PTR 91 Muzzle Thread

[NapaPlinker]

Going to make my PTR featureless vs fixed mag. There are quite a few options for the thread pitch.. Can anyone tell me for sure what I should be looking for?

Thanks!

[ar15barrels]

Should be 15x1 unless PTR used barrels with 5/8-24 threads.

[NapaPlinker]

Should be 15x1 unless PTR used barrels with 5/8-24 threads.

Thank you. That narrowed it down!

[Top Shotta HiFi]

https://www.hkparts.net/shop/pc/HK-G3-91-PTR-NY-CA-Muzzle-Brake-15-X-1-USA-p12746.htm

US Made HK Bird Cage Style Partially Slotted NY, CA Compliant Thread Protector, Faux Flash Hider 15 X 1 Right Hand

[NapaPlinker]

https://www.hkparts.net/shop/pc/HK-G...USA-p12746.htm

US Made HK Bird Cage Style Partially Slotted NY, CA Compliant Thread Protector, Faux Flash Hider 15 X 1 Right Hand

Just saw that. Thank you!

[NapaPlinker]

Just saw this.. "PTR has stated that late 2015 going forward all newly manufactured barrels would come with the US 5/8 X 24 threaded barrels rather than original HK spec 15 X 1 threaded barrel."

I bought mine maybe two years ago.. Is there a way to make sure I do not order the wrong one? DAG FLABBIT

[NATEWA]

https://www.amazon.com/Field-Sport-Thread-Protector-Pitch-936/dp/B009PCKJZU/ref=mp_s_a_1_1?ie=UTF8&qid=1549501518&sr=8-1&pi=AC_SX236_SY340_QL65&keywords=5%2F8+x+24+thread+protector&dpPl=1&dpID=41O-ftnu%2BSL&ref=plSrch

[Neil McCauley]

https://www.hkparts.net/shop/pc/HK-G...USA-p12746.htm

US Made HK Bird Cage Style Partially Slotted NY, CA Compliant Thread Protector, Faux Flash Hider 15 X 1 Right Hand

Ooh just picked one up too, tanks

[NATEWA]

https://hughesprecision.com/product/15x1mm-id-to-58-24-od-barrel-adapter-thread-converter/

[NATEWA]

https://www.hkparts.net/shop/pc/HK-G...USA-p12746.htm

US Made HK Bird Cage Style Partially Slotted NY, CA Compliant Thread Protector, Faux Flash Hider 15 X 1 Right Hand

I had this on my PTR. Took it off because it looked like a flash hider. Put on the thread adapter and a surefire muzzle brake.

[LEAD LAUNCHER]

https://hughesprecision.com/product/...ead-converter/

Just picked up one of these as my PTR is 2013 era.

And for an extra $9.50 I had them throw this in the box too-why not?

https://hughesprecision.com/product/hot-blued-fluted-thread-protector-5-8-24-tpi-7503-4-diameter-5-8-long/

[1919_4_ME]

Just saw this.. "PTR has stated that late 2015 going forward all newly manufactured barrels would come with the US 5/8 X 24 threaded barrels rather than original HK spec 15 X 1 threaded barrel."

I bought mine maybe two years ago.. Is there a way to make sure I do not order the wrong one? DAG FLABBIT

Does your muzzle brake have the little steel retainer spring on the end? If so it's a 15x1mm RH HK thread. If you have to use a wrench to get it off, then its a 5/8-24 thread.

[LEAD LAUNCHER]

Does your muzzle brake have the little steel retainer spring on the end? If so it's a 15x1mm RH HK thread. If you have to use a wrench to get it off, then its a 5/8-24 thread.

Just to note.....

My PTR came straight from Atlantic and had neither the retainer spring nor a wrench flat on the Hider.

I knew it had to be 15x1 because of the date that it was made.

I used a strap wrench to remove it as I had blue Loctited it on myself...Due to it constantly unscrewing while I was firing it.

[loademup]

Does your muzzle brake have the little steel retainer spring on the end? If so it's a 15x1mm RH HK thread. If you have to use a wrench to get it off, then its a 5/8-24 thread.

Latest specifications for the PTR 91 (available as a pdf document at the PTR website) states muzzle threading is 5/8 x 24

Here is the current specifications for the PTR 91 GI rail model as an example:

http://ptr-us.com/wp-content/uploads/2018/02/GIR.pdf

I believe in 2016, they changed the muzzle thread size. So which thread size is on OP's rifle probably depends on when his rifle was manufactured.

If you go to the HKPARTS website, you will therefore see muzzle devices threaded for both 15x1 and 5/8 x 24.

[NATEWA]

Just picked up one of these as my PTR is 2013 era.

And for an extra $9.50 I had them throw this in the box too-why not?

https://hughesprecision.com/product/hot-blued-fluted-thread-protector-5-8-24-tpi-7503-4-diameter-5-8-long/

Very nicely made adaptor but not nearly as deep as the flash Hider that came off so you do see exposed barrel contours and what not that you don’t normally see with the factory flash Hider on.

Not a big deal for me but some people that are super picky about looks may not like it.

Mine is threaded to an extra VG6 gamma 300 blackout 2 port brake I had sitting around that was getting no use.

The adapter pretty much looks like part of the brake now that they are screwed together.

Here is a pic. Not worried about the looks. More concerned with how it works. I finally completed all of the mods to my PTR except for sending off the trigger to Bill. I keep reading mixed results so I probably won’t sent it to him. I also need to do the homemade ambi safety. I’ll post a link to the thread I started in case OP or others are interested.

https://www.calguns.net/calgunforum/showthread.php?t=1401655