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Discussion Starter #1 (Edited)
Guys, I got in a PSG-1 stock, but it has a heavy G3 2 stage buffer in it. Thought maybe someone swapped it out, so I went to replace it with a standard PSG-1 single stage buffer. When I removed the 2 stage heavy G3 I noticed the hole in the metal and stock is HUGE. The rear bolt is also a huge hex head with a massive washer. The PSG-1 buffer is the same length but it does not have any support on the walls of the tube when installed like the G3 2 stage heavy. The G3 2 stage heavy fits like a glove, nice tight fit in the tube, but the PSG-1 buffer has about a 1/8 space on both sides when centered. Anyone taken one of these apart. Is the hole that big in all of them? I have never had reason to check until now, and this is the only PSG-1 stock I have in stock at the moment. Did Hk ever make any special with 2 stage buffers or did someone just do an old swap-a-roo? Date code is "4IJ" on the stock.

Any info would be great. Thanks
Kenw45


 

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Seems like I recall the early PSG1 stocks having the Heavy buffer and the later ones having the single-stage MSG90 unit.

ETA: Going by Buddy Hinton's picture:

 

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It seems like it would shoot pretty smooth. Both of my PSG and MSG90a1 stocks have their standard buffer in them. I will take a look later and see if the have the clearance. The PSG1 is so heavy recoil is minimal.

Update: No extra clearance around my MSG buffers.
 

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I'de like to hear weather or not the Buffer needs support in the stock as well, other than the two screws up front and the one in the back. I'm currently replacing the backplate/recoil rod assembly on a SG1 stock and am considering swapping the 2 stage buffer for the MSG one while the stocks apart, as I hear the MSG is better for semi auto, but like Ken pointed out, while the 2 stage fits nice and snug, there is a large difference in the hole clearence in the backplate and the stock when the MSG buffer is installed, so I am also worried about it not having any support in the middle.
 

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Discussion Starter #5 (Edited)
tmbrwulf,

You said "Update: No extra clearance around my MSG buffers."
So I take it that your's has a smaller internal stock tube and a standard size buffer hole in the metal. What kind of bolt does it have under the cheek piece? Hexhead or flat head?



Ultimate Shield,

Not sure how important the side wall support is, but I am sure HK made the stocks for specific buffer diameters for a reason. You cant fit a heavy buffer into a standard stock. The tube diameter is smaller and the internal support with not fit properly.

Also let me know how you got the SG-1 stock apart. You have internal cheek piece tubes in the way.




As a side note. I have seen where people have dremeled out standard stocks and installed heavy buffers and the stock ened up cracking because the buffer was not popperly supported in the stock.


Someone else out there check your PSG-1 stocks.
 

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Ken, concerning the SG1 stock disassembly.

After looking at the stock for a while inside and out
I used a press to push ONLY the front tube UP, twards where the cheek rest is, so that it got out of the way of the screw. Reason being the tubes are swedged into the stock and I didn't want to ruin the factory swedge at the top of the tube where the cheek rest inserts. After that you can use a very long and THIN shanked screw driver to get past the rear tube to the screw inside. (I used a screw driver with a shank that measures out to .1875, or 3/16). After the screw is out of the buffer the whole assembly can be removed.

If it's easier, I can make a thread with instructions and photos that show how I did it while I'm reassembling it this weekend.



As for the no support issue
That's what I feared, last thing I want is cracking a SG1 stock with a unsupported buffer. Though the solution may be as simple as machining a sleeve that goes around the buffer to fill up the space. But that may be more trouble than its worth
 

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Discussion Starter #7
Please make a thread with pictures for the SG-1 buffer replacement. That would be great!
 

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Sure thing, I'll try and have it up by Saturday.

On another note
I just measured out the stock hole on my PTR91 stock and it measures out to roughly .900 thou, or 23mm
So I measured out the stock hole on my SG1 stock and it measures out to roughly .910 thou, or 23.25mm. This should be the same size hole for the PSG-1 stock with the 2 stage buffer

The PTR/Hk91 standard buffer shank measures .785, has no screw in the back, and is free floating by about .057 thou on all sides inside the PRT stock. And it's only supported be the two screws.
By comparison if it were installed in the SG1 stock, it would be free floating on all sides by about .0625 thou, a difference of only 5.5 thou between the two stocks.

I haven't heard of any PTR stocks breaking using their standard stock & buffer config, So if the MSG buffer is the same diameter as the standard buffer, theoretically speaking, the MSG buffer should be just fine free floating, as long as the extra length/weight of the buffer doesn't have an effect.

But again, I wouldn't necessarily want to prove this with a $500+ stock
 
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