SIG Mk 25 9mm, SIG threaded barrel, Armory Craft Compensator, Blazer 124 gr FMJ - FTE (stovepipe)

[The Heretic]

I picked up the barrel and the comp last week from @ethanww94 for a good price ($150).

Started testing it last week with the comp and Blazer FMJ ammo. Noticeably less recoil (or at least, less muzzle flip). Noticeably faster double taps.

Problem is about every five rounds I get a stovepipe FTE.

Took the comp off and it runs fine. Put it back on and stovepipes return.

Comp came with three recoil springs, so I tried the orange (16# - same as stock braided, but this is single wire) - same results. So I tried the red 14# spring - maybe a little better but I stopped after the first stovepipe.

So I dug out some HST +P 124gr and that worked fine. I noticed with any of the ammo, ejection is weaker than without the comp. A plain barrel throws the cases at least 5-10 feet to the side, with the comp just a couple of feet - if that. Remington std pressure 115gr did not work.

So I got this Wolff spring kit yesterday:

13179

SIG-SAUER P226 9MM RP VAR RECOIL CALIB PAK

Stock No. 13179 - Contains 1 each of the above reduced power variable recoil springs in 10, 11, 12, 13, & 14 pounds. Three extra power firing pin springs are also included.

I loaded up some more Blazer 124gr FMJ ammo and started testing.

I started with the 13# since I already had tried the SIG 14# spring. I went thru a full mag with no issues until I got to the last round and the slide did not lock back.

I tried the 12# and had some FTE and last round FTE

I tried the 11# and last round FTE.

I tried the 10# and had no issues.

One more mag with 10# spring - no issues.

Each # lighter the ejection was a little better - with the 14# & 13# ejection was weak; the spent brass would barely eject and falls at my feet.

Now I will need to figure out which spring works with the Remington 115gr JHP ammo and make note of that. I think I will also run thru another box of the HST 124gr +P ammo to make sure it works with the 14# spring.

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[Koda]

Ive been wanting to add a comp to my build, is it common to need to reduce recoil spring weight when running a comp?

 

[The Heretic]

Ive been wanting to add a comp to my build, is it common to need to reduce recoil spring weight when running a comp?

For a SIG 226/Mk25, I believe it would be true with the Armory Craft comp and weak ammo like the Blazer 124gr FMJ (noticeably weaker than the +P HST 124gr ammo.

I can't speak for other comps or other pistols or other ammo. The AC comp adds weight to the barrel slowing down the recoil, reducing the felt recoil and the muzzle flip. To let the slide recoil fast & far enough to get good ejection. That said, it would not surprise me that similar comps would require similar tuning.

Note that the AC comp is steel and adds 3.1 ounces to the weight of the barrel. If the comp were made of aluminum it would weigh about 1 ounce. Titanium would weigh about 1.6 ounces.

 

[The Heretic]

Alternatively, I should buy/use full power FMJ ammo for practice, that is equivalent to my 124gr defensive ammo. I am given to understand that Federal AE or Winchester NATO ammo is full power.

 

[Koda]

For a SIG 226/Mk25, I believe it would be true with the Armory Craft comp and weak ammo like the Blazer 124gr FMJ (noticeably weaker than the +P HST 124gr ammo.

I guess if I end up trying a comp I will know to be prepared to try reduced recoil springs. I also typically shoot the lighter 9mm, actually whatevers cheapest range ammo. ...

 

[The Heretic]

I guess if I end up trying a comp I will know to be prepared to try reduced recoil springs. I also typically shoot the lighter 9mm, actually whatevers cheapest range ammo. ...

I checked and Winchester NATO 124gr loads are only about 2-3 CPR more than Blazer and are about the same velocity as HST +P ammo.

In the future, I will buy practice ammo that matches the power level of my primary defensive ammo.