Correct Suppressor Clearance

[chap660]

I am new to suppressors and this forum, so I would imagine this question has come up before. I submitted my tax stamp app in April and hopefully will get it soon. My first build will be fairly basic for .243 Win, using 34.3 mm freeze plugs as baffles. QUESTION: Is there a standard or optimum over-drill/clearance for the baffle passage? The clearance or gap between the bullet and the passage or tunnel it travels through? I have been advised that a good standard would be .026 mm gap or over-drill from the actual bullet size = a .269 passage for the .243. I have found two bits that are very close: a letter "I" bit at .2720 giving .029 clearance - or - a "H" bit at .2660 giving .023 clearance.

If this project works well, I plan a later, longer, over-barrel .308 suppressor using a 8,5 metric bit at .3346, giving .0266 clearance.

This is of course a pretty critical part of the build, soooo --- Am I stumbling down the right path here ??

[joe0121]

.060 is generally recommended. For example on my .308 can that would be a bore diameter of 368. since a reamer of that size would have to be custom made I got a .375 reamer. You could also possibly find a metric reamer close to the bore diameter you want. Or you could use a boring bar to machine to the diameter your want.

[Scared_of_zombies]

I am new to suppressors and this forum, so I would imagine this question has come up before. I submitted my tax stamp app in April and hopefully will get it soon. My first build will be fairly basic for .243 Win, using 34.3 mm freeze plugs as baffles. QUESTION: Is there a standard or optimum over-drill/clearance for the baffle passage? The clearance or gap between the bullet and the passage or tunnel it travels through? I have been advised that a good standard would be .026 mm gap or over-drill from the actual bullet size = a .269 passage for the .243. I have found two bits that are very close: a letter "I" bit at .2720 giving .029 clearance - or - a "H" bit at .2660 giving .023 clearance.

If this project works well, I plan a later, longer, over-barrel .308 suppressor using a 8,5 metric bit at .3346, giving .0266 clearance.

This is of course a pretty critical part of the build, soooo --- Am I stumbling down the right path here ??

Do you have a lathe? or at least access to one?

[chap660]

No --- Drill Press only. Would have to go to my gunsmith for that, and that wouldn't be cheap. Decided I would try this initially on my own.

[Scared_of_zombies]

No --- Drill Press only. Would have to go to my gunsmith for that, and that wouldn't be cheap. Decided I would try this initially on my own.

It can be done, but give that bullet an extra wide berth.

[chap660]

--- and that would be the .060 over = .303 for the .243?? Do have a cross-feed vise mounted with a jig, so that should help with accuracy. Thanks for the advice!

[Capt. Link.]

The overbore of .060 is for lathe turned products.You may need to go well over that if a drill press is used and the end-cap is tapped.While professional work is expensive the end results will justify the cost.I imagine a machinist of some sort is available locally at lower cost or you may have a site member close to you that will assist.Where do you live?

[chap660]

Have access to a very good gunsmith, Triple-Rivers, here in the Warsaw, Mo. area. Have not consulted him yet on this project, as I am sure there will be several more months before I receive my stamp and can even begin. I plan to have him thread my barrel, and it sounds like it would be a good idea to see if he can check the finished product for true on the lathe.

Question: Recognizing the dangers of baffle-strike, is it not true that the closer the clearance or gap between bullet and passage, the more the suppression? I am seeing that common clearance for a .22 suppressor is .026, yielding an optimum passage of 1/4" or .25. This is a gap of approx 12% over bullet size. Is there a universally recognized formula or reference that is used to calculate the optimum passage measurement?

[Bendersquint]

Is there a universally recognized formula or reference that is used to calculate the optimum passage measurement?

No, there is no recognized formula, its different for every company on how they come up with their bore diameter.

[Capt. Link.]

Question: Recognizing the dangers of baffle-strike, is it not true that the closer the clearance or gap between bullet and passage, the more the suppression? I am seeing that common clearance for a .22 suppressor is .026, yielding an optimum passage of 1/4" or .25. This is a gap of approx 12% over bullet size. Is there a universally recognized formula or reference that is used to calculate the optimum passage measurement?

Feel free to make the baffles as tight as you like, accuracy will suffer along with baffle damage and possible destruction of the tube.Baffle clearance is more than just bullet clearance.If made to tight its the same as a bullet hitting a baffle.You have been given good information its your choice to use it.

[chap660]

I was pretty much aware of all that before I asked the question --- that is the reason that I asked the question -- but thanks anyway Dad. I do plan to use the information that I get here, to make that choice. I certainly appreciate the response. I thought I would hold out for a few more definitive answers --- Thanks to you joe121 for your info.

[daviscustom]

chap660, you are awfully quick to dismiss one of the guys on this forum who is most likely to tell it like it is and be willing to help you out with information.

You are likely going to be looking at a pretty hefty chunk of change to get the guys in Warsaw to help you out with your project, if he will do it at all. Maybe you should talk to the guy in Lincoln......he's easy to get along with.

Doing your machine work on a drill press will be a trial and error process, but if you can learn from your mistakes and always check things out looking down the bore....hopefully you won't tear anything up.

[kingjamez]

I was pretty much aware of all that before I asked the question --- that is the reason that I asked the question -- but thanks anyway Dad. I do plan to use the information that I get here, to make that choice. I certainly appreciate the response. I thought I would hold out for a few more definitive answers --- Thanks to you joe121 for your info.

You want to build a rifle suppressor with freeze plugs and a drill press and then mouth off to an experienced builder about a subject that you admit to being new to?

Capt. Link. is remarkably patient and answers folks who I wouldn't give the time of day, be appreciative.

-Jim

[chap660]

What did I just say ???!! I came for info, not a lecture!! Not all of us can afford the $500 ++ to purchase a suppressor, but would still like to explore the hearing and recoil benefits of one. Not to mention the challenge of doing something yourself instead of just buying. I am not a youngster by any means -- am a Marine Corps veteran, discharged in 1964, and have been a shooter most of my life. I am just new to this suppressor thing. When you get to be my age, and don't want to give up a favorite a hobby, you look into every edge you can get. I would imagine that I have a few years on most here, so I don't need to be treated like a child. Experience does not give you license to "talk down" to anyone!

Just looking for a little help here --- thought that was the purpose of this forum. I appreciate those that have offered that help freely, without the "better than thou" attitude.

[Capt. Link.]

What did I just say ???!! I came for info, not a lecture!! Not all of us can afford the $500 ++ to purchase a suppressor, but would still like to explore the hearing and recoil benefits of one. Not to mention the challenge of doing something yourself instead of just buying. I am not a youngster by any means -- am a Marine Corps veteran, discharged in 1964, and have been a shooter most of my life. I am just new to this suppressor thing. When you get to be my age, and don't want to give up a favorite a hobby, you look into every edge you can get. I would imagine that I have a few years on most here, so I don't need to be treated like a child. Experience does not give you license to "talk down" to anyone!

Just looking for a little help here --- thought that was the purpose of this forum. I appreciate those that have offered that help freely, without the "better than thou" attitude.

The military still prints on the face of a claymore mines forward toward enemy for the ones that missed the lecture.
I am a older disabled vet and often not in good cheer but try to present respectful language to this community with nurturing advice and humor.
There is a wealth of information here not in print and a little eloquence helps open the door.
I wish you a better day. CL

[chap660]

Thank you CL --- I may have misconstrued. My profound respect to you.

I think best I just sit back now and glean what I may from the wealth of knowledge found here.
Back to the subject and matter at hand --------

[daviscustom]

If you have talked to the gentleman with the shop in Lincoln you already know where I was coming from with the remark about him. He might be more likely to work with you on a form 1 then the guy in Warsaw unless you already have a relationship established. The fellow in Lincoln will put your patience to the test, and if you aren't interested in buying a can from him, he may not be interested in helping you out.....just depends on his mood and how you approach it with him. He knows everything, and you know nothing....that will be where he is coming from, just so you know up front. He has been in the business for a long time and I am not trying to say he has no knowledge....just don't expect him to be in a sharing mood. I don't know how he will react to helping on a form 1 build.

Your big challenge will be building the threaded mount (assuming you can find someone to thread your barrel). As I am typing this I can't remember what caliber you are building for, but if it is for a 22lr, the threaded endcaps that are offered for sale as mentioned in the "DIY felony kit" thread would be a possibility you could look into. Someone will correct me if I am wrong, but I would think you could order a "solvent trap endcap" and repurpose it as a suppressor mount since you will have a form 1 in hand. Then you will just have to form and drill your freeze plugs if that is the route you are taking.

[Bendersquint]

Someone will correct me if I am wrong, but I would think you could order a "solvent trap endcap" and repurpose it as a suppressor mount since you will have a form 1 in hand. Then you will just have to form and drill your freeze plugs if that is the route you are taking.

With Form1 in hand that means you are buying a silencer part.

[chap660]

[quote="daviscustom"]If you have talked to the gentleman with the shop in Lincoln you already know where I was coming from with the remark about him.

You are right on the money there! Been there several times -- when I was lucky enough to even catch he and wife there with the shop open. As a matter of fact, that is where I was first made aware that suppressors are legal, and the benefits of reduced recoil and possible increase in accuracy -- always thought they were a big taboo. He is pretty proud of his work, maybe rightfully so, but he is just as pricey as the big boys. Don't think I will be looking in that direction for help.

[daviscustom]

Someone will correct me if I am wrong, but I would think you could order a "solvent trap endcap" and repurpose it as a suppressor mount since you will have a form 1 in hand. Then you will just have to form and drill your freeze plugs if that is the route you are taking.

With Form1 in hand that means you are buying a silencer part.

That just means the guy selling it is braking the law right? Is it any different then buying a freeze plug?....other then he doesn't have to modify it? I would have thought if he was approved to build a silencer, he could get his parts anywhere he could acquire them .......not correct?

I guess since it would be a silencer part, it is supposed to be transferred as if it was a silencer? So a form 1 builder can't buy parts from a Manufacture with out a form 4 transfer unless the form 1 guy was on premisses and the manufacture helped/made it for them? ( I realize the solvent trap guys are not legal manufactures)

Seems like a technicality if it is ok to be on site and have a manuf. make something for you vs. them make something that is legal for them to make and shipping it to the form 1 guy.......guess then it is a transfer instead of hiring a machinist to make you a part while you are on sight.

I know...just cause it makes sense, doesn't make it legal.

[daviscustom]

I am new to suppressors and this forum, so I would imagine this question has come up before. I submitted my tax stamp app in April and hopefully will get it soon.

I was just rereading your first post, and if you submitted it in April of this year you have lots of time to fine tune your design.......it will most likely be Feb.-March of next year before you get a stamp back.....unless you E-filed the paperwork. It may be longer then that.....the last one I got back was in Feb. I think ( which made my wait about 10.5 months) and I think I was reading about wait times being around a year now.

[chap660]

That is the case -- I heard at the time I sent my paperwork in that the wait was 6 to 9 months. Now I'm hearing that it is even longer. Going to really have to reach down and muster up a lot of patience here!! I can't comprehend any reason for it ??????!!! I understand that if you qualify to purchase a firearm of any kind, you will qualify to build or purchase a suppressor. Hundreds of people purchase a firearm every day in this country and it only takes a matter of minutes to get the approval, and you walk out the door with your purchase. If you qualify for concealed carry, you will qualify for the suppressor and that takes only a matter of weeks. A suppressor is not even a firearm !! It is more or less an inert object -- about the only way you could use it to cause harm would be to knock someone over the head with it! A person can do that with a bag of ice!! We have no problem purchasing a bayonet to attach to the front of a rifle??? You can purchase scopes that enable a hit a mile away - scopes that "paint" a target with a laser and you just pull the trigger and wiggle your gun around until you line up the two dots!! You don't need to pay a tax and wait a year to buy one of those. The suppressor is basically an accessory that makes using a firearm more enjoyable and more tolerable for the shooter and all nearby - well - except for maybe a feral hog or that big buck. I see so many pro's and really no con's that make much sense !!!?? It's not like the suppressor makes your gun invisible or totally audibly undetectable. Just can't see the logic here -- sounds to me like the politicians are at work again -- bad enough we have to fork over the $200!!!

OK --- Rant over --- think I'll go take a nap.

[flashfire157]

I hate to be an idiot...But I am new here and can't tell who is who. What was the final verdict on the bullet clearance? I heard 2 different answers: .026 and .060. Which one is appropriate for a 5.56 out of a 10.3" barrel?

[gunny50]

I hate to be an idiot...But I am new here and can't tell who is who. What was the final verdict on the bullet clearance? I heard 2 different answers: .026 and .060. Which one is appropriate for a 5.56 out of a 10.3" barrel?

What ammo do you use?
I would at least have 2 inconel 718 baffles in there with such a short barrel, more if you have the time and material.
Adding .060 to the .223 diameter is right and one can make each baffle slightly larger. Taper bore, is a good way to make things safe.
Short barrels do not always stabilize the projectile and it also depends on the factor how straight and concentric is the thread to the bore?? Is your barrels shoulder okay?

Its your 200 USD and time, so be smart.
Good way to go if you are building a take apart can is make the connecting cap- tube and end-cap, instal on gun, visual inspect, use a silencer rod if you have one, test fire and inspect.
One can always enlarge the exit hole in that way you will not damage the whole stack.
No markings on your cap? It will be safe make the stack the same. (basic guidance tools)

Again all depending on:
Barrel length, threading job, Crown, shoulder, your work quality.
Your machining capability,
Tube material, concentricity, wall thickness, roundness of tube, (make your own tube if needed)
Threading job, on caps in and outside (cut in one go.)
Baffle type, some baffles can de-stabelize a bullet in flight.
Cut your baffle outside and bullet flight path in one go.
Clearance between baffles and tube.
Direct thread / QD?
Ammo used

And in the end it all comes down in adding all tolerances from parts machined..

Good luck, keep your head straight, plane well, think twice, measure 3 times and cut carefully.
You will have lots of fun in the end by taking care and time in a project like this.

Gunny

[daviscustom]

I hate to be an idiot...But I am new here and can't tell who is who. What was the final verdict on the bullet clearance? I heard 2 different answers: .026 and .060. Which one is appropriate for a 5.56 out of a 10.3" barrel?

Who is new and who is an idiot.....sometimes it is difficult to tell. At least the post count tells who is new to the forum, but finding out who to trust for advice is a bit more of a challenge. If you read enough you will eventually pick up on a group consensus. There are several folks on here that have been in the industry for quite a while and are willing to help out....if not publicly, via email.

Gunny50 and Capt. Link are a couple of guys I would recommend paying attention to for starters, but there are several here that are very knowledgeable and helpful. If you are wanting to build a can, start by learning enough to get your paperwork submitted, and then you will have about a year to work out the details.


Oh...and as gunny50 said, .060" over caliber size for the bore is the standard answer, but it depends on the tolerances you are able to hold when you make the suppressor. Any big screw-ups along the way and .060" isn't much wiggle room.