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Sig357
04-22-2008, 4:26 PM
I have a PTR91 with a Plastic Navy Lower and have the following questions:

1. Will a Steel G3 or HK91 Lower fit my PTR91 rifle.
2. Will my current PTR91 FCG fit in the Steel Lower.

Reason: I have recently acquired a Bell & Carlson Thumbhole stock which the pistol grip part will not fit over the plastic lower pistol grip. So I am in need of a Steel Lower were I can use different types of grips so I can get the stock to fit properly.

I am planning to fill the thumbhole stock so I can use pre-ban mags with my PTR91.

Forever-A-Soldier
04-22-2008, 4:33 PM
I've got a steel lower/trigger group and a navy one. I haven't switched out the trigger group, but my understanding is they are the same. I've got a steel frame from a G3 I intended to clip&pin for future use on a future PTR. If you want to check that out, I'm over in PS. If it works, you can buy one on Gunbroker for around $25 or so.

Drop me a PM if you are interested.

F.A.S. Out

Ak47owner
04-22-2008, 4:36 PM
to answer both of your questions yes; they will all work with the same TG. you may even buy a CETME lower and it will still work! i would get the clipped and pinned version http://www.robertrtg.com/g3seflower.html

Sig357
04-22-2008, 4:46 PM
That sounds like good news. However I am a little confused on the "clip & pin" part. My PTR91 receiver has a block with no hole for a pin.:confused:

Edit: I think I understand. The clip and pin does not go all the way through. It just gives it the look that it has a pin through it. Right?

Sig357
04-22-2008, 6:20 PM
Is this what I would need for my PTR91, just get it clipped and pinned?

http://www.robertrtg.com/g3steellowercomplete.jpg

Charliegone
04-22-2008, 9:26 PM
I have a PTR91 with a Plastic Navy Lower and have the following questions:

1. Will a Steel G3 or HK91 Lower fit my PTR91 rifle.
2. Will my current PTR91 FCG fit in the Steel Lower.

Reason: I have recently acquired a Bell & Carlson Thumbhole stock which the pistol grip part will not fit over the plastic lower pistol grip. So I am in need of a Steel Lower were I can use different types of grips so I can get the stock to fit properly.

I am planning to fill the thumbhole stock so I can use pre-ban mags with my PTR91.

1. Yes it will.

2. Yes it will but the selector switch will not. Why? The steel is thinner so it uses a "regular" selector switch. The plastic one is thicker and uses a longer selector switch. Just keep that in mind.

redcliff
04-22-2008, 9:28 PM
Clipping is cutting out a shelf on the front of a FA pistol grip to use on the semi-auto receivers. The FA trigger group will not fit without modification and doing that modification would potentially create a unregisterred MG if combined with a FA bolt. Therefore you can not use the trigger group in the SEF grip you have pictured and may as well find a compatible stripped, clipped and pinned grip frame plus the grip.

Pinning is just for looks, but it looks cool.

As far as what works with your Navy trigger assembly, do yourself a favor and call:
HK PARTS Adam Webber 801. 440. 5060

Adam will tell you what works for sure and give you a quote. Super nice guy and fast shipping. As was stated, Navy's use different selectors than SEF's.

rorschach
04-22-2008, 9:31 PM
+1 for Adam Webber.

Gordon Miller at hkspecialist.net is an excellent resource as well.

elSquid
04-22-2008, 9:35 PM
to answer both of your questions yes; they will all work with the same TG. you may even buy a CETME lower and it will still work! i would get the clipped and pinned version http://www.robertrtg.com/g3seflower.html

I made the mistake of poking around that website.

ARRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGHHHHHHHHHHHHHH (http://www.robertrtg.com/g3magazinenlikenew.html).

-- Michael

dwtt
04-22-2008, 9:54 PM
I made the mistake of poking around that website.

ARRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGHHHHHHHHHHHHHH (http://www.robertrtg.com/g3magazinenlikenew.html).

-- Michael
That's cheaper than when they were legal here and we were able to buy them at the cow palace gun show. Incredible.

Sig357
04-23-2008, 3:21 AM
Thanks for the help guys, greatly appreciated. I will give Adam a call.

Addax
04-23-2008, 10:57 AM
Adam at Hkparts.net will hook you up.

ptoguy2002
04-23-2008, 12:44 PM
1. An UNMODIFIED G3 lower will not fit. An HK91 lower will fit, provided that the semi auto shelf location on the receiver is in the proper position, just as HK had them. I have read elsewhere about clones having problems with these, and a little shiming needed to get them to fit, but these were all another brand, and have read good things about the PTRs in general. A G3 lower can be modifed to fit. If its a plastic lower, its a matter of cutting out some of the grip frame, but you'd be wise to buy one already done, as its difficult (but not impossible) to get done right if you don't know what you are doing. The metal frame requires a shelf be welded inside to engage the semi auto shelf on the receiver.
http://i71.photobucket.com/albums/i123/ptoguy2002/g3frame.jpg

2. The PTR91 trigger pack (the aluminum one, two piece bolted together, marked either JLD or PTR on the top) will fit inside the converted metal G3 sef frame if its done right, and will fit inside an HK 9X type lower out of the box.
A PTR trigger pack will NOT fit inside of a Navy ambi lower, as the selector switch is different.

A word of cautin to anybody mixing and matching HK lower parts. There were two different methods of limiting trigger travel on HK clones. The first (and proper) method is to drill a hole in the side of the metal HK box, and weld in a pin to actually limit the trigger travel. With this method, it doesn't matter what lower you actually put it in, as the travel is limited by the welded in stop in the trigger housing. Springfield Armory (and maybe others, FAC???), in their infiinte wisdom, decided to limit the travel by welding a little stop to the outside of the converted SEF frame. This prevents trigger overtravel by limiting the movement of the safety selector to keep it from going to "F" position, so the safety selector stops the trigger. The downside to this is that if you switch lowers to another one, you no longer have a trigger stop, and if you pull the trigger too far back, the hammer will NOT engage the sear when it comes down, go back forward again, and ride the bolt carrier forward. This has two obvious problems, I'll let you think about it.
That is your HK clone lesson for the day.

Another pic, note the push pin cut apart, and glued into the frame on the C&P plastic one. Just makes it look cool, thats all.
http://i71.photobucket.com/albums/i123/ptoguy2002/FRAMES.jpg

ptoguy2002
04-23-2008, 12:54 PM
One of my projects that I've been meaning to do is to cut apart a G3 frame, put together in a matter that would use an MMG grip. One of these days........

ptoguy2002
04-23-2008, 12:59 PM
to answer both of your questions yes; they will all work with the same TG. you may even buy a CETME lower and it will still work! i would get the clipped and pinned version http://www.robertrtg.com/g3seflower.html

No, no, no, no.
Doing that would be like putting a cheap, worn out VW air cooled engine in a brand corvette Z06 chassis.
You just can't.




****Though not quite as bad as another board member here wanted to use a CETME kit on an Indep receiver. really bad.
And if you are reading this, I still want to buy your Indep receiver. It will have a real nice home with me !


.........

ptoguy2002
04-23-2008, 1:02 PM
The steel is thinner so it uses a "regular" selector switch. The plastic one is thicker and uses a longer selector switch. Just keep that in mind.

Missed that one, yeah, the steel uses a shorter selector than the plastic one.

http://i71.photobucket.com/albums/i123/ptoguy2002/SELECTOR.jpg

ptoguy2002
04-23-2008, 1:15 PM
Clipping is cutting out a shelf on the front of a FA pistol grip to use on the semi-auto receivers. The FA trigger group will not fit without modification and doing that modification would potentially create a unregisterred MG if combined with a FA bolt. Therefore you can not use the trigger group in the SEF grip you have pictured and may as well find a compatible stripped, clipped and pinned grip frame plus the grip.

Pinning is just for looks, but it looks cool.

As far as what works with your Navy trigger assembly, do yourself a favor and call:
HK PARTS Adam Webber 801. 440. 5060

Adam will tell you what works for sure and give you a quote. Super nice guy and fast shipping. As was stated, Navy's use different selectors than SEF's.

FA G3 trigger packs can be legally modified for use in a semi auto gun. There is even an ATF letter about it, I knowI have it saved somewhere, and even tells what dimensions to cut where. The trigger housing needs to be cut to fit the welded in shelf in the lower, Doing this cut also cuts out the pin location for the FA sear, trim the cut off part to fit the upper section of the cutout, and weld in. Weld in trigger stop. Grind off FA catch on hammer. Of course dispose of FA sear and trip lever. You need a new bushing for the sear spring shaft, and can either buy a new sear spring, or very carfully bend it with plyers. The problem with this all is that now, there are US made parts for these, which you need for 922 compliance anyway.

The FA bolt thing is along the lines of having an FA bolt in an AR. Technically its legal, but I wouldn't want to have to explain that to somebody. And Mr. Olofson (I think that's his name, guy in WI) would probably recommend, there's is no reason to have it, so you might as well spend five minutes with a dremel and cut out that trip lever spot on the FA carrier.

+1 for Adam Webber too

Lon Moer
04-23-2008, 1:45 PM
http://mwdg3.homestead.com/files/G3_91_carriers.jpg

ptoguy2002
04-23-2008, 1:48 PM
Bored at work.

New sig line, you like......

redcliff
04-23-2008, 1:52 PM
FA G3 trigger packs can be legally modified for use in a semi auto gun. There is even an ATF letter about it, I knowI have it saved somewhere, and even tells what dimensions to cut where. The trigger housing needs to be cut to fit the welded in shelf in the lower, Doing this cut also cuts out the pin location for the FA sear, trim the cut off part to fit the upper section of the cutout, and weld in. Weld in trigger stop. Grind off FA catch on hammer. Of course dispose of FA sear and trip lever. You need a new bushing for the sear spring shaft, and can either buy a new sear spring, or very carfully bend it with plyers. The problem with this all is that now, there are US made parts for these, which you need for 922 compliance anyway.

The FA bolt thing is along the lines of having an FA bolt in an AR. Technically its legal, but I wouldn't want to have to explain that to somebody. And Mr. Olofson (I think that's his name, guy in WI) would probably recommend, there's is no reason to have it, so you might as well spend five minutes with a dremel and cut out that trip lever spot on the FA carrier.

+1 for Adam Webber too

Not really any good reason to modify a FA trigger pack when the OP has a SA trigger pack. I believe you that done correctly a highly modified FA trigger pack is legal, however done incorrectly (which is possible) you're creating a mg.

ptoguy2002
04-23-2008, 2:08 PM
Actually, Arizona response systems has a good thing on building G3 rifles, which has a lot of the semi auto trigger stuff I've been talking about.
Figured I'd find it somewhere:
http://www.arizonaresponsesystems.com/notes/sw3build/pagesw3build.htm

ptoguy2002
04-23-2008, 2:16 PM
Not really any good reason to modify a FA trigger pack when the OP has a SA trigger pack. I believe you that done correctly a highly modified FA trigger pack is legal, however done incorrectly (which is possible) you're creating a mg.



The trigger stop thing I mentioned is really important, and yes, needs to be done correctly (for the reasons I explained).
An yes, if you already have one no need, I am just bored at work and am getting a little long winded.

Sig357
04-23-2008, 7:09 PM
Thanks for the help guys. Great information here.:D