I ran into an interesting situation at the range today. I was at a friend's private range and he was shooting a rifle he had inherited from his Grandfather about a decade ago.
It had been sitting in the back of his safe since the Grandfather passed, without being touched.
As we all know, nasty things can happen with bedding, crushed butt pads, etc over a decade, even when properly stored.
The rifle was a push feed/post 64 Winchester model 70, which had been bought new in 1967 and chambered for the 338 Win Mag.
The cartridge, other than similar wildcats, had been accepted by SAAMI less than ten years before, and in truth, not a lot of the data concerning pressures was trustworthy back in those days.
Often it was just a guesstimate.
My friend didn't try using any of the handloads which came with the rifle, but he did break them down and discarded the powder/primers, which were listed on the box as H4831 and just LRM for primer description.
He had the original set of dies, half a dozen 50 count boxes of Speer cup and core, flat base, round nose, 200 grain bullets, all which came with the rifle. He also had 50 rounds of new Remington Peters cases and 50 cases which had been loaded when he got the rifle.
He weighed the charges in each of the cartridges he had pulled apart for components, and they averaged 83.0 grains, which was a slightly compressed load when he substitute H4831sc, which is supposed to be transposable with H4831. Not something I would advise but ?????????
His Grandfather never shot the bullets over a chronograph, so he really didn't know how fast they were being pushed.
The rifle was bought off the shelf from a now out of business store in our town, new off the shelf. Somewhere along the way, it had been expertly glass bedded, and the trigger was tuned to appx 2 pounds. It had a swing out floor plate and internal magazine, and the stock was about as straight grained as Walnut gets. Lovely checkering. 1-10 twist rate.
I brought my Garmin Xpro along to check some velocities on a new load for my 280rem, so it was set up to check the velocities of the 338Win Mag.
The muzzle blast from the first shot was horrendous in that small shooting shack. Even though the Garmin was appx 15 inches behind the muzzle, it moved. It wasn't blown over, just move back about a half inch (1cm) BRUTAL.
Velocity on the first shot was 3236fps and alarm bells started going off in my head.
I knew it would be fast but this was appx 200fps more than it should be under normal, max or close to max loads.
The Federal 250LRM primers, which are medium hot IMHO, weren't cratering or flowing to any extreme, but they were definitely flattening, with the round edge of the primer much smaller than when it was unfired.
I advised him the load was to hot, but he's an experienced hand loader and I would trust his loads. He agreed they were at maximum or slightly over, but felt they were safe enough to continue.
The scope, a Leupold 3x9, fixed 6X, hadn't been touched, other than to make sure the ring cap screws were properly torqued.
It must have been sighted in for 200yds, because the first 5 shots grouped appx 2 inches high at 100yds.
The group was on center, above the bull, and measured appx 3 inches. Another 3 shot group was shot and hit within the first group, same pattern.
He then sighted on the 200yd target and the group encircled the bull, but was smaller. Not a lot, but just over 2 inches.
His grandfather never shot at anything over 250 yds, so he would have been quite happy with that accuracy.
We shot another two 5 shot groups at 200yds and if they hadn't been marked, we wouldn't have been able to tell which group they were fired from. All of the bullets were in a group about 2 1/2 inches.
The rifle was allowed to cool to ambient temperature, 18C and altitude was around 1700ft.
My friend is a very good shot, and his range goes out to 500 yards, so he set the rifle's crosshairs on the 300yd target, and shot 5 bullets at it.
He wasn't expecting what happened and neither was I, but I should have suspected it might.
The group dramatically shrunk again, this time it was appx 1.5 inches.
He shot a couple more five round strings on the same target, allowing the barrel to cool between strings and they all went into the same 1.5 inch group area. Not vertical or horizontal stringing, just a relatively round group, with 15 rounds in it.
The only thing we could blame it on was "over stabilizing" the short bullets at higher than their preferred velocity.
I don't even want to attempt to go into the math involved explaining gyrostatic stability or yaw, air spiral at bullet tip, etc.
Anyone who has shot arrows from a bow knows what happens when you shoot a light arrow with to much velocity. It bends of course, but it "wobbles" within an air spiral until it slows down enough to cause the external forces to dissipate or "go to sleep" and then, gyrostatic stability is maintained.
I've only had this happen twice, once with another 338 Win Mag and another with a 338 Win Mag, necked up to 35 cal, with a 1-12 twist, custom rifle.
It's just not something you can predict will happen.
Usually, it's long/heavy bullets "under stabilizing" because the twist rate is to slow.
It will likely never happen to most here, but it's something to be aware of, for those who are trying to reduce recoil by going to lighter bullets or trying to get screaming velocities with shorter/lighter bullets.
I don't believe this will apply to monometal bullets, but it might, if the bullets are very heavy, as they tend to be much longer than their lead core counterparts.
It had been sitting in the back of his safe since the Grandfather passed, without being touched.
As we all know, nasty things can happen with bedding, crushed butt pads, etc over a decade, even when properly stored.
The rifle was a push feed/post 64 Winchester model 70, which had been bought new in 1967 and chambered for the 338 Win Mag.
The cartridge, other than similar wildcats, had been accepted by SAAMI less than ten years before, and in truth, not a lot of the data concerning pressures was trustworthy back in those days.
Often it was just a guesstimate.
My friend didn't try using any of the handloads which came with the rifle, but he did break them down and discarded the powder/primers, which were listed on the box as H4831 and just LRM for primer description.
He had the original set of dies, half a dozen 50 count boxes of Speer cup and core, flat base, round nose, 200 grain bullets, all which came with the rifle. He also had 50 rounds of new Remington Peters cases and 50 cases which had been loaded when he got the rifle.
He weighed the charges in each of the cartridges he had pulled apart for components, and they averaged 83.0 grains, which was a slightly compressed load when he substitute H4831sc, which is supposed to be transposable with H4831. Not something I would advise but ?????????
His Grandfather never shot the bullets over a chronograph, so he really didn't know how fast they were being pushed.
The rifle was bought off the shelf from a now out of business store in our town, new off the shelf. Somewhere along the way, it had been expertly glass bedded, and the trigger was tuned to appx 2 pounds. It had a swing out floor plate and internal magazine, and the stock was about as straight grained as Walnut gets. Lovely checkering. 1-10 twist rate.
I brought my Garmin Xpro along to check some velocities on a new load for my 280rem, so it was set up to check the velocities of the 338Win Mag.
The muzzle blast from the first shot was horrendous in that small shooting shack. Even though the Garmin was appx 15 inches behind the muzzle, it moved. It wasn't blown over, just move back about a half inch (1cm) BRUTAL.
Velocity on the first shot was 3236fps and alarm bells started going off in my head.
I knew it would be fast but this was appx 200fps more than it should be under normal, max or close to max loads.
The Federal 250LRM primers, which are medium hot IMHO, weren't cratering or flowing to any extreme, but they were definitely flattening, with the round edge of the primer much smaller than when it was unfired.
I advised him the load was to hot, but he's an experienced hand loader and I would trust his loads. He agreed they were at maximum or slightly over, but felt they were safe enough to continue.
The scope, a Leupold 3x9, fixed 6X, hadn't been touched, other than to make sure the ring cap screws were properly torqued.
It must have been sighted in for 200yds, because the first 5 shots grouped appx 2 inches high at 100yds.
The group was on center, above the bull, and measured appx 3 inches. Another 3 shot group was shot and hit within the first group, same pattern.
He then sighted on the 200yd target and the group encircled the bull, but was smaller. Not a lot, but just over 2 inches.
His grandfather never shot at anything over 250 yds, so he would have been quite happy with that accuracy.
We shot another two 5 shot groups at 200yds and if they hadn't been marked, we wouldn't have been able to tell which group they were fired from. All of the bullets were in a group about 2 1/2 inches.
The rifle was allowed to cool to ambient temperature, 18C and altitude was around 1700ft.
My friend is a very good shot, and his range goes out to 500 yards, so he set the rifle's crosshairs on the 300yd target, and shot 5 bullets at it.
He wasn't expecting what happened and neither was I, but I should have suspected it might.
The group dramatically shrunk again, this time it was appx 1.5 inches.
He shot a couple more five round strings on the same target, allowing the barrel to cool between strings and they all went into the same 1.5 inch group area. Not vertical or horizontal stringing, just a relatively round group, with 15 rounds in it.
The only thing we could blame it on was "over stabilizing" the short bullets at higher than their preferred velocity.
I don't even want to attempt to go into the math involved explaining gyrostatic stability or yaw, air spiral at bullet tip, etc.
Anyone who has shot arrows from a bow knows what happens when you shoot a light arrow with to much velocity. It bends of course, but it "wobbles" within an air spiral until it slows down enough to cause the external forces to dissipate or "go to sleep" and then, gyrostatic stability is maintained.
I've only had this happen twice, once with another 338 Win Mag and another with a 338 Win Mag, necked up to 35 cal, with a 1-12 twist, custom rifle.
It's just not something you can predict will happen.
Usually, it's long/heavy bullets "under stabilizing" because the twist rate is to slow.
It will likely never happen to most here, but it's something to be aware of, for those who are trying to reduce recoil by going to lighter bullets or trying to get screaming velocities with shorter/lighter bullets.
I don't believe this will apply to monometal bullets, but it might, if the bullets are very heavy, as they tend to be much longer than their lead core counterparts.
