Linstrum
07-07-2009, 01:05 AM
It has been almost a year since I last worked on my John C. Garand Match rifle last August. I had to stop everything to take care of other things and a few days ago I finally got the time to get back to it.
I had been having a lot of trouble getting the shot groups down to even what a military-issue grade Garand can do. After I did all the standard accurizing procedures, like making sure that the operating-rod and handguards don't touch anything, etc, I built an adjustable gas cylinder plug to adjust the gas system timing to open the bolt after the bullet has left the barrel, and I did get the groups down quite a bit with that device, but at the point where the groups get smaller (but still far from acceptable) the gas operating system stops working and won't cycle.
Okay, I did everything I was supposed to do and it didn't work. GRRR! Time to start tearing my hair out!
Barrels are the biggest source of accuracy problems and even though I had installed a rather expensive new Criterion short-chambered barrel made by Krieger and cut the headspace myself with a match-specification chamber reamer, that still does not mean that the barrel is any darned good. Criterion barrels are among the best of the better grade of barrels, but even they screw up once-in-awhile. Instead of getting a barrel from another manufacturer I ordered another Criterion barrel since they do come highly recommended with enough credible testimony behind them not to give up. Three nights ago I unscrewed the suspect barrel and installed the new one and yesterday morning I cut the chamber with the same reamer and go-no-go gauges I had used on the first barrel. When I got the chamber where I wanted it I put all the parts back on the receiver and dropped it back into the stock and headed for the range with some handloads made using 42-grains IMR4895 pushing 153-grain U.S. military pull-down jacketed bullets from 1950s Lake City .30-06 ammo.
Anticipation!
At the range it was quiet.
There was just a young father with his 12-year-old son shooting a 1911A and SKS. That made my day to see a father passing on the torch to his son! They spent more time laughing and talking to each other than shooting, a good sign.
I set up my first target at 25 yards to be sure I hit paper to see exactly where the sights were set. I had set the rear sight on center using the engraved lines on the receiver and set the elevation by turning the elevation knob ten clicks up from the bottom position. My first shot was on horizontal center as expected, but a few inches to the left. Using the sight windage clicks I adjusted the original-issue Garand rear sight and my next shot was just about in the middle. I moved the target out to 50 yards and fired another shot and readjusted the rear sight again. I moved the target out to 100 yards and fired another shot and did the last necessary adjustment. The next four shots were all within 1/2" on center (a half-minute of angle) and showed a tiny trend to vertical stringing. That is the performance I am after and the first Criterion barrel could not deliver. This barrel did, and except for some cosmetic things to do, I am finished building this rifle. Too bad the first Criterion barrel is too long for a tent stake, that is about all it is good for at this point since it grouped a whopping 6" at 100 yards, well outside even the rather lax military specs. Before I throw it out, though, I'll keep it around to try out on another Garand receiver I have and maybe I'll find some combination of powder and projectile it likes well enough to get some kind of use out of it.
rl573
I had been having a lot of trouble getting the shot groups down to even what a military-issue grade Garand can do. After I did all the standard accurizing procedures, like making sure that the operating-rod and handguards don't touch anything, etc, I built an adjustable gas cylinder plug to adjust the gas system timing to open the bolt after the bullet has left the barrel, and I did get the groups down quite a bit with that device, but at the point where the groups get smaller (but still far from acceptable) the gas operating system stops working and won't cycle.
Okay, I did everything I was supposed to do and it didn't work. GRRR! Time to start tearing my hair out!
Barrels are the biggest source of accuracy problems and even though I had installed a rather expensive new Criterion short-chambered barrel made by Krieger and cut the headspace myself with a match-specification chamber reamer, that still does not mean that the barrel is any darned good. Criterion barrels are among the best of the better grade of barrels, but even they screw up once-in-awhile. Instead of getting a barrel from another manufacturer I ordered another Criterion barrel since they do come highly recommended with enough credible testimony behind them not to give up. Three nights ago I unscrewed the suspect barrel and installed the new one and yesterday morning I cut the chamber with the same reamer and go-no-go gauges I had used on the first barrel. When I got the chamber where I wanted it I put all the parts back on the receiver and dropped it back into the stock and headed for the range with some handloads made using 42-grains IMR4895 pushing 153-grain U.S. military pull-down jacketed bullets from 1950s Lake City .30-06 ammo.
Anticipation!
At the range it was quiet.
There was just a young father with his 12-year-old son shooting a 1911A and SKS. That made my day to see a father passing on the torch to his son! They spent more time laughing and talking to each other than shooting, a good sign.
I set up my first target at 25 yards to be sure I hit paper to see exactly where the sights were set. I had set the rear sight on center using the engraved lines on the receiver and set the elevation by turning the elevation knob ten clicks up from the bottom position. My first shot was on horizontal center as expected, but a few inches to the left. Using the sight windage clicks I adjusted the original-issue Garand rear sight and my next shot was just about in the middle. I moved the target out to 50 yards and fired another shot and readjusted the rear sight again. I moved the target out to 100 yards and fired another shot and did the last necessary adjustment. The next four shots were all within 1/2" on center (a half-minute of angle) and showed a tiny trend to vertical stringing. That is the performance I am after and the first Criterion barrel could not deliver. This barrel did, and except for some cosmetic things to do, I am finished building this rifle. Too bad the first Criterion barrel is too long for a tent stake, that is about all it is good for at this point since it grouped a whopping 6" at 100 yards, well outside even the rather lax military specs. Before I throw it out, though, I'll keep it around to try out on another Garand receiver I have and maybe I'll find some combination of powder and projectile it likes well enough to get some kind of use out of it.
rl573