Official BumpSAW thread: version 3.0.

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[ARCHIVED THREAD] - Official BumpSAW thread: version 3.0. (Page 1 of 2)

Posted: 7/10/2017 3:49:50 PM EDT

Apparently my big thread went to the archives and the site staff couldn't or wouldn't resurect it. Saddest story ever told.

Anyway, I brought the BumpSAW out for another round of turning money into noise. It ran good for the first run seen here, but my gas key came unstaked again, and I had a few other rookie mistakes that gave me problems.

It's still a load of fun and the rate of fire is getting pretty high! (Tech thread discussion here)

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https://www.youtube.com/watch?v=oLodCxCbKKQ

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Posted: 7/10/2017 3:51:37 PM EDT

[#1]

How do you keep it from outrunning the bolt?

Posted: 7/10/2017 3:52:59 PM EDT

[#2]

Quote History

Quoted:
How do you keep it from outrunning the bolt?

View Quote

I put a really low mass carrier, AR-10 spring, and took the weights out of the buffer. It still happens sometimes.

Posted: 7/10/2017 3:53:11 PM EDT

[#3]

How about a build list?

Posted: 7/10/2017 3:56:28 PM EDT

[#4]

You should post a full comprehensive list of what you currently have in your build onto this thread, Id love to get a project like this going.

Posted: 7/10/2017 4:00:01 PM EDT

[#5]

Quote History

Quoted:
How about a build list?

View Quote

This one is easy. The guys with the SAW lookalikes are a bit harder to list.

This gun is:

—Stag 16" M4 carbine contour barrel (thy burn out fast...)
—AIM surplus low mass carrier
—Fostech Outdoors DefendAR-15
—Stock buffer with weights removed
—AR-10 buffer spring
—Stock trigger
—M60 bipod
—PSA slick side upper
—YHM flip up gas block (Modified; non-fucntional in the dissipator position)
—Rifle length MOE handguard
—low pro gas block (any type will do)
—Matech rear BUIS
—LOTS of Drums (Prefer the D60 or MWG 90)

I think that about covers it. Pic in OP.

Posted: 7/10/2017 4:24:36 PM EDT

[#6]

#BumpsawAllTheThings

- Clint

Posted: 7/10/2017 4:34:13 PM EDT

[#7]

Quote History

Quoted:
This one is easy. The guys with the SAW lookalikes are a bit harder to list.

This gun is:

—Stag 16" M4 carbine contour barrel (thy burn out fast...)
—AIM surplus low mass carrier
—Fostech Outdoors DefendAR-15
—Stock buffer with weights removed
—AR-10 buffer spring
—Stock trigger
—M60 bipod
—PSA slick side upper
—YHM flip up gas block (Modified; non-fucntional in the dissipator position)
—Rifle length MOE handguard
—low pro gas block (any type will do)
—Matech rear BUIS
—LOTS of Drums (Prefer the D60 or MWG 90)

I think that about covers it. Pic in OP.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
How about a build list?

This one is easy. The guys with the SAW lookalikes are a bit harder to list.

This gun is:

—Stag 16" M4 carbine contour barrel (thy burn out fast...)
—AIM surplus low mass carrier
—Fostech Outdoors DefendAR-15
—Stock buffer with weights removed
—AR-10 buffer spring
—Stock trigger
—M60 bipod
—PSA slick side upper
—YHM flip up gas block (Modified; non-fucntional in the dissipator position)
—Rifle length MOE handguard
—low pro gas block (any type will do)
—Matech rear BUIS
—LOTS of Drums (Prefer the D60 or MWG 90)

I think that about covers it. Pic in OP.

I've got a lower I've been wanting to make a bump gun out of but just haven't pursued it. I presume a heavier contour barrel will last longer due to dealing with heat better? Or is it just friction taking out the rifling?

Posted: 7/10/2017 4:36:14 PM EDT

[#8]

Any bolt on BumpSaw kits for the M249?

Posted: 7/10/2017 4:37:17 PM EDT

[#9]

Quote History

Quoted:
I've got a lower I've been wanting to make a bump gun out of but just haven't pursued it. I presume a heavier contour barrel will last longer due to dealing with heat better? Or is it just friction taking out the rifling?

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
How about a build list?

This one is easy. The guys with the SAW lookalikes are a bit harder to list.

This gun is:

—Stag 16" M4 carbine contour barrel (thy burn out fast...)
—AIM surplus low mass carrier
—Fostech Outdoors DefendAR-15
—Stock buffer with weights removed
—AR-10 buffer spring
—Stock trigger
—M60 bipod
—PSA slick side upper
—YHM flip up gas block (Modified; non-fucntional in the dissipator position)
—Rifle length MOE handguard
—low pro gas block (any type will do)
—Matech rear BUIS
—LOTS of Drums (Prefer the D60 or MWG 90)

I think that about covers it. Pic in OP.

I've got a lower I've been wanting to make a bump gun out of but just haven't pursued it. I presume a heavier contour barrel will last longer due to dealing with heat better? Or is it just friction taking out the rifling?

That's probably a question that someone more experienced with real machine guns can answer better. The previous barrel on this gun actually shot out the rifling at the muzzle end. I don't know if this is normal or not, and I don't know if a heavier barrel would mitigate this problem.

I shoot steel case BTW. It's too expensive not to.

Posted: 7/10/2017 4:40:05 PM EDT

[#10]

In before some salty arfcommers writes the BATF

To see if it should be made illegal because you redesigned it with all those parts to make it run bumply.

Posted: 7/10/2017 4:42:42 PM EDT

[#11]

Tag

Posted: 7/10/2017 4:45:50 PM EDT

[#12]

Quote History

Quoted:
In before some salty arfcommers writes the BATF

To see if it should be made illegal because you redesigned it with all those parts to make it run bumply.

View Quote

The stock is still "stock" aside from the shoulder pad. I'm still pushing forward and the bipod doesn't do anything but jiggle around (no forward pressure added by it).

If this is a machine gun, then so is every semiautomatic rifle.

Posted: 7/10/2017 4:46:16 PM EDT

[#13]

Quote History

Quoted:
Tag

http://imageshack.com/a/img905/599/Mj3Cvr.jpg

View Quote

Posted: 7/10/2017 4:50:43 PM EDT

[#14]

Quote History

Quoted:

The stock is still "stock" aside from the shoulder pad. I'm still pushing forward and the bipod doesn't do anything but jiggle around (no forward pressure added by it).

If this is a machine gun, then so is every semiautomatic rifle.

View Quote

You ain't gotta tell me. But arfcom is arfcom. They like writing their masters.

Posted: 7/10/2017 4:53:08 PM EDT

[#15]

I built one; cheap $170 radical upper (FINALLY A USE FOR M4 CUT BARRELS!), low mass carrier, 308 buffer spring with gutted buffer, slide fire stock, Chinese bipod from Amazon (wiggle is a good thing for these), and slapped on some chi-com iron sights. I took it out ONCE. Now I know to save my money and NOT buy a machine gun LOL. Ammo disappears in a hurry.

Posted: 7/10/2017 5:00:32 PM EDT

[#16]

Quote History

Quoted:

I put a really low mass carrier, AR-10 spring, and took the weights out of the buffer. It still happens sometimes.

View Quote

I would put the weights back in the buffer. You may actually be getting a little bolt bounce.

Posted: 7/10/2017 5:03:05 PM EDT

[#17]

Quote History

Quoted:
How do you keep it from outrunning the bolt?

View Quote

If you want to ensure it never outruns the bolt (and you live in a state that allows it), get a Fostech Echo trigger. Then use the echo trigger in semi auto. The echo has an automatic trigger lockout that will prevent you from pulling the trigger until the moment the bolt closes.

I've got an SBR with the Echo in it. I'm thinking about dropping my fostech stock on it just to play with

Posted: 7/10/2017 5:03:06 PM EDT

[#18]

Quote History

Quoted:

I've got a lower I've been wanting to make a bump gun out of but just haven't pursued it. I presume a heavier contour barrel will last longer due to dealing with heat better? Or is it just friction taking out the rifling?

View Quote

Chrome lined will last longer, but most of us are putting cheap barrels in because they will wear out pretty fast. heavy is bad.

Posted: 7/10/2017 5:17:57 PM EDT

[#19]

Quote History

Quoted:

Chrome lined will last longer, but most of us are putting cheap barrels in because they will wear out pretty fast. heavy is bad.

View Quote

Mine is heavy. As long as you have enough recoil to reset a little weight should last a bit longer.

Posted: 7/10/2017 5:25:02 PM EDT

[#20]

Quote History

Quoted:
I would put the weights back in the buffer. You may actually be getting a little bolt bounce.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

I put a really low mass carrier, AR-10 spring, and took the weights out of the buffer. It still happens sometimes.

I would put the weights back in the buffer. You may actually be getting a little bolt bounce.

I had actually considered that, but discounted it because it was working so well initially. I have so many spare buffers that I will just stick another in.

Posted: 7/10/2017 5:36:45 PM EDT

[#21]

Much as the best hunting vehicle is your buddy's sports car, the McManus maxim, I would posit the best bbl for a BumpSAW is the one mounted on your buddy's upper, that you borrow,"Just to see if it'll run." He's getting to shoot it, right? He should probably have a little rifling in the game.

Getting down into BumpSAW militia tactics, every rifleman is a BumpSAW ammo carrier and carries a spare bbl already sighted in w/ its own optic & BUIS. They also carry spare bolts, bolt carriers, even replacement lowers for the BumpSAW.

Posted: 7/13/2017 11:14:26 AM EDT

[#22]

Quote History

Quoted:
Chrome lined will last longer, but most of us are putting cheap barrels in because they will wear out pretty fast. heavy is bad.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

I've got a lower I've been wanting to make a bump gun out of but just haven't pursued it. I presume a heavier contour barrel will last longer due to dealing with heat better? Or is it just friction taking out the rifling?

Chrome lined will last longer, but most of us are putting cheap barrels in because they will wear out pretty fast. heavy is bad.

I use chrome lined, mostly because I use cheap steel case and I want to reduce the amount of stuck cases.

Posted: 7/17/2017 11:14:58 PM EDT

[#23]

Just a pretty picture. Finally had a chance to tinker with my AIM lightweight carrier I got back after I had a hole drilled for the CH. Ran into the issue of the handle binding on the bottom of the receiver due to the CH hole being recessed with the cuts on the BCG. With a little dremel work the aluminum spacer will do the trick. If there is one thing an ACE hardware is good for, it's its nuts and bolts section.

Will update Wed after range time with before and after video, see if we get an increase in ROF.
At the moment, I have

s3g vs mil spec
reg buffer spring vs ar10 sprinco orange
spikes t2 vs regular H

hopefully it's not too hot Wed

Posted: 7/23/2017 1:47:49 PM EDT

[#24]

Quote History

Quoted:
Just a pretty picture. Finally had a chance to tinker with my AIM lightweight carrier I got back after I had a hole drilled for the CH. Ran into the issue of the handle binding on the bottom of the receiver due to the CH hole being recessed with the cuts on the BCG. With a little dremel work the aluminum spacer will do the trick. If there is one thing an ACE hardware is good for, it's its nuts and bolts section.

Will update Wed after range time with before and after video, see if we get an increase in ROF.
At the moment, I have

s3g vs mil spec
reg buffer spring vs ar10 sprinco orange
spikes t2 vs regular H

hopefully it's not too hot Wed

http://i.imgur.com/6QkeE2z.jpg

View Quote

Any videos?

Posted: 7/23/2017 2:56:33 PM EDT

[#25]

Not yet, didn't get a chance Wed (stupid heavy rain) and Today is the 1k shoot. The 1k shooting overhangs the member portion of the range, so it's closed til 1pm. I know bumpsaw is bumpsaw, but training under fire is an exercise I'm not up to yet

Too hot after 1pm to spend a while futzing with it. Off Wed, 100% going. Waking up at 0545, drinking a shit ton of butter coffee and will get video

Posted: 7/23/2017 4:55:24 PM EDT

[#26]

I wonder how useful something like the StraightJacket barrel system would be this application.

Posted: 7/24/2017 11:25:07 AM EDT

[#27]

If it wasn't so much (I'd have to have it custom made from them if even possilbe)
I'd give it a whirl. I actually might try to dremel some cuts out of the frame of mine to lighten the front a tad. It's a heavy bitch, not sure if it would help enough to do the work.

Posted: 7/24/2017 11:56:03 AM EDT

[#28]

I found this photo of someone's modified Shrike- any ideas on how the M249 handguard and SAVIT stock could be mounted to a standard upper and buffer tube? I really like the idea of an M249-lookalike psuedo-SAW with an Echo trigger...

Posted: 7/24/2017 12:22:10 PM EDT

[#29]

Quote History

Quoted: If it wasn't so much (I'd have to have it custom made from them if even possilbe)
I'd give it a whirl. I actually might try to dremel some cuts out of the frame of mine to lighten the front a tad. It's a heavy bitch, not sure if it would help enough to do the work.

View Quote View All Quotes

View All Quotes

Quote History

Quoted: If it wasn't so much (I'd have to have it custom made from them if even possilbe)
I'd give it a whirl. I actually might try to dremel some cuts out of the frame of mine to lighten the front a tad. It's a heavy bitch, not sure if it would help enough to do the work.

Once they get a .223" or 7.62x39mm out, a DRACOS might pay for itself:

http://www.dracosbarrels.com

To back up our claim, we offer a 100% money back guarantee and an industry first LIFETIME WARRANTY on the barrel.

Though, I wanna say doesn't Stag offer a lifetime warranty on their complete guns?

http://www.stagarms.com/model-9-bones

Every complete rifle from Stag Arms comes with a Transferable Lifetime Warranty, an Infinite Shot Barrel Guarantee, a magazine and a rifle case

I see a Stag in my future.

Posted: 7/24/2017 3:13:54 PM EDT

[#30]

Quote History

Quoted:
I wonder how useful something like the StraightJacket barrel system would be this application.

View Quote

That's pretty neat. I've never even heard of that product until now. I'd try one!

Posted: 7/24/2017 6:36:02 PM EDT

[#31]

With Fostech Echo being out, what do you think is the appropriate niche for bumpfire stocks?

Posted: 7/24/2017 11:34:13 PM EDT

[#32]

Quote History

Quoted:
With Fostech Echo being out, what do you think is the appropriate niche for bumpfire stocks?

View Quote

Pretty much what you see above: prone fire, bipod supported guns. Something like an LMG. The binary triggers are cool for bursts, but the high and even rate of fire is a lot better out of a bump fire stock.

Posted: 7/25/2017 12:48:13 PM EDT

[#33]

@SouthernPhantom

I can't see if that lower is a 3rd hole, guessing it is. Otherwise how boring

I will upload my pics by the end of tomorrow (fuck photobucket

) and you can see how @AlaskanCajun helped me build a mock m249.

Posted: 7/26/2017 11:29:49 AM EDT

[#34]

Bumpgeniuses

S3g standard spring H buffer.
Switch to sprinco orange, only get 2 rounds before it stops. No recharging of the bcg needed. What issue am I running into here. I'm tarded.

Posted: 7/26/2017 11:34:52 AM EDT

[#35]

Quote History

Quoted:
Bumpgeniuses

S3g standard spring H buffer.
Switch to sprinco orange, only get 2 rounds before it stops. No recharging of the bcg needed. What issue am I running into here. I'm tarded.

View Quote

Did you hear the disconnector releasing?

My guess is that you are beating the bolt home.

Posted: 7/26/2017 11:56:28 AM EDT

[#36]

I'm deaf as fuck haha. Its possible. Best fix?

Posted: 7/26/2017 1:26:09 PM EDT

[#37]

Quote History

Quoted:
I'm deaf as fuck haha. Its possible. Best fix?

View Quote

@jaqufrost and I seem to have different ways of solving the same problem. I did the SD3G trigger and found ti to have nothing but trouble. I went back to a stock trigger. It seems to work OK but the disconnector is the problem. I have added a bit of reliability to my system by adding silicone grease to the stock and slowing down the cyclic rate. This makes it harder to beat the bolt home and trip the trigger.

This is the "at work/15 second reply' version.

If it doesn't make sense I will explain more later.

Posted: 7/26/2017 1:26:51 PM EDT

[#38]

So, no malfunction, your burst just stops?

Posted: 7/26/2017 1:35:08 PM EDT

[#39]

Quote History

Quoted:
I found this photo of someone's modified Shrike- any ideas on how the M249 handguard and SAVIT stock could be mounted to a standard upper and buffer tube? I really like the idea of an M249-lookalike psuedo-SAW with an Echo trigger...

http://i.imgur.com/zutZcdc.jpg

View Quote

Savit buffer tube is just about same as the mil-spec outer dia receiver extension, I just slide an OD CAR Stock on my Cannuckified SAW;

You can put the Savit stock on your AR15 for use with the AN/PVS-4 Night Vision Weapon Sight for better cheek weld.

Posted: 7/27/2017 1:20:18 PM EDT

[#40]

Quote History

Quoted:
So, no malfunction, your burst just stops?

View Quote

Correct.

I was also having issues with my modified CH. I, like a dumbfuckistani, didn't function check with the bolt inside it too well. Apparently since the aluminum spacer is so soft, it flexes just a weeee bit. When tightening down the screw, it locks the bolt from rotating, leading to a BCG that won't move.

Sooo I need to nix that problem before we can go forward haha. Plus it was super fucking hot, 95deg plus 60% humidity

so I spent more time practicing with my CCW.
The 2 dipshits in the next stall must have whined to the RO, because he came over asking what I was doing. They had complaints recently of ppl with full autos shooting over the berm

I really felt like being a dick, and bitching about the spall that was hitting my lanes awning from them pinging steel, but figured it wasn't worth it. RO was cool, I showed him where my impacts were (after 300 rounds it was a nice sized pocket 2ft from the ground) and he was satisfied.

I'm going to have to find a steel replacement for the spacer, or shave the screw head down a smidge more. Only a few threads holding it in the BCG, so unsure which route I'll go. Finding a suitable steel spacer the right size is going to be a pain, we'll see what ACE hardware has.

I think I got 1 full d60 with the AIM LW carrier / s3g / H buffer / standard spring combo, I have to go thru the GoPro still.

I'll try to post video tonight, it's been a crazy past few days.

Posted: 7/27/2017 9:16:47 PM EDT

[#41]

Quote History

Quoted:
Savit buffer tube is just about same as the mil-spec outer dia receiver extension, I just slide an OD CAR Stock on my Cannuckified SAW;

You can put the Savit stock on your AR15 for use with the AN/PVS-4 Night Vision Weapon Sight for better cheek weld.

View Quote

Huh. I'd heard that the Savit stock was incompatible with the AR buffer tube.

Posted: 7/29/2017 12:35:44 AM EDT

[#42]

This is the longest burst I got, I may just switch the s3g out. I brought all the tools to do it with me, but the humidity was obnoxious.

*eta can def tell it's a bit faster, anyone wanna find out the rpm?

and my car is FILTHY, no idea the GoPro featured a turtlewax filter

bump 2 2

https://www.youtube.com/watch?v=5zUuCkIf4m4

Old video, milspec trigger, full weight BCG

ar15 bumpsaw m249para :D

https://www.youtube.com/watch?v=VLpYlxLc1vU

@SouthernPhantom
Pitchurs

Railing off a random forend, holds the metal airsoft m249 frame on

airsoft frame and bipod

Posted: 8/2/2017 12:54:34 PM EDT

[#43]

Quote History

Quoted:
This is the longest burst I got, I may just switch the s3g out. I brought all the tools to do it with me, but the humidity was obnoxious.

*eta can def tell it's a bit faster, anyone wanna find out the rpm?

and my car is FILTHY, no idea the GoPro featured a turtlewax filter

https://www.youtube.com/watch?v=5zUuCkIf4m4

Old video, milspec trigger, full weight BCG

https://www.youtube.com/watch?v=VLpYlxLc1vU

@SouthernPhantom
Pitchurs

http://i.imgur.com/tbikFaS.jpg

http://i.imgur.com/ZtKc0wl.jpg

http://i.imgur.com/kwnTJti.jpg

http://i.imgur.com/BtsOzXO.jpg

http://i.imgur.com/9thVSaJ.jpg
Railing off a random forend, holds the metal airsoft m249 frame on
http://i.imgur.com/oendJMO.jpg

airsoft frame and bipod
http://i.imgur.com/VqIR9gD.jpg

View Quote

My magic earball says 800 rpm ish.

Posted: 8/2/2017 1:15:57 PM EDT

[#44]

Cool. In on one. You need an Armatac 150rnd drum. I like to bump by SBR with S3G trigger now and then.

Posted: 8/2/2017 1:34:15 PM EDT

[#45]

Which hammer spring do you have with the S3G? I had issues with the hammer not resetting when other shooters were firing the rifle. I use a deliberate trigger pull and release but assume they were not. Contacted Geissele and they sent me a new hammer spring that's a bit more stout and works great.

Posted: 8/4/2017 8:31:23 PM EDT

[#46]

Best bump stock?

Posted: 8/4/2017 8:40:39 PM EDT

[#47]

Quote History

Quoted:
Best bump stock?

View Quote

Fostech. Mix it with a Fostech echo trigger and you have the recipe for an error free bump experience. The stock just glides and the timing control built into the trigger prevents hammer follow issues.

Posted: 8/4/2017 9:06:06 PM EDT

[#48]

Quote History

Quoted:
Fostech. Mix it with a Fostech echo trigger and you have the recipe for an error free bump experience. The stock just glides and the timing control built into the trigger prevents hammer follow issues.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Best bump stock?

Fostech. Mix it with a Fostech echo trigger and you have the recipe for an error free bump experience. The stock just glides and the timing control built into the trigger prevents hammer follow issues.

Their trigger is it legal in my state

Posted: 8/4/2017 9:09:37 PM EDT

[#49]

That sucks.

I've got drawings for a timing control device for regular triggers. Uses an AIM ambi selector turned down. I was talking with a small machine shop about getting them cut, but it's kinda stalled out for now. I'll have to mod the triggers myself for it to work.

Posted: 8/4/2017 9:10:19 PM EDT

[#50]

We don't need no stinking bumpstock...

[ARCHIVED THREAD] - Official BumpSAW thread: version 3.0. (Page 1 of 2)

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