Shimming the 209 Primer Pocket - updated 4/7/16

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I use the Lehigh plug in my disc extreme and normally use Winchester primers but they were crushing 0.010 , I am now using CCI primers and they are crushing 0.006. I did have to add 0.005 to the mountaineer plug using W209 primers.
 
Re: Shimming the 209 Primer Pocket

I had the blowback problem with my CVA Accuras & someone in one of the forums suggested to use these O-Rings which I found really solved my problem. The O-Ring will last for 20/40 shots & you get 100 for $5. They work with different sizes primers.

McMaster-Carr
I use them in my accura and I get no blowback now. I use federal 209a.

It's tough because it seems like it takes about five shots for them to break in. I'm a little uncomfortable with how much force it takes to close the gun when the o-ring is fresh. Did you experience that?
 
Ok just put four .005 shims in without the firing pin bolt was just just free falling with four it’s still dropping fast but stops with the window or door on the bolt just opened shy of an1/8 inch. Then I have to have it a wack with my palm to finish the last little bit. So does that sound about right for you guys that have done it. I don’t want to over do it
 
Ok just put four .005 shims in without the firing pin bolt was just just free falling with four it’s still dropping fast but stops with the window or door on the bolt just opened shy of an1/8 inch. Then I have to have it a wack with my palm to finish the last little bit. So does that sound about right for you guys that have done it. I don’t want to over do it
It sounds good to me, with one exception. The quantity of shims. As a mechanic i would tell you to use as few shims as possible to achieve your needed dimension. So you have four 0.005” shims = 0.020”. I would remove them and get a single 0.020”shim or at most two 0.010” shims. Or a 0.015” and a 0.005”. But thats if i was shimming gears and bearings and such. In this case it most likely will make no dif in performance. But if you just wanted to make it a little less snug fewer shims (of the same dimension) could lighten it up just a teeny tiny bit. Just me being extra picky about something that probably makes zero difference. If it’ll close snug and not leak then its good to go.
👍
 
It sounds good to me, with one exception. The quantity of shims. As a mechanic i would tell you to use as few shims as possible to achieve your needed dimension. So you have four 0.005” shims = 0.020”. I would remove them and get a single 0.020”shim or at most two 0.010” shims. Or a 0.015” and a 0.005”. But thats if i was shimming gears and bearings and such. In this case it most likely will make no dif in performance. But if you just wanted to make it a little less snug fewer shims (of the same dimension) could lighten it up just a teeny tiny bit. Just me being extra picky about something that probably makes zero difference. If it’ll close snug and not leak then its good to go.
👍
Welp I hope it’s gonna be good and not to much I pretty much follow the instructions above. Two shims did nothing the third showed a tad bit of resistance I added a fourth and the last 1/8 of inch or less I have to give it a wack or lean on it a little nothing crazy
 
My UL and my Elite, both with SSK bare primer conversions, both of their bolt handles will not close all the way and that's without a primer in place, like they do when I take out the primer adapter,
 
Maybe your Primer Adapter is rubbing on the face of the hex on the breechplug. I had this issue. I machined the face of the hex back so that the bolt closed easily without a Primer. Others have machined or sanded the Adapter to provide clearance. It should close with no resistance without a Primer.
 
I believe that is problem also, the adapter a bit to long
 
It will effect that amount of Primer crush.
Mine was closing without any effort with or without the primer till I added the shims now it closes but takes some effort witch a thought was a good thing. It’s gonna be another two weeks before I can get to the range to see how it performs. If it didn’t close all the way then I would be worried
 
The front lip on the primer adapter that seats on the breach plug measures 5mm thich, I've taken it down to 3mm and it still doesn't close like it should, but it will fully close with the adapter removed
 
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The front lip on the primer adapter that seats on the breach plug measures 5mm thich, I've taken it down to 3mm and it still doesn't close like it should, but it will fully close with the adapter removed
Are you certain you have the correct breech plug in there? The disc extreme bare primer? Not the Mountaineer or UltraLite bare primer, or the RPJ plug?

That adapter isnt supposed to seat on, or even contact the plug.
 
It's my UL with the correct SSk bare primer kit, it works fine with the Knight factory parts for the red fpj but when I put the ssk breech plug in and the adapter, the bolt won't fully close
 
Ok like I said above I added 4 shims and I think that was one too many because after a few shots I’m having a real hard time closing my bolt. So I just ordered a new one from sks. Here’s what the original looked like after 6 shots
1703706254101.jpeg
It was taped but there is little to none remaining and seems to be fowling all the way to the top threads
 

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