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Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Wed Sep 03, 2014 6:46 pm
by calinb
I'm designing an all-Ti can for a 243 bolt action hunting rifle (supersonic loads) using 60 degree cones. From what I've learned here, it doesn't take very many baffles to adequately get this job done, using a long blast chamber and perhaps tightening-up the spacing of the cones toward "business end" of the silencer. On the other hand, I'm wondering whether I should use more than three or four baffles and reduce the blast chamber length (maybe use 8 or 9 cones in my 8-1/2" long tube. Oh--I'm not planning to risk an accuracy degradaton by clipping the cones.

If I end up occasionally using the can on a .22 LR, woudn't decreasing the length of the blast chamber and increasing the number of cones improve its noise attenuation for that application? How about occasional use on a 223 Remington?

Other than weight, materials cost, and fabrication time, is there a downside to the increased number of cones when using the can for its primary purpose (243 WSSM hunting rifle)? This rifle is a dual-purpose varminter/goat gun (antelope). I'm still trying to understand all the trade-offs.

Thank you for any advice, Silencertalk Gurus!

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Wed Sep 03, 2014 7:41 pm
by MCKNBRD
Bottom line: more baffles work the gas better. Clipped baffles work the gas best.

If max suppression is the goal, stuff as many baffles as possible in that tube. Clip them symmetrically, and adjust the zero as needed on your rifle.

If you're going to use it on the .243WSSM, I'd venture to guess you need to look at .30 cal designs and copy them. I'd also HIGHLY recommend that you don't get your hopes up. The WSSM family are blowtorches and you're going to have a handfull with getting the can to work well.

I'd consider looking at tons of pics and bridging the gap between 5.56 and .30cal cans, and seriously consider using some kind of muzzle brake in the can to act as a sacrificial baffle.

Byrdman

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Wed Sep 03, 2014 10:02 pm
by calinb
MCKNBRD wrote: If max suppression is the goal, stuff as many baffles as possible in that tube. Clip them symmetrically, and adjust the zero as needed on your rifle.
Thanks, MCKNBRD! By symmetric, are you recommending to just make sure the the "U" on each cone is symmetrically cut on that cone? Obviously, having only a single clipped "U," the cone isn't symmetric in the opposite direction. Does the position of the cones (orientation of their "U"s within the tube) even matter or should the "U"s alternate by 180 degrees or all be in a line or something like that when inserting them into the tube?
MCKNBRD wrote:If you're going to use it on the .243WSSM, I'd venture to guess you need to look at .30 cal designs and copy them. I'd also HIGHLY recommend that you don't get your hopes up. The WSSM family are blowtorches and you're going to have a handfull with getting the can to work well.
Yeah--I'm looking at 30 cal. designs (.308 Win/7.62 NATO). At least the 243 WSSM is a relatively small bore blow torch! :shock: I also mostly use it as a goat gun (100gr. bullets at 3150 fps) rather than a 4000 fps+ 55gr. long range prairie dog detonator! Maybe, as a big game hunting rifle, I can reasonable expect decent results. Still, it's interesting to note that a plain base 100 gr. WSSM load has a trjectory that's identical to a plain base 50 gr. 223 Remington load out to 400 yards or so. (After 400 yards, the WSSM is flatter). It does take a little extra "fire" to do that.
MCKNBRD wrote:I'd consider looking at tons of pics and bridging the gap between 5.56 and .30cal cans, and seriously consider using some kind of muzzle brake in the can to act as a sacrificial baffle.
Great advice and information! I have plenty of 17-4 steel to add a muzzle brake.

USRAC even recognized the wear and tear problem when they introduced the now orphaned WSSM and hedged their bet by producing all WSSMs with chrome lined barrels. They didn't market the feature much but I do recall a Winchester brochure that claimed the chrome lining increased WSSM barrel life from roughly 2000 rounds to 4000 rounds. Widespread USRAC hatred notwithstanding, the Winchester and Browning chrome barreled WSSMs are some of few chrome barrels from any factory that can be expected to generally shoot well!

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 10:15 am
by Capt. Link.
calinb wrote: Oh--I'm not planning to risk an accuracy degradaton by clipping the cones.
This is a myth.
Clipping and porting work the gases long after the bullet has left and dose not negatively effect accuracy.
A large volume suppressor with a long blast chamber will ease gas cutting in this caliber.

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 10:35 am
by MCKNBRD
calinb wrote:
MCKNBRD wrote: If max suppression is the goal, stuff as many baffles as possible in that tube. Clip them symmetrically, and adjust the zero as needed on your rifle.
Thanks, MCKNBRD! By symmetric, are you recommending to just make sure the the "U" on each cone is symmetrically cut on that cone? Obviously, having only a single clipped "U," the cone isn't symmetric in the opposite direction. Does the position of the cones (orientation of their "U"s within the tube) even matter or should the "U"s alternate by 180 degrees or all be in a line or something like that when inserting them into the tube
Make a jig to hold your cones after they're turned; set a ball mill at a given height, and make the same cut in all of them. My version of 'symmetrical' is that all the notches/clips/cuts are oriented the same when they're welded up.

Once again, look at what is out there by the big names...they have the money to research and experiment, we don't. There is a reason they do what they do...

Byrdman

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 2:16 pm
by calinb
Capt. Link. wrote:
calinb wrote: Oh--I'm not planning to risk an accuracy degradaton by clipping the cones.
This is a myth.
Good to hear it's a myth. Thanks!

I just read some claims here and kept thinking about how the condition of a barrel crown is generally regarded as important to accuracy and thought I'd forgo the clipping, but then I also recall an experiment where a guy who deliberately damaged the crown of a rifle in stages and measured the effect on the point of impact. The bottom line was it took a lot of damage to make a significant difference and, even then, the effect (POI shift) was consistent and he could just zero it out on his scope. So maybe the importance of barrel crown condition is a myth too--or at least overrated.

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 2:23 pm
by calinb
MCKNBRD wrote:Make a jig to hold your cones after they're turned; set a ball mill at a given height, and make the same cut in all of them. My version of 'symmetrical' is that all the notches/clips/cuts are oriented the same when they're welded up.

Once again, look at what is out there by the big names...they have the money to research and experiment, we don't. There is a reason they do what they do...
Byrdman
Yup--I've seen all this stuff on the big name cans. Thanks for helping me to figure out how to do it. Welding all the baffles is a bit much for me and I'll need help with any welding, but I can press them into the tube with a floor press. I can probably keep them well-alligned, if I cut them with a jig and also align them with a jig when starting them into the tube. Then I can press-in the endcaps and get the help I need welding them.

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 2:29 pm
by dex
What barrel length and what wall thickness on the tube do you intend to use? What grade material?

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 4:07 pm
by calinb
dex wrote:What barrel length and what wall thickness on the tube do you intend to use? What grade material?
My current 243 WSSM bolt action has a 22" barrel length, but I also have an AR-15 WSSM with a 22" barrel and a Krieger 243 AR barrel ready to chamber (28" light Palma). I'm planning to use the can primarily on the 22" bolt gun but I might end up threading the Krieger's muzzle someday too. Hard to say now.

I have a 0.054"/1.5" grade 9 Ti tube but I'll probably turn a thou from the OD. The grade 5 baffles, spacers, and end caps will be a press-fit into the tube and the end caps welded. I'm planning to "integrate" the spacers into the cones, like Dr.K did, as much as possible. I'm planning on 0.63 walls for the spacers and cones.

Based on the input here, I'm now thinking that I'll make a muzzle brake from my 17-4 PH SS bar. Given that the brake diverts much of the blast to the walls (the blast chamber spacer), I don't know if longevity would significantly benefit by making the first baffle from 17-4 PH too.

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 4:49 pm
by Capt. Link.
calinb wrote:
I just read some claims here and kept thinking about how the condition of a barrel crown is generally regarded as important to accuracy and thought I'd forgo the clipping, but then I also recall an experiment where a guy who deliberately damaged the crown of a rifle in stages and measured the effect on the point of impact. The bottom line was it took a lot of damage to make a significant difference and, even then, the effect (POI shift) was consistent and he could just zero it out on his scope. So maybe the importance of barrel crown condition is a myth too--or at least overrated.
The barrel crown has a major impact on accuracy and point of aim.
Poorly run experimentation by unqualified ballistic technicians lead to more myths.
If you don't deal with the high pressures and gas cutting issues related to the 243 wssm your work will be temporary.Try inconel for the first 3 baffles along with a brake and a long chamber.

Re: Multi duty can (243 WSSM can on a 22 cal.)?

Posted: Thu Sep 04, 2014 4:59 pm
by calinb
Capt. Link. wrote:
calinb wrote: If you don't deal with the high pressures and gas cutting issues related to the 243 wssm your work will be temporary.Try inconel for the first 3 baffles along with a brake and a long chamber.
Inconel? Yikes! :cry: I remember Dr.K relating its challenges. I've machined some test pieces of the Ti and it's no sweat but inconel sounds like a PITA!