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Two Sako Questions
- Thread starter alextran
- Start date
Harry Bonar
New member
Sako
Dear Sir:
The Sako L579 has a thread O.D. of 1" dia with 16TPI.
The Sako L-57 had an O.D. of 25MM and 1.5 MM thread.
The Sako L-46 O.D. is .855 and 16 TPI.
Not able to find the Sako 75 specs.
With Sako actions you reallyy have to unscrew the bbl to be sure!
I once rebbled a Sako A11 action, taking off a 22-250 bbl that shot 1/2" groups at 200 yds I installed a 308 bbl.
Upon checking the original Sako bbl. in the lathe it ran out over .020" in the middle and when looking through the bore with lathe running the inside ranout a corresponding amount!!!
So much for barrels having to be straight to shoot good!
Harry B.
Dear Sir:
The Sako L579 has a thread O.D. of 1" dia with 16TPI.
The Sako L-57 had an O.D. of 25MM and 1.5 MM thread.
The Sako L-46 O.D. is .855 and 16 TPI.
Not able to find the Sako 75 specs.
With Sako actions you reallyy have to unscrew the bbl to be sure!
I once rebbled a Sako A11 action, taking off a 22-250 bbl that shot 1/2" groups at 200 yds I installed a 308 bbl.
Upon checking the original Sako bbl. in the lathe it ran out over .020" in the middle and when looking through the bore with lathe running the inside ranout a corresponding amount!!!
So much for barrels having to be straight to shoot good!
Harry B.
Harry,
This is a little off topic, but I read something within the last year also stating bent barrels don't mean much in and of themselves. Can't recall where? I think maybe it was a reprint of an article on barrel making processes from Precision Shooting? I believe the trick was the barrel had bent during stress-relieving, and not because of assymetrical stress. The bore had to be coaxial with the contour all down its length so there is no differential heat expansion.
Ditto the comments on the Sako barrels. They seem to have wanted to follow in the large and small ring Mauser tradition. Thank goodness they didn't complicate life by copying the Whitworth thread form.
Nick
This is a little off topic, but I read something within the last year also stating bent barrels don't mean much in and of themselves. Can't recall where? I think maybe it was a reprint of an article on barrel making processes from Precision Shooting? I believe the trick was the barrel had bent during stress-relieving, and not because of assymetrical stress. The bore had to be coaxial with the contour all down its length so there is no differential heat expansion.
Ditto the comments on the Sako barrels. They seem to have wanted to follow in the large and small ring Mauser tradition. Thank goodness they didn't complicate life by copying the Whitworth thread form.
Nick
Harry Bonar
New member
Sako Question
Hey Nick!
At Douglas barrels here is their mfg. process:
Bbl. steel is 4140, heat treated already to their specs and they are having very little scrap.
A piece is cut off the end and Rockwelled (it must be a certain C-scale for reasons to be given later).
It is cut off in lengths and lathed to their specs to fit the Pratt &Whitney deep drilling machine specs.
It is drilled and then reamed and gets the first "air gauge test."
Then, if o.k. it gets sent to the rifling area where the rifling is "ironed in" by a metal displacement button. The twist is controlled by the machine built be G.R. Douglas - a hydraulic cylinder that does the whole operation together with the button and gear driven chuck assy. that turnes the bbl as its rifled.
It is then air gauged again and sent to the "stress reliveing" oven where it is kept at about 500 to 600 degrees for hours, then left to cool.
It is then sent to Mr. Fred Depoy for visual straightness test by eye and air gauged again and the taper, if any (.0001-.0002) is marked by stencil on bbl.
If the stress relief has caused strains to be released in the blank then it is put in "scrap." (There is very little "scrap" at this time from the new steel vendor.)
Totally "straight barrels" are marked "premium" and put in stock, or contoured in a new high speed machine for customer. In my opinion they are the smoothest and best bbls. made!
Harry B.
Hey Nick!
At Douglas barrels here is their mfg. process:
Bbl. steel is 4140, heat treated already to their specs and they are having very little scrap.
A piece is cut off the end and Rockwelled (it must be a certain C-scale for reasons to be given later).
It is cut off in lengths and lathed to their specs to fit the Pratt &Whitney deep drilling machine specs.
It is drilled and then reamed and gets the first "air gauge test."
Then, if o.k. it gets sent to the rifling area where the rifling is "ironed in" by a metal displacement button. The twist is controlled by the machine built be G.R. Douglas - a hydraulic cylinder that does the whole operation together with the button and gear driven chuck assy. that turnes the bbl as its rifled.
It is then air gauged again and sent to the "stress reliveing" oven where it is kept at about 500 to 600 degrees for hours, then left to cool.
It is then sent to Mr. Fred Depoy for visual straightness test by eye and air gauged again and the taper, if any (.0001-.0002) is marked by stencil on bbl.
If the stress relief has caused strains to be released in the blank then it is put in "scrap." (There is very little "scrap" at this time from the new steel vendor.)
Totally "straight barrels" are marked "premium" and put in stock, or contoured in a new high speed machine for customer. In my opinion they are the smoothest and best bbls. made!
Harry B.
casingpoint
Moderator
Two Sake Questions
Sake: Japanese rice wine. Wonderful stuff.
Ammount of Intake: Limited, or it will put you flat on your a$$.
Sake: Japanese rice wine. Wonderful stuff.
Ammount of Intake: Limited, or it will put you flat on your a$$.