Primers bulging out when fired from Enfield P17.

[tobnpr]

Mr. Guffey;

If you have a true "zero" clearance chamber- where the boltface pushes the shoulder tight against the shoulder wall- and at the same time there can exist no gap between the casehead and boltface, then obviously it can't be driven forward by the firing pin.

Most chambers are not like that, with the case pushed tightly against the chamber shoulder threre is a gap of a couple of thousandths or so between the boltface and casehead. In this situation, simply pushing the case into the chamber does NOT seat the case as far forward-tightly- as it can go.

The FP does indeed take up the slack of those thousandths prior to primer detonation.

Not going to debate the point further...

 

[F. Guffey]

If you have a true "zero" clearance chamber- where the boltface pushes the shoulder tight against the shoulder wall- and at the same time there can exist no gap between the casehead and boltface, then obviously it can't be driven forward by the firing pin.

We have members that claim the firing pin shortens the case between the shoulder and case head .005" before the primer is busted. For keeping up if the case is minimum length and the chamber is go-gage length we are talking about .010" clearance. And at one time I would ask if there was a chance they were leaving something out in the sequence of events; they never said, "NO" or "I do not know" and they never listed the design of the receiver.

.010" clearance is no go-gage length + .001" for a 30/06 chamber.

F. Guffey

 

[F. Guffey]

I have a really nice condition pattern 1917 Enfield in 30-06.

Hahaha, looks like the original poster hasn't been back since his post.

There is a story told a long time ago about the M1917. The story does not start out as "once upon a time..." . it does not start out as "you are not going to believe this..."; but your

Hahaha,

reminded me of the story and how it developed. There were a lot of smiths doing the "Hahaha" because they could not figure out what was going on.

F. Guffey

 

[tango1niner]

But in reality it's the same old:

" if you can't dazzle them with brilliance, baffle them with BS ".

 

[RC20]

Each area of expertise has its own lingo.

My favorite twist is the Sprinkler World people insisting that what ever other engineering filed calls static pressure is residual pressure. Not a clue where that came from.

Surveyors have their etc.

Its fine as long as its inside the community, but then there is the rest of the world and they neither give a hoot nor want to about the subtleties of the various definitions.

A working one suffices just fine. And when trying to work with and or convey things, working and effective trumps the true at the heart purely accurate nuances of the trade.

Life's a bit short to make everyone conform to on area of endeavors standards when only two chamber engineers talking to each other cares anyway.

Having been the master or 4 or 8 fields of work, I have no issue with the sprinkler folks other than think they are engineeringly weird when you are the only obelisk on an otherwise flat plain sticking up insisting that residual really means anything.