Planning my next build

[cdhknives]

Tips/advice/commentary appreciated. I have an approved form 1 for 45 caliber and 8" length. Goal is a very multipurpose can. Initially I thought carbine and rifle only, but seriously considering a booster for use on Glock and 1911 style pistols...may as well make that an option. I would like to safely run 458 SCOM down to 9mm semi-auto pistol and carbine. I already have a YHM Phantom 30 cal for heavy shooting from the AR's in 5.56 through 308 Win, and my form 1 build 22lr can. This needs to complement those, not as heavy as the YHM Phantom but rugged enough for occasional rifle and moderate carbine use. No full auto. Ever. Again the YHM can handle that if I go there. The YHM is a brick, want to get lighter, but know I will not be at the under 4oz of my 22lr can.

My first form 1 was 7075 aluminum cones, so I am comfortable with them. I do not have a useful mill for exotic cuts, only the milling attachment for my lathe and it is about as sturdy as half cooked pasta when cutting metal. I am not looking to be exotic and fancy, just want a solid performing unit on par with decent commercial cans. No welding, threaded only. I am still learning as I go with this lathe after 5 or so years tinkering with it. Slow is the name of the game but I get there, but standard turning and threading operations are about the limit of my confidence.

My initial thoughts:
Titanium tube. 17-4 mount and blast cone...would consider also titanium but have 17-4 on hand.

60 degree cones for the baffles. Material??? Will Al handle this level of usage? I understand the lack of heat tolerance issue, but don't rapid fire enough carbines to really have a feel for how hot a can would get after a mag dump. I know 5.56 will heat up my YHM a LOT after a 30 round mag but that's 5.56.

1.25" diameter...maybe better to go us to 1-3/8" or 1.5"???

Buy or build a booster and a spacer to cover pistol and carbine use? The last I recall it is legal to make a boosted endcap and a non boosted endcap as they were classified as 'adapters'...right? Other designs seem to look a lot like QD mounts with booster 'muzzle brakes' and non booster 'muzzle brakes'. Is there a real reason to prefer one option over the others?

Building a material list...let the fun begin!

[ECCO Machine]

60 degree cones for the baffles. Material??? Will Al handle this level of usage? I understand the lack of heat tolerance issue, but don't rapid fire enough carbines to really have a feel for how hot a can would get after a mag dump. I know 5.56 will heat up my YHM a LOT after a 30 round mag but that's 5.56.

1.25" diameter...maybe better to go us to 1-3/8" or 1.5"???

Consider 65° cones. I've found them to work better than 60° with high pressure cartridges. I run .040"-.050" over bullet diameter as well, so a .458 can I'd run aperture at .505" or so, basically bore with a 1/2" drill, make the cones, then chuck up the cone and take a finish pass with a boring bar as a final step.

Aluminum will not withstand any volume of rifle fire. if you're planning on more than a couple shots per minute, go steel, Ti or inconel. I make an ultralight hunting model with 17-4 blast baffle and 9 7075-T651 cones in a .035" wall Ti tube with 6/4 rear mount and front cap. It weighs just 9 ounces at 1.5 x 8", but it's a fire your 3 or 5 shot group then wait 10 minutes proposition. 3 shots on my .25-06 and it's too hot to handle.

If .458 SOCOM and the like are what you want to do with it, I'd go at least 1.5" x 9". .45 caliber is a big hole, lots of room for gas to escape, need plenty of length and volume to offset that.

[cdhknives]

Thanks! 458 SOCOM is a dream at the moment, an extreme upper limit, a maybe in the far future. If it ups the scales significantly and sticking with 45 ACP/40S&W/357Mag(rifles)/9mmPara cartridges is a lot easier I can give it up. I have the 'cartridge spectrum' ends covered with 2 cans, 22lr lightweight and 30 cal heavy, looking to take care of the middle...big bore pistols and pistol caliber carbines. These can be high volume shooters but relatively low pressure cartridges. I know my autoloaders get pretty hot after a couple mags worth of double tap drills...I guess I should stick with something better at heat strength than Al.

I'm not scared of SS or titanium but it does take a lot longer to machine, especially with my lightweight lathe. I know, sharp tools and lots of lube...and light cuts! It also makes screwups more expensive!

If the cool weather sticks around I have the next few months to gather materials and start making chips. It is hard to get motivated to work a lathe in 100 degree weather here in South Texas!