the extractor cut, or cuts on the chamber sleeve of the barrel
There is usually plenty of forgiveness here - at least there should be - much more than the <20 minutes of the front sight. More off topic, but I say "should be" because I can report from experience that on brand new criterion krag barrels the extractor relief cut is quite exact - no tolerance at all. I scratched my head first one I did wondering by the bolt was sticking. Took the new barrel off and compared against originals I had and...yep. the originals are all ~10 thous. wider than the new one. Haven't had similar issues on any other make of rifle and criterion barrels.
Originally Posted by 1903Collector
AS the fixture gets tightened onto the barrel shank
correct. I should have said "AFTER".
Originally Posted by 1903Collector
I cant comment on the M1917 as I have not studied the manufacturing process. Its a Brit design, so there may be operation differences.
There was an historic video posted and discussed some time ago of m1917 manufacturing that showed a workman installing barrels onto receivers. If I remember correctly, the receiver was held stationary while the barrel was turned by a machine. It looked like the operator manually stopped turning when the marks were in alignment. Maybe someone with better googlefu can find it.
Originally Posted by MAC702
We were taught to lightly tap on the gas cylinder that will be the final one to use with that assembly
Don't forget to first peen the edges of the barrel splineways, as needed! Both sides of the top one, and the lower edges of the other two.
I suppose I will finish by saying, with a smile, that we have expended exponentially more words on all the many steps needed or accomplished to ensure draw lines are accurate enough than we have on the rather simple process making sure an m1 barrel gets timed to spec. without draw lines. This should also be evidence that the garand production crew had a good handle on the topic.
I am just too much of a mech design and manufacturing engineer to accept that this is possible when all of the design and manufacturing engineer specs are met and followed.
two words - government employees. They come in many different varieties of enthusiasm, effort, character, ethics, etc. I'm sure this was just as true back then as it is now. Canfield's book references labor turnover reports as well. I think at the start of M1917 production Winchester was at 269% attrition per month for a workforce in the thousands, giving an average time on the job of ~10 days. Competition for skilled labor was fierce, and most didn't last for lack of skill but because of substandard or no housing, access to food, etc. Communities around the factories couldn't just switch on access to necessities for 13,000+ new employees and their families.
Here is my m1917 drawing marks.
The darker area of finish is a perfect "shadow" of the lower band. There is another even more perfect shadow of the upper band, complete with screw hole, just in front. Must have been during the last arsenal refurb when it was parked. My guess is bands and front sight were left on and the sandblaster operator neglected to move the bands to get underneath. The blued areas of course didn't take the park. Original finish under the front sight too. I corrected the timing of my 03a3 since it was very noticeable by eyeball and effected the zero. I have no reason to touch this m1917.
1:50 spline milling. given the man doesn't seem too careful in inserting the barrel to the fixture, I'd guess the threads and draw line are indexed off the spline he cuts.
Ok, I was wrong about attaching receivers. I must have been thinking of a different video of a different rifle's assembly
5:33 barrel attached to receiver, looks like it's all eyeballs.
EDIT: Just to stay on topic...m1 rifles attached to receivers and aligned starting at 1:38
Well now, I see the video in my post and yours.
"https://youtu.be/39wM-lzDWE4" is the 1917 video (which you also found)
"https://youtu.be/44GtT7yxJEw" is the second video I posted showing garand production in case you can't see it either.
Originally Posted by 1903Collector
PM
