TC Encore shimming primer pocket

[Mallen]

While waiting on my new shims, I decided I'd shoot a primer so I have a spent primer to drive the shim(s) in. I chose a .30 length CCI 209 magnum primer, because I had a box and I was looking for a primer with that length. I fired the primer (and BTW, it didn't seal the pocket) and I couldn't open the breech. I ended up removing the hinge pin to to open it. The spent primer grew to .307. So I guess now I know what my measurement is for my primer pocket?
I also spent some time knurling my new Thor bullets. I bought them in .500 because I felt the .501 sample was too tight, but the .500 nearly fell down the barrel. The best way to knurl these ended up to be staying away the end of the bullet with the cup. It's easy to deform the cup slightly enough to ruin the progress. I just kept the files off 1/4" or so, the end of the cup. I knurled the bullets until I could see scrapes from the rifling on the knurling. I feel better knowing the bullet will stay seated on the charge. Once I get my primer pocket shims and fix that, I'll take it to the range and see how everything works. Has anyone had issues with "too much crush" to where the hammer will not cock?
Late MZ season in Iowa is approaching fast!

 

[Mallen]

Shims arrived today. .005 shims from McMaster. I have some old Remington 209 primers, the one I used was .294. With 5 .005 shims I got a crush of .001. With 6, I got a crush of .005. The action needed slightly more pressure, but it locked down and the hammer would cock. The Remington STS primers are readily available locally, I'll pick up some of those and measure those.

 

[ElDiablo]

I also spent some time knurling my new Thor bullets.

The other way to get those Thors to fit just right is to flare the rear skirt slightly as has been described in other posts. Have you seen that method?

 

[ElDiablo]

https://www.modernmuzzleloader.com/threads/custom-sizing-thor-bullets.52864/

 

[Mallen]

I do remember seeing that, but I kind of forgot. I just looked and I don't have anything with the correct size. I may have to improvise.

 

[scratcherky]

I do not use shims. I found that a proper size oring completely eliminates blowback and works much better than a shim.

 

[Mallen]

I tried the oring first. It became too difficult to find the correct thickness for my application. So I went with the shims. So far so good. We'll see how it goes after a range session.

 

[Mallen]

Today I have a new issue. The .248 SS shims fall right into the 2 breech plugs I have. The one that came with my Begara barrel and a BH breech plug I bought. Has anyone ran across this? I thought maybe the plugs had a taper so I tried to tap them in place anyway, and the shims fall into my hand. Has anyone actually measured the shims you got? Maybe McMaster pulled the wrong ones? I measured the one I got, that measured .246.

 

[GM54-120]

Dont the Encore line have a way to adjust headspace? Could have sworn i read about it on Bellm website?

https://www.bellmtcs.com/tc-encoreprohunter-headspace-shims-eph-shims
Sure looks like you can shim the firing ping bushing OUT to get it closer to the primer.
https://www.thereloadersnetwork.com/2020/06/28/tc-encore-headspace-how-to/

 

[jsteurrys]

0.025" is a lot of shim. With that much shim a Parker 5-193 "O"-ring should work just fine. It sounds like your primer pocket is kind of loose if a 0.248" shim falls in. It should be closer to 0.243".

 

[GM54-120]

The one that came with my Begara barrel and a BH breech plug I bought.

Just noticed that. The primer pocket in plugs from across the pond are larger ID. A primer like the Nobel 686 have no taper so its the same size at the nose. Looks to me like your best bet is the Bellm shims and a fatter primer. Plugs for the Bergara Encore barrels are pretty much dried up and not the same as T/C plugs.

 

[Mallen]

So here's a crazy idea. With breech plugs like the picture, why not shim the plug on the flange?

 

[GM54-120]

BTW MBsportinggoods still has some Encore Bergara plugs for $22ish.
https://www.mbsportinggoods.com/cva-gun-parts.html#
BLACKHORN BREECH PLUG FOR TC 31655B
Blackhorn breechplug for Bergara Thompson Center Barrels
$21.95

 

[GM54-120]

why not shim the plug on the flange?

Or you know, shim the bushing out and not risk flame cutting a bad seal.