- Joined
- May 9, 2017
No, I removed the barrel because I did something stupid that I don't want to talk about.
Mega Rad Gun Thread
- Thread starter The Hunter
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- Joined
- Jun 9, 2016
the BEV block has a steel barrel extension insert for the locking lugs and also takes up space on the interior of the upper receiver. it's not the hinge pin taking all the force.
Pretend To Imagine
kiwifarms.net
- Joined
- Mar 26, 2024
The bev block holds the barrel extension, but it doesn’t look like it prevents the upper from trying to rotate with the barrel nut. The index pin on the barrel extension is what is stopping the upper from moving, and all that force is put on the notch for the barrel extension in the upper. The pin can break or damage that notch.
T-800
kiwifarms.net
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- Sep 28, 2016
Ive used it for torqueing on muzzle devices so I dont see why it wouldnt work for a barrel nut.
- Joined
- Jun 9, 2016
a reaction rod doesn't prevent the upper from rotating either soi'm not sure what you're getting at.
the BEV block does do a pretty good job of preventing the upper from rotating with installing or uninstalling a barrel nut. the BEV block prevents the upper from rotating with multiple contact points (hinge pin, charging handle journal, the interior BCG raceway) as well as engages the barrel extension to positively hold the barrel in place for muzzle device work. it isn't the "index pin on the barrel extension is what is stopping the upper from moving", the rest of the BEV block's features do as mentioned, and "all that force is put on the notch for the barrel extension in the upper" isn't true, as the force is both spread along a very large area with multiple points and the amount of force needed to break off the steel pin against the journal's lip or completely tear off or shear the upper off the BEV block is very far in excess of what is reasonable for assembling the barrelled upper.
a reaction rod holds the barrelled upper in position so you can torque down the barrel nut, however it does this by holding the barrel in place - it doesn't interact with the upper and the upper is free to move as it wants to. it is in this situation where it's only the indexing pin that is holding the barrel in position because there is nothing actually holding the upper in place with this method. and again, a reaction rod does this well enough that you can torque a barrel nut without too much issue.
originally, a reaction rod wasn't intended for working on receivers (although you can do so purely to hold an assembled receiver in a vise if you're doing muzzle work or installing a free float, et c) because it isn't positively holding onto the receiver at all. a reaction rod only holds the barrel in place via (in an AR's case) the barrel extension's locking lugs and if it wasn't for both the indexing pin on the barrel extension and the clamping force of the barrel nut, you can freely spin the upper/barrel nut assembly on a reaction rod. reaction rods are generally for working on muzzle devices or similar so you aren't trying to screw on a flash hider on a barrel that is passing that torque through the upper receiver into the vise. bypass the upper receiver entirely and hold the barrel in place when doing that sort of work to avoid problems.
a reaction rod for a G36 or SCAR works the same way, it's for "clamping" the receiver and barrel together with the barrel retaining nut or breaching nut and adding on a muzzle device, installing the gas block, et c without disturbing the receiver at all and not transmitting force through the receiver to the vise - the reaction rod directly takes force from the barrel to the vise bypassing the receiver for the most part.
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- Joined
- Apr 18, 2019
I can't tell if this is the crap slim handguard or what, any (Bundes)wehraboos know which one that is? Also wondering about the gas tube being exposed, and if I should just go full comfy and get a wide handguard instead.
Sidenote: It's been a decade and change since I looked up the wide G3 handguards, people are fucking gay. Three hundred dollars for the ability to hold a G3 without burning yourself after two magazines is sad. Step up your game PTR, nobody likes the skinny handguards except people that have never held the good ones.
- Joined
- Jun 9, 2016
i don't really recognize the hole pattern, they almost look like SLR / L1A1 handguards kinda, but they do appear to be cut down G3 wide handguards with the bipod locking spring that i guess someone cut some slots into.
- Joined
- Apr 18, 2019
The holes look misaligned so I'm leaning towards that too, and apparently the wide handguard is sometimes known as "tropical" for whatever reason so this is my understanding of the chop.
That's a pretty short barrel. Rad.
EDIT: Guesstimated it to be a ~14" barrel, they were certainly ahead of their time.
I'll probably skip the SBR route since I already have a Dissipator on the side, as a bonus it possibly saves me the stress of cutting up even a modern production wide handguard.
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- Joined
- Jun 9, 2016
sort of looks closer to this: the plastic is molded around the steel insert for the retaining pin, and the retaining spring for the bipod is present and that's riveted in place.
- Joined
- Apr 18, 2019
Good eye. So the handguard got chopped to roughly 7 1/2" for a <14" barrel.
Not a terrible conversion, I wonder how reliable it was with the new gas tube length.
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MrJokerRager
kiwifarms.net
- Joined
- Nov 2, 2019
I noticed Anderson and PSA get their forging from the same aluminum factory.
Romulus augustulus
kiwifarms.net
- Joined
- Apr 6, 2023
Not strictly AR related but a lot of firearms that are made with cast frames/parts are cast by pine tree castings AKA Sturm Ruger & company. they've got this stock image on their sight:
I see a desert eagle frame, M14 action (i want to say they supplied Springfield armory at one point), and the action to what looks like a O/U shotgun. among other things.
MrJokerRager
kiwifarms.net
- Joined
- Nov 2, 2019
Their AR lowers got a unique aesthetic going.
- Joined
- Jun 9, 2016
Ruger makes some of the best steel/aluminum castings in the industry, no joke. they are OEM for a lot more than small arms.
Pretend To Imagine
kiwifarms.net
- Joined
- Mar 26, 2024
The Midwest URR prevents the upper from rotating. All of the other fixtures usually work fine under normal torque values.
I’m not very familiar with the bev block, but it looks like there is only a small part that interfaces with the charging handle path in the upper to prevent the upper from rotating.
SHIGGSHOGG
kiwifarms.net
- Joined
- Nov 2, 2023
Bruh y'all can just thug it out and just use a regular vise lol.
Just pop off your upper and put some cardboard on your vise jaws, and push the upper down so the front pin post is resting on the jaws. Plenty of material to grab onto, no worries about crushing.
Holding the barrel or the receiver doesn't matter if you only hold one, as you're gonna be relying on that lil steel pin digging into the aluminum. No need to buy useless shit. To make one of those bolt things work you'd need to make use of the charging handle slot and have a matching lengthened gas key situation. Issue with that is upper tolerance, so you'd never be able to get it right enough where that's holding the barrel before the pin while still fitting even half the uppers floating around out there. If you're super worried or have a shit upper, put a metal shim next to the pin and bias it whatever direction is good and it'll self center when torqued.
You have to wonder how the ARs without locking lugs are assembled
Just pop off your upper and put some cardboard on your vise jaws, and push the upper down so the front pin post is resting on the jaws. Plenty of material to grab onto, no worries about crushing.
Holding the barrel or the receiver doesn't matter if you only hold one, as you're gonna be relying on that lil steel pin digging into the aluminum. No need to buy useless shit. To make one of those bolt things work you'd need to make use of the charging handle slot and have a matching lengthened gas key situation. Issue with that is upper tolerance, so you'd never be able to get it right enough where that's holding the barrel before the pin while still fitting even half the uppers floating around out there. If you're super worried or have a shit upper, put a metal shim next to the pin and bias it whatever direction is good and it'll self center when torqued.
You have to wonder how the ARs without locking lugs are assembled
Pretend To Imagine
kiwifarms.net
- Joined
- Mar 26, 2024
With a fixture that holds the upper or barrel.
The reason a Midwest URR was being recommended was the poster saying he couldn’t get the barrel nut off with a normal amount of force and was concerned with breaking the upper.
Under normal torque values and proper assembly practices a Midwest URR isn’t necessary and any fixture designed for the task should be fine.
- Joined
- Jan 20, 2014
i might be retarded. the MFI rail i got for my MP5 is listed for an MP5K but on the MFI website they're saying i can do whatever. there isn't a real difference, is there? i could have just slapped the rail on the whole time? i haven't opened the packaging up since i've found out how anal HKparts is with returns
- Joined
- Jun 9, 2016
the MWI URR (and a few others) have a sail that engages the charging handle journal, yes, this prevents rotation. the BEV block has a similar "nub" that isn't as substantial that also prevents rotation as well as the entire "block" portion that sits vertically in the BCG path. if you want, you can remove the bolt and install the BCG as well as the BEV block and it will not rotate.
i think you are overplaying how much rotatable moment is going on here as well as not understanding that when you engage with the barrel extension, you are transmitting force from the wrench, through the barrel nut, through the upper, which is free to rotate slightly but kept from doing so by a sail or nub as the case may be. the clamping force exerted by the nut is immediately relieved during removal, and when installing, that clamping force is not intended to be significant. 35-80 ft-lb about arm's strength. this is not the shear failure or plastic deformation point of 7075 aluminum, it is well below it.
if you are applying enough torque to go well beyond this, that is a problem of the person using the breaker bar or whatever trying to goon the nut on the upper (which you should not do), and during removal if there is excessive force needed to remove, there are methods that can make it easier such as penetrating oil, heat, cut off wheels, et c. i can dig around for a junk upper and see what exactly it would take to actually break it through ineffective rotation stopping power. i guarantee you it will be far in excess of any human's arm strength.
you do you though, if you sleep easier with using an MWI URR and then i think you're all the better for it vs bubba using a piece of carpet, some cardboard, and a couple whacks on the vise's arm.
the optic rail is the same between the MP5K, MP5-PDW, SP89, HK94, SP5, MP5 and it's variations. the few that are different you likely will never see in the wild like the SMG, MLI, or MP5KA1. the mounting point differ between receivers typically, so a G3, HK33, and MP5 might have some difference with the claw mount or low profile mounts, although the "high" NATO claw mount should work on all of them.
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T-800
kiwifarms.net
- Joined
- Sep 28, 2016
As long as it clamps on I dont see any diffrence.