Geissele Reaction Rod
- Thread starter WileyX585
- Start date
Haven't bought one (yet) but have seen a few videos of guys using them to assemble uppers. Seems to be a lot easier thank the plastic block style. Only thing by that has kept me away has been price - expensive at $100 but prob worth it if building multiple rifles.
C3D
.338 Win Mag
I have one and have used it. It is superior to the upper receiver vice blocks (on takedown lugs or clamshell) because stress from tightening the barrel nut is not put into the receiver. Worth it, but wait for one off the Geissele 25 off sales to buy it.
I wouldn't use it. It's essentially the same as using aluminum vise block to hold the barrel. That method was blamed for damaging alignment pin in the barrel extension and corresponding slot in the receiver. Receiver block that clamps around the receiver is better by far. It takes the stress out of that area.
The threads are on the receiver. The block is holding it directly, instead of holding it through a barrel. Unless the receiver is shaped that it doesn't fit the block, I don't see a reason to use anything else.
The threads are on the receiver. The block is holding it directly, instead of holding it through a barrel. Unless the receiver is shaped that it doesn't fit the block, I don't see a reason to use anything else.
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C3D
.338 Win Mag
Can you link to some photos of that damage? That's surprising to me given the reaction rod holds the barrel on the locking lugs of the barrel itself. A receiver block puts all of the torque of the turning efforts on the soft alumnium and that's what seems to bend those receiver index pins.
The reaction rod or its knock offs are becoming pretty standard for gunsmith level AR work.
camper4lyfe
.308 Win
What @Mosinitis said. The torque isn't transferred to the barrel like it claims. It goes right to the indexing pin in the barrel by way of the slot in the upper receiver. Since the receiver is aluminum, this doesn't give me a warm fuzzy.
Plus, the price is ridiculous!
Plus, the price is ridiculous!
You are not analyzing it correctly. The receiver is where the threads are. Barrel nut is threaded onto receiver. Barrel with barrel extension is jammed in between. Think it through. I am not going to search the internet for pictures, but years ago the common way was to clamp the barrel with the aluminum vise blocks. This was when iron sights were predominately used on AR's. The problem would show up with the front post being several minutes off horizontally, this very small bent would not even be visible. That's the main reason clamp-shell blocks became popular and were recommended by Bushmaster. This was even mentioned in their video. With optical sights it's no longer an issue, but still this is not the best way to do it, popular or not.
ManrisFrack
6.5 Creedmoor
The locking lugs are part of the barrel extension. The extension is a separate piece that is threaded onto the barrel and pinned in place. Shearing this pin is very bad because this pin (along with the bolt) sets the headspace. As Mosinitis mentioned, it also times your barrel to your receiver (important for sight and gas block/tube alignment).
Hold the receiver to install a barrel nut. Hold the barrel (not the extension) to install a muzzle device.
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BDSKJCHRIS
.40 S&W
i have one, have used it to build 2 rifles. absolutely no issue with the indexing pin. if you manage to shear the indexing pin you need to use less torque. and even if you do shear that pin you can drill it out and replace it. it doesn't hold the barrel extension on the barrel, it is just an alignment pin.
Eddie Gunks
.338 Win Mag
This is correct. Most damage seems to be on 308. The A.R. 15 seem to hold up fairly well.
They are a great tool so you do not more the upper receiver in anyway. It also allows you to work on the upper without removing optics etc. etc.
As far as damaging the pen, I have damaged a couple of pens, I've also hogged out the indexing slot, causing issues with the boat lining up with the extension.
It is all a learning experience, it is cost me several hundred dollars in the course of building.
the thing to remember is the torque specs say 30 foot pounds to 90 foot pounds for installing a barrel, there is no reason to torque to 90 foot pounds.
I use shims to allow me to index correctly without putting severe undue stress on any parts. Most manufacturers of enhanced style upper receivers say to torque to 50 foot pounds. At these relatively low specs, there is no damage done to the pin for the receiver.
BDSKJCHRIS
.40 S&W
you mean an Armorer? that is an armorer level repair. not even a gunsmith job, (any gunsmith would be able to do it as well).
a muzzle device is only torqued to 15-20 ft/lbs max. holding it by the locking lugs is fine.
ManrisFrack
6.5 Creedmoor
Where do I find one of these armorers? I'd imagine they're way cheaper than a gunsmith. Better yet, how can I be an armorer? Is there a regular people school or do I have to re-enlist for that?
Anyone can become a certified armorer, they have 2 day classes in NC all the time.
BDSKJCHRIS
.40 S&W
most people could function as an armorer, being certified is more of a manufacturer specific. an armorer is pretty much just a mechanically skilled person who has the access to and knows how to use a shitload of specialty tools.
acting like torquing a barrel extension and pounding in an index pin is some super complex task that only a handful of individuals can do it a bit ridiculous.
ManrisFrack
6.5 Creedmoor
If it's just an index pin, the manufacturer took a shortcut. It's supposed to engage the barrel metal otherwise your headspace is dependent on the torque holding and hopefully some loctite.
You're right though. I'm sure you can find someone to get it close enough or even do it yourself. Most people will never notice if that pin is off TDC by a half a degree or so. I've rescinded that particular statement - you cool now?
In any case, the reaction rod will be okay if you don't over-torque any thing. If you overdo it, as many do when trying to index breaks or for the gas tube, you run the risk of damaging the pin or the receiver slot. Google "reaction rod pin sheared" and see for yourself.
You're right though. I'm sure you can find someone to get it close enough or even do it yourself. Most people will never notice if that pin is off TDC by a half a degree or so. I've rescinded that particular statement - you cool now?
In any case, the reaction rod will be okay if you don't over-torque any thing. If you overdo it, as many do when trying to index breaks or for the gas tube, you run the risk of damaging the pin or the receiver slot. Google "reaction rod pin sheared" and see for yourself.
I use them for building both 15 and 10 uppers I have not noticed any damage to either size upper.
I have uppers that I rebarreled up to 5 times. Sometimes you need quite a bit of torque for the "U" in the barrel nut to line up with the gas tube hole in the receiver. Then to un-tighten you have to use the same torque in the opposite direction. After a few barrel changes without clamping the receiver, it will at the least loosen the fit of the index pin in a slot. Not something you need to develop considering how easy it is to do it the right way.
I can knock in nails with a pair of pliers, but using a hammer will do a neater job.
I can knock in nails with a pair of pliers, but using a hammer will do a neater job.
What set up do you use ? I currently use the teo piece action block with a BCG mock unit. I thought about getting the Magpul BEV I've heard good things about as well.
BDSKJCHRIS
.40 S&W
stop changing barrels so often lol. in all seriousness, if someone is that worried about damaging the index pin or upper receiver with a reaction rod, they make the upgraded version with blocks to preload the upper just for removing stubborn barrel nuts.
another thing worth noting is the fit between the barrel extension and the upper receiver, the actual mil-spec design calls for a slight interference fit, (next time you need a stripped upper go with BCM), with a fit that tight, the relatively low barrel nut torque spec should not be enough to rotate the barrel extension in the upper.
if used properly, there is no reason the reaction rod or any other similar tool would damage the receiver or barrel extension.
the BEV block is nice, i use one mostly for the magwell block. but i have tried it out as an upper block and it was simple and secured the upper just fine.
no worries. truthfully, even though it engages the barrel, the pin doesn't hold it together, it acts as an indexing pin and a failsafe in the event that the loctite fails and the barrel extension is no longer fully torqued to the barrel.
people who over torque a barrel nut while trying to index the holes for the gas tube need to learn to use a torque wrench to prevent over torquing. plenty of people on the internet can fuck something up by using it wrong, i won't judge a tool based on user error.
I use this type of block. It comes with an insert as in the picture. It will fit A1, A2 and flat-top uppers. Perhaps there are others that work just as well. I bought it 18 years ago.
that is the exact set up i have as well. i have another one that is a 4 piece set up and im just not a fan of that one
