After an 8 month wait, my Son took possession of a SOCOM RC2 suppressor. The SOCOM was attached to a Sig M400. My Son was questioning the need to purchase an alignment rod to "ensure proper concentricity along the bullet flight path when firing suppressed on a new platform."
As I have never owned or even shot a weapon with a suppressor I am ill-equipped to advise him.
May I get some opinions from knowledgeable owners ?

I personally wouldn't shoot any suppressed weapon without checking it. stuff happens in barrel threading, muzzle device installs, etc. And with the long wait to fix anything or replace it just spend a few bucks and get an alignment rod.

hrcjon and I often agree, but I'll dissent, in this case; and I may be the only one. Over a decade of silencer ownership, and a total of eleven different silencers on many different hosts, I have never used an alignment rod, and don't see the need for one. Ensure the weapon is clear, attach the muzzle device and silencer properly, ensure the weapon is clear, lock the action open, point the muzzle at your face, and shine a flashlight at the bolt face, through the ejection port. You'll be presented with a mess of circles, all of which should be concentric: the bolt face, the chamber end of the barrel, the muzzle end of the barrel, and the muzzle end of the silencer. If something is off enough that a baffle strike can occur, you'll be able to see it. As far as I can tell, the only baffle strike I have ever had was inside a properly aligned silencer, caused by an ammunition anomaly. I would never put any effort into arguing against the use of an alignment rod; it's a useful tool, and you should get one, as hrcjon suggests. I don't think it's necessary though. As the saying goes: opinions are like b-holes, and I know darn well mine usually stinks.

Direct thread suppressors tend to loosen after shooting--checking to ensure they are secure is a good habit to start. Always bring a set of welders gloves or fireplace gloves to the range.

I always check a barrel that was modified (threaded not by manufacturer) to ensure concentricity to the bore. An alignment rod inserted from the breach and then passed thru the suppressor will identify by feel if the bore is not concentric. This mimics the bullet path and will identify which baffles are not aligned. An alignment rod with a flush end, not a rounded or snag free end is best. A rounded end does not give you a true "visual" confirmation nor by feel.
McMaster-Carr rod blanks are an inexpensive option for this purpose.
https://www.mcmaster.com/drill...-w1-tool-steel-rods/

I've always used the visual alignment method suggested by KSGM, although I do it from the breech because IMO it's much easier to see if the silencer is out of alignment. However, that only works if you are able to see clearly from the breech through the muzzle of the device, which won't work for certain weapons (some lever actions, older autos with solid receivers, etc). I also don't think an alignment rod is absolutely necessary, but it is definitely a quick and inexpensive failsafe. "I've always done it that way" is a terrible mindset, especially when working with high pressures and tight tolerances.

I have had exactly one endcap strike, which was due to using an adapter from my AUG's metric threads to 1/2-28 to mount an AAC 51T mount. This was back before you could get mounts in whatever threading you liked, and is unnecessary these days. It was very minor but still concerning enough that I prefer not to repeat it.

SIGfourme offers good advice - I suspect the majority of endcap/baffle strikes are a result of the silencer or its mount loosening under recoil and heating/cooling cycles. Ensure all threads are cleaned thoroughly and torque to spec. A welder's glove is a handy item regardless of your mounting system.

Those drill rods look like a great, cheap option for this purpose. I might have to pick a few of those up in various calibers.

just personal experience. I tried the drill rod from MM and there was too much runout to make it work. So I use actual alignment rods (I got mine from Geissle). They have most of the common calibers and some odd ones as well. In addition .22lr has a different bore and those can be hard to find, I got those rods from Pacific Tool and Guage.

I believe that checking by using the visual method mentioned, if nothing else, is essential.

When I wanted to use my suppressor with a T/C Contender barrel chambered for 300 Blackout, I ordered the barrel from a company that I’d purchased barrels from before and that seemed to have a good reputation. I also asked that it be threaded at the same time. When I first started using it, though, the precision and accuracy with the suppressor were terrible and I discovered that the bullets were grazing the end cap. The misalignment of the can and bore were visually obvious when I finally checked.

I fortunately had ordered the barrel long enough for it to be cut and rethreaded by Thunder Beast, but that experience with a manufacturer that originally threaded one of its own barrels convinced me of the need to always check alignment.

I have seen a direct tread suppressor (not mine) go down range as a result of not being tightened properly and personally experienced gross POI changes when my own loosened slightly. I carry a silicone kitchen hot pad in my range bag which is good enough for how I use my can.

KSGM and I agree to disagree on a very small number of issues and this is one of them. I want a reliable, repeatable, measuring tool and he wants his eyeballs peering down a barrel with a flashlight at the other end. The last time he 'beat' me up on this I tried the KSGM eyeball method and I can't tell sh**. I had a configuration I knew was bad so I tried to see if I could tell it, and no I couldn't. So if you can make that work, save your money. For me the comfort of looking at that rod centered in the suppressor at the end of a bunch of stacked tolerances is worth the $. Now for the record I don't check this crap every time, I do it when I build/assemble it or change something. After that I know from hundreds of mounts/dismounts that its not going to change.
In any case my second try at this discussion.

Well, I was advised one of my barrels was a bit off and told the .30 can should not be a problem but a 5.56 might be. Second barrel was GTG.

quote:

I had a configuration I knew was bad so I tried to see if I could tell it, and no I couldn't.

What was problematic about this setup? A big POI shift? It didn't pass the rod test, and you were unable to see the misalignment with your eyes? I do concede that my method is not the "right" answer, and I'd never consider it a good hill to die on. I use it as verification that there will not be a strike, and I do believe it's good enough for that. It is very possible that the eyeball method will not detect a deviance that is enough to impose a POI shift, but not enough to cause a strike. We may have discussed this before, and may do it again in the future; we'll learn a bit every time.

For anyone interested, Brownells has 7.62 and 5.56 Geissele alignment rods for about $61, which is half the price of what Geissele sells some of its gages for. I wonder if they are about to be discontinued.

All my years of suppressor shooting on my 8 cans I have never used an alignment rod. I don't check the bore either. Hell, I just screw the cans on and go for it. Never had a problem. I do clean the threading on my rifles and cans often but that all I am willing to bother with.

There are countless precautions that wouldn’t be necessary if nothing bad ever happened.

But sometimes they do and then the reasons for precautions become obvious. And no matter how large a “no problem” sample size is, if it’s just a sample then it doesn’t guarantee that there will never be a problem. On the other hand, a single incident in which a problem occurs is enough to demonstrate that they can occur. I was fortunate that my experience with a misaligned muzzle thread didn’t have serious consequences, but if it had, I would have wished for some advance warning that it was possible and that I had heeded the cautions.

I did once check the alignment on a rifle setup where I had to use an adapter because the barrel was threaded in a funky metric thread pattern, and I was concerned about tolerance stacking. Everything turned out to be concentric and aligned. The rest I just screwed on and shot.

quote:

Originally posted by sigfreund:
There are countless precautions that wouldn’t be necessary if nothing bad ever happened.

But sometimes they do and then the reasons for precautions become obvious. And no matter how large a “no problem” sample size is, if it’s just a sample then it doesn’t guarantee that there will never be a problem. On the other hand, a single incident in which a problem occurs is enough to demonstrate that they can occur. I was fortunate that my experience with a misaligned muzzle thread didn’t have serious consequences, but if it had, I would have wished for some advance warning that it was possible and that I had heeded the cautions.

Spot on.

Given how little time and effort it takes to conduct a visual inspection, and given the potential ramifications of a misalignment, it is unwise not to at least visually confirm the alignment.

As sigfreund alluded to, eventually your sample size becomes large enough to find an issue.

I recently went the mcmaster-carr route for two rods. I forget the exact cost but cheap comes to mind. I haven't checked mine in the past but now that I'm finally updating my collection I said why not.

In my experience the Mcmaster rods are insufficiently processed to be usable at least in the produced lengths. They have way too much runout. They weren't designed for this so I suggest you just suck it up and get some that are if you are going to bother (I use either surefire or geissle).

quote:

Originally posted by sigfreund:
There are countless precautions that wouldn’t be necessary if nothing bad ever happened.

I agree with this. Whether you choose to use an alignment rod or not, the anecdotal musings of everybody who "has never had a problem" are merely anecdotal musings and I would not be reassured by them or try to use them as justification. If you're "not worried about it", then so be it, but don't use somebody else's good fortune as you security blanket.

Hrcjon, I am still curious as to the circumstances of your bad setup. I agree that rods from a source that doesn't guarantee their perfection are pointless. I trust my eyes more than an unverified rod.

I have used the McMaster precision ground rods and they have been perfect. No perceivable run-out on the ones that I purchased. Obviously anything can come in varying levels of quality, and for the ~$5 each one cost me at the time it was well worth it.

The ones I received had rough ends from where they had been cut to length, so I did need to carefully trim the ends with a fine tooth hack saw and then chamfered the edges. Overall it was a simple project and I have used them dozens of times since.