Built two form 1 Silencers for our gun trust. All ATF approved, purchased and built after approval.
We have rattle in the tubes after a couple hundred shots. But my question is what would cause compression inside the tube, is it heat and cooling condensing and expansion? is it compression from the air and gas from firing, how does steel and titanium not hold up to that and compresses? How do commercial manufactures not have to worry about compression if they have a baffle design and not a monocore?
If one silencer is all titanium and the other is all steel with a titanium blast spacer where would we be losing tolerance? We ground the blast spacer just a tiny bit larger then the tube and press fit tight but now even at maximum tightness there is still rattle and something has compressed.
For design and metal notes- solventtrapdirect tubes D cell titanium and steel. We went direct thread- with a 2" blast chamber spacer and 3 baffles and an end cap. These are both 6" long.
One silencer- all titanium tube end caps and baffles and blast chamber.
Second silencer- all steel tube and end caps and steel baffles and titanium blast chamber spacer
I am all ears for design tips and if someone can answer about metallurgy and compression I am all for it.
Home built Form 1 rattle
Home built Form 1 rattle
Last edited by wallace91 on Mon May 13, 2019 2:05 pm, edited 1 time in total.
Re: Home built Form 1 rattle
Also a little more info- these are 5.56 cans with a internal Bullet diameter drilled for .28”. We started small and worked up to .28” to make sure the baffles and end cap are in line and centered.
- T-Rex
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Re: Home built Form 1 rattle
A couple Q's
1. Are you in the US?
-If so, STOP adding parts (and documenting it on the internet). This is in violation of federal law, regardless of how ridiculous, and we'd all hate to see something bad happen to you (from a legal standpoint).
2. Your parts are rattling in both directions?
3. How were your spacers cut (lengthwise)?
4. Your 5.56mm bore is only .280" in dia (letter "J" would be .281, for Ref.)?
-This would be a very tight bore. My 5.56mm bores are closer to .295-.302
1. Are you in the US?
-If so, STOP adding parts (and documenting it on the internet). This is in violation of federal law, regardless of how ridiculous, and we'd all hate to see something bad happen to you (from a legal standpoint).
2. Your parts are rattling in both directions?
3. How were your spacers cut (lengthwise)?
4. Your 5.56mm bore is only .280" in dia (letter "J" would be .281, for Ref.)?
-This would be a very tight bore. My 5.56mm bores are closer to .295-.302
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Re: Home built Form 1 rattle
I have no idea what you are talking about. Design is the same we submitted.
What would have been a better design choice? How do manufactures account for whatever is happening with the cans if they also have a baffle design?
Is it heat and cooling expansion? is it from the gas and pressure of firing causing the cans to rattle and compress?
What would have been a better design choice? How do manufactures account for whatever is happening with the cans if they also have a baffle design?
Is it heat and cooling expansion? is it from the gas and pressure of firing causing the cans to rattle and compress?
Last edited by wallace91 on Mon May 13, 2019 2:14 pm, edited 1 time in total.
Re: Home built Form 1 rattle
So should the bore have been bigger? A lot of research said that most commercial manufactures use a .281 bore for 5.56 that why went close to this. The drill bit used was 9/32nds works very well no baffle strikes, all in line.
We cut blast chamber spacer lengthwise and ground to fit for an over long fit and the rattle still happen. It is rattling up and down. it is now not long enough inside the tube to be press fit tight. it is not rattling side to side the tolerance is within spec there.
We cut blast chamber spacer lengthwise and ground to fit for an over long fit and the rattle still happen. It is rattling up and down. it is now not long enough inside the tube to be press fit tight. it is not rattling side to side the tolerance is within spec there.
Last edited by wallace91 on Mon May 13, 2019 2:26 pm, edited 1 time in total.
Re: Home built Form 1 rattle
Let's just say hypothetically, not that I am going to do it cans still work, how would someone fix a silencer if they are the manufacturer? Are you allowed to recut a spacer tube, do you have to submit design changes? Is it a whole new tax stamp? If the spacer tube was in the design before is that considered altering it?
Very new to all this and am treading the thin line.
Very new to all this and am treading the thin line.
- T-Rex
- Silent But Deadly
- Posts: 1865
- Joined: Wed Oct 29, 2014 3:38 pm
- Location: CT - The AntiConstitution State
Re: Home built Form 1 rattle
Your added edits, while I was typing.wallace91 wrote: I have no idea what you are talking about. Design is the same we submitted.
Regardless, it is unlawful to create new silencer parts (as simple as adding a washer to an already complete asembly) w/o another approved tax stamp. These are not my rules or interpretations.
What would have been a better design choice? How do manufactures account for whatever is happening with the cans if they also have a baffle design?
The vast majority of Mfr's do not use an end cap with a shoulder. This negates all the issues you're having.
Is it heat and cooling expansion? is it from the gas and pressure of firing causing the cans to rattle and compress?
If you heat a metal and return it to it's original temperature, there will/should be no difference in length. How much length, to the internal stack, have you lost?
So should the bore have been bigger? A lot of research said that most commercial manufactures use a .281 bore for 5.56 that why went close to this.
Regardless of what Mfr's do, .057 is on the smaller side of diametrical clearance. Form 1 makers should stick to >.08in.
We cut blast chamber spacer lengthwise and ground to fit for an over long fit and the rattle still happen. It is rattling up and down. it is now not long enough inside the tube to be press fit tight. it is not rattling side to side the tolerance is within spec there.
You never answered me as to how you cut the spacers.
Badsaw, Hacksaw, Cutoff Wheel, Lathe, Mill, etc
wallace91 wrote: Let's just say hypothetically, not that I am going to do it cans still work, how would someone fix a silencer if they are the manufacturer?
A form 1 does NOT make you a Manufacturer. You are a Maker. HUGE difference. You are not on the same playing field as someone who's licensed.
Are you allowed to recut a spacer tube, do you have to submit design changes?
You can cut a spacer, but you can NOT make a new one. As stupid as it may be, a new spacer would be a new silencer and require another tax stamp.
Is it a whole new tax stamp?
Yes.
If the spacer tube was in the design before is that considered altering it?
Not sure I 100% understand the question.
Very new to all this and am treading the thin line.
You may have stepped over it
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Re: Home built Form 1 rattle
You can legally remove material from the suppressor. Options are to cut the tube slightly shorter or remove some of the shoulder on the endcap(s).
On your next builds, leave the spacer .020"+ longer and keep checking the tightness of the cap over time. If the spacers are not cut with a square end, they'll compress what thin material is hanging on a lot.
I don't see anything wrong with your .280" bore. I'd probably went bigger being on an AR-15 for less blow back. At least on the first couple of cones.
On your next builds, leave the spacer .020"+ longer and keep checking the tightness of the cap over time. If the spacers are not cut with a square end, they'll compress what thin material is hanging on a lot.
I don't see anything wrong with your .280" bore. I'd probably went bigger being on an AR-15 for less blow back. At least on the first couple of cones.
Re: Home built Form 1 rattle
We did not add anything. I am asking about this for future reference. We have more stamps in the works. So what I can learn about design I am trying to do.
We cut with a hacksaw and ground down to size with a grinder.
We cut with a hacksaw and ground down to size with a grinder.
Re: Home built Form 1 rattle
So you don't believe the baffles have shrank from heating and cooling its just the spacer?
- T-Rex
- Silent But Deadly
- Posts: 1865
- Joined: Wed Oct 29, 2014 3:38 pm
- Location: CT - The AntiConstitution State
Re: Home built Form 1 rattle
Metal doesn't change dimensions, once returned to original temp (albeit a microscopic amount from heat treat). What you're seeing is what #40 is describing. Your cuts arent absolutely square and the metal is ever slightly working itself right. Compound this through the stack and you'll lose enough material to notice.
This is one reason I stopped putting a shoulder on my end caps.
This is one reason I stopped putting a shoulder on my end caps.
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Re: Home built Form 1 rattle
How would you take the shoulders off of an end cap? Can it be done without a lathe? Would you have to put in a place for a tool to tighten it down? Like two holes for a wrench with two pegs?
Re: Home built Form 1 rattle
You can remove the shoulder with a grinder. Might not look pretty, but will get the job done.
If you don't have a way to hold onto the EC you can use the thread adapter to make the stack tight. With the adapter loose, screw the modified EC in until where you think it needs to be, tighten the adapter.
If you don't have a way to hold onto the EC you can use the thread adapter to make the stack tight. With the adapter loose, screw the modified EC in until where you think it needs to be, tighten the adapter.