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

[ronlaughlin]

Remington STS are uniform length, but they are a way hotter than the 777 primers. STS run about 0.294"; vary very little from that. Perhaps the Remington muzzle loader primers are uniform length???????

 

[Far Sighted]

There is a different way to eliminate the excess headspace for 209 primers which I found works for me on both of my CVA Optima MLs.

I accomplished this by adjusting both the breech plug and the firing pin body CCW from their seating point. I turned each CCW the amount needed to stop the blowby and to get a clean spent primer.

The approximate amounts of CCW movement for the breech plugs was 30 degrees. I found this by turning the breech plus excessively until the action wouldn't close to lock. Then turned the plug CW enough to allow the action to close to lock without much force. At this point the back of the breech is seated squarely with the firing pin housing.

Then I did similar on the firing pin housing but it required only about 20 degrees of CCW action. I tested this on a primer to see it was being shortened any by measuring before and after results. I used a caliper.

This isn't something everyone can do so be aware. It takes some experience and patience. Now when I clean in this area or remove the breech plug I know the location that I need to get the same results. I have shot both rifles many times since I discovered this tuning action. It is doing very well.

Here are some photos of results after several shoots:

 

[GM54-120]

That is not going to work so well on the current CVA plugs. The action wont close if the QRBP is not seated all the way but the real issue is the plug seals on the nose too. Your Optima Pro is a pre 2009 style plug. You can shim out the firing pin bushing to achieve the same goal or shim the primer pocket.

Backing out the plugs is a good way to increase the chance of flame cutting and it wont be just the plug. The barrel will end up being cut too.

 

[Far Sighted]

Thanks GM!

It is doing very well on my Optima V2 LR which is 13 months old.

On each I apply a small amount of thread seal compound at the first few threads instead of grease. Pipe thread sealing tape works but isn't as easy to apply .

Both are much cleaner around a normally dirty action especially the VI pro. The V2 wasn't as bad to start but very clean now.

All the primers are sealing very good. I was amazed at the improved results.

BH 209 is being used in each.

 

[DaMitch]

I have a Cooper 50 cal bolt in line ML. I still shoot 2F swiss as I have a load of same. I found that blow-back was a real problem with the depth of the primer pocket within the breech plug. Am using an O'ring (would have to check for the size) to make for a press fit of the primer. It has worked very well and the O'rings last for a large number of shots.
Dave

 

[Matthew323]

What size o-ring should I purchase for a new-to-me, lightly-used, Optima V2 pistol; which will be equipped with a new, Lehigh Defense QRBP breech plug with interchangeable vent liners?

This will be my first inline.

Thanks

 

[michiganmuzzy]

What size o-ring should I purchase for a new-to-me, lightly-used, Optima V2 pistol; which will be equipped with a new, Lehigh Defense QRBP breech plug with interchangeable vent liners?

This will be my first inline.

Thanks

Same as the other CVAs use
9262K611 from McMaster-Carr
4.5mm ID 1.0mm thickness Buna-N

 

[birdog]

I may have missed it but how much crush are we looking to achieve? I have shimmed my breech plug. My primer measured .300 and after installing and checking the primer was .2915. I'm curious if that is too much?

 

[HC]

I Usually try for .005 or .006. For light to medium loads then .003 or .004 will work just fine.

 

[BrantSFGDS]

FYI, there's place in Michìgan named Badger Ridge Industries that sells the various shims in pack of 3.

 

[outdoorsmen]

On the McMaster site I dint see the size .0241 or .0248. Only .250.

 

[GM54-120]

18-8 Stainless Steel Shims for Lengthening Screw Shoulders

18-8 Stainless Steel
1/4" No.10 ID .171 x OD .241 x .005 thickness
Part# 90135A431
$12.83/50

These are the .248s. Just search the site using the part#s

 

[outdoorsmen]

Thanks!

The .005 the best option?

 

[HC]

Thanks!

The .005 the best option?

Yes

 

[smy1]

Great info. I did this on my new CVA Optima V2. The .248 shims were looser than I wanted. I went with these at mcmaster.com McMaster-Carr These are .250 OD and .125 ID and were a better fit

 

[GM54-120]

But with a CVA you can shim the firing pin bushing out instead. Shimming the bushing out keeps more primer IN the breech plug.

 

[outdoorsmen]

How many .005 shims is the average to use? I just tried 4 and measured before and after and there wasn't any difference on the primer .300 w209 and cci 209m. The bolt handle was a bit harder to close

 

[HC]

The most that I’ve heard of was .035 total. That was in an original disc knight.

 

[GM54-120]

Remove the bolt internals for a better FEEL when closing the bolt on the primer. Just use the bolt body. If the bolt handle falls down with almost no effort its not getting any primer crush. About .003 crush using ONLY the bolt body will get you into a good range assuming primers are consistent in length.

 

[gregdaws]

Just curious, I have a disc Extreme with a knight 209 conversation. I'm thinking of using the original bolt and going over to the Lehigh adaptor / breech plug. Are people shimming the lehigh breech plug or Is it a better fit? It's my understanding that Lehigh make the breech plugs for Knight which coincidently are twice the price with no vent liner !!