To reduce the liklyhood of a baffle strike typical rule of thumb is to go .040 over bore your caliber if your sure of your runout and .060 if your not sure so a 45 cal would have a .49- .51 through hole a .308 cal would be .348-.368 through hole.
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To reduce the liklyhood of a baffle strike typical rule of thumb is to go .040 over bore your caliber if your sure of your runout and .060 if your not sure so a 45 cal would have a .49- .51 through hole a .308 cal would be .348-.368 through hole.
Understanding the size of the can:
If you shoot a 22 CCI CB short through a 24" non semi 22 rifle, pointed at a soft target, it will sound like a BB gun.
This is because gas escapement from behind the bullet is less than one atmosphere above ambient, the threshold of supersonic gas escapement.
A rule of thumb is 1 gr of powder for every cubic inch of bore plus chamber volume.
The CCI CB short has 0.45 gr of powder.
The same amount of powder in a LR cartridge would make the same noise, but have lower velocity due to lower expansion ratio, peak pressure, and efficiency.
bumping this one back up.
So before Obama's BATFE boys mess up the Form 1 for Trust or Corp application - I'm putting in for another can. Gosh, they are addicting.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Tempted to make a 22 also. Got my first, a Octane 45 out of jail recently and it works well with 22 even though it is more a 9mm and 45. Btw, they may classify as a multi caliber for sales purpose, you (I) had to classify to the largest caliber that I would use, (45) on my form 4........ Per dealer who should know.
It's like you say - Form 1 efile had choices but not Multi - I'm going to make a 45 cal. And I'll probably make it shorter than the 12" I put on it. After I get approval and make it I'll have to send in addendum to let 'em know how long it turns out. I'll probably go the SDTA route with a premade solvent trap and then add baffles and modify as it's pretty cheap that way. And I'll have to decide which rifles to thread next - might do my
Marlin 45-70 and 44 Mag lever guns as the Rossi 357 turned out so fun.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Got 4 I built. Waiting on 5 more approvals.
My Straight shooter thread
http://castboolits.gunloads.com/show...traightshooter
One of the few benefits of living in the UK is that sound moderators are relatively easy to obtain. If I have a sub 12 ft/lb rifle which doesn't require a firearms licence (yet!) then I can buy .22 sound moderators without a problem. Several very good ones on the market for £35-£60 (about $50-$90?). One of the oddities is that many of the same air rifle moderators work fine on .22 rimfires. I have about half a dozen laying around the house at present.
Yes, in the US to have a sound modulator on any air rifle (non-firearm) it has to be permanently attached to the barrel. Funny thing is I think with right ammo and firearm/suppressor it's actually quieter than the suppressed air rifles I have heard. You want really Quiet go bow and arrow.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Just to nitpick, I do not believe that being permanently attached is the only way to legally suppress an air gun in the US. I think the general guidance is that it must not be able to be readily affixed to a firearm.Originally Posted by Artful
My suppressed air gun is louder than my suppressed .22. I attribute this to not cutting off the airflow from the tank quickly enough and to not having the benefit of cooling to reduce gas volume.
And if you want to go the trust route you should apply now. Sometime in July 2016 you will not be able to submit a Form 1 on a Trust.
I submitted 2 Form 1s recently and am now playing the waiting game. Last update on wait times I read is 5 months. you are ok to submit it on a trust up to then.
I am going to purchase a Solvent Trap Adapter from SDTA and convert this after I get my stamps.
I wouldn't want to try that defense in court
- If it is removable it can be mated to a firearm.
The BATFE has prosecuted people in possession of European sound modulator's without any firearm (or air gun) being present. And the device's construction was probably only good for 1 shot then it would have come apart if used on a firearm. (Plastic and Felt construction)
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
That's a good way to go - you going to use freeze plug's or cone's?
And going to use Aluminum, Steel or Titanium?
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
I don't want to get into an argument about it, but by the same logic there is no such thing as "permanently attached" and any piece of tubing could be an unregistered suppressor, and any handful of washers could be the same. So, we each must decide if we will cower in fear of a government agency that has greatly overreached in rule making, but that has prosecuted almost no cases where there was not clear intent to violate the law.
I wouldn't make this decision for anyone else, but when each of you decide how you will comply with the law please consider that the overwhelming proportion of people that discuss NFA items on the Internet are hyper-conservative. This is perhaps a natural result of BATF being intentionally unpredictable at times combined with potentially high penalties, but I think it worth opposing what boils down to fear of our own government.
Artful, I don't know you and the above rant is not directed at you specifically, you just happened to have hit on a pet peeve of mine on a day that I'm laid up with a back injury.
Here in the UK you can have a silencer for low powered airguns without restrictions but can’t put it on a real firearm. I have several- I just bought a SAK last week for £40 ($60) and got a couple of parket hale silencers last month for £20 ($30) second hand J. Silencers for firearms are a lot more hassle as they need has to be justified to the police before purchase. I asked and they said not for target shooting. (It is swings and roundabouts – we get cheap silencers for airguns but no powder burners without jumping through hoops).
I’ve made a reflex design for my spring air rifle that is quieter than the mechanical internals of the gun (I can’t hear any muzzle blast). This was based on a cheap 240mm long silencer body.
If you have a pneumatic air rifle then the energy absorbing materials/baffles that are in many firearm silencers will warm up the air (that will have got very cold as it expands down the barrel). This will increase the air’s energy and so noise of the exiting air. This doesn’t happen with spring and gas ram airguns as the air starts out cold, is compressed and heated in the cylinder. It is still hot and under pressure as it exits the barrel.
I’m sad enough to have done a lot of air flow and sound modelling on silencers. It is pretty easy to get an estimate of noise levels if you know the exit pressure (quickload) and density (powder charge/barrel volume) of the muzzle blast. The results are pretty close to book values for firearms based on the limited pressure data I have.
I would enjoy seeing your design.
I agree that for a pneumatic air rifle the gas is cold coming down the barrel, and is heated somewhat by the barrel and any suppressor material. As far as I know this is dealt with by planning for the larger volume of gas created, unfortunately requiring a larger can. iIs there another approach? I have a suppressed airforce talon and am no yet happy with the level of suppression, so looking for ideas.
Go to silencertalk.com. There is a wealth of information there and a lot of knowledgeable people.
JimB.., sorry to hear about your back - I'm also an ache and pain away from being a grouch - damn arthritis etc. - All the failed fun times of your youth come back to haunt you. Any way, here's a link or two for you to ponder as you wait for the pain med's to kick in.
https://www.atf.gov/firearms/docs/20...l-gun/download
http://www.beemans.net/silencers_on_airguns.htm
http://www.pyramydair.com/blog/2006/...encer-illegal/
http://www.ar15.com/archive/topic.html?b=1&f=5&t=479815
http://www.newsobserver.com/news/cri...y/1300054.html
http://www.rimfirecentral.com/forums/showthread.php?t=135054
http://www.airgunone.com/forums/arch...hp/t-7833.html
Feel better soon - and advice Doc gave about my back is strengthen my abdominal's and
I should loose weight - the toughest medicine to swallow.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Artful, thanks for understanding, and for the suggested reading, sorry that you met me at a bad time.
Jim
Artful, I am thinking the suppressor for my 7 RM is going to be titanium, and the other steel, both with freeze plugs.
On the SDTA forum a member just got his stamp he applied for at the end of January. Looks like it is going to be a long wait so I'll purchase the solvent traps and get the guns I want to use these on threaded and use them as solvent and patch traps.
I have 7 guns already threaded with muzzle brakes on them already with 4 different threads. I may purchase extra end caps versus adapters, or get some with larger threads rethreaded to a smaller size.
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