M60-SAR Build - AR15.COM

Site Notices

[ARCHIVED THREAD] - M60-SAR Build (Page 1 of 2)

Posted: 9/17/2015 10:04:00 AM EDT

Hello all, I finally broke down and decided to do an M60-SAR. I know it is not full auto, but I felt this would be the best place to post. Mods feel free to move if needed. I am going to be doing this one a little different from my previous builds of the M249 and M203 in that I will be purchasing as much of the finished receiver components as I find them in stead of making them from scratch or buying partially finished parts. I have a budget of $8k and will keep a running tally of how much parts cost and where I found them should any one else need a source. I have located the JRW sports files for the upgraded M60-SAR originally made by Eugene Peruski back in the late 80's I think. Some of the files available on line are incomplete but I have a full file now with all manuals and also notes from JRW on their different ideas for the secondary sear block and striker/plunger.

For those that don't know how the operation of the semi-auto JRW systems works I will try to offer a brief explanation. First JRW had to change some of the rail dimensions from the Peruski prototype as ATF felt that the sample sent in using the Peruski design could to too easily converted back to full-auto. JRW thickened the bottom channel rail and designed long blocking bars in the side rails to prevent use of a full-auto bolt an op-rod. The bolt itself is modified with a blocking insert in the firing pin hole to prevent the use of a full-auto firing pin. The firing pin is cut down at the front shoulder to stop the gun from firing from forward pressure on the op-rod when the bolt is in a locked position, basically a "slam fire" open bolt system that is common in machine guns. The gun is fired by a spring loaded plunger/striker in the secondary sear block, which is attached at the back of the bolt. The motion of cocking the op-rod pushes the firing pin, firing pin bushing and the plunger/striker to the rear. As it goes to full rear position, the secondary sear locks into a notch on the plunger/striker. At the same time the cam surface on the left side of the secondary sear block resets a small spring loaded hammer in the secondary trigger pack, located in the left rail. The secondary trigger pack houses the hammer, sear and disconector and has a linkage rod to connect it to the lever arm attached to the sear in the main trigger housing. The whole op system moves forward, loading and locking a round of ammunition into battery. When you pull the trigger the sear and attached lever arm pivot counter clock wise, that in turn moves the linkage arm to the rear which trips the secondary trigger and sear releasing the hammer. The hammer strikes the secondary sear which releases the striker/plunger hitting the firing pin. A round detonates, the gas op-system operates as normal to cycle the next round and the whole thing starts over again once the trigger is released and the disconnector engages the trigger/sear. Simple eh?

So as it stands now, I have a trunnion, receiver body, op-rod and bolt group. some parts have arrived, others are in the mail and will be here soon. I the mean time I am going to be concentrating a doing 3D drawings of all the secondary trigger pack components, for eventual manufacture by a local CNC shop. Anyone interested in jumping in on this part send me a PM. I know some followers of my AT-4 tracer trainer project were disappointed when the head spacing problems came up and I had to scrap that line and go back to the design stage. That one is on the back burner for now, sorry, but I think this project is a tried functional system so there are no concerns for me there. Anyway, once I have everything drawn up and the bugs worked out, I will do a short run or parts so others can have fun doing their build and not have to spend $10k-13k . I am going to try to incorporate some sort of "Gatling gun" style removable crank that is built into the main trigger housing so I can have some fun "blasting away" without building a post-sample machine gun. As always, comments, concerns, ideas or just sharing your personal build or shooting experience always welcome. I will post up pictures as I go.

Update 11/15
Here is a list of prices and running total on the project:
M60 E3 Parts kit $4400
90% JRW Receiver (no trunnion) $1995
Op Rod $209
Bolt Group $300
Trunnion $525
Op Rod Tube $95
Rivet Set $30
Goose Neck Pintle Mount and T&E $250
Semi auto bolt extension, plunger and spring $175

Running Total $7979 still under budget!!!

We will see if I can pull of the semi auto trigger parts for less than $250 as I am doing them in short runs of 25 each I will calculate the total per unit at the end, plus I will use the sale of the extra secondary trigger pack parts to off set the cost of the project overruns.

Posted: 9/21/2015 11:18:49 AM EDT

[#1]

Just my opinion but semi-auto belt feds are kind of silly, especially at the $8,000 - $13,000 price range.

You can pick up multiple sub-machine guns for that prices. For $8k you can get a Ruger AC556 and at $13k you can pick up a RLL for a AR15, toss in $4k for a shrike and you now have a belt fed full auto.

Also, if youre looking for a budget crank machine gun grab a semi-auto M1919, they can be had for under $2k used.

But hey i wish you the best of luck on your project, just makes sure you do your research and follow all the laws before you start doing work on semi-autos to make them resemble full auto.

Posted: 9/21/2015 9:23:34 PM EDT

[#2]

I do these projects for the fun of the build, adding machining and gun smithing experience through out the process. The primary goal is to round out my military weapon collection. I get plenty of access to full auto at work and at my rifle club hosting Class 3 shoots, which is fun...but just having a machine gun is not the point. If that was the case I would just buy an Uzi or Mac and call it a day. The Gatling crank is just for fun on my annual "pumpkin shoots" so the friends and family can blast away without having to register a post sample like we(my shooting buddy is SOT 7) did with the M249 trigger pack or DD with the M203. When I was attached to the 0331's at 1st Battalion 5th Marines we had M60 E3's, so it is up on the build list, I also got cross trained with heavy weapons and the mortar platoon so I want to build one of those as well but my M2HB 50 will come before the 60mm mortar. I think the great thing about firearms and the shooting sports is that there is a type or style of weapon for everyone to enjoy no matter what level of investment they want go with. At the end of the day all of my projects so far, 1/2 scale 12lb. mountain howitzer, M249, M203 and now an M60 have been fun, fulfilling and a great investment that looks awesome sitting in my war room. Sometimes me and the boys just sit in there smoking a good cigar with a tall glass of scotch and tell war stories about the good old days back in the Corps. Very therapeutic and cheaper than a sports car. You are 100% correct on caution with semi clones of full auto weapons. This design, specific details are listed in my first post, was sent it to BATFE firearms branch and approved for distribution and sale. JRW sports sold kits for a few years with a great video, low budget production in his garage, of him pounding one out in about 2 hours. I have 100% confidence that this model and design is legal. Thanks for the support and keep the ideas coming.

Posted: 9/21/2015 9:40:03 PM EDT

[#3]

Subscribing to this one too. And yeah, I was really looking forward to the AT4 subcaliber insert. That's something that I would definitely want.

Posted: 10/26/2015 4:41:17 PM EDT

[#4]

It has been a while since I last posted but I have collected all the parts needed to assemble the receiver and now I will move on to the job of putting all the old JRW drawings in 3D cad for a short production run of secondary trigger packs and semi-auto bolt extensions. I paid a little extra for the E3 kit all from one supplier but it was much easier than parting it out and having the whole thing held up by one or two missing smalls. The only issue I have had so far was that the op rod tube hole in the barrel trunnion was over sized by about 0.030 so I am going to use shim stock around the op rod tube to fill the gap before I rivet and weld. Anyway...long awaited pictures.

Posted: 10/30/2015 12:26:28 PM EDT

[#5]

So here is the basic drawing of the bolt extension. It houses the secondary sear, plunger and retaining pin. It will screw into the back of the bolt. Once I have decided on which plunger to go with, there are several different ideas and designs for use with modified and standard length firing pins, I will start the 3D CAD drawing for a production run.

Posted: 10/30/2015 10:34:39 PM EDT

[#6]

Be nice to do a Slide Fire type of mechanism. ??

Posted: 10/31/2015 10:51:25 AM EDT

[#7]

Quote History

Quoted:
Be nice to do a Slide Fire type of mechanism. ??

View Quote

in deed, a M60 slide fire would be pretty cool stuff

Posted: 10/31/2015 1:23:03 PM EDT

[#8]

I will have to see how light the two part trigger system is to see if it can bump fire or not. I prefer a crank fire for semi-auto belt feed. That way you can mount it on a tripod. I did a bit more work drawing out another part. The second pic is of a complete trigger pack courtesy of Thompsonmachine's build thread.

Posted: 11/11/2015 7:55:22 PM EDT

[#9]

So today I got into the shop for a few hours to get some work done on the receiver. I made a shim to take up the extra space in the op rod tube hole, cleaned up a few other out of spec locations on the trunnion like the lower trigger group pin area and the feed tray slot. I started with a rivet on the op rod tube and then the two main rivets on the trunnion. I will finish the other 3 smaller rivets and welds at a later date. I had to do a little hand fitting with the barrel locking lug to get it to close properly but with any part not made by a real machine gun manufacture you should expect to have to hand fit your parts. Here are some pictures of the work to date:

Posted: 11/14/2015 9:21:07 AM EDT

[#10]

Another day in the shop working on modifications to the bolt, cam actuator and finished the mod to the buffer yoke. I buggered up an op rod real good, but I think the welder can fix that. Most of the parts are heat treated or fully hardened so solid carbide cutters were the order of the day. The secondary trigger blanks came back from water jet cutter today, very nice finish. I had them cut oversize on outer dimensions and undersized on the holes to let me hand fit and finish after machining slots, holes and cut outs. The JRW instructions said to uses an M1 Carbine trigger dimensions from 3 reference points, lucky for me, someone had done a 3D model of their M1 Carbine trigger pack so I used their drawing. They are made of 01 tool steel and I will have to come up with a fixture for final machining as they are very small parts.

Posted: 11/14/2015 12:00:57 PM EDT

[#11]

Nice, going to be sweet when it's done! But where, oh where did you find the receiver channel?? Been looking for ages . . .

Posted: 11/14/2015 6:52:34 PM EDT

[#12]

I found it on www.gunbroker.com there were several ones of varying quality in finish, this on looked the most complete and nicest finish. The auction was from Carlos Rose [email protected] is well known for good supply of most of the parts for JRW style M60 SAR. I paid a premium for it but I think it was a good investment and it sure saved me a lot of time. I also purchased the bolt extension, with plunger and spring from him. He has quite a few parts in stock and also dose the machining of your full auto parts to semi-auto if you don't have access to the machines and tooling. His prices are not unreasonable for the work but not cheap. If you want it all done by him with all the semi parts too be prepared to drop about a grand. I saved myself over $500 just doing the modifications to the bolt, op rod and firing pin. I have is contact info if you want to PM me. I see several offerings from Cajun Country Arms but the rivets look flat and protrude a bit, I have no idea if that matters...probably not, and no T&E mounting plate which was a must for me as I love a tripod mounted area defense weapon. His receiver is about $400 less than I paid for mine. He also has trunions but they are machined flat not rounded on the lower mounting points. Its an easy fix but I found mine on www.ebay.com for less than $600 and it was 100% finished and heat treated. There were some small issues with tolerances but you get what you pay for. I know www.sarco.com has trunions at 90% for a few hundred bucks too.

Posted: 12/8/2015 12:04:25 AM EDT

[#13]

question about kit versions.

you're using an E3 kit. is that required or make it easier than a standard M60 kit? mainly wondering about the top cover. I'm reading that with a standard M60, you had to have the bolt locked back when you closed the top cover or you would bend stuff. Whereas with the E3, it could be closed with the bolt either forward or back. but on a SA M60, there isn't a way to lock the bolt back AFAIK. so are we needing 3 hands to load an M60 if we have to hold the bolt back, place the belt into position, and close the top cover at the same time? But with the E3, we wouldn't have to worry about having to hold the bolt back, right?

could one just use a E3 top cover with an otherwise standard kit? or would more stuff need to be E3-spec to use the E3 top cover?

Posted: 12/9/2015 5:46:21 PM EDT

[#14]

I'm doing an E3 because that is what I had in the service. Being able to close the top cover and charge the weapon is just an added bonus. I think if you have and E3 cover with all the internals everything else is the same.

Posted: 12/9/2015 7:50:25 PM EDT

[#15]

thanks for the info.

Posted: 12/29/2015 10:07:56 PM EDT

[#16]

I am in the process of building a M60 E1 SAR. Can I get some more info from you? email?

Thanks
Hueydoctor

Posted: 1/4/2016 6:57:53 PM EDT

[#17]

Folks that want to email me with questions, please use the message service for primary contact first. If I don't answer you in a few days, try again...my junk filter kicks stuff out from ar15.com sometimes. I have no idea why. I guess that's why I'm a gun guy not an I.T. guy.

Posted: 1/15/2016 3:58:30 PM EDT

[#18]

TAG for later

- Clint

Posted: 6/29/2016 4:18:34 PM EDT

[#19]

I see by your posts that you built a number of the secondary trigger parts for the JRW M60SAR. I am in the middle of a build and those are some of the remaining parts I am looking for. Please let me know if you have any for sale. Always easier when someone else has done the machining

Posted: 8/1/2016 6:04:32 PM EDT

[#20]

Just a quick update. The sear blanks are in as well as the triggers for the secondary trigger pack. The hammer blanks are on order and may come in sometime in the next 2 weeks. Once I have all the blanks I will start machining, heat treating and finishing the components. I did a revised design of the secondary trigger pack which copies a scaled down version of the AR15 FCG and will make a prototype of that as well to send to ATF when I have the time. My idea with that was to use the disconector/ trigger combo in a possible "double tap" pull & release fire design to simulate full auto fire and to eventually register a trigger pack post sample as select fire. The top is the new design the bottom is the JRW design.

Posted: 12/10/2016 9:25:45 PM EDT

[#21]

Anxiously waiting for updates on this fine build.

Posted: 12/11/2016 6:43:59 PM EDT

[#22]

I hope to get into the shop some time in the next 2 weeks. Full time work and new part time store/FFL are keeping me busy. I have to get some thing done before the end of the year because I am having another back surgery in Jan. and I will be out for a few months. Sucks getting old too soon. Plus projects are starting to pile up. My M2HB parts are almost all here and I am waiting on my new MK19 40mm kit to see how much work that is going to be. 3 more years and I am going to retire and do the gun stuff full time.

Posted: 1/31/2017 7:06:58 PM EDT

[#23]

Here is my son Ryan with my JRW serial #40 receiver.

I had about 3K into this M60 and it was built with all NIW parts back in the mid 90s. I traded it for a NIB Colt M16 Model 901.

I was on the phone with John Weaver the day before he was killed discussing his 556 conversion kit. John also told me he was developing a plastic semi auto M60 receiver. John was a Great person to work with and was always full of information and ideas/suggestions.

Posted: 3/11/2017 12:13:14 AM EDT

[#24]

Cool pic, I am hoping to have mine done soon. I have been out of the shop for a while due to a back surgery, again, they say 6-8 more weeks for full recovery. I have also been busy with the new store I am planing to open in April, lots of construction and modification, done by others of course, but I am hoping to move forward soon. I got the blanks for the hammers in and will be working on the holding fixtures first thing once I am back in the shop. The project is on budget but well past the time I wanted to be done by. I have 2 other kits sitting on a shelf because this one is holding things up. Oh well, that's the nature of this kind of thing. It normally cost twice as much and takes twice as long.

Posted: 3/11/2017 4:38:21 PM EDT

[#25]

Quote History

Quoted:
Here is my son Ryan with my JRW serial #40 receiver.

I had about 3K into this M60 and it was built with all NIW parts back in the mid 90s. I traded it for a NIB Colt M16 Model 901.

I was on the phone with John Weaver the day before he was killed discussing his 556 conversion kit. John also told me he was developing a plastic semi auto M60 receiver. John was a Great person to work with and was always full of information and ideas/suggestions.

View Quote

Nice pic!
So you traded the $3k semi-auto M60 for a transferable Colt 901? Great decision!

I found this article about John Weaver and JRW Sports. It mentions the composite receiver.
http://www.smallarmsreview.com/display.article.cfm?idarticles=3144

Posted: 4/13/2017 9:37:06 PM EDT

[#26]

Great build! It's so hard to find good information on semi M60's. I am pretty far along with getting a parts kit together and now the focus is on the secondary trigger group and rear of bolt trip items. If you can provide information on sourcing those parts it would be a tremendous help. Not sure if you still have some of the extra trigger parts you have made around... Any help would be greatly appreciated

Posted: 4/21/2017 11:00:45 PM EDT

[#27]

Hello guys.

I just purchased a 95% complete semiauto M60 E1 kit on Gunbroker a few weeks ago. I was planning on posting pictures of the secondary trigger and the bolt trip. I was also lucky enough to get my hands on the JRW build video!

Please let me know what you would be interested in seeing from the gun (rails, trigger mods, etc.).

Posted: 4/21/2017 11:48:25 PM EDT

[#28]

I sent you the info I have. Hope it helps, post up pics of progress.

Posted: 4/22/2017 11:42:45 AM EDT

[#29]

Quote History

Quoted:
Nice pic!
So you traded the $3k semi-auto M60 for a transferable Colt 901? Great decision!

I found this article about John Weaver and JRW Sports. It mentions the composite receiver.
http://www.smallarmsreview.com/display.article.cfm?idarticles=3144

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Here is my son Ryan with my JRW serial #40 receiver.

I had about 3K into this M60 and it was built with all NIW parts back in the mid 90s. I traded it for a NIB Colt M16 Model 901.

I was on the phone with John Weaver the day before he was killed discussing his 556 conversion kit. John also told me he was developing a plastic semi auto M60 receiver. John was a Great person to work with and was always full of information and ideas/suggestions.

Nice pic!
So you traded the $3k semi-auto M60 for a transferable Colt 901? Great decision!

I found this article about John Weaver and JRW Sports. It mentions the composite receiver.
http://www.smallarmsreview.com/display.article.cfm?idarticles=3144

FWIW, when I bought my as-new Colt M16A1 in 1994 (for $2k!), the same dealer had a minty Maremont M60 transferable for sale for $3.5k.

How times -- and prices -- have changed!

Posted: 4/23/2017 2:54:09 AM EDT

[#30]

So here are a few pictures of my Vietnam period M60 Semi. It came with an E3 trigger group and I just received an E3 topcover (so one can close the topcover with the bolt forward) and have spent the last two weeks just getting to know the parts and the assemblies. The receiver back half came separate from the trunion and I believe it was from one of the JRW kits. I am currently trying to get some rivets from beltfeds.com (thank you Aaron) and have realized that the cam actuator on the back of the bolt is not in the correct position. It appears that the factory actuator was not included and a new one was added to the top of the firing pin striker body. As the bolt articulates, the feed cam in the topcover does not move far enough to grab the next round in the feed tray and move it over. I got 1,000 links and a handful of dummy rounds to confirm feeding functionality. Just ordered the correct part on Gunbroker and it should arrive in a week or so.

Was also able to get my hands on the JRW semi build video and it was eye opening. No really specialized equipment was used to fabricate the receiver, just a hammer, steel bar stock and a drill press.

The complete kit:

A close-up of the complete bolt assembly and the firing pin trip:

Here is a close-up of the secondary hammer assembly:

** Sorry for the links - they are not showing up on the final post **

Posted: 4/23/2017 7:10:28 PM EDT

[#31]

that does not look at all like the original JRW design for the bolt extension and cam actuator but not a big deal. You sound like you have a plan. Keep us posted on progress.

Posted: 4/26/2017 7:51:55 PM EDT

[#32]

Great pictures! That really helps seeing an "exploded view" of the bolt all. So my biggest hurdle is actual mechanical drawings so I can manufacture or, provide to someone that can assist if proves too difficult or requires specialized tooling. I believe the OP said he can possibly email them. Really hoping to complete by July.

Posted: 6/27/2017 6:59:30 PM EDT

[#33]

I finished my JRW semi E1 about a year ago, still trying to get it to cycle in live fire. Anyone else wringing one out yet or still building? I've went through a lot of tinkering with the JRW trigger system, can't seem to get the bolt sear to reset after firing one round.

Posted: 6/30/2017 8:15:32 PM EDT

[#34]

I have not finished the build yet. Just need to rivet the receiver together. Hopefully I can get it done during this long weekend. My M60 dry fires fine but required adjustment of the bolt striker by unscrewing it a few turns off the back for the bolt. You might want to try that.

Posted: 7/1/2017 9:26:40 AM EDT

[#35]

I'll try that, did you replaced your firing pin trip? It doesn't look like the JRW. When did you get your JRW semi auto parts? Thanks, HD

Posted: 7/1/2017 9:35:23 PM EDT

[#36]

Does anyone have drawings with good measurements for the trip mechanism and secondary trigger group? Pics and measurements would greatly appreciated.

Posted: 7/3/2017 8:36:18 PM EDT

[#37]

email sent

Posted: 8/31/2017 4:07:03 AM EDT

[#38]

I have a kit and most of the JRW semi parts that I would like to finish by an '07
Or, I could list it on the for sales pages if any of you are interested... I bought a Desert Ordnance gun.

Posted: 9/9/2017 3:49:29 PM EDT

[#39]

I know a company that will be releasing all the semi auto parts for the m60 by the end of Sept. The used my jrw to get all the measurements to cnc all parts rails,sear block with all components ,secondary trigger assembly.

Posted: 9/23/2017 8:14:02 PM EDT

[#40]

Quote History

Quoted:
I know a company that will be releasing all the semi auto parts for the m60 by the end of Sept. The used my jrw to get all the measurements to cnc all parts rails,sear block with all components ,secondary trigger assembly.

View Quote

Please keep us updated on this.

Posted: 10/8/2017 9:15:08 AM EDT

[#41]

I am now FFL 07/02 SOT for anyone needing build service. The shop will be officially open this month.

Posted: 10/13/2017 6:22:14 PM EDT

[#42]

Quote History

Quoted:
I know a company that will be releasing all the semi auto parts for the m60 by the end of Sept. The used my jrw to get all the measurements to cnc all parts rails,sear block with all components ,secondary trigger assembly.

View Quote

Whats the latest on this?

Posted: 11/10/2017 4:43:37 PM EDT

[#43]

Bump...

If anyone has the JRW drawings I sure could use a set

ETA; Cajun Country Arms has the semi sear blocks in stock

click me

Posted: 11/21/2017 3:46:42 PM EDT

[#44]

I have drawings, probably over 40 pages, these are original copies and may not match what some mfg's are making exactly. It will take a few days to copy or I may be able to scan to pdf and send email. I have had mine assembled for over a year and it still does not run, it will reset the bolt plunger when manually cocked but will not reset when live fired. I haven't had time to sort it out yet. If you want to talk, let me know.

Posted: 11/22/2017 2:01:38 PM EDT

[#45]

Quote History

Quoted:
I have drawings, probably over 40 pages, these are original copies and may not match what some mfg's are making exactly. It will take a few days to copy or I may be able to scan to pdf and send email. I have had mine assembled for over a year and it still does not run, it will reset the bolt plunger when manually cocked but will not reset when live fired. I haven't had time to sort it out yet. If you want to talk, let me know.

View Quote

That would be awesome! There is little to nothing out there on the net besides 10 year old threads with dead links..

Posted: 12/31/2017 11:57:53 PM EDT

[#46]

I'm am getting a few emails requesting updates, I have been busy with the new gun store I opened and have not been into the shop for projects in a while. I just picked up another secondary trigger pack, finished and will be comparing it to the parts I already have once I finish with customer orders for gun smithing, to pay the bills, then I will have time to finish the M60 and parts. My new years resolution is to get it done by spring of 18' for when the weather warms up enough to shoot. It was -2 F outside and I am too old too go the the outdoor range in that kind of weather. I know I have been on this for over a year...or is it two now, LOL It will get done.

Posted: 1/1/2018 2:00:49 PM EDT

[#47]

FYI, shop at your own risk. Cajun Country Arms stiffed me $710 for a set of their semi auto m60 rails. Cashed money order, never sent any product.

Posted: 1/4/2018 1:01:05 PM EDT

[#48]

Quote History

Quoted:
FYI, shop at your own risk. Cajun Country Arms stiffed me $710 for a set of their semi auto m60 rails. Cashed money order, never sent any product.

View Quote

When was that? They now have a new owner as of about a year ago

Posted: 1/18/2018 9:30:58 PM EDT

[#49]

HueyDoc

I believe you emailed me mid summer. Sorry, I’ve been off my project for some time. But with the holidays behind me, I’m ready to get back to it. If you have time this weekend to talk, that would be great. I believe I still have your email w/ number. Let me know if that works.

Posted: 1/18/2018 9:35:29 PM EDT

[#50]

rhino911

That news is no good. I was very close to purchasing from them. But now I’m concerned. Their prices, although prob pretty fair for the niche market, it’s still a lot to throw out there and get stiffed on product, Any update on receiving your items? When exactly did you send them funds?

[ARCHIVED THREAD] - M60-SAR Build (Page 1 of 2)

Armory » Machineguns (MG)

Warning

Confirm Action

About AR15.COM

Stay Connected

Newsletter

Contact Us