I'm trying to figure out if a silencerco front cap will fit on the thread pitch for DM Tube. The DM tube is labeled for ASR Mount, but I can't figure out if an SiCo endcap/front cap will still fit on that tube. I was thinking the Saker specifically since the OD is the same as the DM tube.

The DM ASR tube's distal end cap threads are slightly larger diameter than the Silencerco design. So while an Omega end cap will thread into the DM ASR tube, there is not enough thread engagement for a full strength connection.  Thread locker can resist torquing forces but doesn't really have lap shear strength to prevent end cap blowout.  Under repeated pressure loading poorly engaged threads will wear at the thread points until failure. It won't be fun to see your end cap and stack become a Wiley Coyotte Acme Titanium confetti canon.

Either a short adapter section or asking Chris to bore a custom ended ASR tube might be a solution.  Somebody also needs to make a Griffin taper mount adapter for the ASR tube back end.

What if I had someone lightly hit the front cap/tube with a mig or tig welder?

I think you would be trying to weld dissimilar metals. The SiCo flat caps are slightly magnetic and are likely 17-4 corrosion resistant steel. The Anchor Brake is the same weight as the flat caps and non magnetic but I don't know if SiCo uses titanium or aluminum to get the more massive brake down to the same weight.  Other than welding Ti to Ti the weld integrity would be suspect. Plus you lose the ability to easily push the stack out the cleaner front end.

I don't see not being able to use SiCo front caps as a deficiency as the DM Ti caps are lighter and cheaper and the Super Precision Products ones get high badass, custom look points with a practical hex tool removal feature.  So that just leaves the Anchor Brake front cap. It may be titanium. You could probably get someone to fab you a front cap in 7075 Al along the lines of the YHM Nitro muzzle brake front cap.  You also might want your Form 1 front cap aperture diameter to be different from SiCo design. Many people claim coned front caps such as DMs are quieter or improve POI shift. In my experience it's largely cosmetic but that's also a benefit to a custom build.  Having titanium front caps matches the tube material's thermal coefficient of expansion and the stresses that mismatched materials can apply.  7075 expands faster with heat and starts to weaken at around 400 F whereas Ti is good to 700-800 F.

If you already have an Omega 300 or Hybrid 46 setup then being able to use their parts would save you some money, but not much.  If you don't already have an approved Form 1 having functional parts that fit a DM tube is also ill advised.

If you just like the look of the SiCo end caps, have DM make you a custom one which fits their tube.

Solvent traps are not silencer parts. The end caps, for solvent traps, have no hole drilled in them and are not silencer parts. SiCo end caps, available for retail sale, are also not silencer parts. Having them together, in a non-silencer configuration, does not constitute a silencer. If any of this was so, the solvent trap retailers would be in violation of NFA law just the same.

I ask because I have 4 spare 1.347 skirtless Ti 60 degree cones and Precision Griffin Adapter so I figured I'd save some money and try to use the SiCo tube with SiCo cap, but it doesn't sound like that'll work out :/

This information is very helpful though.

It sounds like we are talking about the same configuration. The 7.8" long DM ASR tube takes 1.347 OD internals. I measured the major diameter of the DM front cap threads at 1.434". The SiCo is 1.416".  Assuming somewhere around 0.026" thread death for 24tpi 75% thread engagement the SiCo front cap is probably just under 50% thread engagement. But it feels really loose. I wouldn't feel comfortable using it.