Question about shimming

[Chundoo]

I have gone the the trial swimming of my Knight Elite with an SSK bare primer BP with adapter. I get a very slight "feel" closing the naked bolt with one .005" shim. The primers measure the same afterward so no crush is happening. With two shims I get .005" crush. Is that too much? I've read .002 to .003" is the ideal target.

Thanks for the help.

 

[michiganmuzzy]

.005 isnt too much, imho. .002-.003 is ideal. And it will vary with the lengths of primers used too, as the measurements vary even among primer from the same lot, in the same pack. Were you sorting your primers first and testing with the longest or shortest?

 

[Chundoo]

Yes, these were using the shortest.

 

[michiganmuzzy]

Yes, these were using the shortest.

Ok. Only put in one .005” shim. Then sort out some of your shortest primers and see if you get much, or any blow by into the breech when you shoot it. If two .005 shims are giving you .005 crush then you should be perfect with all but the shortest. And those may not even leak.

 

[Chundoo]

With one .005" shim and using the longest 777 primers I get around .002" crush. I did have one primer that didn't want to come out, is that common?

 

[michiganmuzzy]

With one .005" shim and using the longest 777 primers I get around .002" crush. I did have one primer that didn't want to come out, is that common?

Was that after shooting or just testing for crush? Its not uncommon, but it shouldnt be a common event. It may happen occasionally when you are shooting heavy loads. I was getting stuck primers occasionally in a Knight when shooting 80gr Volume and a 345gr lead bullet. I switched to Winchester 209s and stopped getting stuck primers. That only happened in that one rifle.

 

[Chundoo]

Not shooting, just testing for crush.

I assume the .002" crush is adequate but not overkill.

 

[michiganmuzzy]

Yessir that is acceptable crush. Shoot some with your shortest primers and let us know what you get. I think it’ll be good to go tho.