I am asking this question because I am considering moving my Lane Scorpion 5.56 suppressor from my .22 WMR over to a .243 rifle.    Before everyone freaks out, that is correct... I said put a 5.56 suppressor on a .243 rifle.    I have spoke with Cory at Lane Suppressors who says the Scorpion 5.56 will handle any of the non-magnum 6mm rifles with ease.

Here is a link to the Lane site that even lists the same info.

http://lane-products.com/products/scorpion-556.html

Before I go an do something I may regret, I did some measuring to the exit end of a couple of my cans just to get an idea of how much "overbore" they had for safety.

Suppressed Armament Systems Reaper.    This is .30 caliber can with an exit diameter of .350".   It gives a clearance of .042" when passing a .308 caliber bullet.

Lane Scorpion 5.56 has an exit diameter of .280"   It has a clearance of .037" when passing a .243 (6mm) diameter bullet.


Guess what I'm trying to ask here is would you feel comfortable passing a .243" bullet through a .280" hole or is that a bit too close for comfort?   Of course there are other factors that could reduce my safety margin such as non-concentric threads, or the suppressor backing off the threads when hot.  

If it helps, my Scorpion 5.56 has 5/8x24 threads and I am currently using a 5/8x24 to 1/2x28 adapter for my .22 WMR.

my knee jerk reaction would be NO, but if the boss says its ok and you have that in writing from him for any warranty purposes, let'er rip!

Guess I will give it a try on Friday.

Did you lay calipers to the hole?

Are all the baffles the same size?  

Are they tapered in any way?

You have to cut your clearance numbers by half. Its literally evenly split L/R.  You really only have .0185 clearance between the projectile and the aperture.

I personally wouldn't do it.  But hey, maybe the guys that make it will bless it.   Like our hippy-kicking friend hinted at, the baffles probably gradually get larger as they go.  That means they're even tighter down inside.  Don't forget that baffles can also "push" a bullet also as it goes through each of them.  Slant-wall baffles are even better at this.  

I think this is supposed to be a take-apart can right?  You might be able to have a gunsmith ream the bore larger for you.

I laid my calipers in the exit aperture to measure its ID.   The Scorpion is designed as a take apart can, but I have not opened it up yet.   The monocore may be tighter as it gets closer to the muzzle.

I would personally feel better if it had .300" freebore.

Its a neat can and I'm very happy with it so far.    It is overly large for my .22 WMR and probably a bit undersize for my 243.    I was hoping to dedicate the Scorpion to my 243 and get a more appropriate size rimfire can for my 22 WMR.

Wish that was possible, but NFA rules specifically prohibit changing the caliber of a "silencer".  It's considered a new manufacture.

Clearance is clearance

Just be sure that your muzzle threads are concentric, the tighter bore will make that more critical

Well folks, here is the answer directly from Cory Johnston (co-owner of Lane LLC)   He is giving it his full blessing to go out and shoot with my 243.    Just thought I would share his response.


Jeremy,
    Thank you for your inquiry.  We try to keep the bore around .040 over the bullet diameter on all of our platforms.  This is pretty standard for most suppressor manufacturers aside from QD mount systems which require larger bores.  Direct thread systems can hold tighter tolerances.
Also the drill tolerances generally add .002-.004 to diameter
Scorpion Rimfire  17/64 (.266)  .223 bullet  Max  =.043-.047
Scorpion 556        9/32  (.281)  .243 bullet  Max  =.038-.042
Scorpion King      11/32 (.344)  .308 bullet  Max  =.036-.040
Scorpion 458         1/2  (.500)   .458 bullet max  =.042-.046
Scorpion Magnum   3/8  (.375)  .338 bullet max  =.037-.041

    When we measure the run out on a finished suppressor it has to be within .0075 of centerline of the bore so you can have as much as .015 while dial indicating one side to the other of the bore from a fixed spot. 
What we have found is that when the barrels are indicated and threaded correctly there is no issue with alignment. Even factory threaded rifles rarely have a problem.  When the barrels are threaded incorrectly, it does not matter if we add another .020 or .030 to the bore diameter, they will still not work. Generally it is because it has more to do with angular alignment than concentric alignment which throws the alignment out farther as you move towards the end of the suppressor.  When we have identified alignment issues, either with the suppressor or the barrel,  increasing the diameter of the bore a reasonable amount would not have corrected the issue.
    I currently compete in PRS style long range matches using a 6XC and my daughter runs a straight 243 both using our Scorpion 556 suppressors without issue.

    Go ahead and run it.  There is really no danger running the suppressor as far as safety is concerned.  Generally, if alignment is out you will find accuracy becomes the issue and you may see some copper swipe marks on end of the suppressor.  If it is so bad as to tumble the projectile, it will damage the suppressor, opening the bore on the way out.  Nothing will come back at the shooter or damage your rifle.  The worst case scenario, we would have to replace the core on your suppressor which we cover under warranty.  This case is extremely rare.

Thanks,
    

Cory Johnston
Lane LLC
4604 STURGIS ROAD
Rapid City S.D. 57702
phone#  605-791-0740
www.lane-products.com
www.facebook.com/lanellc.silencers

It's hair splitting at this point, but NFA rules state that you can't change the marking, not bore diameters.  As long as your baffle is still relative to that marking you really should be OK.  I'm not a lawyer and all that.  Many, many, 5.56 suppressors have bores larger than what he needs, so the ATF shouldn't argue that he's trying to change from 5.56.  A reaming of a few thou' can often be considered a repair if there's been a baffle strike as well--which is fully acceptable.  An 07/02 should do the work.  

With the manufacturer stating that it's OK, it's moot anyway.  I'm curious to see how it works out over time, though.

That first shot is going to be mighty exciting.

We will find out today.

Fired 5 rounds this morning.    All 5 hit their point of aim at 50 yards.    No baffle strikes of any kind were noted.   Time to shoot for a accuracy at 100 yards for further evaluation.

So far I have 20 rounds of 243 through the Scorpion between two different rifles.   So far, it has been flawless.