDT
[#10]
Is the limitation on rotation/cant due to the rear step contacting the gas block? Personally, I'd whack them suckers off just to prevent that contact (if that's the case).
Link Posted: 6/25/2013 8:53:28 PM EDT
[#11]
Quoted:
Is the limitation on rotation/cant due to the rear step contacting the gas block? Personally, I'd whack them suckers off just to prevent that contact (if that's the case).


Interesting suggestion.

Do you think having that much cant would be a good thing?
Link Posted: 6/25/2013 8:58:38 PM EDT
[#12]



Quoted:



Quoted:

Is the limitation on rotation/cant due to the rear step contacting the gas block? Personally, I'd whack them suckers off just to prevent that contact (if that's the case).




Interesting suggestion.



Do you think having that much cant would be a good thing?


For me it wouldn't be necessary to have more can't, I just wouldn't want anything there to possibly rotate the gas block (granted that would take a bit of force). Then again you'd have a freely rotating bipod (for the most part it appears), which might be an issue in itself.

 
Link Posted: 6/25/2013 9:05:57 PM EDT
[#13]
Quoted:

Quoted:
Quoted:
Is the limitation on rotation/cant due to the rear step contacting the gas block? Personally, I'd whack them suckers off just to prevent that contact (if that's the case).


Interesting suggestion.

Do you think having that much cant would be a good thing?

For me it wouldn't be necessary to have more can't, I just wouldn't want anything there to possibly rotate the gas block (granted that would take a bit of force). Then again you'd have a freely rotating bipod (for the most part it appears), which might be an issue in itself.  


I am starting to think you are on to something. More cant would be good on awkward slopes.

Luckily the gas block is really only a front sight in this case. It's a carbine gas system.
Link Posted: 6/25/2013 9:38:37 PM EDT
[#14]
Everytime I see your mod, I can't help but see this:



If I'm ever to go down the retro route, It will be the M16A1 with the M60 bipod.
Link Posted: 6/25/2013 9:44:27 PM EDT
[#15]
Quoted:
Everytime I see your mod, I can't help but see this:

http://25.media.tumblr.com/03e6dc8b4f6f4a131b75ef08bdf1e298/tumblr_mo3oite5gn1r9khx4o1_1280.jpg

If I'm ever to go down the retro route, It will be the M16A1 with the M60 bipod.


Yeah, I saw a few of those and was inspired by them to go forth with this project.

At first, I had a handmade bipod. It was pretty cool, but sort of flimsy...  

Link Posted: 6/25/2013 9:59:57 PM EDT
[#16]
Glad to see this thread!!
Link Posted: 6/26/2013 12:08:29 PM EDT
[#17]
Quoted:
Glad to see this thread!!


Thanks! Hope to see your bipod mock up soon.
Link Posted: 6/26/2013 12:17:49 PM EDT
[#18]
Nice.  I bet your barrel was hot as hell.

Link Posted: 6/26/2013 1:42:31 PM EDT
[#19]
Quoted:
Nice.  I bet your barrel was hot as hell.



Yeah....  it was smoking a bit.

The day that video was taken, the temps were right around freezing with moments of horizontal rain. After that video was taken I held onto the handguards for warmth. Felt GOOOOOOOOD!
Link Posted: 6/27/2013 8:01:30 AM EDT
[#20]
looks good
Link Posted: 6/27/2013 12:47:41 PM EDT
[#21]
awesome video :rofl:
Link Posted: 6/27/2013 4:17:49 PM EDT
[#22]
Dude, that is gorgeous.
Link Posted: 6/27/2013 4:29:26 PM EDT
[#23]
Thanks to all who have posted! Hope to at least see one other gun like this (with the M60 bipod and bump fire stock) someday.
Link Posted: 6/27/2013 5:19:29 PM EDT
[#24]
Quoted:
Thanks to all who have posted! Hope to at least see one other gun like this (with the M60 bipod and bump fire stock) someday.


my next build is a ar in 308 for long range shooting. I might just get a m60 bipod and figure out a way to attach it.
Link Posted: 6/27/2013 5:22:18 PM EDT
[#25]
Quoted:
Quoted:
Thanks to all who have posted! Hope to at least see one other gun like this (with the M60 bipod and bump fire stock) someday.


my next build is a ar in 308 for long range shooting. I might just get a m60 bipod and figure out a way to attach it.
After looking at the Parker-Hale bipod mount, it looks like you could mod it to use the M16 bipod with.

Link Posted: 6/27/2013 6:32:07 PM EDT
[#26]
Quoted:
Quoted:
Quoted:
Thanks to all who have posted! Hope to at least see one other gun like this (with the M60 bipod and bump fire stock) someday.


my next build is a ar in 308 for long range shooting. I might just get a m60 bipod and figure out a way to attach it.
After looking at the Parker-Hale bipod mount, it looks like you could mod it to use the M16 bipod with.



I'd love to have gotten a proper mount, but I didn't want to have my barrel taken in to be turned down to .625" at the end. I figured this way was actually cheaper, and will work when I finally need to swap the barrel out.

This is also an option for those that like to tinker. Here is an archived thread by catmantim about it. Bayonet lug bipod

Link Posted: 6/27/2013 6:42:33 PM EDT
[#27]
Quoted:
Quoted:
Quoted:
Quoted:
Thanks to all who have posted! Hope to at least see one other gun like this (with the M60 bipod and bump fire stock) someday.


my next build is a ar in 308 for long range shooting. I might just get a m60 bipod and figure out a way to attach it.
After looking at the Parker-Hale bipod mount, it looks like you could mod it to use the M16 bipod with.



I'd love to have gotten a proper mount, but I didn't want to have my barrel taken in to be turned down to .625" at the end. I figured this way was actually cheaper, and will work when I finally need to swap the barrel out.

This is also an option for those that like to tinker. Here is an archived thread by catmantim about it. Bayonet lug bipod

http://i1235.photobucket.com/albums/ff421/rodgravy1976/100_1514.jpg


I had meant to say the M-60 bipod.

Link Posted: 6/27/2013 6:47:03 PM EDT
[#28]
Quoted:
I had meant to say the M-60 bipod.



I figured. I guess the only thing I can even think of that would be an "M16" bipod would be one of these!

Link Posted: 6/27/2013 6:58:57 PM EDT
[#29]
Quoted:
Quoted:
I had meant to say the M-60 bipod.



I figured. I guess the only thing I can even think of that would be an "M16" bipod would be one of these!

http://www.mooremilitaria.com/M16%20Bipod%20&%20Case.JPG


Link Posted: 6/27/2013 7:02:07 PM EDT
[#30]





Quoted:





Quoted:


I had meant to say the M-60 bipod.











I figured. I guess the only thing I can even think of that would be an "M16" bipod would be one of these!





http://www.mooremilitaria.com/M16%20Bipod%20&%20Case.JPG



Hey now! Those will work, if you have an M4 profile barrel (shown on my dedicated .22 upper).







 
 
Link Posted: 6/27/2013 7:03:10 PM EDT
[#31]
Quoted:
Quoted:
Quoted:
I had meant to say the M-60 bipod.



I figured. I guess the only thing I can even think of that would be an "M16" bipod would be one of these!

http://www.mooremilitaria.com/M16%20Bipod%20&%20Case.JPG




Yeah, not as aesthetically pleasing as the M60 bipods, but way easier to get to mount...
Link Posted: 6/27/2013 7:04:21 PM EDT
[#32]
Quoted:

Quoted:
Quoted:
I had meant to say the M-60 bipod.



I figured. I guess the only thing I can even think of that would be an "M16" bipod would be one of these!

http://www.mooremilitaria.com/M16%20Bipod%20&%20Case.JPG

Hey now! Those will work, if you have an M4 profile barrel (shown on my dedicated .22 upper).

http://i215.photobucket.com/albums/cc68/gunnyg_photos/Private/AR15/DSC07617.jpg    


Holy cow... That is the first time I have ever seen the M203 cut barrel be useful!
Link Posted: 6/27/2013 7:11:51 PM EDT
[#33]



Quoted:



Quoted:




Quoted:


Quoted:

I had meant to say the M-60 bipod.







I figured. I guess the only thing I can even think of that would be an "M16" bipod would be one of these!



http://www.mooremilitaria.com/M16%20Bipod%20&%20Case.JPG


Hey now! Those will work, if you have an M4 profile barrel (shown on my dedicated .22 upper).



http://i215.photobucket.com/albums/cc68/gunnyg_photos/Private/AR15/DSC07617.jpg    




Holy cow... That is the first time I have ever seen the M203 cut barrel be useful!


.. not that I have ever actually felt the desire to use it. I have much better options that involve free floated picatinny rails, or at least a HSGI shooting rest/fannypack that won't change the barrel's point of impact.









 
Link Posted: 6/27/2013 7:56:14 PM EDT
[#34]
I dig it
Link Posted: 6/28/2013 7:35:43 PM EDT
[#35]
Your video makes me want to give one of those Slide Fire stocks a go, but the price kicks me in the nuts every time I do a search for one.
Link Posted: 6/29/2013 1:45:40 PM EDT
[#36]
Quoted:
Your video makes me want to give one of those Slide Fire stocks a go, but the price kicks me in the nuts every time I do a search for one.


If you are going to do it, I suggest the Fostech route. I got my SF stock used for a decent price, but WISH I had saved up the money for the better, more high-quality one.
Link Posted: 6/29/2013 10:50:44 PM EDT
[#37]
cool I have an old heavy barrel that I have thought about modding to work with an FAL bipod,this thread makes me want to do it
Link Posted: 6/30/2013 4:29:20 PM EDT
[#38]
Quoted:
cool I have an old heavy barrel that I have thought about modding to work with an FAL bipod,this thread makes me want to do it


That sound's like a good project! I considered a FAL bipod as well. Please post pics if/when you do it.

Found this on google: How to add a FAL bipod to your PSL. Seems like that could be a pretty good option for someone wanting to make something that functions similar to my gun. I just love the look of the M60 bipods.

Link Posted: 6/30/2013 11:34:19 PM EDT
[#39]
First OP, awesome thread and thanks for the link. I went out yesterday and bought a Slidefire stock and 2 60 Surefire mags because of it.

It's might be a dumb question,but does the bipod make it difficult to use the Slidefire when you use your off hand to pull forward on the gun?
Link Posted: 7/1/2013 2:59:37 AM EDT
[#40]
Quoted:
First OP, awesome thread and thanks for the link. I went out yesterday and bought a Slidefire stock and 2 60 Surefire mags because of it.

It's might be a dumb question,but does the bipod make it difficult to use the Slidefire when you use your off hand to pull forward on the gun?


Not at all! I actually grip the rear of the gun back behind the charging handle and push forward. It's a very natural grip position from bipod-supported prone.

Once you get a set of bipods mounted, try it out for yourself. You will see what I mean.  

Not sure why this screen cap is so blurry, but you get the idea.
Link Posted: 7/1/2013 3:09:36 AM EDT
[#41]



Quoted:





Quoted:

Nice how to. The M60 bipod is a good, strong design, better than the gun itself IMHO. While my idea of a bipod on the AR platform is either a Harris or a grip-pod, that still looks sexy though.



I honestly think you should invest in purchasing a Lightning Link, and get rid of that stock.


I think MG's aren't allowed in WA.  Besides, its cheap and works.  

 
Exactly.





Plus, it's non-NFA, no stamp or waiting, and for the price of a lightning link, you can buy a SHIT TON of ammo and get good with the slidefire.





 
Link Posted: 7/1/2013 3:34:35 AM EDT
[#42]
Quoted:
Quoted:
First OP, awesome thread and thanks for the link. I went out yesterday and bought a Slidefire stock and 2 60 Surefire mags because of it.

It's might be a dumb question,but does the bipod make it difficult to use the Slidefire when you use your off hand to pull forward on the gun?


Not at all! I actually grip the rear of the gun back behind the charging handle and push forward. It's a very natural grip position from bipod-supported prone.

Once you get a set of bipods mounted, try it out for yourself. You will see what I mean.  

Not sure why this screen cap is so blurry, but you get the idea.
http://i72.photobucket.com/albums/i172/schkoot/Screenshot_2013-06-30-23-56-13_zps7b03e277.png
Natural?



I'm going with M249 training/experience here myself. That is not a natural position for firing that rifle. But it's muscle memory that keeps you using it that way.

Link Posted: 7/1/2013 4:08:15 AM EDT
[#43]
Quoted:
Quoted:
Quoted:
First OP, awesome thread and thanks for the link. I went out yesterday and bought a Slidefire stock and 2 60 Surefire mags because of it.

It's might be a dumb question,but does the bipod make it difficult to use the Slidefire when you use your off hand to pull forward on the gun?


Not at all! I actually grip the rear of the gun back behind the charging handle and push forward. It's a very natural grip position from bipod-supported prone.

Once you get a set of bipods mounted, try it out for yourself. You will see what I mean.  

Not sure why this screen cap is so blurry, but you get the idea.
http://i72.photobucket.com/albums/i172/schkoot/Screenshot_2013-06-30-23-56-13_zps7b03e277.png
Natural?



I'm going with M249 training/experience here myself. That is not a natural position for firing that rifle. But it's muscle memory that keeps you using it that way.



That is a good point. I learned that grip from shooting the SAW. I never had an AR with a bipod before that, so I can't say what I would have done prior. I will say this. It's an easy grip to get the forward pressure needed to bump AND to control the aim. I would say the only drawback is the eye-relief issues with the optic. I got it as a cheap-o experiment, so I may graduate to a better optic with longer eye relief at a later point. Right now, any money that goes to guns will be spent on ammo or better mags. My old PMAGs may have been causing some stops in the gun this week. That and under-powered, uncrimped ammo.
Link Posted: 7/1/2013 4:21:47 AM EDT
[#44]
Quoted:
Quoted:
Quoted:
Quoted:
First OP, awesome thread and thanks for the link. I went out yesterday and bought a Slidefire stock and 2 60 Surefire mags because of it.

It's might be a dumb question,but does the bipod make it difficult to use the Slidefire when you use your off hand to pull forward on the gun?


Not at all! I actually grip the rear of the gun back behind the charging handle and push forward. It's a very natural grip position from bipod-supported prone.

Once you get a set of bipods mounted, try it out for yourself. You will see what I mean.  

Not sure why this screen cap is so blurry, but you get the idea.
http://i72.photobucket.com/albums/i172/schkoot/Screenshot_2013-06-30-23-56-13_zps7b03e277.png
Natural?



I'm going with M249 training/experience here myself. That is not a natural position for firing that rifle. But it's muscle memory that keeps you using it that way.



That is a good point. I learned that grip from shooting the SAW. I never had an AR with a bipod before that, so I can't say what I would have done prior. I will say this. It's an easy grip to get the forward pressure needed to bump AND to control the aim. I would say the only drawback is the eye-relief issues with the optic. I got it as a cheap-o experiment, so I may graduate to a better optic with longer eye relief at a later point. Right now, any money that goes to guns will be spent on ammo or better mags. My old PMAGs may have been causing some stops in the gun this week. That and under-powered, uncrimped ammo.
Hey, if it works for the bumpfire, why not? FA or in your case, bumping is an area fired weapon, so may I suggest a scout optice, or a CQO?

As for the positioning, since AIT with the M-60, to the M-249, and the M-240, I've always shot that way from the prone or prone supported as in standing up in a hole/ditch/window/wall. But I've also been issued the M16 amd M4 too, both with an M203. It just boils down to what systems you're used and are used to and knowing blindfolded where to place everything and where anything is. I want an M1A, not practical, so I built an LR308 because I already know , am trained, and been to war with it so I know six ways from Sundays with how the AR system works.

Oh, I saw some steel cased on Cabella's in .223 for $6 a pop of 20. Timegonow.
Link Posted: 7/1/2013 4:31:18 AM EDT
[#45]
Quoted:
Hey, if it works for the bumpfire, why not? FA or in your case, bumping is an area fired weapon, so may I suggest a scout optice, or a CQO?

As for the positioning, since AIT with the M-60, to the M-249, and the M-240, I've always shot that way from the prone or prone supported as in standing up in a hole/ditch/window/wall. But I've also been issued the M16 amd M4 too, both with an M203. It just boils down to what systems you've used and are used to and knowing blindfolded where to place everything and where anything is. I want an M1A, not practical, so I built an LR308 because I already know and trained how the AR system works.

Oh, I saw some steel cased on Cabella's in .223 for $6 a pop of 20. Timegonow.


Yeah, the "point target" stuff about the SAW is really something I can't quite understand. I suppose it does OK, but it's always really a cone of fire. Madcap can attest, this gun does remarkably well in the accuracy department. I was actually traversing the gun a bit and the groups looked like a horizontal jagged line. Not bad for bumpfire!

About the Steel case, I prefer it for now. I don't like running expensive 92 octane gas through this thing considering what it is/does. I will need to swap the barrel soon anyway, so steel it is!
Link Posted: 7/8/2013 10:02:03 PM EDT
[#46]
Any interest in a adapter that would screw onto the end of the gun and allow for a m60 bipod? Similar to the one below?


Link Posted: 7/8/2013 10:56:31 PM EDT
[#47]
Quoted:
Any interest in a adapter that would screw onto the end of the gun and allow for a m60 bipod? Similar to the one below?


http://i61.photobucket.com/albums/h53/jntmjt1/1008072753_4wugz-L.jpg


Yeah, I would love one!
Link Posted: 7/8/2013 11:50:51 PM EDT
[#48]
Ill see what i can come up with.
Link Posted: 7/9/2013 12:17:53 AM EDT
[#49]
Fuckin' A.

That was cool.
Link Posted: 7/9/2013 2:19:40 PM EDT
[#50]
Quoted:
Ill see what i can come up with.


Are those adapters the ones that need the barrel to be .625"? I would like one just on principal, but I do like the way I mounted mine.
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