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Posted: 11/4/2014 4:57:51 PM EDT
[#1]
I am pretty excited to see this one go. I like all the Bump-SAW builds out there, but this one is extra special to me.
Make sure to post video in the GD thread! I'll put it in the OP with a pic.
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Posted: 11/5/2014 11:01:50 AM EDT
[#2]
Quote HistoryQuoted: As promised, moar pics of my bumpfire SAW. I finished it on Sunday, have not shot it yet, will this weekend though. I hand cycled it with the charging handle to simulate recoil and it worked every time. I used JacqueFrost's method with Magpul FCS and MIAD. The MIAD is loose and can slip off the reciever even with the roll pin but I attached it to the metal bracket with two screws threaded into the metal so it is not coming off. That metal bracket was a MAJOR pain in the ass to fit. The worst part is where it curves around the reciever from the grip to the stock. Seriously, start with that bend first then form the rest. I ground some metal from the stock fin to allow more clearance and oiled it up to reduce friction. To make all the holes and slots I lifted my drill press with a piece of scrap board then attached a drill press vise to a board that was locked in a milling vise to allow X and Y axis movement in sort of a poor man's mill. Enough jibber jabber: http://i267.photobucket.com/albums/ii307/Cramerica1/Mobile%20Uploads/IMG_20141102_190453484_HDR_zpsrytvgltv.jpg http://i267.photobucket.com/albums/ii307/Cramerica1/Mobile%20Uploads/IMG_20141102_190520494_HDR_zpswt4xna7e.jpg http://i267.photobucket.com/albums/ii307/Cramerica1/Mobile%20Uploads/IMG_20141102_190627052_HDR_zpsu6iri8rt.jpg http://i267.photobucket.com/albums/ii307/Cramerica1/Mobile%20Uploads/IMG_20141102_190539019_HDR_zpssq9b7i5e.jpg http://i267.photobucket.com/albums/ii307/Cramerica1/Mobile%20Uploads/IMG_20141102_190601963_HDR_zpsnxb0mxpf.jpg http://i267.photobucket.com/albums/ii307/Cramerica1/Mobile%20Uploads/IMG_20141102_190615531_HDR_zpswikryimu.jpg |
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Posted: 11/9/2014 8:59:14 PM EDT
[#3]
Well, Gentlemen...I took the bump60 to the range today.
oh, you probably wanted to hear how it went. No video, I only took 120 rounds just to see if it worked. I got a few good bursts of 3-7 rounds each, but mostly all semi from not getting the bump to work properly. I've never used a bump stock before so there was a learning curve, to wit I didn't get the hang of it. Also, I think the 2 stage RRA NM trigger is not the preferred nomenclature for this venture. I would love to try a Tac Con 3MR but not for the price tag they ask for them. Perchance a stock milspec trigger with JP light springs is then ticket. I might have also been gripping the stock too much instead of pushing forward on then charge handle. Any coaching on my technique? The pistol grip area needs work as well. I only used one pin to go all the way through and stick out both sides of the lower. The grip itself will slide off the lower and barely rides on the pin. I need a way to add a metal insert into the grip to make it slide better. maybe add a shelf to each side of the lower? As for the shooting part, it sounds like absolute titties when it went on burst with my silencer. Did I mention that? I used a YHM Phantom QD 30 cal. My first 7 round burst I immediately heard everyone else on then firing line stop what they were doing and look over. Then the range manager comes over and asked if I had my stamp. I said Nope, its semi auto. He was in disbelief until I showed him the stock sliding. He was very impressed that I had built it. If only it worked 100%... On another note, I emailed slide fire about their belt fed upper and if I could get just the drop in mechanism and maybe mill out my receivers. They said they're only making enough for the full guns (for $4500  ) but put my name on a list if they ever do a customer supplied rifle program.
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Posted: 11/9/2014 10:00:21 PM EDT
[#4]
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Posted: 11/10/2014 9:51:37 AM EDT
[#5]
Quote HistoryQuoted: Well, Gentlemen...I took the bump60 to the range today. oh, you probably wanted to hear how it went. No video, I only took 120 rounds just to see if it worked. I got a few good bursts of 3-7 rounds each, but mostly all semi from not getting the bump to work properly. I've never used a bump stock before so there was a learning curve, to wit I didn't get the hang of it. Also, I think the 2 stage RRA NM trigger is not the preferred nomenclature for this venture. I would love to try a Tac Con 3MR but not for the price tag they ask for them. Perchance a stock milspec trigger with JP light springs is then ticket. I might have also been gripping the stock too much instead of pushing forward on then charge handle. Any coaching on my technique? The pistol grip area needs work as well. I only used one pin to go all the way through and stick out both sides of the lower. The grip itself will slide off the lower and barely rides on the pin. I need a way to add a metal insert into the grip to make it slide better. maybe add a shelf to each side of the lower? As for the shooting part, it sounds like absolute titties when it went on burst with my silencer. Did I mention that? I used a YHM Phantom QD 30 cal. My first 7 round burst I immediately heard everyone else on then firing line stop what they were doing and look over. Then the range manager comes over and asked if I had my stamp. I said Nope, its semi auto. He was in disbelief until I showed him the stock sliding. He was very impressed that I had built it. If only it worked 100%... On another note, I emailed slide fire about their belt fed upper and if I could get just the drop in mechanism and maybe mill out my receivers. They said they're only making enough for the full guns (for $4500 ) but put my name on a list if they ever do a customer supplied rifle program. |
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Posted: 11/10/2014 10:27:16 AM EDT
[#6]
I had 20 rounds of tulammo and got only two or three round bursts, maybe 2 of them total. Monarch steel case got the good bursts. I had some federal bulk pack brass that seemed to work well also.
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Posted: 11/10/2014 2:33:28 PM EDT
[#7]
For $100 I would get one of those BFS stocks and have something to make a side-by-side comparison with.
I have never used a homemade BF stock so I can't say what the problem is. I can only say that weight vs recoil is always a factor, along with resistance of the rifle by the stock and rearward movement and the behavior of the trigger. In the bipod-supported prone your grip should be one that applies minimal downward force. That's adding friction. I also like to clear the rifle, drop the hammer and test my forward pressure by simulating recoil with my trigger finger. It's really not hard to do, but I get bored and like to practice. I wish you guys could all try the Fostech and see why it's worth the money. It's so nice I have to put silicone grease on the rail so it doesn't bump too freely. My only real complaint is that it pinches the shit out of your hand if you grab it high. There are some easy fixes that I will be doing to minimize that though.
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Posted: 11/10/2014 3:13:28 PM EDT
[#8]
Quote HistoryQuoted:
For $100 I would get one of those BFS stocks and have something to make a side-by-side comparison with. I have never used a homemade BF stock so I can't say what the problem is. I can only say that weight vs recoil is always a factor, along with resistance of the rifle by the stock and rearward movement and the behavior of the trigger. In the bipod-supported prone your grip should be one that applies minimal downward force. That's adding friction. I also like to clear the rifle, drop the hammer and test my forward pressure by simulating recoil with my trigger finger. It's really not hard to do, but I get bored and like to practice. I wish you guys could all try the Fostech and see why it's worth the money. It's so nice I have to put silicone grease on the rail so it doesn't bump too freely. My only real complaint is that it pinches the shit out of your hand if you grab it high. There are some easy fixes that I will be doing to minimize that though. If you want to send it on over I'd be happy to. I'll go ahead and IM you my shipping address as you seem pretty set on it already. 
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Posted: 11/13/2014 6:22:00 PM EDT
[#9]
Quote HistoryQuoted: If you want to send it on over I'd be happy to. I'll go ahead and IM you my shipping address as you seem pretty set on it already. Quote HistoryQuoted: Quoted: For $100 I would get one of those BFS stocks and have something to make a side-by-side comparison with. I have never used a homemade BF stock so I can't say what the problem is. I can only say that weight vs recoil is always a factor, along with resistance of the rifle by the stock and rearward movement and the behavior of the trigger. In the bipod-supported prone your grip should be one that applies minimal downward force. That's adding friction. I also like to clear the rifle, drop the hammer and test my forward pressure by simulating recoil with my trigger finger. It's really not hard to do, but I get bored and like to practice. I wish you guys could all try the Fostech and see why it's worth the money. It's so nice I have to put silicone grease on the rail so it doesn't bump too freely. My only real complaint is that it pinches the shit out of your hand if you grab it high. There are some easy fixes that I will be doing to minimize that though. If you want to send it on over I'd be happy to. I'll go ahead and IM you my shipping address as you seem pretty set on it already. Even without that devastating power added, it's worth the money to buy outright. Trust me.
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Posted: 11/14/2014 1:02:49 AM EDT
[#10]
So apparently there is a machinist in Texas making the holy grail - a bumpfire stock, machined out of aluminum w/ only a few plastic parts, that has an adjustable stock that extends from the rear. Don't know the price, and I think it probably violates several of Slidefire's patents. Of course, I think Slidefire's patents are probably unenforceable anyway, as they seem to have patented design features of the Atkins Accelerator, which existed prior to the patents.
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Posted: 11/14/2014 2:56:34 AM EDT
[#11]
This may interest you guys, last week, after talking a bit with Jacquefrost, I sent a letter to the FTB asking for a letter clarifying the legality of using M16 parts to make the "select fire" trigger that was discussed in this thread.
Not a bumpfire thing, but similar in theme, a way to boost the rate of fire to IAR/SAW levels. I figured some of you may like to know how that turns out. |
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Posted: 11/14/2014 3:05:15 AM EDT
[#12]
Quote HistoryQuoted: So apparently there is a machinist in Texas making the holy grail - a bumpfire stock, machined out of aluminum w/ only a few plastic parts, that has an adjustable stock that extends from the rear. Don't know the price, and I think it probably violates several of Slidefire's patents. Of course, I think Slidefire's patents are probably unenforceable anyway, as they seem to have patented design features of the Atkins Accelerator, which existed prior to the patents.  Please... tell him to jump in this thread. I *NEED* to see this stock!
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Posted: 11/14/2014 4:31:19 PM EDT
[#13]
Quote HistoryQuoted: So apparently there is a machinist in Texas making the holy grail - a bumpfire stock, machined out of aluminum w/ only a few plastic parts, that has an adjustable stock that extends from the rear. Don't know the price, and I think it probably violates several of Slidefire's patents. Of course, I think Slidefire's patents are probably unenforceable anyway, as they seem to have patented design features of the Atkins Accelerator, which existed prior to the patents. |
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Posted: 11/14/2014 6:29:12 PM EDT
[#14]
Lol. I've only seen one example @ a gunshop - which I'll be doing some work for shortly; and they're not the folks who made it. I'll see if I can get more details. Has a plastic safety detent holder like all the rest. When I first saw it I assumed it was a Fostech.
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Posted: 11/17/2014 2:37:45 PM EDT
[#15]
I'm not going to lie shooting a bump fire was a lot more interesting than I thought it would be, I went from saying I had zero interest to figure out what the build will end up being like.
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Posted: 11/17/2014 3:31:00 PM EDT
[#16]
Quote HistoryQuoted: I'm not going to lie shooting a bump fire was a lot more interesting than I thought it would be, I went from saying I had zero interest to figure out what the build will end up being like. You have your own or was it a friend's? If you get video, feel free to post it in my GD thread. The more, the merrier.
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Posted: 11/29/2014 12:50:13 AM EDT
[#17]
Cheap beater barrel if anyone needs one.
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Posted: 11/29/2014 6:56:32 PM EDT
[#18]
I feel that jaqufrost's design is pure GENIUS!!!
That being said, I can't help but TRY and tweak it. 1. - Instead of cutting a slot in the stock and pressing a roll pin around the mid point of the stock. What about slightly cutting back the rail at the front of the Receiver Extension (buffer tube) and utilizing the stock Magpul screw that normally is used to tighten the Magpul Fixed Carbine stock to the receiver extension to limit the travel? 2. - Drill and tap a hole parallel to the top of the receiver into the web the pistol grip attaches to instead of pressing two roll pins into the area and cutting a corresponding slot into pistol grip. Take a stainless bolt and cut the head off, thread it into the hole leaving a smooth rod protruding. Then (the hard part), drill a hole in the correct location into the pistol grip and through the steel strap that is attached to the stock. (See my crappy drawing showing the aforementioned rod in yellow) 
Any comments? |
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Posted: 11/29/2014 7:10:13 PM EDT
[#19]
Quote HistoryQuoted: Any comments? You CLEVER bastard. |
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Posted: 11/29/2014 8:29:17 PM EDT
[#20]
Quote HistoryQuoted: I feel that jaqufrost's design is pure GENIUS!!! That being said, I can't help but TRY and tweak it. 1. - Instead of cutting a slot in the stock and pressing a roll pin around the mid point of the stock. What about slightly cutting back the rail at the front of the Receiver Extension (buffer tube) and utilizing the stock Magpul screw that normally is used to tighten the Magpul Fixed Carbine stock to the receiver extension to limit the travel? 2. - Drill and tap a hole parallel to the top of the receiver into the web the pistol grip attaches to instead of pressing two roll pins into the area and cutting a corresponding slot into pistol grip. Take a stainless bolt and cut the head off thread it into the hole leaving a smooth rod protruding. Then (the hard part), drill a hole in the correct location into the pistol grip and through the steel strap that is attached to the stock. (See my crappy drawing showing the aforementioned rod in yellow) http://i135.photobucket.com/albums/q125/PursuitSS/Postings%20photos/e7484525ca6b2c0ead81899cc0900e3e.jpg Any comments? I had something like this planned a while ago. Not only that, but it would be able to run a thumb selector for the bump function with the elector being the finger tab itself.  |
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Posted: 11/30/2014 10:27:01 AM EDT
[#21]
I don't exactly follow Skillets drawing, but PursuitSS's idea would fix my problem of the grip slipping off the roll pin downward. Well done, Pursuit.
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Posted: 12/1/2014 2:15:06 PM EDT
[#22]
Quote HistoryQuoted: I feel that jaqufrost's design is pure GENIUS!!! That being said, I can't help but TRY and tweak it. 1. - Instead of cutting a slot in the stock and pressing a roll pin around the mid point of the stock. What about slightly cutting back the rail at the front of the Receiver Extension (buffer tube) and utilizing the stock Magpul screw that normally is used to tighten the Magpul Fixed Carbine stock to the receiver extension to limit the travel? 2. - Drill and tap a hole parallel to the top of the receiver into the web the pistol grip attaches to instead of pressing two roll pins into the area and cutting a corresponding slot into pistol grip. Take a stainless bolt and cut the head off, thread it into the hole leaving a smooth rod protruding. Then (the hard part), drill a hole in the correct location into the pistol grip and through the steel strap that is attached to the stock. (See my crappy drawing showing the aforementioned rod in yellow) http://i135.photobucket.com/albums/q125/PursuitSS/Postings%20photos/e7484525ca6b2c0ead81899cc0900e3e.jpg Any comments? 2. - Good idea. I think I would use a large roll pin instead of a bolt though, that would keep a smooth surface, you wouldn't have to tap anything and you wouldn't have to cut the head off. If I make another I think I will use this method. |
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Posted: 12/8/2014 4:29:27 PM EDT
[#23]
Hey Jaqufrost, SkilletsUSMC , Man you guys are doing a banging Job! Thanks a ton. I'm a little stuck, How do you hog out the inside of the stock 7inches ? Semper Fi Devil Dogs! Mark |
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Posted: 12/8/2014 6:31:05 PM EDT
[#24]
Quote HistoryQuoted: Hey Jaqufrost, SkilletsUSMC , Man you guys are doing a banging Job! Thanks a ton. I'm a little stuck, How do you hog out the inside of the stock 7inches ? Semper Fi Devil Dogs! Mark |
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Posted: 12/9/2014 2:14:25 PM EDT
[#25]
Jaq
Yes sir, I'm using a Moe Fixed Carbine Stock, Your Post " Then I cut the inside of the stock so a 7" long 1/2" by 1/8" steel rod could be inserted." How do I cut the inside of the stock out 7 Inches? Thank You Much God Bless the Corps Mark |
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Posted: 12/9/2014 2:20:40 PM EDT
[#26]
Quote HistoryQuoted: Jaq Yes sir, I'm using a Moe Fixed Carbine Stock, Your Post " Then I cut the inside of the stock so a 7" long 1/2" by 1/8" steel rod could be inserted." How do I cut the inside of the stock out 7 Inches? Thank You Much God Bless the Corps Mark |
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Posted: 12/9/2014 11:49:20 PM EDT
[#27]
Thats the Best news I heard in years...:) Thanks Man, SemperFi Mark |
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Posted: 12/12/2014 5:23:19 PM EDT
[#28]
Glad I could help. Post some video when you get it running.
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Posted: 12/20/2014 11:27:26 PM EDT
[#29]
I finally got to shoot my bumpsaw today, and had a few problems. Build specs on it:
16" carbine gas PSA barrel G2S trigger Surefire SOCOM flash hider WOA lower build kit Harris Bipod BumpFire Systems stock Initially i had trouble with the stock constantly binding. I adjusted the screw out until the binding isn't really a problem now. I only had time to shoot 80 rounds, usually in 5-7 round mags. I had 2 instances of hammer follow (i think anyways). My problem, is i had trouble getting it to run more than 2 rounds at a time. It seems that after the second shot, the rifle doesn't recoil enough to reset the trigger. It seems like the bumpfire stock doesn't move far enough forward, and i have to pull the gun into my shoulder to reset the trigger. I managed to get one 5 round burst, and one 7 round burst, but the rest were usually 2 rounds, sometimes 3. These were a combination of offhand and bipod supported. I've also got aSOCOM556 i cash throw on if that would help. Any ideas? Do i just need to learn how to run the thing? edit: please excuse the phone typing. I don't know exactly how heavy the rifle is, but i tried to keep it relatively light. I would guess 7-8lbs without a mag in the rifle. |
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Posted: 12/21/2014 11:13:59 AM EDT
[#30]
What BCG, buffer, spring and ammunition are you using? Any idea on what size gas port it has? SkilletsUSMC gets his to run on wolf/tulammo, but mine doesn't like it. My gas system is really long for my barrel length though. If you are running underpowered ammunition like tulammo or pmc gold you may just need more recoil. A shorter reset trigger would probably help as well.
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Posted: 12/21/2014 3:41:09 PM EDT
[#31]
Ares armor BCG, carbine buffer, unsure of the spring. And i was shooting 62gn Wolf Military classic. I'll have to give the ZQ1 and Wolf Gold a try. Would a mil spec FCG usually work better than a G2S? I've got one i could try. Shouldhave just bought a Jard adjustable trigger
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Posted: 12/22/2014 9:41:54 AM EDT
[#32]
Skillets gets his to run pretty well with a mil spec trigger and wolf.
I measured the reset on my S2S (pre-cursor to the G2S, it should be pretty close) and it took .09" for the trigger to reset. I measured a stock PTAC fcg and it took about .095. Very similar in length. What grip technique are you using to get it to run? You may just need a little more gas to run with the low powered .223. |
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Posted: 12/22/2014 2:30:21 PM EDT
[#33]
Its all your form the follow and other issues sound like your fighting it. I had no issue bumping mags with a sloppy gritty usgi trigger, regular 6 pos stock and standard buffer / spring using the cheapest wolf I can find. Runs suppressed and un suppressed. It's all about the form. Took me about 6 mags to "get it" because I was fighting the form.
When in doubt, take it back to stock and ensure function then add a part at a time... Anyone building one, my second unopened slidefire and lightly used jp thermal dissapator are up in the EE. Just let me know it's for a bump saw and we can wiggle price. |
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Posted: 12/23/2014 4:40:44 AM EDT
[#34]
Gentlemen, et al, who are building your own bump-fire stocks, I call your attention to this part:
http://www.brownells.com/rifle-parts/grip-parts/pistol-grip-components/ar-15-m16-rite-pull-grip-adapter-prod7378.aspx?avs|Make_3=AR-15/M4 
Like as not you can achieve a similar effect by just chopping a pistol grip, but this might prove useful. ca_longshot uses one on his rifle, which he posted a picture of here: http://www.ar15.com/forums/t_3_4/484783_Vader_Spade_s_80__AR_15_build___Milling__Etching__and_Anodizing.html&page=11#i6603441 
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Posted: 12/23/2014 10:05:10 PM EDT
[#35]
So i finally got o take the BumpSaw out and get it to run. While not perfect, the gun will definitely work with a G2S, and I think my earlier problems stemmed from two things. (1) Shitty Wolf Military Performance ammo. It actually choked my Mk18 clone on a unsuppressed setting with a SOCOM556 on....so way overgassed. (2) Just not knowing how to do it. With the long reset on the G2S, I have to finesse the pull, and only pull the minimum needed to keep the bump going. If you pull to hard, the gun will end up not recoiling enough to reset the trigger. I think I'm going to have to buy a JARD adjustable and just be done with it.
I got to run three mags through it today, the first I had some problems, but got the last 20ish rounds to run. Then I got another 2 mags to shoot no problem. I'm still having trouble using the charging handle push method, and was using the magwell/magazine grip. I just can't seem to figure out how to push the gun forward enough to get it to shoot using the handle behind the charging handle method. Also, I loosened up the harris bipod so there is some back and forth movement, and that seemed to help make it work. I'm also considering sending off the barrel and having the gas port expanded big time to make it run cheaper ammo easier.....that way it isn't so expensive. Sorry for the shitty movie, my dad was taking it with his phone, this is the back half of the first mag. Could someone run the sound and see how many round per minute it was? If anyone has any tips, I'm of course willing to listen. Mando movie:  |
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Posted: 12/24/2014 5:20:19 PM EDT
[#36]
Quote HistoryQuoted: So i finally got o take the BumpSaw out and get it to run. While not perfect, the gun will definitely work with a G2S, and I think my earlier problems stemmed from two things. (1) Shitty Wolf Military Performance ammo. It actually choked my Mk18 clone on a unsuppressed setting with a SOCOM556 on....so way overgassed. (2) Just not knowing how to do it. With the long reset on the G2S, I have to finesse the pull, and only pull the minimum needed to keep the bump going. If you pull to hard, the gun will end up not recoiling enough to reset the trigger. I think I'm going to have to buy a JARD adjustable and just be done with it. I got to run three mags through it today, the first I had some problems, but got the last 20ish rounds to run. Then I got another 2 mags to shoot no problem. I'm still having trouble using the charging handle push method, and was using the magwell/magazine grip. I just can't seem to figure out how to push the gun forward enough to get it to shoot using the handle behind the charging handle method. Also, I loosened up the harris bipod so there is some back and forth movement, and that seemed to help make it work. I'm also considering sending off the barrel and having the gas port expanded big time to make it run cheaper ammo easier.....that way it isn't so expensive. Sorry for the shitty movie, my dad was taking it with his phone, this is the back half of the first mag. Could someone run the sound and see how many round per minute it was? If anyone has any tips, I'm of course willing to listen. Mando movie:  http://www.youtube.com/watch?v=3ZCxqD8W2-A |
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Posted: 12/26/2014 1:10:04 AM EDT
[#37]
I finally really figured the BumpSaw out today. I got good video
running a 40rd PMag through it (38 rounds straight). I was really surprised at how controllable it was. I tossed on the SOCOM556, and got it to really run with the cheap Wolf ammo, so hopefully I shouldn't have to get the gas port enlarged. Video included, and my wife took the original in 240 slow-mo on an iphone, so I'll update the post when I get it in an email. Also, what programs are people using to determine the RPM? Slo-Mo Video since it was discussed earlier in the thread
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Posted: 12/26/2014 10:55:49 AM EDT
[#38]
Very nice. The audio was much easier to decipher with the can on. I calculated 740rpm.
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Posted: 1/2/2015 4:53:18 PM EDT
[#39]
Here is an interview with Jim Sullivan and some interesting thoughts on auto AR's. Great reading if you like light auto weapons.
http://www.ar15.com/forums/t_3_118/664783_Jim_Sullivan_interview_on_AR_design_improvements.html |
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Posted: 1/4/2015 8:02:55 AM EDT
[#40]
Have you guys discussed the JP heat sink, yet? I believe it may have been talked about in one of the bump-SAW threads, but I can't recall. I watched a video about the Lewis gun, yesterday, that's had me thinking about using fins to cool an AR-based "LMG," since interchangeable barrels isn't really a feasible feature without spending a ton of money.
The outer tube and "muzzle blast creates suction to cool" idea is kind of hokey, imo,(And was apparently abbreviated on some later models, and of course, on aircraft guns.) but the JP fins would definitely draw heat away from the barrel. Bear in mind it will be a bit before I can get this set up, (Read, I have other projects, so don't expect results by next week ) but I was considering trying to mock up a Lewis style shroud and testing it on an AR with just the barrel itself, the fins, then a shroud over top, and checking with a temperature gun.
What do you guys think? Worthwhile endeavor? |
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Posted: 1/4/2015 9:48:53 AM EDT
[#41]
Quote HistoryQuoted: Have you guys discussed the JP heat sink, yet? I believe it may have been talked about in one of the bump-SAW threads, but I can't recall. I watched a video about the Lewis gun, yesterday, that's had me thinking about using fins to cool an AR-based "LMG," since interchangeable barrels isn't really a feasible feature without spending a ton of money.
The outer tube and "muzzle blast creates suction to cool" idea is kind of hokey, imo,(And was apparently abbreviated on some later models, and of course, on aircraft guns.) but the JP fins would definitely draw heat away from the barrel. Bear in mind it will be a bit before I can get this set up, (Read, I have other projects, so don't expect results by next week ) but I was considering trying to mock up a Lewis style shroud and testing it on an AR with just the barrel itself, the fins, then a shroud over top, and checking with a temperature gun.
What do you guys think? Worthwhile endeavor? We've talked of the JP radiator fins, and of quick change bbls. Given we are in the era of the $200 upper, I'm of the opinion that spare complete uppers may be the most cost effective solution, as well as solving sighting issues. |
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Posted: 1/4/2015 11:35:18 AM EDT
[#42]
Quote HistoryQuoted: Have you guys discussed the JP heat sink, yet? I believe it may have been talked about in one of the bump-SAW threads, but I can't recall. I watched a video about the Lewis gun, yesterday, that's had me thinking about using fins to cool an AR-based "LMG," since interchangeable barrels isn't really a feasible feature without spending a ton of money. The outer tube and "muzzle blast creates suction to cool" idea is kind of hokey, imo,(And was apparently abbreviated on some later models, and of course, on aircraft guns.) but the JP fins would definitely draw heat away from the barrel. Bear in mind it will be a bit before I can get this set up, (Read, I have other projects, so don't expect results by next week ) but I was considering trying to mock up a Lewis style shroud and testing it on an AR with just the barrel itself, the fins, then a shroud over top, and checking with a temperature gun.What do you guys think? Worthwhile endeavor? |
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Posted: 1/4/2015 11:48:26 AM EDT
[#43]
Quote HistoryQuoted:
Have you guys discussed the JP heat sink, yet? I believe it may have been talked about in one of the bump-SAW threads, but I can't recall. I watched a video about the Lewis gun, yesterday, that's had me thinking about using fins to cool an AR-based "LMG," since interchangeable barrels isn't really a feasible feature without spending a ton of money. The outer tube and "muzzle blast creates suction to cool" idea is kind of hokey, imo,(And was apparently abbreviated on some later models, and of course, on aircraft guns.) but the JP fins would definitely draw heat away from the barrel. Bear in mind it will be a bit before I can get this set up, (Read, I have other projects, so don't expect results by next week ) but I was considering trying to mock up a Lewis style shroud and testing it on an AR with just the barrel itself, the fins, then a shroud over top, and checking with a temperature gun.
What do you guys think? Worthwhile endeavor? Mine worked ok, but I had really thin/close hand guards and it transferred too much heat to my hand. My second bump stock and a jp heat sync are up in the ee, grab both for a bump saw and I'll drop price some. |
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Posted: 1/4/2015 11:59:16 AM EDT
[#44]
Quote HistoryQuoted: I've considered using one, seems like it would help without causing too many weight issues. I agree with backbencher that a spare upper makes for a feasible quick change barrel with a slight weight penalty. Unfortunately the nicer your optics the more difficult / expensive it gets. You might be able to use a BOBRO QD mount for a single optic that swaps but their may be zero issues that are hard to overcome. My thought is to forgo irons in favor of backup uppers, w/ cheap small red dots, and a swappable flip-off magnifier. That should solve the zero issues that plague QD barrels. Then you have to figure out how to mount the bipod to the lower.
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Posted: 1/4/2015 12:33:21 PM EDT
[#45]
Two bipods would be easier.
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Posted: 1/4/2015 5:54:33 PM EDT
[#46]
I would say forgo optics and sight in irons, then walk rounds in from there, but then I remembered we've only got 30-40 rounds to work with; when you get on target, you might only have a burst or two left for the effect. Kind of related to that, I still kind of want to buy one of the belt fed uppers on the market, but that's contingent on making the "semi-auto, but shoots really fast" idea work for my wants. Also, of course, finding one of those beltfed contraptions that actually works reliably.
Every time I start to doubt the practicality of guns like this, I go back and watch videos of people shooting Nordenfelts and Gatlin guns.
(I'm sure you've gleaned, I've got a hardon for weird light machine guns.) |
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Posted: 1/5/2015 5:22:35 PM EDT
[#47]
I like the light machineguns as well. I've been thinking about getting a Mac 11/9 and one of the Alliance Armament 5.56 uppers.
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Posted: 1/12/2015 5:30:09 PM EDT
[#48]
It's been quiet in here for a week. Anyone got some new pictures or videos?
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Posted: 1/12/2015 9:01:22 PM EDT
[#49]
This thread has me collecting parts for a build, this will be fun
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Posted: 1/13/2015 10:50:34 PM EDT
[#50]
[youtube]https://www.youtube.com/watch?v=VRXZx3M6bd0[/youtube]
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