Next Form1 for a 7mm REM Mag

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kbillet
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Next Form1 for a 7mm REM Mag

Post by kbillet » Sun Apr 03, 2016 8:55 pm

Next Form1 build is for my sons 7mm Rem Mag. Gun is used for hunting. Bolt action so no high volume dumps. It’s a fluted pencil barrel so I’m trying to keep the weight down. I am attaching a concept for review and comments. Barrel was threaded 1/2-28 for a brake. The approved Form1 list the length as 9 inches. I might go shorter to save weight. Maintaining accuracy is important. Weight second. Suppression third in importance. The Mount, Blast Tube and first Baffle are to be 17-4 Stainless, everything else is Titanium. The slots in the spacers are machined off center to create a spin in the flow. At least that's the idea. The below picture shows everything except the tube. As shown is 1.5 inches by 9. Spacing on the cones is .600. Cones are 53.7 degrees. The intent is for the suppressor to go over the barrel 1 inch behind the thread area to save length. Contact area on the barrel is .610 diameter.
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curtistactical
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Re: Next Form1 for a 7mm REM Mag

Post by curtistactical » Mon Apr 04, 2016 6:43 pm

I only see two things I would change. Even with the blast chamber around the brake I would remove two baffles and enlarge the blast chamber. On magnum rounds a large blast chamber really helps, it is opposite of what you would do for sub sonic or rim fire suppressors. The second thing I would change is the large ports leading to the coaxial chambers, just drill two 1/8" holes toward the rear of the spacers and get rid of the large ports. This will allow plenty of gas into the coaxial chamber and will do a better job of trapping it. Leave the first two baffles unclipped then alternate clips 180 degrees apart after that. With these few changes you should have a nice sounding accurate suppressor.
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fishman
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Re: Next Form1 for a 7mm REM Mag

Post by fishman » Mon Apr 04, 2016 7:25 pm

if you want to save A LOT of money, instead of making each baffle and spacer one piece, make it two pieces. this will cut the amount of titanium round bar needed to make the baffles in half, then make the spacers from 1" grade 9 titanium tubing which is far cheaper per inch than 1.5" titanium bar.

roughly 6" of 1.5" titanium bar and 8" of 1" tubing will cost much less than the roughly 12" of titanium bar needed for the baffle stack as designed
Last edited by fishman on Tue Apr 05, 2016 11:29 am, edited 1 time in total.
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293

5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647

kbillet
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Re: Next Form1 for a 7mm REM Mag

Post by kbillet » Mon Apr 04, 2016 8:41 pm

Thanks Joe and fishman. In the next day or two I will redraw with suggested changes. I would still like to shorten. Going from 9 to 7 baffles, would it hurt to go to .45 spacing rather then the .600 shown?

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curtistactical
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Re: Next Form1 for a 7mm REM Mag

Post by curtistactical » Mon Apr 04, 2016 9:13 pm

kbillet wrote:Thanks Joe and fishman. In the next day or two I will redraw with suggested changes. I would still like to shorten. Going from 9 to 7 baffles, would it hurt to go to .45 spacing rather then the .600 shown?
.45" spacing should be fine.
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Re: Next Form1 for a 7mm REM Mag

Post by Samson1044 » Tue Apr 05, 2016 10:52 am

Would the Omega style baffles offer that much more over just a full diameter cone??

After playing with a Sig suppressor for a little bit I was impressed with how well it worked with such tight cone spacing especially on hot MK-248 ammo

Sig is in the middle
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gunny50
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Re: Next Form1 for a 7mm REM Mag

Post by gunny50 » Tue Apr 05, 2016 1:37 pm

"Samson1044"

Sig is also bigger in Diameter so more volume.
The volume between each baffle might be even more than a 1.5" can has with larger spacing.

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Re: Next Form1 for a 7mm REM Mag

Post by T-Rex » Tue Apr 05, 2016 1:45 pm

I would like to see a cutaway of their Steel suppressor of same model designation. The shown pic is of the Ti version, I believe.
It has a smaller OD and is almost 1.5" shorter.
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kbillet
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Re: Next Form1 for a 7mm REM Mag

Post by kbillet » Tue Apr 05, 2016 9:09 pm

Image
Made the recommended changes. Eliminated two baffles, clipped the 3rd, 4th, 5th and 6th baffle alternately. 1/8 inch holes drilled to create swirl. Spacers are .425 making the spacing .475. Thanks again for the help and direction.

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curtistactical
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Re: Next Form1 for a 7mm REM Mag

Post by curtistactical » Tue Apr 05, 2016 9:42 pm

That looks good, I think you will be happy with this design.
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Re: Next Form1 for a 7mm REM Mag

Post by fishman » Tue Apr 05, 2016 10:02 pm

would clipping the cones off center, similarly to how the ports are drilled off center, create even more swirl and be beneficial?
im not recommending this, just thinking out loud
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293

5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647

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Re: Next Form1 for a 7mm REM Mag

Post by fishman » Tue Apr 05, 2016 10:14 pm

if it were me, and i were trying to keep weight light, i would thin up the front endcap a lot and ditch the multi channel design.
i have no idea how much that effects suppression or tone, but i do know that making the endcap thinner will make it lighter all the way at the front, where it matters most.

thats just what i would do. i wouldnt think that keeping the current design is a bad idea, do whatever you want.
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293

5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647

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Re: Next Form1 for a 7mm REM Mag

Post by gunny50 » Wed Apr 06, 2016 2:54 am

fishman wrote:if it were me, and i were trying to keep weight light, i would thin up the front endcap a lot and ditch the multi channel design.
i have no idea how much that effects suppression or tone, but i do know that making the endcap thinner will make it lighter all the way at the front, where it matters most.

thats just what i would do. i wouldnt think that keeping the current design is a bad idea, do whatever you want.

Making it out of Ti or 7075 will NOT ad much weight.
And as He made one with that cap design before its not that much extra work once you know how to.

Gunny

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