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FAL Thread Adapter

dfletcherdfletcher Member Posts: 8,148 ✭✭✭
edited April 2017 in Ask the Experts
I'd like a few more options for a FAL brake. The current threading is 9/16x24 LH and I'd like to know if a thread adapter going to 5/8x24 is available. Not the stepped type with a female to male to the barrel, male to femal for the device, but a slipover type. I know there's not alot of "meat" left for the walls, but I see the adapter offered taking 9/16x24 RH (used on the 6.5 Grendel) so it seems the same with LH threading would work. So far, no luck.

Comments

  • nononsensenononsense Member Posts: 10,935 ✭✭✭✭
    edited November -1
    dfletcher,

    There are almost no examples of left hand threads in the U.S. firearms industry because they are not necessary. Adapters are not difficult to make but the effort required to make a one-of-a-kind adapter is usually not worth it since the customer will rarely if ever pay what it costs to make it.

    If you have a buddy with a lathe, you could buy a left hand tap for the FAL barrel then turn and thread the outside of that piece. I don't think that there is enough meat left to perform the o.d. threading but it could be done I suppose. Be sure to leave some extra material somewhere to facilitate getting the adapter on the barrel.

    It might be easier[}:)] to cut off the offending threads from the barrel and have the barrel threaded properly, assuring you of an infinite variety of choices for the brake. [;)]

    Best.
  • gunnut505gunnut505 Member Posts: 10,290
    edited November -1
    It may turn out to be easier to replace the barrel with one in the desired threading.
  • dfletcherdfletcher Member Posts: 8,148 ✭✭✭
    edited November -1
    quote:Originally posted by nononsense
    dfletcher,

    There are almost no examples of left hand threads in the U.S. firearms industry because they are not necessary. Adapters are not difficult to make but the effort required to make a one-of-a-kind adapter is usually not worth it since the customer will rarely if ever pay what it costs to make it.

    If you have a buddy with a lathe, you could buy a left hand tap for the FAL barrel then turn and thread the outside of that piece. I don't think that there is enough meat left to perform the o.d. threading but it could be done I suppose. Be sure to leave some extra material somewhere to facilitate getting the adapter on the barrel.

    It might be easier[}:)] to cut off the offending threads from the barrel and have the barrel threaded properly, assuring you of an infinite variety of choices for the brake. [;)]

    Best.




    Thank you.

    I don't have enough barrel to cut off and re-thread, this is a FAL STG carbine with the bipod adapter on the barrel. I was also considering having the 9/16" threaded section turned down to use 1/2"X 28 - then either use AR 15 brake with a 30 caliber exit hole or slip a shoulderless 5/8X24 adapter over it.

    Is 1/2" sufficiently smaller diameter than 9/16" so that the original threading will be obliterated?
  • charliemeyer007charliemeyer007 Member Posts: 7,348 ✭✭✭
    edited November -1
    Perhaps about a 1.25" long adapter. Your barrel threads on one end and what you want on the other end.
  • dfletcherdfletcher Member Posts: 8,148 ✭✭✭
    edited November -1
    quote:Originally posted by charliemeyer007
    Perhaps about a 1.25" long adapter. Your barrel threads on one end and what you want on the other end.


    Thought of that, don't like the "added on" look.

    PTR went to "308" threading on their HK91 style rifles, kind of wish DSA did the same.
  • nononsensenononsense Member Posts: 10,935 ✭✭✭✭
    edited November -1
    dfletcher,

    Turning the 9/16" down to 1/2" for threading 1/2x28 does not leave enough meat around the muzzle for safety sake especially when threaded. Yes, I know you will put a brake on it but the original barrel will be too thin at that point.

    What style of brake are you looking to use on your carbine? Can you post a couple of pictures of examples similar or exactly like you would enjoy having?

    It's easy to buy a brake that has undersize threads, bore out the original threads and the re-cut the new threads LH 9/16x24.

    Best.
  • dfletcherdfletcher Member Posts: 8,148 ✭✭✭
    edited November -1
    quote:Originally posted by nononsense
    dfletcher,

    Turning the 9/16" down to 1/2" for threading 1/2x28 does not leave enough meat around the muzzle for safety sake especially when threaded. Yes, I know you will put a brake on it but the original barrel will be too thin at that point.

    What style of brake are you looking to use on your carbine? Can you post a couple of pictures of examples similar or exactly like you would enjoy having?

    It's easy to buy a brake that has undersize threads, bore out the original threads and the re-cut the new threads LH 9/16x24.

    Best.




    Thank you for the above.

    I like the PRI brake, have it on a few rifles to include a Ruger GSR, and find it to be very effective. Granted the GSR has a forward mounted low power scope, but it's effective enough to keep my eye on target during recoil.

    https://www.midwayusa.com/product/2367125087/pri-muzzle-brake-quiet-control-5-8-24-thread-ar-10-lr-308

    What would be the mechanics of modifying a brake to match the 9/16 threading and 308 exit hole? Most 308 exit hole brakes have 5/8" threading, which is larger than 9/16". If I bought a 1/2" threaded brake that will have a 223 exit hole, the work to be done is open the threading to 9/16" and the exit hole to 308, yes?

    Is taking a 1/2" to 5/8" thread adapter such as the attached, opening up the 1/2" threads to 9/16" viable? I see 9/16 to 5/8 adapters offered, but they are RH threading. Advantage to this is I can easily mail them to my gunsmith.

    http://www.brownells.com/rifle-parts/muzzle-devices/thread-adapters/shoulderless-thread-adapter-1-2-28-to-5-8-24-prod58022.aspx

    Would re-threading the barrel to 14mmX1 be safe? There are a number of AK based brakes similar to the above PRI. Or, buying an AK brake with 14mm threading, opening up to 9/16"? The brake would already have a 308 exit.

    Also, I have an AR in 7.62X39 and it came with 1/2X28 threading, I use a PRWC brake. Should I be concerned or is it compatible with the X39 cartridge while a 308 based is not?
  • nononsensenononsense Member Posts: 10,935 ✭✭✭✭
    edited November -1
    dfletcher,

    Actually, it's a very simple process.

    I would make a test piece out of bar stock by drilling and boring a hole in it to the thread size for 9/16" x 24. Then either tap or single point the threads as a test for fit.

    Buy a brake with a 1/2x28 thread.

    Open that thread by boring it out to the thread size for 9/16" x 24.

    Buy a 9/16" x 24 LH tap, use it in the hole bored out in the brake. Barring this your machinist or GS can single point the LH thread.

    Be sure to trial fit the brake to the muzzle before removing from the chuck.

    Then, simply bore the .22 caliber hole on the brake out to accommodate the .30 cal. bullets. All of this needs to be done in a lathe to insure that the brake is in cylinder with the bore of the barrel. It needs to be fitted with the shoulder perpendicular to the bore and brake hole.

    It actually takes more time to type and explain this than to get it done. It's a simple process made to be handled with a lathe.

    Best.
  • dfletcherdfletcher Member Posts: 8,148 ✭✭✭
    edited November -1
    quote:Originally posted by nononsense
    dfletcher,

    Actually, it's a very simple process.

    I would make a test piece out of bar stock by drilling and boring a hole in it to the thread size for 9/16" x 24. Then either tap or single point the threads as a test for fit.

    Buy a brake with a 1/2x28 thread.

    Open that thread by boring it out to the thread size for 9/16" x 24.

    Buy a 9/16" x 24 LH tap, use it in the hole bored out in the brake. Barring this your machinist or GS can single point the LH thread.

    Be sure to trial fit the brake to the muzzle before removing from the chuck.

    Then, simply bore the .22 caliber hole on the brake out to accommodate the .30 cal. bullets. All of this needs to be done in a lathe to insure that the brake is in cylinder with the bore of the barrel. It needs to be fitted with the shoulder perpendicular to the bore and brake hole.

    It actually takes more time to type and explain this than to get it done. It's a simple process made to be handled with a lathe.

    Best.




    Many thanks. I think it's time to send off to the gunsmith. Modifying the less expensive brake and not the rifle makes sense too.
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