I pulled double-duty yesterday at Ben Avery range zeroing a new (upgraded replacement) IOR-Valdada 2-5-10x42 illuminated scope (with Ken Farrell 20MOA base) and testing a new load (having just purchased 200 pieces of .308 Lapua brass, replacing some mixed first and second-hand Federal brass).
Background:
When I started this project, so many months ago, I began with the basic Savage 10FP rifle and (factory stock, later glass-bedded just to practice and a somewhat stout, unadjusted factory trigger), using Fed match ammo and got .67 to .75 MOA at 100 yards. I replaced the trigger with one from SharpShooterSupply, factory set at about 15 ounces (their choice, not mine), and found the accuracy improve to .5 to .67 MOA.
All this despite my rather lousy technique, short attention span, lack of patience, and other negative personal attributes
I worked up some loads running Varget powder with passable Winchester primers pushing a 168 grain Nosler J4 bullet with "weight-matched" Federal brass of partially known origin and got the accuracy to improve to solid .5 MOA. I later bought a Choate "Plaster Disaster," glass bedded it and found the consistancy improve (due, in part, to the club-like weight of the stock) marginally. BTW, 43.9 grains of Varget was my sweet-spot with 43.8 and 44.0 grains impacting in the same area with similar group size (I am using the "Total Charge" method of working up loads. Velocity was around 2,750fps.
I had a hunch that I could squeeze more out of the rifle, if not myself. So, I bought a whole bunch of reloading tools that I hoped would allow me to really understand the process of accurized reloading. Chamber measuring devices, OAL guage, primer pocket uniformer, neck-sizing die, the Lapua brass, etc. And decided to try maxing most of my 2.877-inch chamber by using a 2.860" over-all length cartridge (pretty conservative, I gather).
I worked up three rounds each at powder throws of 43.5 grains up to 44.4 grains in tenth-grain increments. Temperature was a pleasant 67 degrees so I expected less velocity than I had been getting my last few times shooting at 90+ degrees, and I had no idea what difference the Lapua cases would make when compared to the Federal cases I had been using.
43.5 grains got me 2730 fps out of my Beta Chrony yesterday (I always wonder if that darn thing is reading 100 fps or so high) and 2,790 fps at 44.4 grains. I got wavering chrony results near my target velocity of 2,750, but 43.9 to 44.0 hit the mark nicely. Hodgdon says Varget is consistant at varying temperatures. Well, here is two data points in Arizona confirming this.
Now to the results on paper.
The good news is that all groups were well under 1MOA *and* they all printed in the 7:30 position on paper within about 1.5 inches of point-of-aim. This POA thingy means, according to the "Total Charge" method of working up a load, that since all of these loads impact in the same sector of the paper, if I am off by one or two grains, I will still be hitting my target. Cool. BTW, this didn't happen with my other brass. I'm a little bit perplexed as this was not expected.
Shooting difficulties:
I made the mistake of trying a new rest for the first four sets of loads which flexed and put me higher off the shooting bench than would be optimal. These groups netted me .67 to .8 MOA. It was too unstable.
I went back to trusty sandbags and my groups tightened. But I noticed that I had developed an odd habit of flexing my butt support hand just as the trigger released. I would be on-target, feel the trigger go (I must be getting in tune with my rifle because I used to not be able to anticipate it).
Quite a few times I would begin to take a shot and just before it went bang (as if locktime stood still), I would see the crosshairs move from the center of the target to down and too the left. What I was doing (which I am unaware of doing before) is that as the trigger would release, I would squeeze my butt-support-hand. As I am left-handed, this would move the rear of the rifle to the right (and the muzzle to the left), while at the same time, it would move the butt up (and the muzzle down). Each time I shot I would say before I went to the spotting scope, "Welp, that one will be low and to the left." Each time I was correct.
The bummer is that each time I did this it was as if I rolled a perfect ball into a 4-10 split. One time I got two shots off before the break, went down to measure and found a .25-inch spread on the two shots, only to have me "flinch" the next shot, widening the group to .67, or so. Another time it was a .33 MOA two-shotter. One time I sqeezed on the second shot after I told myself not to squeeze my hand. The first and third shots were a little over .33 but the middle shot dropped the group left and low again.
I only had two groups where I managed not to squeeze the rear support hand. Those gave me .35 and .45 MOA groups.
Clearly my rifle is better than me, just yet. I'll catch up eventually. After all, I'll have much more practice just to develops come-ups out to 800 yards. Yep. It looks like I have a mighty fine rifle, however, the phrase, "casting pearls to swine" comes to mind right about now.
Not Good Vibrations:
The other thing I noticed from the mid-loads on up was an odd vibration.
I would shoot the gun, get the recoil as usual, and before all was done, I would feel this "whuppata-whuppata" vibration at the front of the rifle. Dare I say a violent vibration?
What the heck was that?!? I thought something had come loose. I checked my actions screws. Tight. Scope / rings / base? Tight. Barrel? Tight. Keep in mind that this wobble began when I was achieving sub .5MOA groups.
Was that some sort of barrel whip I got from that heavy barrel?
Was the not-particularly-stiff plastic Choate stock vibrating on the forearm?
Back to the range next week.
Rick
Background:
When I started this project, so many months ago, I began with the basic Savage 10FP rifle and (factory stock, later glass-bedded just to practice and a somewhat stout, unadjusted factory trigger), using Fed match ammo and got .67 to .75 MOA at 100 yards. I replaced the trigger with one from SharpShooterSupply, factory set at about 15 ounces (their choice, not mine), and found the accuracy improve to .5 to .67 MOA.
All this despite my rather lousy technique, short attention span, lack of patience, and other negative personal attributes
I worked up some loads running Varget powder with passable Winchester primers pushing a 168 grain Nosler J4 bullet with "weight-matched" Federal brass of partially known origin and got the accuracy to improve to solid .5 MOA. I later bought a Choate "Plaster Disaster," glass bedded it and found the consistancy improve (due, in part, to the club-like weight of the stock) marginally. BTW, 43.9 grains of Varget was my sweet-spot with 43.8 and 44.0 grains impacting in the same area with similar group size (I am using the "Total Charge" method of working up loads. Velocity was around 2,750fps.
I had a hunch that I could squeeze more out of the rifle, if not myself. So, I bought a whole bunch of reloading tools that I hoped would allow me to really understand the process of accurized reloading. Chamber measuring devices, OAL guage, primer pocket uniformer, neck-sizing die, the Lapua brass, etc. And decided to try maxing most of my 2.877-inch chamber by using a 2.860" over-all length cartridge (pretty conservative, I gather).
I worked up three rounds each at powder throws of 43.5 grains up to 44.4 grains in tenth-grain increments. Temperature was a pleasant 67 degrees so I expected less velocity than I had been getting my last few times shooting at 90+ degrees, and I had no idea what difference the Lapua cases would make when compared to the Federal cases I had been using.
43.5 grains got me 2730 fps out of my Beta Chrony yesterday (I always wonder if that darn thing is reading 100 fps or so high) and 2,790 fps at 44.4 grains. I got wavering chrony results near my target velocity of 2,750, but 43.9 to 44.0 hit the mark nicely. Hodgdon says Varget is consistant at varying temperatures. Well, here is two data points in Arizona confirming this.
Now to the results on paper.
The good news is that all groups were well under 1MOA *and* they all printed in the 7:30 position on paper within about 1.5 inches of point-of-aim. This POA thingy means, according to the "Total Charge" method of working up a load, that since all of these loads impact in the same sector of the paper, if I am off by one or two grains, I will still be hitting my target. Cool. BTW, this didn't happen with my other brass. I'm a little bit perplexed as this was not expected.
Shooting difficulties:
I made the mistake of trying a new rest for the first four sets of loads which flexed and put me higher off the shooting bench than would be optimal. These groups netted me .67 to .8 MOA. It was too unstable.
I went back to trusty sandbags and my groups tightened. But I noticed that I had developed an odd habit of flexing my butt support hand just as the trigger released. I would be on-target, feel the trigger go (I must be getting in tune with my rifle because I used to not be able to anticipate it).
Quite a few times I would begin to take a shot and just before it went bang (as if locktime stood still), I would see the crosshairs move from the center of the target to down and too the left. What I was doing (which I am unaware of doing before) is that as the trigger would release, I would squeeze my butt-support-hand. As I am left-handed, this would move the rear of the rifle to the right (and the muzzle to the left), while at the same time, it would move the butt up (and the muzzle down). Each time I shot I would say before I went to the spotting scope, "Welp, that one will be low and to the left." Each time I was correct.
The bummer is that each time I did this it was as if I rolled a perfect ball into a 4-10 split. One time I got two shots off before the break, went down to measure and found a .25-inch spread on the two shots, only to have me "flinch" the next shot, widening the group to .67, or so. Another time it was a .33 MOA two-shotter. One time I sqeezed on the second shot after I told myself not to squeeze my hand. The first and third shots were a little over .33 but the middle shot dropped the group left and low again.
I only had two groups where I managed not to squeeze the rear support hand. Those gave me .35 and .45 MOA groups.
Clearly my rifle is better than me, just yet. I'll catch up eventually. After all, I'll have much more practice just to develops come-ups out to 800 yards. Yep. It looks like I have a mighty fine rifle, however, the phrase, "casting pearls to swine" comes to mind right about now.
Not Good Vibrations:
The other thing I noticed from the mid-loads on up was an odd vibration.
I would shoot the gun, get the recoil as usual, and before all was done, I would feel this "whuppata-whuppata" vibration at the front of the rifle. Dare I say a violent vibration?
What the heck was that?!? I thought something had come loose. I checked my actions screws. Tight. Scope / rings / base? Tight. Barrel? Tight. Keep in mind that this wobble began when I was achieving sub .5MOA groups.
Was that some sort of barrel whip I got from that heavy barrel?
Was the not-particularly-stiff plastic Choate stock vibrating on the forearm?
Back to the range next week.
Rick
