I am not an engineer but I do build suppressors and firearms as a 07/02. I have ported barrels in only the groves and ported them into the lands and groves. I saw no significant difference between the two. Both worked well and I have no problem with porting either way.

I bet that sooty black powder was hell on it.

I would look up the spec in Machinist Handbook and use that. Or, buy your mount and use it as the gauge. It’s probably the safest bet.

Use 309L rod for filler if needed. I dont think you would have a problem with just fusion.

I have a stick of 1-1/2 316 SS DOM tube. I hadn’t thought about using it until now. You could weld your 17-4 baffles and mount to it.

I would use 17-4 and make it tubeless. You stated this is going on a 556 SBR so durability is key. 17-4 turns and welds great.

Use 17-4 and make it tubeless. 17-4 welds great. Most everything I build is tubeless unless it’s going on a .22.

Listen to the good Captain. A welded can as he describes works. You will be far happier with it than your original idea.

I normally use the fully collapsed stock and include your muzzle device in the measurement.

Like Link said, weld it. Unless the customer wants a threaded tube, I weld just about everything now.

I would start porting close to the chamber. Again, use the mp5sd as an example.

It’s going to be trial and error to get the correct amount and diameter. You can search the old threads here and probably find a starting point. You could also tap the ports and use allen headed set screws to block them off when not needed.

Porting will not ruin your gun. Look at the mp5sd.

Thread a collar 5/8-24 ext. and 1/2-28 internal, then rocksett it.

I have a mandrel that I clamp it together with.

I will have to try and get my post count up.

Here’s a one that I am building for a 458 Socom. It’s all 4140 and will be welded. It has eleven baffles. I didn’t clip the first or last but may do so before I weld it up. I also have not weighed it since I have to get a new scale. I will try to get a video posted after I complete it. I tried to po...