Completed titanium .308 caliber build

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cal50
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Completed titanium .308 caliber build

Post by cal50 » Fri Jul 10, 2015 8:45 pm

After getting sidetracked with numerous auto & home repairs and the work thing I managed to complete my .308 titanium can.....

Finished OAL length: 10.250"
Diameter 1.750 OD.
Wall thickness is .070"
End cap is 24 TPI.
Finished weight: 872.4 Grams / 30.77 oz / 1.9 lbs.
Direct thread mount : 5/8-24

The tube is grade nine (9) from Tiger Metals. The tube started at 12" long and I checked it for internal straightness and run out and cut it down and faced it to its finished length. I originally was going to make both ends threaded but changed my mind and pressed and welded one end and threaded the muzzle cap. Baffles are traditional cone shaped baffles that stack on each other. Grade five (5) titanium for the baffles and end cap. My blast baffle is stainless steel as well as the blast chamber spacer. I turned a bronze plug to gauge the ID or the tube and pressed it thru until I had a nice fit. I made my baffles .002" smaller than this plug.

It has 6 titanium cones , one stainless steel blast baffle and rebated / counter-bored end cap of titanium.


The large gas lens ( CK ) works well for shielding once I cranked the argon flow rate up. My first weld was a darker color but once I had the gas flow right the rest were shiny. I used the plug gauge I made for a support and to rotate it welding the seam where the tube and mounting piece meet. I put my ground clamp there and back purged it with a hose of argon in the muzzle end.

I had Veritas do the laser engraving and they did an EXCELLENT job on the tube.

Now I am looking forward to hit the range and try it on my SIG 716 & 556R

The thinking phase.....

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Cutting baffles~

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Tube with gauge plug and steady rest marks~

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Some obscene stainless steel for the blast baffle and spacer~

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Pile of baffles~

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Measuring the stack and doing some math~

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Threading Mount~

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Getting ready to press into main tube. 1/4" diameter hole in tube X 6 to plug weld thru. Insert to tube has a .002" press fit.

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Pressed in and ready to weld~

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Welded ~

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Weld hit with Scotch Brite~

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Done with all the guts~

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CMV
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Re: Completed titanium .308 caliber build

Post by CMV » Fri Jul 10, 2015 10:05 pm

Very, very nice!
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Re: Completed titanium .308 caliber build

Post by fastfire » Sat Jul 11, 2015 5:50 pm

Like to see a report and maybe a video of the sound or lack of sound :lol:

By the looks of the linotype? you cast your own boolets, I started few of years back my self.

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Re: Completed titanium .308 caliber build

Post by cal50 » Sat Jul 11, 2015 7:35 pm

Range report ( good or bad ) and a vid will follow at some point.

I got out of casting many years back only to get back into it recently from necessity. I play around with a couple sharps rifles and have a custom mold for my 500 mag's (600 grain). You do not get many bullets per pound of lead and the real reason is I can make my own bullets and not be totally dependent on the store shelves.

When there is a run on supplies everything is in short supply and if you have a specialty caliber its even worse.
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Re: Completed titanium .308 caliber build

Post by fastfire » Sat Jul 11, 2015 8:03 pm

If you cast very much look into getting a PID, it makes temp control a piece of cake.
I run 2 20lb pots at a time, one heating up after refilling while casting from the other.
I seldom have any waiting time for pots to get up to temp unless casting big boolits where the pots empty purdy fast.

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cal50
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Re: Completed titanium .308 caliber build

Post by cal50 » Sat Jul 11, 2015 8:07 pm

fastfire wrote:If you cast very much look into getting a PID, it makes temp control a piece of cake.
I run 2 20lb pots at a time, one heating up after refilling while casting from the other.
I seldom have any waiting time for pots to get up to temp unless casting big boolits where the pots empty purdy fast.

Its the only way to fly.......

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Re: Completed titanium .308 caliber build

Post by djinni » Mon Jul 13, 2015 5:19 pm

Awesome to finally see you get time to finish it up, Cal50! Definitely interested in the performance. As mine is definitely following the same design as yours. Did you use rod when you welded? and how much argon flow did you find optimal?

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Re: Completed titanium .308 caliber build

Post by cal50 » Mon Jul 13, 2015 6:01 pm

djinni wrote:Awesome to finally see you get time to finish it up, Cal50! Definitely interested in the performance. As mine is definitely following the same design as yours. Did you use rod when you welded? and how much argon flow did you find optimal?

I used titanium rod on the 1/4" holes I filled in. The tube and end cap butted up tight and I just made a pass around and puddled it / blended it together.
I had my flow rate set at 15 and bumped it up to 25 and maxed out the time on my post flow.

You can tell quickly looking at the color of the weld or the color of your electrode if you have enough shield.
I used the CK Gas saver lens / cup.


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Re: Completed titanium .308 caliber build

Post by nbw123 » Mon Jul 13, 2015 9:40 pm

Good choice in beer.

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Re: Completed titanium .308 caliber build

Post by djinni » Fri Jul 24, 2015 3:29 pm

I'm definitely going to try the CK gas saver cup when I do mine. Any update on a range report? :P The people want to know!

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Re: Completed titanium .308 caliber build

Post by cal50 » Fri Jul 24, 2015 4:44 pm

djinni wrote:I'm definitely going to try the CK gas saver cup when I do mine. Any update on a range report? :P The people want to know!

Mixed bag for the 1st range trip....

I overlooked a detail on my SIG 716 host rifles with the factory barrel thread and my mounting design. SIG does / did not relieve the threaded diameter against the barrel shoulder. The minor diameter is .574 and SIG leaves it turned at .616 diameter which means my suppressor will not screw down tight against the barrel shoulder and the mounting surface on the suppressor.

( I discovered this at the range)

I did screw it on until it stopped and test fired a few shots. No baffle strikes ( good ) but a sharper tone than I anticipated. I was on the fence about clipping the cone baffles so this made the decision easy to give it a try. I simply removed the end cap and pushed the baffles out. I clipped all of them except the blast baffle. I also made a precision spacer to locate the suppressor against the barrel shoulder. I will tweak the length if I get an impact shift from the clipped baffle stack.

A trip to the range hopefully tomorrow.


Thread NOT relived to minor diameter ( .574 ) mic's at .616 so a can will NOT shoulder out on my SIG 716~

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Parallel machined spacer to mound against barrel shoulder~

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My Clipped baffle / .250 diameter mill .130 deep from edge~

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Re: Completed titanium .308 caliber build

Post by cal50 » Sat Jul 25, 2015 2:09 pm

Just returned home from the range after test firing with a smile on my face.
:mrgreen:


This trip I was able to properly attach my suppressor to my rifle and run some ammo thru it. My spacer allowed me to tighten down the suppressor against the barrel shoulder as I intended. Test firing with and without the suppressor and all round went to the same point of aim / impact. I am shooting Portuguese ball ammo and its does 2 MOA in this rifle and did the same with and without the suppressor attached.

My crappy cell phone video does not do the can justice but a few things can be seen. Recoil is reduced quite a bit with the suppressor attached. I am firing under a steel roof and concrete floor and its louder than firing out in the open. The suppressor REALLY drops the muzzle blast and you can hear the sonic crack down range.
(You can hear a guy with a lawnmower in the background ) I walked out in the open and fired a few shots and its pretty sweet.

I will say there is a HUGE difference in muzzle signature using the same baffles clipped vs UN-clipped. I aligned all "clips" the same way inserting them into the tube.
All baffles are clipped except the blast baffle. I want to put a radius on the inside area of my end cap and tweak a few other things to see if it improves.
I can also thin out some of my baffles to increase volume and drop some weight but it sounds nice and hopefully only get better.


Crappy cell phone video~

Unsuppressed 5 shots ball ammo~

https://www.youtube.com/watch?v=gpf6J6XTtR4



Suppressed~

https://www.youtube.com/watch?v=QhUAskXPoYY
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Re: Completed titanium .308 caliber build

Post by djinni » Thu Jul 30, 2015 2:50 pm

Definitely hard to tell with the phone video, but the delta looks promising. Also had a chance to try any subsonic ammo?
cal50 wrote:Just returned home from the range after test firing with a smile on my face.
:mrgreen:


This trip I was able to properly attach my suppressor to my rifle and run some ammo thru it. My spacer allowed me to tighten down the suppressor against the barrel shoulder as I intended. Test firing with and without the suppressor and all round went to the same point of aim / impact. I am shooting Portuguese ball ammo and its does 2 MOA in this rifle and did the same with and without the suppressor attached.

My crappy cell phone video does not do the can justice but a few things can be seen. Recoil is reduced quite a bit with the suppressor attached. I am firing under a steel roof and concrete floor and its louder than firing out in the open. The suppressor REALLY drops the muzzle blast and you can hear the sonic crack down range.
(You can hear a guy with a lawnmower in the background ) I walked out in the open and fired a few shots and its pretty sweet.

I will say there is a HUGE difference in muzzle signature using the same baffles clipped vs UN-clipped. I aligned all "clips" the same way inserting them into the tube.
All baffles are clipped except the blast baffle. I want to put a radius on the inside area of my end cap and tweak a few other things to see if it improves.
I can also thin out some of my baffles to increase volume and drop some weight but it sounds nice and hopefully only get better.


Crappy cell phone video~

Unsuppressed 5 shots ball ammo~

https://www.youtube.com/watch?v=gpf6J6XTtR4



Suppressed~

https://www.youtube.com/watch?v=QhUAskXPoYY

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cal50
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Re: Completed titanium .308 caliber build

Post by cal50 » Thu Jul 30, 2015 8:01 pm

djinni wrote:Definitely hard to tell with the phone video, but the delta looks promising. Also had a chance to try any subsonic ammo?


I will get a real camera and try is again and in open ground.
I never had any interest in .308 subs , its why I have one of these......


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Re: Completed titanium .308 caliber build

Post by ranb » Fri Jul 31, 2015 2:57 pm

Can you give any details on machining the inside of the baffles? How thick are the baffles? Thanks.

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Re: Completed titanium .308 caliber build

Post by cal50 » Fri Jul 31, 2015 5:54 pm

ranb wrote:Can you give any details on machining the inside of the baffles? How thick are the baffles? Thanks.

Ranb


Credit to whomever created / drew this up, I found it somewhere on this forum.
I simply modified the diameters to fit my tube and kept the angles the same.

I did keep a heavier wall thickness and planned ( now ) on maybe tweaking it to drop some weight , increase internal volume.
It will be a minimal amount but I am more focused on tweaking the end cap with a radius mini cone inside.

I mentioned above how I clipped the baffles. All of them except the blast baffle.


Drawing I used as a base line~

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Re: Completed titanium .308 caliber build

Post by ranb » Fri Jul 31, 2015 6:04 pm

Have a photo of the cutting bit you used? I'm finding that it is hardest to machine the inside of a cone baffle that is less than half an inch wide.

Ranb
SilencerTalk was a place I could disccuss making registered silencers without being told I was a criminal. That is no longer true. http://www.silencertalk.com/forum/viewtopic.php?f=132&t=99273

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Re: Completed titanium .308 caliber build

Post by cal50 » Sat Aug 01, 2015 1:24 pm

ranb wrote:Have a photo of the cutting bit you used? I'm finding that it is hardest to machine the inside of a cone baffle that is less than half an inch wide.

Ranb

Criterion ABT-250A / solid carbide boring bar

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Re: Completed titanium .308 caliber build

Post by L1A1Rocker » Sat Aug 01, 2015 5:52 pm

cal50 wrote:
ranb wrote:Have a photo of the cutting bit you used? I'm finding that it is hardest to machine the inside of a cone baffle that is less than half an inch wide.

Ranb

Criterion ABT-250A / solid carbide boring bar

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The flat that's ground into the bar, is that sufficient to keep the bar from twisting? I ask because I've run into this problem with boring bars twisting in the holder when turning titanium. I've been thinking of possible solutions before I continue my Form 1 Titanium build.

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cal50
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Re: Completed titanium .308 caliber build

Post by cal50 » Sat Aug 01, 2015 7:19 pm

I have been using these boring bars for over 25 years and I have never had any twist using their carbide bars or steel bars. Carbide will crack / break and never twist. HSS bars can bend but I have never twisted one.
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Re: Completed titanium .308 caliber build

Post by saigatechusa » Wed Aug 05, 2015 12:16 pm

I'm sure he meant slipping in tool holder

carbide tipped are plenty strong and much cheaper

http://www.mcmaster.com/#boring-bars/=yd4vvn

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Re: Completed titanium .308 caliber build

Post by L1A1Rocker » Wed Aug 05, 2015 1:31 pm

saigatechusa wrote:I'm sure he meant slipping in tool holder

carbide tipped are plenty strong and much cheaper

http://www.mcmaster.com/#boring-bars/=yd4vvn
Correct

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Re: Completed titanium .308 caliber build

Post by cal50 » Wed Aug 05, 2015 3:49 pm

My bad.
No, I have never had one slide in a tool holder or boring head.
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Re: Completed titanium .308 caliber build

Post by yondering » Wed Aug 05, 2015 8:11 pm

cal50 wrote: Parallel machined spacer to mound against barrel shoulder~

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Instead of the spacer, you could just relieve a little bit of thread in your end cap, then you wouldn't have an extra piece to lose. It would only be a thread or two, and wouldn't affect mounting to anything else. The non-relieved thread seems to be pretty common on AR barrels these days.

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Re: Completed titanium .308 caliber build

Post by cal50 » Wed Aug 05, 2015 9:05 pm

yondering wrote:
cal50 wrote: Parallel machined spacer to mound against barrel shoulder~

Image
Instead of the spacer, you could just relieve a little bit of thread in your end cap, then you wouldn't have an extra piece to lose. It would only be a thread or two, and wouldn't affect mounting to anything else. The non-relieved thread seems to be pretty common on AR barrels these days.

I have a 5C soft collet I can bore to hold the spacer and face to length.

I want to see if the point of impact changes with the position of the baffles "clips". If so I can control the indexing of my can by the thickness of the spacer to tweak my POI. Besides I already have my end cap fully machined and I really do not want to touch it. The spacer stays on behind the FH when not in use.
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