Suppressors Help with surefire can issue

[Mongoose0311]

I built a clone correct XM-3 this year, and the last thing I need is the suppressor. I am currently deployed so taking the rifle into my shop to test what I am about to explain wont be possible for another couple months. The FA762SS can seems to be impossible to find, however my LGS recently got in some of the mk20 (FA762SV) cans. instantly I was interested in one, but we are having trouble determining if they will work on the mount I have.

The reply from Surefire was this -

"They will attach but there will not be any retention for the lock-ring if tha FA762SV adapter is installed on the MB762SSAL/RE brake. the flash hider for the SCAR(FA762SV-SCAR) has teeth machined into the back for the suppressor latch to engage. These teeth are missing on the brake for the FA762SS (MB762SSAL/RE) and therefore will not retain. The SV suppressor uses a different latch and lock-ring system than the SS suppressor does. Basically this is not ideal in either situation. The FA762SV suppressor should only be installed on the FH762SZ-SCAR flash hider "

so some things I want to clarify, the XM-3 uses the CA762SSAL/RE, not the MB. there MUST be 2 models of the CA762SSAL/RE because Mine has teeth on it like the Scar version does, which is making me confused. The old owner of my flash hider had the FA762SS can on it, so that was basically a dead end.

Has anybody ran into this before? Does anybody by chance have both items on hand that can test this for me?

 

[Mongoose0311]

Bump

 

[onetopgun]

Mongoose

Please find attached a pic of one of the original DARPA XM-3’s IBA fielded during performance testing phase of the program. The weapon is a marked prototype and was received from IBA fitted with the MB762SSAL/RE adapter to run the the SureFire FA762SS suppressor and Badger M-4 bottom metal to run a detachable AICS magazine. I have inspected the adapter on the weapon and have noted no knurling or “teeth” on the circumference of the “upstream” end of the adapter as on the FH762SZ-SCAR adapter. I have also inspected a spare CA762SSAL/RE and a spare MB762SSAL/RE that I have in my inventory and have noted no knurling on either. I have attached pics of both spares as well as the adapter on my XM-3, FYI.

A couple of observations for your consideration...

You might want to look a little harder for the SureFire FA762SS Suppressor. While not as common as other SureFire Suppressors such as the SOCOM RC2, I have seen them available from time to time and, although they are part of the “Legacy” Suppressor line, believe that SureFire may still manufacture them when they get enough for a run.

As SureFire has recommended, I would be suspect of running the FA76SV without the proper FH762SZ-SCAR adapter. A baffle strike induced by a suppressor that has inadvertently backed off is the last thing you want.

Stay Safe, Dog. Watch your Six

Semper Fidelis

 

[Mongoose0311]

The actual issued XM-3's did not have the MB762SSAL/RE, nor a badger M5 bottom metal like yours.

Here is a picture of my CA762SSAL/RE. Notice the teeth at the bottom.

 

[onetopgun]

Never doubted your assertion that your CA762SSAL/RE had knurling... My goal was to provide you a number of examples of what I’ve always run across on all the CA762SSAL/RE’s and MB762SSAL/RE’s I’ve seen to date.

You obviously have a rare variant of the CA762SSAL/RE, so I’d keep that rascal if I were you! Holdout for an FA762SS... Betcha it’ll take longer for your NFA approval to clear than to find one.

I do a bit of culling and predator control on a ranch in south Texas. Although the issued XM-3’s were, in fact, fitted with the CA762SSAL/RE and Badger M5 bottom metal, Ive found that the Detachable Box Magazine and Muzzle Brake to be excellent additions in the field.

IBA fielded my XM3-DM during the performance testing portion of the program and submitted that configuration to DARPA for consideration. I have no doubt they had good reasons to choose the configuration they did, but I find it curious to note that both the M40A5’s and M40A6’s are configured with DBM’s and Muzzle Brakes. Taking that line of thought one step further, like the XM-3s, the M40A6’s have 18.5”, 1 in 10 twist barrels.

Good Luck with your search, Partner.

 

[j-huskey]

@Mongoose0311

Question.... below are pics of the fa762ss adaptors. CA and MB. They all have knurling at pictured. I have never seen an adaptor for the can without knurling.

I have been told they exist as OTG states.

Do you possess either version of this adaptor......

OR do u possess a different adaptor ? If so, please post a full size image.

 

[j-huskey]

I have both these adaptors for my 762ss....
I do not understand the TEETH reference to the back of the adaptor. None of my legacy cans have teeth on the adaptors.

They have teeth on the nut.

The legacy cans have a stud inside that fits in the notch on the CA and in the slot on the MB, which prevents the can from rotating around on the adaptor. This slot is at the mouth of the adaptor.
The nut tightens down and the teeth on the nut lock the can, not the knurling on the adaptor. The knurling on the adaptor plays no part of the locking mechanism.

I have been led to believe the knurling was added to prevent, or slow carbon fouling from locking the can and adaptor together.

I am struggling with the information presented to try to answer your question. Therefore several posts follow.

These two adaptors will only work with the legacy cans.

And are correct for your build.

 

[j-huskey]

The second gen cans and socom variants have no knurling on the mount, but have the slot at the rear of the can and a raised stud on the mount, and have a different locking mechanism.

A legacy can "MAY" lock on these mounts, but will rotate freely because there is no front slot to lock the stud into to keep it from rotating. Not recommended.

 

[j-huskey]

The Scar "can" uses the following adaptor, and is definitely not compatible with any other can.

Does any of this help ?

 

[chrome]

Agreed with the above, would hold out for the right can I got my FA762SS here on the hide via RWS Gunsmithing. He regularly gets the FA762SS in his inventory. I was lucky on the timing. Solid and quick transaction, as expected.

RW Snyder Custom Guns – Our focus in on quality!

www.rwsgunsmithing.com

 

[j-huskey]

Snyder also has sold the scar can when the fa762ss was not available.

 

[onetopgun]

We’re not in Kansas anymore, Toto. It is readily apparent from our collective experiences that both versions exist. I guess the question now is “why?”.

J-Husky May be on to something with his remark that he had been led to believe that the knurling was to slow or prevent fowling that induced the can to lock onto the adapter.

Jeff Bosserman, 2112 RET with GA, built my A-6 during the spring of 2018. I had an FA762SS lock up on that weapon (fitted with an an MB762SSAL/RE without knurling) after only 20 rounds or so in +/-40 degree weather. While trying to coax the can’s lock ring to unlock by various less intrusive methods, I wound up backing the adapter off of the threads on the muzzle by hand with the can still attached and was able to tap the breech end of the adapter to get the lock ring to release.

Upon disassembly, I did not find any shims in between the adapter and the muzzle brake thread tenon on the barrel, but did note evidence of Rocksett. I wouldn’t have thought twice about the lack of shims, but re-installation of the adapter as outlined in TM 05539-IN, Maintenance Manual for Sniper Rifle, 7.62 MM, M40A3/A5, required several shims to bring it to BDC (Bottom Dead Center) with 25 ft-lbs of torque.

Fortunately, the problem has not repeated itself, but I’ve diligent about releasing the lock ring immediately after firing a string in cold weather.

 

[deltawiskey]

@Mongoose0311

Question.... below are pics of the fa762ss adaptors. CA and MB. They all have knurling at pictured. I have never seen an adaptor for the can without knurling.

I have been told they exist as OTG states.

View attachment 7103805View attachment 7103806View attachment 7103807View attachment 7103809

Do you possess either version of this adaptor......

OR do u possess a different adaptor ? If so, please post a full size image.

I have two different versions of the MB762SSAL/RE

 

[j-huskey]

The left pictured brake with the part number is a mil contract unit.

 

[Mongoose0311]

Attached are 2 photos. The first is my rifle and muzzle device.

Second is an actual issued XM-3 from CMP sales.

Third is a CA762SSAL/RE without teeth

I ended up finding a Fa762ss, but I'm still curious about this.

 

[Mongoose0311]

The Scar "can" uses the following adaptor, and is definitely not compatible with any other can.

View attachment 7103836



Does any of this help ?

This is what started this post. A FA762SV most certainly lock down on a CA762SSAL/RE With teeth.

 

[NighthawkCG]

Couple of shots from the SF 2012 catalog...

1) "Newer" mounts don't have indexing teeth like the older style. The system was improved at some point.


2) Compatibility matrix.



The cans definitely can be found with a bit of looking and time. If you want a hard to find item, try finding the MB556SSN 1/2-28 for the 762SS.

 

[Mongoose0311]

Update to this thread.

We went back with both an FA762SS and FA762SV with both the CA762SSAL/RE with teeth and the FH762SV-scar muzzle devices to try and see if the SV locked on the toothed version of the CA762SSAL/RE, which we had originally done, and vice versa. Mainly to determine why the teeth are on the older CA762SSAL/RE.

Unlike what we had originally thought, the teeth are NOT engaged by the SV can, but it will "mount" to the CA762SSAL/RE, however the FA762SS appears to mount completely fine on the FH762SV-scar muzzle device essentially confirming what the Surefire rep had originally told me and disproved my original post and suspicions.

With all of that said, I did find a dealer able to work a deal with SF to make me an FA762SS, so I should have that soon.

 

[onetopgun]

Curious... If you don't mind me asking, what's the FA762SS going for now?

 

[Mongoose0311]

Pretty much MSRP. $1,850 for a black one.

 

[onetopgun]

Don’t look back... It’s “Tits” on an XM-3...

 

[Mongoose0311]

Don’t look back... It’s “Tits” on an XM-3...

I found out one of my Gunnys actually used an XM-3 back in Iraq. After I needed out and showed him the lengths I went to in order to clone it we talked about his experience with it and he used the same expression about it.

It's always need to learn more information about it. I've devoted the last year basically to tracking down every photo, anybody who has used one, every prototype and CMP XM-3 sold, and put together my own.