Sunday, 11-02-08 TUNNEL REPORT

G

Gene Beggs

Active member
Barrel Indexing continued:

Last week I was disappointed and a bit discouraged after my experience with small diameter tenons. With each reduction in diameter, extraction became more difficult.

The tenon diameter of the Stiller drop port is 1.062. Normally, I shoot a hot load of H4198 which chronographs 3350 fps and I did not experience 'click-at-the-top' extraction until installing the second barrel with the .875 tenon. The .875 and .800 tenons will not withstand the pressures we normally shoot in the PPC's and 6mm Beggs cartridges.

My first prototype has proven the best so far. Before threading, the tenon was .940. After threading and making a light skim cut to remove the sharp tops of the threads, it measures .930. It works perfectly and cases extract easily. Indexing adjustments are quick and easy requiring about ten to fifteen minutes to accomplish.

After re-installing this barrel with the .930 tenon, shooting at the tunnel this morning went well. The barrel was declared 'junk' by its former owner but is now shooting in the mid to low ones when indexed in one particular position. Judging by the change in point of impact as the barrel is rotated, this barrel shoots best with the curve pointed 'UP' at twelve o'clock. :eek::

Later,

Gene Beggs
 
Gene Beggs said:
Barrel Indexing continued:

Last week I was disappointed and a bit discouraged after my experience with small diameter tenons. With each reduction in diameter, extraction became more difficult.

The tenon diameter of the Stiller drop port is 1.062. Normally, I shoot a hot load of H4198 which chronographs 3350 fps and I did not experience 'click-at-the-top' extraction until installing the second barrel with the .875 tenon. The .875 and .800 tenons will not withstand the pressures we normally shoot in the PPC's and 6mm Beggs cartridges.

My first prototype has proven the best so far. Before threading, the tenon was .940. After threading and making a light skim cut to remove the sharp tops of the threads, it measures .930. It works perfectly and cases extract easily. Indexing adjustments are quick and easy requiring about ten to fifteen minutes to accomplish.

After re-installing this barrel with the .930 tenon, shooting at the tunnel this morning went well. The barrel was declared 'junk' by its former owner but is now shooting in the mid to low ones when indexed in one particular position. Judging by the change in point of impact as the barrel is rotated, this barrel shoots best with the curve pointed 'UP' at twelve o'clock. :eek::

Later,

Gene Beggs
Click to expand...

Well Gene, there is your solution!

The differencial threaded insert wall thickness must be pretty thin, I am guessing around .080" wall thickness, not very thick in order to cut o.d. and i.d. threads and still have some material separating the two.

Wonder how much you could open up your present Viper action 1.062 thread without hurting the intergrety of the present action insert?................Don
 
Another thought.........

............for Gene, could the original Viper 1.062 insert be removed, and the threaded portion be separated from the bolt lug portion, with the lug portion permanently re-installed, and the threaded portion turned into a differential threaded insert, thereby retaining the original 1.062 dimension, great tennon integrety, no need for re-chambering barrels from original dimensions, no need for additional parts or machining operations except for the alteration to the original insert.

How does Stillar install the original inserts, are they threaded and locktited?...........Don
 
Last edited by a moderator:
Don said:
............for Gene, could the original Viper 1.062 insert be removed, and the threaded portion be separated from the bolt lug portion, with the lug portion permanently re-installed, and the threaded portion turned into a differential threaded insert, thereby retaining the original 1.062 dimension, great tennon integrety, no need for re-chambering barrels from original dimensions, no need for additional parts or machining operations except for the alteration to the original insert.

How does Stillar install the original inserts, are they threaded and locktited?...........Don
Click to expand...

Nope, will not work, you lose the steel lug to barrel integrety, when separating the lugs from the threads, and then rely upon the aluminum action housing for bridging, which just will not cut it.

Sorry, bad idea.....................Don
 
Thanks Don. With the 'think tank' we've got going on this project, we are sure to come up with some good ideas.

Later,

Gene Beggs
 
For the first 1.25 inches

you could probably go out to an 1.125 thread. Dont cut the 1.0 diameter below the threads out. No, I am not making any special inserts and installing them. Sorry.
 
stiller said:
you could probably go out to an 1.125 thread. Dont cut the 1.0 diameter below the threads out. No, I am not making any special inserts and installing them. Sorry.
Click to expand...


Jerry, I won't be modifying any of your actions. They are too nice to cobble up. I love 'em. :)

Gene Beggs
 
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