I am about to do my first form 1 suppressor. First off, the host will be a 5.56 Sig M400 pistol with a 10.5" barrel that I am converting to an SBR on another form 1. I believe it has a 1:7 twist.

I am planning on using SD tactical parts. I am thinking the SD tactical muzzle brake, the thread protector that fits it, the 5.5" steel D-cell tube, steel endcap, and stainless spacer material. Freeze plugs from Napa Auto, the steel 34.3mm Sealed Power ones. I plan on buying the SD tactical centering tool too.

I was leaning toward titanium for the light weight, but I figured the steel might be better since it dissipates heat quickly. I chose to do it all steel so the thermal expansion is all pretty much the same. I may be overthinking the effects of heat.

My biggest concerns are durability, length, and weight. I'm not terribly concerned about how loud it is, I just want to tame the muzzle blast and flash a bit, and don't want it to be extremely ear shattering if I had to use it indoors for home defense.

Do you think an aluminum endcap would be sufficient and worth it to save weight? Is the 5.5" tube sufficient for my intent? Any other advice will be greatly appreciated. I have a plan for forming the baffles, and I will worry about arrangement and hole sizes, etc later when its time to build.

EDIT: Also, for a dedicated can (probably won't shoot the gun without it) should I skip the muzzle brake and go direct thread?

You concern about weight and heat dissipation . The steel can on my AK gets hot, not nearly as it does running Ti on the AR.


YES,
Using as a HD gun. The last thing you'll be worrying about is your hearing

No on the Al end caps (search function)  or,  IIRC $100 or $250 build. No i don't know what page it's discussed, you'll have to read through them like everyone else did. Or someone will link to it. Possibly the last 2-3 pages of either thread?

I went direct thread and switched over to a MB instead.  3 reasons
1: you said "probably won't shoot with out it"
Having the Brake is (for me) easier & quicker when switching to another host. PLUS, those pesky thread protectors seem to get misplaced a lot. Or end up at the bottom of your range bag.

2: i had less 1st round pop and the brake, by allowing "gases" to vent elsewhere beside straight / forward reduced the Db's enough, those i shoot with noticed the difference.

3: On a 10.5" bbl definitely the brake to minimize blast baffle erosion.


I'd go Ti running a MB and use a 7" can. But that's what i did. The final decision is yours to make. The 5.5 would look nice on that SIG.  Either way. I doubt this will be your one and only BYO.  I have steel for the AK and Ti for the AR and MVP.  

If my reply is vague, sorry,  been up since 4 wed morning.

Thanks.

Correction, it is a 11.5" barrel if that matters.

I am now leaning towards the all steel sdta build with the 5.5" tube and the sdta muzzle brake. I'm just trying to imagine what almost 2 lbs will feel like hanging off the end.

My opinion -

5.5 = 6" (ish) in length and will take the bite off the blast.  I went 7" for my last two and am reasonably happy with them.  One is SS and one is titanium but the shorter you go the less weight you save between the two materials.  And stuffing it full of heavy FP's and the weight starts to normalize between the two.   I went titanium for a purpose built light weight 9mm ar but all my other F1's are stainless and are in the same ballpark as my commercial cans.

DT cans unscrew in my experience unless you go LH thread where the natural torquing of the barrel as the bullet is forced into the rifling causes them to tighten rather than loosen.

A good QD mount, I use Griffin Taper's, will lock your can on and you won't have to worry about it.

With a 5.5" can I wouldn't worry about spacers, just have your blast chamber about 1.2 - 1.75" and then stack freeze plugs end to end, you should get the best results in suppression that way.

If you're not mag dumping or have a very high volume don't worry too much about durability, even if you have a ATF agent sleeping in your garage you can always rotate your baffles to equalize wear and you should get many 1000's of rounds through it before wear becomes significant.   I have about 600-700 through my first F1 and there's no real perceptible wear on the VSR I use as the first baffle, but I also don't heat it up red hot.

Ok I'm sold on the griffin taper mount. I really like the looks of the flash comp version:

http://www.griffinarmament.com/Taper-Mount-Flash-Comp-p/tmfc.htm

I hope it will work well for this application.

I'm also considering drilling it for 308 because it's only matter of time before I get a 300 AAC sbr upper (after I get my tax stamp). And I could also use it on my 308 bolt gun.