mtjccmotel 12 Posted March 5, 2012 Report Share Posted March 5, 2012 Anyone install an AMD-65 style brake on their 308? Any thoughts on the AMD brake? As I have not shot an AMD, how effective of a brake are they? I am in the process of finalizing the front end of my 308. Like most in todays economy I am cash starved and need to utilize my funds wisely. I found surplus AMD-65 Brakes for $10. While they are M14x1L thread I don't think there would be any issue moddifying it to 5/8"x24R, which is what I plan on threading my barrel to. As funds permit I plan to upgrade to either an FSC30 or Big Chubby. Any thoughts would be appreciated! Quote Link to post Share on other sites
jimdigriz 580 Posted March 5, 2012 Report Share Posted March 5, 2012 (edited) Anyone install an AMD-65 style brake on their 308? Any thoughts on the AMD brake? As I have not shot an AMD, how effective of a brake are they? I am in the process of finalizing the front end of my 308. Like most in todays economy I am cash starved and need to utilize my funds wisely. I found surplus AMD-65 Brakes for $10. While they are M14x1L thread I don't think there would be any issue moddifying it to 5/8"x24R, which is what I plan on threading my barrel to. As funds permit I plan to upgrade to either an FSC30 or Big Chubby. Any thoughts would be appreciated! Well, as long as you are modifying the $10 brake to the 5/8x24 threads, and not the rifle to the M14x1L, it's an experiment that costs nearly nothing to try. After you are done, I'd love to hear the report. (I imagine it will be pretty loud ). I recommend saving for a Battlecomp for your future purchase. Works awesome on my rifle. Much better than a FSC30. I don't really know what a Big Chubby is... EDITED TO ADD: Have you considered cutting the barrel down? Not very wieldy with all that extra length and weight out there. I cut mine to 18" and find it to be just about perfect. Edited March 5, 2012 by Jim Digriz Quote Link to post Share on other sites
mtjccmotel 12 Posted March 5, 2012 Author Report Share Posted March 5, 2012 I plan on modifying the brake. Have access to machining tools and plenty of time just limited funds at this point in time. The Battlecomp is another nice brake. Quote Link to post Share on other sites
mtjccmotel 12 Posted March 5, 2012 Author Report Share Posted March 5, 2012 (edited) Considered cutting, but I prefer the extra length and few extra fps. The Collapsible stock helps shorten the OAL and allow for better maneuverability. I plan on re-crowning the barrel and as soon as I can buy the cutter, maybe I'll shorten after that, but for the last 5 years the rifle has served me well at the current length. I don't care for the extra front end weight however. Edited March 5, 2012 by Noob308 Quote Link to post Share on other sites
jimdigriz 580 Posted March 5, 2012 Report Share Posted March 5, 2012 Considered cutting, but I prefer the extra length and few extra fps. The Collapsible stock helps shorten the OAL and allow for better maneuverability. I plan on re-crowning the barrel and as soon as I can buy the cutter, maybe I'll shorten after that, but for the last 5 years the rifle has served me well at the current length. I don't care for the extra front end weight however. The muzzle brake, even weighing little as it does, is likely to significantly increase that unpleasant front heaviness. 2-3 ounces close to your body is scarcely felt; 2-3 ounces dangling out there over 40 inches from the body will definitely be noticed. I originally was going to keep the full-length barrel too, but I dummied up the extra weight of the brake by taping a few 308 rounds out to the end of the barrel. I didn't like the feel of that at all. Ended up cutting exactly 4 inches from the barrel for a 17.8" length. Anyhow, try dummying it up and see how it feels. The extra FPS is nice, but the target is likely to be just as dead hit from a 308 round out of a 18 inch barrel as a 21.8 inch barrel. Good luck. Let us know how it goes. :-) Quote Link to post Share on other sites
mtjccmotel 12 Posted March 5, 2012 Author Report Share Posted March 5, 2012 Good point I will dummy up as you suggested, as my friend has a machine shop cutting it down in the future would not be a problem. Quote Link to post Share on other sites
mtjccmotel 12 Posted April 17, 2012 Author Report Share Posted April 17, 2012 I finally completed the modification of an AMD-65 Brake and attached it to my S308. Bored the brake out on a lathe increasing the diameter from the 14mm left hand thread and tapped the brake for 5/8"-24. Used lathe to create a TAT out of aluminum which was rather interesting as the aluminum did not like threading on the lathe very cleanly, but no worries since the 5/8"-24 die cleaned it up nicely. After moving my FSB back my barrel was .670". I started threading my barrel with the die but didn't like how much pressure was put on the die removing as much metal was required to thread the .670" to 5/8". Utilizing my trusty files and dremel I removed some of the extra metal while maintaining the round profile. I reduced the diameter of the barrel to .640", which allowed a much easier time threading the barrel. Unfortunately, I didn't take any pictures throughout the process. On another note the AMD-65 brakes that I received were not perfectly in-line with the bore and required opening up once timed. 1 Quote Link to post Share on other sites
Dad2142Dad 6,559 Posted April 17, 2012 Report Share Posted April 17, 2012 Very nice, how does it shoot now? Quote Link to post Share on other sites
mtjccmotel 12 Posted April 17, 2012 Author Report Share Posted April 17, 2012 Don't know how it shoots yet as just completed today and between kids coming home from school and the poor weather of the Pacific NW haven't got chance to take it out in the woods. I plan on reporting back as soon as I do. 1 Quote Link to post Share on other sites
mtjccmotel 12 Posted April 30, 2012 Author Report Share Posted April 30, 2012 Got a chance to shoot last week with the recent modifications. As far as handling and balance is concerned not that much difference with the modified AMD brake. There is definitely less muzzle jump, can't really tell if there is less recoil as the 308 recoil never bothered me before. I notice recoil based on my mood and how focussed I am on proper shooting techniques. Fired a few shots without ear protection and while it is a bit louder it is not so bad that it is painful. The brake is not quite effective enough to control the muzzle jump to the point that you can watch your bullets impact the target through the scope but it is much closer, you can at least see the target throughout the recoil. Ideally my end goal would be able to control the recoil to the point where you can completely watch the impact and perform follow up shots with only minor adjustments to point of aim. The AMD-65 brake does not accomplish this, but it is much better than without. For the cost at $10 it was worth the time to modify the brake. I will eventually by a precision machined American brake but for now this will do. Quote Link to post Share on other sites
poolingmyignorance 2,191 Posted April 30, 2012 Report Share Posted April 30, 2012 What about drilling a few small holes in the top of the AMD break, allowing gas to escape and pushing down as well as sideways? Just start small and ease up in size. Quote Link to post Share on other sites
mtjccmotel 12 Posted April 30, 2012 Author Report Share Posted April 30, 2012 Thought about drilling the brake haven't decided, but if so I will start small. While I am at it I may angle the holes a few degrees toward the shooter and see if I can get more recoil reduction. The nice thing about modifying this brake as it is not an expensive loss if it becomes a paperweight. Quote Link to post Share on other sites
jojo200517 68 Posted May 1, 2012 Report Share Posted May 1, 2012 That looks pretty freakin sweet to me. Glad to hear it give some improvement and look forward to reading about your adventures in drilling the top of it Quote Link to post Share on other sites
buddharacing-1 2 Posted May 5, 2012 Report Share Posted May 5, 2012 How was the flash reduction? Quote Link to post Share on other sites
patriot 7,197 Posted May 5, 2012 Report Share Posted May 5, 2012 The AMD brake works well, but it is definitely a loud brake. It was designed to make "an intimidating noise". Try two 0.250" ports on the top of the brake, centered above the horizontal ports closest to the muzzle. That should get you a decent amount of thrust to counter the muzzle rise. Chamfer the holes on top, and stick at 90 degrees to the bore or you'll start eating scopes from backblast. Quote Link to post Share on other sites
poolingmyignorance 2,191 Posted May 5, 2012 Report Share Posted May 5, 2012 The AMD brake works well, but it is definitely a loud brake. It was designed to make "an intimidating noise". Try two 0.250" ports on the top of the brake, centered above the horizontal ports closest to the muzzle. That should get you a decent amount of thrust to counter the muzzle rise. Chamfer the holes on top, and stick at 90 degrees to the bore or you'll start eating scopes from backblast. Sounds like you found this out the fun way! Quote Link to post Share on other sites
patriot 7,197 Posted May 5, 2012 Report Share Posted May 5, 2012 I know this from shooting 50BMG target rifles. Brake blast destroys optics, and, in the case of 50BMG or above can give you concussion sickness. Not fun. Quote Link to post Share on other sites
Dad2142Dad 6,559 Posted May 5, 2012 Report Share Posted May 5, 2012 (edited) Ouch, get that man a beer STAT Edited May 5, 2012 by Dad2142Dad Quote Link to post Share on other sites
mtjccmotel 12 Posted May 7, 2012 Author Report Share Posted May 7, 2012 Can't comment on flash reduction as I have not shot the gun in low light with the brake on, but with the 21" barrel there is normally little fireball. I tend to shoot reloads which also reduces muzzle flash. Will post a pick of low light shooting as soon as I can. Patriot thanks for the advice on the top ports. I think I'll start with two holes that are 7/64" (if I remember correctly I think the bit is what I used for the 3mm FSB pins) and move up from there, but I'll take your suggestion regarding 90 degrees to bore and chamfering. Will keep you all updated with progress. On another note, when I initially bought the brake I purchased two. Over the weekend I bored and tapped the other to 5/8-24. I'll experiment on the original brake and modify the second to what works best. Quote Link to post Share on other sites
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