Considering QD mounts for form 1

[daviscustom]

Waiting patiently for my "mother may I" to be approved, and trying to decide whether to build my own QD mount system or save up and buy parts. Having laid hands on zero QD mounted suppressors I am at a disadvantage as to where to head for the most rugged and repeatable design. I see a lot of love for the Surefire mounting system, and for about $290 I could purchase a Warden and a mount.....modify the warden into a rear cap and presto chango I'm done. But then I have all the other rifles i would need to buy $150 surefire mounts for....and then it gets to the point where I need a new plan because I don't want to sink that much money into it when I can build something serviceable myself.

I can't really say that I need something that fancy, QD is not a must have... but I also want to do this right the first time.

I have access to a CNC lathe so I can easily design a brake and make multiples with different sized internal threads to mount on all the different rifles. I am not sure if I need to include a locking mech in the design, or if that is overkill. The general plan is to build a combination flash suppressor/brake that will incorporate either 1 or 2 alignment tapers and an external multi-start thread for the quick attach thread. I am not dead set against standard threads for the mounts if the multi-start threads are just asking for problems coming loose.

I am a cheapskate at heart, and on a limited budget so I will likely build what I use, but I would consider buying a rear cap/mount combo if it would be easy enough to copy the brake for my other rifles. Curious to hear what your thought are on the best QD designs.

[T-Rex]

I think fishman has a dimensional drawing of a Griffin tapermount brake floating around.

[Meb959]

Q makes a brake called the cherry Bomb that might work for you can also get an end cap for an omega or saker prob under 200 for the brake and cap if you shop around

[ECCO Machine]

I'm not a huge fan of secondary retention locking mechanisms for most purposes, but they have their place. A proper ratio of taper to surface area with thread pitch accounted for is plenty for most purposes, though.

The general plan is to build a combination flash suppressor/brake that will incorporate either 1 or 2 alignment tapers and an external multi-start thread for the quick attach thread. I am not dead set against standard threads for the mounts if the multi-start threads are just asking for problems coming loose.

The only reason to use multi start threads is to have the installation speed of courser threads where part dimensions don't allow the thread depths of the courser threads with standard single start. Since you essentially have a blank canvas, I'd just use NC or NF standard, or ACME threads.

My taper lock brakes are 1"-12 UNF with 4 threads, crests blunted & gently rounded. My taper is 12° included with a .275" long bearing surface. The taper is 1.115" at the fat end:

[daviscustom]

I think fishman has a dimensional drawing of a Griffin tapermount brake floating around.

If it is the one I am thinking about, I really like the looks of that one. That would be interesting to see those drawings.

The only reason to use multi start threads is to have the installation speed of courser threads where part dimensions don't allow the thread depths of the courser threads with standard single start. Since you essentially have a blank canvas, I'd just use NC or NF standard, or ACME threads.

My taper lock brakes are 1"-12 UNF with 4 threads, crests blunted & gently rounded. My taper is 12° included with a .275" long bearing surface. The taper is 1.115" at the fat end:

What material are you using? Is that 17-4? Have you experimented with more of a flash hider design at all to see if there is a difference in performance?

That makes sense about the multi-start. Thanks for pointing that out. I will have to keep that in mind in case I get into a design situation where I need to use shallower threads to save weight. Standard threads will be less hassle for sure.

Q makes a brake called the cherry Bomb that might work for you can also get an end cap for an omega or saker prob under 200 for the brake and cap if you shop around

I saw that one....it looks kind of like what I have in mind.....partially. Sort of.....I was interested until I saw the taper on the id, and no taper on the od(unless that is a taper in front of the threads)




After taking stock of everything I would want to use this can on, there is no reason to not build my own. I may as well get material for 10 and make extras.

[3strucking]

I'm not a huge fan of secondary retention locking mechanisms for most purposes, but they have their place. A proper ratio of taper to surface area with thread pitch accounted for is plenty for most purposes, though.

The general plan is to build a combination flash suppressor/brake that will incorporate either 1 or 2 alignment tapers and an external multi-start thread for the quick attach thread. I am not dead set against standard threads for the mounts if the multi-start threads are just asking for problems coming loose.

The only reason to use multi start threads is to have the installation speed of courser threads where part dimensions don't allow the thread depths of the courser threads with standard single start. Since you essentially have a blank canvas, I'd just use NC or NF standard, or ACME threads.

My taper lock brakes are 1"-12 UNF with 4 threads, crests blunted & gently rounded. My taper is 12° included with a .275" long bearing surface. The taper is 1.115" at the fat end:

you do some nice work. those look really good.

[fishman]

I think fishman has a dimensional drawing of a Griffin tapermount brake floating around.

viewtopic.php?f=10&t=139206&p=950872#p950872



I'm quite a fan of this system. Simple. Functional. Repeatable.

I would skip the multi-start threads. The taper will lock better with standard threads

[Chips26]

I think fishman has a dimensional drawing of a Griffin tapermount brake floating around.

Edit nevermind just saw them.

[daviscustom]

I think fishman has a dimensional drawing of a Griffin tapermount brake floating around.

viewtopic.php?f=10&t=139206&p=950872#p950872



I'm quite a fan of this system. Simple. Functional. Repeatable.

I would skip the multi-start threads. The taper will lock better with standard threads

Perfect, thank you. That’s the one I like the looks of the best so far .

[Capt. Link.]

Would you call these flash suppressors a short brake or hybrid design.The execution is magnificent!

[daviscustom]

Wondering about milling out three sections of threads to create an interrupted thread so I could slide the can all the way on and twist to lock...... a simplified QD attachment that should still tighten down just as secure, but be faster to mount/ remove.

It would allow more gunk to get back into the threads and back to the front of the taper. It would increase the amount of work involved in making the brakes....and the thread protectors. I guess the thread protectors wouldn't have to have the interrupted thread, they could just screw on.

[fishman]

It takes like 4 seconds to screw one on. The extra carbon fouling isnt worth saving 2.5 seconds

[ECCO Machine]

What material are you using? Is that 17-4? Have you experimented with more of a flash hider design at all to see if there is a difference in performance?

Those ones are 17-4 H900, yes. I also use 440c sometimes. Both are suitable, really just depends on which material is at a better price when I need it. I like the higher hardness & strength of 440c, but it's superfluous, and 440 doesn't play quite as nice in annealed machining as far as finish quality, and definitely sucks to finish machine after heat treating.

I really don't mess with flash hider designs, don't see much point when it's going inside a can.

Would you call these flash suppressors a short brake or hybrid design.The execution is magnificent!

Thank you!

I consider them a brake, and the design seems to contribute significantly to suppression. Compared to previous open chamber direct thread designs, the performance is noticeably better, so much so that my DT cans now have this design as an integral part of the mount.

I have a .375 RUM that is a pleasure to shoot with my 1.8x10" Accipiter prototype on it using this brake design. That one is made from 500° temper 440c stainless



The can is 600°F temper 422 crucible stainless, fully welded tubeless design with ten 50° cone baffles. I haven't metered it yet, but I'm betting on 137-138 dB. Very pleasant volume & tone, and also took the recoil of this lightweight rifle from a brutal >70 ft.lbs @ 26 FPS to a much more tolerable level I liken to that of my Marlin 1895 shooting 405 gr/2000 FPS loads at 45-ish ft lbs @ ~20 FPS.

[1911rocks]

Unless you are going to remove/replace several times (*>10x in an hour) I'd avoid Multi-Start threads. If someone else is doing the work, it's going to cost you more. If you're doing it yourself the opportunity for an "oops". I use a simple .750 -12TPI Acme with the Mount/Brake using a 45deg shoulder. I was going to use a Metric Trapezoidal, but opted for something simple. The advantage of the Trapezoidal is the ability to tighten and then the load, especially pulse/shock load does not tend to loosen/walk. The ACME thread can be tightened/loosened under load. The 12TPI is a relatively fast install. I did a few at 8TPI, but I found that the mount depended on the "shoulder" to maintain the tightness. After the photos I went back and put an 11deg crown on the muzzle. These photos were after the first Blue Tank shot. 4140CRM steel

[daviscustom]

It takes like 4 seconds to screw one on. The extra carbon fouling isnt worth saving 2.5 seconds

Yeah I know, I was momentarily sucked into the QD being worth the hassle. Part of that I think is because of the 40 tpi threads I put on the end caps of my last can....leaves a lasting impression since the back cap has about 3/4" of threads....but I wanted to keep the thread depth as shallow as I could for extra insurance.

Those ones are 17-4 H900, yes. I also use 440c sometimes. Both are suitable, really just depends on which material is at a better price when I need it. I like the higher hardness & strength of 440c, but it's superfluous, and 440 doesn't play quite as nice in annealed machining as far as finish quality, and definitely sucks to finish machine after heat treating.

I really don't mess with flash hider designs, don't see much point when it's going inside a can.

Would you call these flash suppressors a short brake or hybrid design.The execution is magnificent!

Thank you!

I consider them a brake, and the design seems to contribute significantly to suppression. Compared to previous open chamber direct thread designs, the performance is noticeably better, so much so that my DT cans now have this design as an integral part of the mount.

The thought was that a flash hider is designed to disperse the flames and might possibly contribute to reduced FRP. I saw the Griffin flash hider/brake is also supposed to eliminate the metallic ping as well.

The three cuts around the bore on the front face of your brake.....are they cut kind of like the scoop on the face of a K baffle or do they go deeper? It is hard to tell from the lighting. I am assuming they would somewhat function as a mini flash hider....at least they should create turbulence and spread out the flame some.

Unless you are going to remove/replace several times (*>10x in an hour) I'd avoid Multi-Start threads. If someone else is doing the work, it's going to cost you more. If you're doing it yourself the opportunity for an "oops". I use a simple .750 -12TPI Acme with the Mount/Brake using a 45deg shoulder. I was going to use a Metric Trapezoidal, but opted for something simple. The advantage of the Trapezoidal is the ability to tighten and then the load, especially pulse/shock load does not tend to loosen/walk. The ACME thread can be tightened/loosened under load. The 12TPI is a relatively fast install. I did a few at 8TPI, but I found that the mount depended on the "shoulder" to maintain the tightness. After the photos I went back and put an 11deg crown on the muzzle.

I think I will just stick with a fairly coarse standard thread, just because I know we already have the tooling on hand. There may be some acme stuff around but I think I will keep it simple. The lathe I use is fairly simple to program for multi-start threads but I haven't had the need to try it yet so I will probably skip it for now. That would be traveling into personally uncharted territory and it isn't really needed so I don't feel like wasting any material figuring it out.

[T-Rex]

The thought was that a flash hider is designed to disperse the flames and might possibly contribute to reduced FRP

I doubt this would be the case. A flash suppressor is designed to divide the muzzle blast and rapidly mix it with the surrounding air. This causes the gases to exhaust and cool, limiting a flash signature. FRP is exactly this, just inside of the can. The sound is from the secondary detonation occurring inside of the blast chamber when the available oxygen is consumed. Not saying a muzzle brake performs better, but it's almost the opposite thought. Instead of a rapid diffusion, the brake sends high pressure jets in a predetermined patterned. Possibly, not lending enough surface area to complete combustion. In either regard, keeping the blast volume to a minimum is ideal. There are other techniques to help equalize the initial release.

[daviscustom]

The thought was that a flash hider is designed to disperse the flames and might possibly contribute to reduced FRP

I doubt this would be the case. A flash suppressor is designed to divide the muzzle blast and rapidly mix it with the surrounding air. This causes the gases to exhaust and cool, limiting a flash signature. FRP is exactly this, just inside of the can. The sound is from the secondary detonation occurring inside of the blast chamber when the available oxygen is consumed. Not saying a muzzle brake performs better, but it's almost the opposite thought. Instead of a rapid diffusion, the brake sends high pressure jets in a predetermined patterned. Possibly, not lending enough surface area to complete combustion. In either regard, keeping the blast volume to a minimum is ideal. There are other techniques to help equalize the initial release.

It would seem likely in an enclosed space you might not see a lot of difference in the effect of a flash hider vs a brake, but if it actually helps blend it with the surrounding air and eliminate the flash, I would have thought that would be a good thing. It is interesting that Griffon claims their hybrid mount eliminates the "ping" though.....but they also use lots of very small ports which I would think would also reduce flash and diffuse the blast more than larger ports.

[ECCO Machine]

The thought was that a flash hider is designed to disperse the flames and might possibly contribute to reduced FRP. I saw the Griffin flash hider/brake is also supposed to eliminate the metallic ping as well.

First round pop really isn't an issue with supersonic rifle rounds.

The three cuts around the bore on the front face of your brake.....are they cut kind of like the scoop on the face of a K baffle or do they go deeper? It is hard to tell from the lighting. I am assuming they would somewhat function as a mini flash hider....at least they should create turbulence and spread out the flame some.

Those cuts are at a compound angle. My brakes are a chambered design, the ID of the brake larger than the aperture at the front. Those cuts, along with the angled ports on the sides, are designed to swirl the gasses in the blast chamber and up the face of the blast baffle. Airflow that's forced into a vortex can't follow the bullet as easily.

I tried applying that feature in a different way on the snout of cone baffles. Unlike the brakes, that idea was a bust.



I was actually kinda glad they didn't work out. Those things are a pain in the ass to make on manual machines.

[daviscustom]

The thought was that a flash hider is designed to disperse the flames and might possibly contribute to reduced FRP. I saw the Griffin flash hider/brake is also supposed to eliminate the metallic ping as well.

First round pop really isn't an issue with supersonic rifle rounds.

The three cuts around the bore on the front face of your brake.....are they cut kind of like the scoop on the face of a K baffle or do they go deeper? It is hard to tell from the lighting. I am assuming they would somewhat function as a mini flash hider....at least they should create turbulence and spread out the flame some.

Those cuts are at a compound angle. My brakes are a chambered design, the ID of the brake larger than the aperture at the front. Those cuts, along with the angled ports on the sides, are designed to swirl the gasses in the blast chamber and up the face of the blast baffle. Airflow that's forced into a vortex can't follow the bullet as easily.

I tried applying that feature in a different way on the snout of cone baffles. Unlike the brakes, that idea was a bust.



I was actually kinda glad they didn't work out. Those things are a pain in the ass to make on manual machines.

Yeah those look like they are a bear to make.

I thought it looked like the cuts might be skewed at a similar angle to the ports. Thanks for the explanation.

[fishman]

I thought of another reason to not use multi start threads. Similar to a 3 lug, there will be more than 1 way to mount the can. This will mean the poi shift wont always be the same unless you keep track of how you install it.

[daviscustom]

I thought of another reason to not use multi start threads. Similar to a 3 lug, there will be more than 1 way to mount the can. This will mean the poi shift wont always be the same unless you keep track of how you install it.

Very good point!....pretty well decided not to use them anyway. I guess it could be a bonus too though, since it would give you the ability to choose the best position for POI shift. You would just have to mark the can for a reference, but it could conceivably be different for every rifle. I guess if you have a witness mark for the starting position on the can then each mount could be marked with the best start point for that rifle.