First Form 1 Build 6.5 CM

Yes, it can be legal to make a silencer. For everything Form-1, from silencer designs that are easily made, to filing forms with the BATF, to 3D modeling. Remember, you must have an approved BATF Form-1 to make a silencer. All NFA laws apply.

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fulldraw 11
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First Form 1 Build 6.5 CM

Post by fulldraw 11 » Thu Jun 11, 2020 2:09 pm

OK, building my first form 1 for my 6.5 Creedmoor. I am using all size D titanium parts from SD Tactical. My question is, what is the minimum safe sized hole for my baffles/end cap? I have access to a fabrication shop and they said they can precision cut/tap anything. Obviously, I want it is tight as possible (this can will never go on anything but my 6.5 CM) but don't want baffle strikes etc. Is there a definitive safe ID over caliber size? Any help is sooooo much appreciated.

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CMV
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Re: First Form 1 Build 6.5 CM

Post by CMV » Mon Jun 22, 2020 7:43 pm

I'd do a P or 21/64 size. .060" over. That's just me, some would go tighter. There is very little gain going as tight as possible on bore size all else equal and 6.5CM is still going to be loud. I've never seen published subsonic load data for it but if you were planning to work down a light trailboss load with 150ish gr pills that would be even more reason to go with a larger, not tighter bore because no idea how well that stabilizes....
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fulldraw 11
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Re: First Form 1 Build 6.5 CM

Post by fulldraw 11 » Wed Jun 24, 2020 4:50 pm

Thank you for the insights. I found some info saying that .040 over is tightest you want to go, but if there isn't much advantage to 'as tight as possible' and it will stabilize better at .060 over, than accuracy always reigns supreme when comparing trade-offs. I will likely shoot SOME subsonics now that they are becoming commercially available, but will shoot 99% 140 grain Nosler, both range and out hunting. Not looking for 'hollywood' quiet, just something I can shoot in the woods without muffs (so I can actually hear the animals roaming about) and not bleed from my ears. Thanks again!

Mousehouse
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Re: First Form 1 Build 6.5 CM

Post by Mousehouse » Thu Jun 25, 2020 8:23 pm

The last one I built was .320. The one I am building now will be about the same. Using a bigger tube this time (1.625” OD)

The first one i built was a 1.5” OD, 8.8 inches long. It works but want to see if there is any difference.

748
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Re: First Form 1 Build 6.5 CM

Post by 748 » Sun Jun 28, 2020 6:37 am

How long are you going to go on that size D tube?
So much has changed since my last form 1

fulldraw 11
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Re: First Form 1 Build 6.5 CM

Post by fulldraw 11 » Wed Jul 08, 2020 12:42 pm

It's a 10 inch can, but I think it actually measures out to 9.8 inches or something close to that.

748
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Re: First Form 1 Build 6.5 CM

Post by 748 » Sat Jul 11, 2020 6:08 pm

Let us know how it goes.
If I make a 6.5cm silencer I will use size D for sure, don't know if I would go with a 10 or a 12.
So much has changed since my last form 1

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