Is there a rule of thumb for the size of hole in the baffles/ end caps in regards to bore diameter?
Suppressors Form 1 suppressor, drill size
- Thread starter cattleman99
- Start date
I have always gone 0.030" and it's worked for me from 22lr to 0.300 win mag form 1 cans
Depending on how sure you are of concentricity and alignment, a lot of form 1 guys will drill/ream .05"-.06". I've done as small as .015" over bullet diameter on arrangements I was very confident in.
I found this to be very helpful. Personally I think a minimum of .08 inches bigger that your caliber diameter is recommended for safety especially if it's your first build. Then if you are confident in your machining ability as said above you can bring it in closer to .05". For myself I would not go below that because you risk a baffle strike and IMO the sound difference would be negligible. I have heard of groups opening up a little bit when the baffle bore diameters are too tight, but I don't know if that's true.
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I've always heard .06. I've got one planned specifically for a finicky piston gun and I'm going .400ish to help reduce back pressure, as well as a couple other measures. I think I'd go .06 over for a bolt gun can for max sound reduction though.
.400 over? Is that a typo.
I've got a 338 Lapua suppressor with a .402 bore through the baffles and endcap. Its a little more than .060 over the bullet diameter. We have metered this can with proper meters and procedures on a number of cals and found it to have very good suppression on all. In comparing it to a suppressor made specifically for the 6.5 cal with a much smaller bore of .312" the difference was not noticeable to the ear or the meter. So basic fact here is that keeping the bore tight to the bullet is unnecessary. Your gains will be marginal if any and your liability could be huge.
Many rounds like the 223 have issues with the bullets wobbling out of the muzzle and for that reason you'll find that most suppressors made for the military have a much larger bore through the can. This is to prevent baffle strikes from wobbly bullets. Doc Dater at GemTech posted some very good articles concerning nutation (wobbling) of 223 bullets out of the muzzle. Extended strings of fire exacerbated the issue as did shorter barrels. While 223 is especially bad about this most of the rest have some amount of wobble going on as well. Clearance in the baffles to prevent strikes is more important than the .001 db you might gain by keeping your bore tighter.
I'd say .060" should be good, tighter won't gain you anything worthwhile and larger won't either.
Frank
Many rounds like the 223 have issues with the bullets wobbling out of the muzzle and for that reason you'll find that most suppressors made for the military have a much larger bore through the can. This is to prevent baffle strikes from wobbly bullets. Doc Dater at GemTech posted some very good articles concerning nutation (wobbling) of 223 bullets out of the muzzle. Extended strings of fire exacerbated the issue as did shorter barrels. While 223 is especially bad about this most of the rest have some amount of wobble going on as well. Clearance in the baffles to prevent strikes is more important than the .001 db you might gain by keeping your bore tighter.
I'd say .060" should be good, tighter won't gain you anything worthwhile and larger won't either.
Frank
Bore will be ~.400. Will basically give me the option to use it with 33-35 caliber on bolt guns and should have a little lower backpressure on the picky 308.
-Dan
I usually play it safe and just go with about 8 mm holes for a .308, 10mm for a 9mm, and similar. They still work well without nitnoid tight tolerance on the holes.
8mm is way too tight of a bore for .308. Convert 8mm to inches and you'll see why.
I suggest you edit your post so someone doesn't read it and follow your reasoning later on.
8mm = .315 inch
I wish this thread was around years ago..
For what its worth.. serious builders hear me out.
For those who are building 5.56 longer than 7 inches. I have a steel 5.56 suppressor thats 10 inches long. The bore begins 9/32 for 7 inches and the last 3 inches is 19/64. This follows rule on suppressor longer than 7 inches. Ive heard subsonic ammo can cause issues here with occasional wobble. And then there's suppressors with no index notches which could effect more behaviors. I havent indexed my suppressor yet. I will, but Im doing more research on this. I found most are using half 1/4 inch notches as a rule. BUT the difference in drilling vs lathe is another story worth looking into. Drilling makes bigger holes and the holes or notches need to be reamed. Data shows burs can cause extremely bad effects (regardless of adjustable gas blocks) and all kinds of other uneeded damaging effects internally. There are so many types of index cuts now its hard to keep up but I do know aligning them and reaming the cuts and drill holes are just as important. You might think burs are slowing gas down when in fact they cause chaotic turbulence and undesired eroding and eventually sheer off micro particles that cause catastrophic failures after so many random rounds. Reaming is a key part of your bore. smooth it out. Burs need to be looked at.
Personally I added 4 bleed holes around the bore of the first blast baffle.
The 4 holes are 1/4 and spaced like a cross in the center of the baffle from bore to modular wall. You cant just put them anywhere. Im using data on a suppressor currently marketed.
Suppressor companies are adopting this blast baffle mod and I believe it will be a rule soon. First baffle gets blasted so hard every shot. Why allow all that pressure on the baffle when you could direct some to the 2nd baffle without adding or taking away suppressor efficiencies? I understand its more relevant if you have 8 baffles to play with in a 10 inch suppressor. But longer suppressors are more efficient than shorter so I went with 10 inch. Everyone's trying to escape the weight value, i get it. But a lot are truthfully cutting corners and sacrificing efficiency to accommodate convenience. Example..Suppressor QD mounts vs direct thread. Know your trade offs. It seems the market is lead by convenience over max efficiency. Example is 2 inch blast chamber vs 3 inch. How about dual blast chambers? That one will grab you.
If I was going to convert my supressors muzzle attachment I'd go with silencerco's 1.375 x 24 Hub adapter.
However there is not only logic but more efficiency in direct thread.
I also want remove my supressor to shoot unsuppressed. The only thing you have to do which i see QD users don't want to is check your suppressor after shot strings to prevent it locking up or backing off. The permanent adapter QD isn't better its just preferred the way i see it. Ive read many reports on tests showing QD mounts sacrificing DB and have to make up by modifying the entire can around this to circumvent, often subtracting efficiency not adding it.. Depending on due diligence with direct thread you can circumvent these wear factors too. Remember that. Dont substitute intuitive awareness with an adapter and trade offs. I want a hardcore tough suppressor well made. You CAN maintain direct thread suppressors and seat them perfectly to barrel face and maintain the tightness. Dont let anyone tell you false "facts" that ultimately imply a reluctance to maintain. Tapered barrels are a good reason to add these mods but not with a 90° face thats perfectly capable. This is something that bothers me really to a stressed exhortation.
Don't mean to offend anyone here. some people building suppressors bind to claims for reasons that don't make it better but rather a preferred way.
Im trying to build a scientifically sound suppressor. Not get caught up in design fads that are and have been led by ease, not efficiency.
QD mounts are convenient. Direct threads require constant maintenance to prevent the wear associated with it. You choose. There huge groups of suppressor users that shoot and check the can. Its a normal process. Its still ongoing. I dont like that this has caused the marketing of devices taking away from one thing for comfort or ease.
Threaded modular baffles is what I went with. 304 steel. Id advise not going with aluminum if you're building. Buy one if you want an aluminum can. Aluminum is ok for some small calibers but the good that comes with aluminum ends in tragedy. You'll see companies selling em too. Trust me It fails. 5.56, 7.62 and 308 require steel at least. Steel is all around the best choice for first builds even though it can weigh more. 7 inches if you want it light. 10 if you're serious about suppressing during hunting or at night on coyotes or hogs. Inconel blast baffles are the best thing now. (Aero Precision just released a new suppressor. Curious to know how its made.) Stellite and chromium molybdenum vanadium are good too. CMV would be my preferred type.
Titanium? It seems a total winner and then you'll find its...well not. highly recommend you research even when you find the answer or a can made of aluminum or titanium, research more. There is a sea of high opinion over conclusive data and such a pain to wade through it all. Theres even suppressors built on pure hype because they sell. Dont believe me? thats your choice. If you're trying to make friends you'll never find truth.
Go by the .060 over bore and add another 0.015/.020 over bore past 7 inches. You'll thank yourself later, not regret it. Its not going to lessen DB rating. Most suppressor companies are going with larger bore designs for Multi cal which suffers DB loss but multi cal is the trade off.
All variables with DB, longevity and safety are centered around .060 overbore. Its smaller and larger bores which begin to suffer. Know that much. I cant say exact percentages but I can guess increases in failure around 25 - 40% (more likely to suffer strikes, baffle failure or DB loss above or below .060 over your bullet diameter). The data is out there. Failures happen regularly with builds and youtube isn't the only place (in some cases its the worst place) to find data. You might find results of catastrophic failures but not where they got their DIE HARD design plans. Go by rules. Over bore and indexing are general rules. past that is experimental unless its showing new conclusive data.
You should research supressor companies if you ask me. Look at their designs. Stay out of the sea of disinformation or hobby form 1 until you got rules in mind. You can build one successfully or with hiccups and God forbid injury. This mixing of metals to reduce weight WILL factor in bad chances.
There are few websites by vets who go deep into suppressor building more lately than say 5 years ago.
Retired Major Rob Robinette has a site dedicated to form 1 building if you want to check it out.
how to build a suppressor
The site is a bit ghetto but the data is reflecting some military specs which little has been revised or updated. Hes also building monocore to demonstrate but you know my feelings about that. Take what you "can".
There's a lot of great info on building suppressors in general to begin your study. Again look for the rules. suppressors 7 to 10 inches should be your target. Some suppressor companies are designing new blast baffles. Some are using inverted cone bores (bore opens gradually towards the exit which shows good results).
If you're building you'll run into tons of monocore stuff. I suggest you stay away from it for now. Its not better (no matter what you hear) and in all cases it falls short. Do not build with convenience as your catalyst. Aluminum ISN'T suppressor friendly. not 7075, etc... I repeat....
When they fail (and monocore do often) they do lots of insane things. mostly explode. very few monocore build designs work, or they work the same as baffle designs but don't last. They require super fine tuning. Soteria Suppressors made a monocore design that works really well but its almost impossible to machine at home. Its also vastly different than these monocores made at home. The harmonic effect is solved in this design to such a high degree its nuts. In comparison to baffles its not better, its the same. Baffle design doesn't need redesign, it could use fine tuning as seen with the silencerco indexing tests (indexed vs random alignment).
Baffle stacks are king. Monocore will need much more to improve on what already reaches maximum benefit. The HUGE problem is that monocore succumbs to extreme harmonics with single core construction causing it to violently vibrate uniformly till it literally crosses a frequency exploding it. Aluminum adds to this. It slowly cracks first and explodes later. You should see videos on it. Its insane. People try making them out of everything to get around this and the same thing happens. And then the machining is so complex. At its best it only arrives at what baffles do and baffle stacks dont have harmonic failures. Even welded ones dont. The leading argument i always hear is easy cleaning and they're easy to build. if one breaks you got another. I wasted nearly 2 years on researching monocore. And in case you're wondering, the newest designs of monocore are nothing like these cheap bars of aluminum with all these concentric holes drilled in it looking like 3d quasi crystals. Its sad that some builders are going straight to monocore instead of baffles.
Another website with some good info if you want is here: Silencer Research
Go with Christ, go with rules and go with baffles.
For what its worth.. serious builders hear me out.
For those who are building 5.56 longer than 7 inches. I have a steel 5.56 suppressor thats 10 inches long. The bore begins 9/32 for 7 inches and the last 3 inches is 19/64. This follows rule on suppressor longer than 7 inches. Ive heard subsonic ammo can cause issues here with occasional wobble. And then there's suppressors with no index notches which could effect more behaviors. I havent indexed my suppressor yet. I will, but Im doing more research on this. I found most are using half 1/4 inch notches as a rule. BUT the difference in drilling vs lathe is another story worth looking into. Drilling makes bigger holes and the holes or notches need to be reamed. Data shows burs can cause extremely bad effects (regardless of adjustable gas blocks) and all kinds of other uneeded damaging effects internally. There are so many types of index cuts now its hard to keep up but I do know aligning them and reaming the cuts and drill holes are just as important. You might think burs are slowing gas down when in fact they cause chaotic turbulence and undesired eroding and eventually sheer off micro particles that cause catastrophic failures after so many random rounds. Reaming is a key part of your bore. smooth it out. Burs need to be looked at.
Personally I added 4 bleed holes around the bore of the first blast baffle.
The 4 holes are 1/4 and spaced like a cross in the center of the baffle from bore to modular wall. You cant just put them anywhere. Im using data on a suppressor currently marketed.
Suppressor companies are adopting this blast baffle mod and I believe it will be a rule soon. First baffle gets blasted so hard every shot. Why allow all that pressure on the baffle when you could direct some to the 2nd baffle without adding or taking away suppressor efficiencies? I understand its more relevant if you have 8 baffles to play with in a 10 inch suppressor. But longer suppressors are more efficient than shorter so I went with 10 inch. Everyone's trying to escape the weight value, i get it. But a lot are truthfully cutting corners and sacrificing efficiency to accommodate convenience. Example..Suppressor QD mounts vs direct thread. Know your trade offs. It seems the market is lead by convenience over max efficiency. Example is 2 inch blast chamber vs 3 inch. How about dual blast chambers? That one will grab you.
If I was going to convert my supressors muzzle attachment I'd go with silencerco's 1.375 x 24 Hub adapter.
However there is not only logic but more efficiency in direct thread.
I also want remove my supressor to shoot unsuppressed. The only thing you have to do which i see QD users don't want to is check your suppressor after shot strings to prevent it locking up or backing off. The permanent adapter QD isn't better its just preferred the way i see it. Ive read many reports on tests showing QD mounts sacrificing DB and have to make up by modifying the entire can around this to circumvent, often subtracting efficiency not adding it.. Depending on due diligence with direct thread you can circumvent these wear factors too. Remember that. Dont substitute intuitive awareness with an adapter and trade offs. I want a hardcore tough suppressor well made. You CAN maintain direct thread suppressors and seat them perfectly to barrel face and maintain the tightness. Dont let anyone tell you false "facts" that ultimately imply a reluctance to maintain. Tapered barrels are a good reason to add these mods but not with a 90° face thats perfectly capable. This is something that bothers me really to a stressed exhortation.
Don't mean to offend anyone here. some people building suppressors bind to claims for reasons that don't make it better but rather a preferred way.
Im trying to build a scientifically sound suppressor. Not get caught up in design fads that are and have been led by ease, not efficiency.
QD mounts are convenient. Direct threads require constant maintenance to prevent the wear associated with it. You choose. There huge groups of suppressor users that shoot and check the can. Its a normal process. Its still ongoing. I dont like that this has caused the marketing of devices taking away from one thing for comfort or ease.
Threaded modular baffles is what I went with. 304 steel. Id advise not going with aluminum if you're building. Buy one if you want an aluminum can. Aluminum is ok for some small calibers but the good that comes with aluminum ends in tragedy. You'll see companies selling em too. Trust me It fails. 5.56, 7.62 and 308 require steel at least. Steel is all around the best choice for first builds even though it can weigh more. 7 inches if you want it light. 10 if you're serious about suppressing during hunting or at night on coyotes or hogs. Inconel blast baffles are the best thing now. (Aero Precision just released a new suppressor. Curious to know how its made.) Stellite and chromium molybdenum vanadium are good too. CMV would be my preferred type.
Titanium? It seems a total winner and then you'll find its...well not. highly recommend you research even when you find the answer or a can made of aluminum or titanium, research more. There is a sea of high opinion over conclusive data and such a pain to wade through it all. Theres even suppressors built on pure hype because they sell. Dont believe me? thats your choice. If you're trying to make friends you'll never find truth.
Go by the .060 over bore and add another 0.015/.020 over bore past 7 inches. You'll thank yourself later, not regret it. Its not going to lessen DB rating. Most suppressor companies are going with larger bore designs for Multi cal which suffers DB loss but multi cal is the trade off.
All variables with DB, longevity and safety are centered around .060 overbore. Its smaller and larger bores which begin to suffer. Know that much. I cant say exact percentages but I can guess increases in failure around 25 - 40% (more likely to suffer strikes, baffle failure or DB loss above or below .060 over your bullet diameter). The data is out there. Failures happen regularly with builds and youtube isn't the only place (in some cases its the worst place) to find data. You might find results of catastrophic failures but not where they got their DIE HARD design plans. Go by rules. Over bore and indexing are general rules. past that is experimental unless its showing new conclusive data.
You should research supressor companies if you ask me. Look at their designs. Stay out of the sea of disinformation or hobby form 1 until you got rules in mind. You can build one successfully or with hiccups and God forbid injury. This mixing of metals to reduce weight WILL factor in bad chances.
There are few websites by vets who go deep into suppressor building more lately than say 5 years ago.
Retired Major Rob Robinette has a site dedicated to form 1 building if you want to check it out.
how to build a suppressor
The site is a bit ghetto but the data is reflecting some military specs which little has been revised or updated. Hes also building monocore to demonstrate but you know my feelings about that. Take what you "can".
There's a lot of great info on building suppressors in general to begin your study. Again look for the rules. suppressors 7 to 10 inches should be your target. Some suppressor companies are designing new blast baffles. Some are using inverted cone bores (bore opens gradually towards the exit which shows good results).
If you're building you'll run into tons of monocore stuff. I suggest you stay away from it for now. Its not better (no matter what you hear) and in all cases it falls short. Do not build with convenience as your catalyst. Aluminum ISN'T suppressor friendly. not 7075, etc... I repeat....
When they fail (and monocore do often) they do lots of insane things. mostly explode. very few monocore build designs work, or they work the same as baffle designs but don't last. They require super fine tuning. Soteria Suppressors made a monocore design that works really well but its almost impossible to machine at home. Its also vastly different than these monocores made at home. The harmonic effect is solved in this design to such a high degree its nuts. In comparison to baffles its not better, its the same. Baffle design doesn't need redesign, it could use fine tuning as seen with the silencerco indexing tests (indexed vs random alignment).
Baffle stacks are king. Monocore will need much more to improve on what already reaches maximum benefit. The HUGE problem is that monocore succumbs to extreme harmonics with single core construction causing it to violently vibrate uniformly till it literally crosses a frequency exploding it. Aluminum adds to this. It slowly cracks first and explodes later. You should see videos on it. Its insane. People try making them out of everything to get around this and the same thing happens. And then the machining is so complex. At its best it only arrives at what baffles do and baffle stacks dont have harmonic failures. Even welded ones dont. The leading argument i always hear is easy cleaning and they're easy to build. if one breaks you got another. I wasted nearly 2 years on researching monocore. And in case you're wondering, the newest designs of monocore are nothing like these cheap bars of aluminum with all these concentric holes drilled in it looking like 3d quasi crystals. Its sad that some builders are going straight to monocore instead of baffles.
Another website with some good info if you want is here: Silencer Research
Go with Christ, go with rules and go with baffles.
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