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Re: Will rounds tumble at 100 yards?
If they are tumbling (or are otherwise unstable), you should see evidence of it at 100yds without any trouble.
If they are tumbling (or are otherwise unstable), you should see evidence of it at 100yds without any trouble.
Re: Will rounds tumble at 100 yards?
What is your twist rate and barrel length?
Unless your twist is WAY, WAY off optimal, what you are most likely to see is your groups opening up a lot more than would be expected (with an optimal twist rate) as you go from 100 yd to 200, 300, etc. It is certainly possible to get tumbling at 100 yd, but probably less likely under most circumstances than accuracy/grouping issues. If you see oblong "holes" in your target, then you know you have a tumbling issue.
You might want to bring some other ammo you know is properly stabilized by your weapon along for comparison to the 75/77 gr (longer) rounds. That way, if you have a stabilization issue with the longer rounds that is not severe enough to cause tumbling at 100 yd, but IS enough of a problem to decrease accuracy and increase you group spreads, you have something to directly compare.
FYI, stabilization is really an issue of bullet length, not weight, although longer is often heavier as well.
What is your twist rate and barrel length?
Unless your twist is WAY, WAY off optimal, what you are most likely to see is your groups opening up a lot more than would be expected (with an optimal twist rate) as you go from 100 yd to 200, 300, etc. It is certainly possible to get tumbling at 100 yd, but probably less likely under most circumstances than accuracy/grouping issues. If you see oblong "holes" in your target, then you know you have a tumbling issue.
You might want to bring some other ammo you know is properly stabilized by your weapon along for comparison to the 75/77 gr (longer) rounds. That way, if you have a stabilization issue with the longer rounds that is not severe enough to cause tumbling at 100 yd, but IS enough of a problem to decrease accuracy and increase you group spreads, you have something to directly compare.
FYI, stabilization is really an issue of bullet length, not weight, although longer is often heavier as well.
Re: Will rounds tumble at 100 yards?
In some cases I think you can see tumbling well before 100yds. I have an old CAR-15 upper (1/12" twist I think) that begins keyholing M855 62gr stuff at 25 yds! Freaked me out first time I saw it!
In some cases I think you can see tumbling well before 100yds. I have an old CAR-15 upper (1/12" twist I think) that begins keyholing M855 62gr stuff at 25 yds! Freaked me out first time I saw it!
Re: Will rounds tumble at 100 yards?
Yep, buddy has an old sks. It must have no rifling left cause it key holes in 10ft
Yep, buddy has an old sks. It must have no rifling left cause it key holes in 10ft
Re: Will rounds tumble at 100 yards?
Just this week took a .223 rem 700 of a friends out who told me it was a 1:9. Shot a bunch of 55s through it and they shot great, easily moa when I was doing my job. Threw some 75gr factory Vmax in it just to see if it liked them and I could barely keep them on an 8" sight target at 100. Took it home and checked sure enough 1:12.
1moa to 8+ moa at only 100. That was my first experience with unstabilized rounds. I'm sure you will be able to spot yours as well.
Just this week took a .223 rem 700 of a friends out who told me it was a 1:9. Shot a bunch of 55s through it and they shot great, easily moa when I was doing my job. Threw some 75gr factory Vmax in it just to see if it liked them and I could barely keep them on an 8" sight target at 100. Took it home and checked sure enough 1:12.
1moa to 8+ moa at only 100. That was my first experience with unstabilized rounds. I'm sure you will be able to spot yours as well.
Re: Will rounds tumble at 100 yards?
Bolt action .223s tend to have slow twist barrels unless barreled with long range in mind.
Mostly they're intended as varmint rigs, so light bullet/flat trajectory is the dominating parameter.
Bolt action .223s tend to have slow twist barrels unless barreled with long range in mind.
Mostly they're intended as varmint rigs, so light bullet/flat trajectory is the dominating parameter.
Re: Will rounds tumble at 100 yards?
and that is exactly why I am rebarreling my 223 VS from a 1:12 to a 1:8 as I want to get into the 75-77 size rounds. The 1:12 shoots my 60GR VMAX pretty well but that is about as high as I can get with the 1:12 barrel.
and that is exactly why I am rebarreling my 223 VS from a 1:12 to a 1:8 as I want to get into the 75-77 size rounds. The 1:12 shoots my 60GR VMAX pretty well but that is about as high as I can get with the 1:12 barrel.
Re: Will rounds tumble at 100 yards?
I shot some 77SMK's out of my 22-250 and they were sideways by the time they hit 25 yards.
I shot some 77SMK's out of my 22-250 and they were sideways by the time they hit 25 yards.
Re: Will rounds tumble at 100 yards?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ORD</div><div class="ubbcode-body">If they are tumbling (or are otherwise unstable), you should see evidence of it at 100yds without any trouble. </div></div>
Right. If your barrel twist is too low, bullets will begin to tumble immediately and can keyhole at the 100-yard target.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ORD</div><div class="ubbcode-body">If they are tumbling (or are otherwise unstable), you should see evidence of it at 100yds without any trouble. </div></div>
Right. If your barrel twist is too low, bullets will begin to tumble immediately and can keyhole at the 100-yard target.
Re: Will rounds tumble at 100 yards?
I probably should have been a little clearer about what I meant by "normal circumstances" in my reply. I would consider pushing 855s through a 12 twist to be pretty extreme in this day and age, given that so many AR-type weapons can be had with 8 or 7 twist barrels. 855s are quite long for their weight anyhow, and the 12 twist is just way too slow. That particular combination is really one of the classic examples of inadequate stabilization that led to use of the higher twist rates commonly seen in .223 barrels today. Of course, I'd classify "no rifling at all" as pretty extreme as well (LOL).
My personal experience with this issue came along with a 21" 1 in 10" twist barrel that I was told by many would absolutely NOT be able to stabilize anything over 69 gr, and that they would keyhole if I tried them. As it turned out, that was untrue. That particular barrel handles 77 gr SMKs just fine out to 200 yd. However, I've noticed that at 300 and 400 yd, the spread starts to open up a lot more than it really should, which I suspect is the inadequate twist starting to show itself. But I have yet to see any evidence of tumbling at any range.
My guess is that your 18.5" 9 twist is going to be very close to the edge of whether it can handle the longer loads like 75s/77s. I probably got away with it out to 200 or 300 yds because even though it is a 10 twist, the 21" barrel length gives a couple hundred fps greater muzzle velocity than a 16" 10 twist barrel would, for example. Higher muzzle velocity means faster spin, so I probably got away with that sub-optimal twist rate for that reason.
Your best bet is to just see how your 18.5" 9 twist handles the 77s at 100, 200, 300 yds, etc. You might get lucky and find it's ok, even if it starts to open up like mine did at longer ranges. If 77s tumble at 100 yd, well...then you know. You could then try 69s, 68s, etc., until you figure what the maximum length (weight) it will handle, and go with those. Anyhow, good luck with it, I'm sure you'll figure out what works best.
I probably should have been a little clearer about what I meant by "normal circumstances" in my reply. I would consider pushing 855s through a 12 twist to be pretty extreme in this day and age, given that so many AR-type weapons can be had with 8 or 7 twist barrels. 855s are quite long for their weight anyhow, and the 12 twist is just way too slow. That particular combination is really one of the classic examples of inadequate stabilization that led to use of the higher twist rates commonly seen in .223 barrels today. Of course, I'd classify "no rifling at all" as pretty extreme as well (LOL).
My personal experience with this issue came along with a 21" 1 in 10" twist barrel that I was told by many would absolutely NOT be able to stabilize anything over 69 gr, and that they would keyhole if I tried them. As it turned out, that was untrue. That particular barrel handles 77 gr SMKs just fine out to 200 yd. However, I've noticed that at 300 and 400 yd, the spread starts to open up a lot more than it really should, which I suspect is the inadequate twist starting to show itself. But I have yet to see any evidence of tumbling at any range.
My guess is that your 18.5" 9 twist is going to be very close to the edge of whether it can handle the longer loads like 75s/77s. I probably got away with it out to 200 or 300 yds because even though it is a 10 twist, the 21" barrel length gives a couple hundred fps greater muzzle velocity than a 16" 10 twist barrel would, for example. Higher muzzle velocity means faster spin, so I probably got away with that sub-optimal twist rate for that reason.
Your best bet is to just see how your 18.5" 9 twist handles the 77s at 100, 200, 300 yds, etc. You might get lucky and find it's ok, even if it starts to open up like mine did at longer ranges. If 77s tumble at 100 yd, well...then you know. You could then try 69s, 68s, etc., until you figure what the maximum length (weight) it will handle, and go with those. Anyhow, good luck with it, I'm sure you'll figure out what works best.
Re: Will rounds tumble at 100 yards?
The over the course shooters I was with a few years ago did just fine with 77s and 1:9 twists.
The 80-grain longload (ogive NOT designed to be loaded to mag length) are enough longer with their extra 3 grains of weight (lotta air up front like a .308 Lapua 155-gr Scenar) that THEY are the ones that don't work so well with a 1:9 twist. Thus we have the 1:8 and those odd fractions.
1:7 is needed to stabilize the really, really long USGI tracer rounds, all the way into subzero (Farenheit) temperatures. It's an air density and length of bullet and weight distribution thing.
The over the course shooters I was with a few years ago did just fine with 77s and 1:9 twists.
The 80-grain longload (ogive NOT designed to be loaded to mag length) are enough longer with their extra 3 grains of weight (lotta air up front like a .308 Lapua 155-gr Scenar) that THEY are the ones that don't work so well with a 1:9 twist. Thus we have the 1:8 and those odd fractions.
1:7 is needed to stabilize the really, really long USGI tracer rounds, all the way into subzero (Farenheit) temperatures. It's an air density and length of bullet and weight distribution thing.
Re: Will rounds tumble at 100 yards?
My buddies del-ton (16" 1in9) was keyholing silver bear 55gr at about 80 yards last time I went shooting with him. It was pretty strange. I thought 55gr was a good weight for that twist. Maybe a ammo quality (or lack thereof) issue?
My buddies del-ton (16" 1in9) was keyholing silver bear 55gr at about 80 yards last time I went shooting with him. It was pretty strange. I thought 55gr was a good weight for that twist. Maybe a ammo quality (or lack thereof) issue?
Re: Will rounds tumble at 100 yards?
I'm lucky that my 1:12 VSS 223 will shoot 69gr BTHP into bugholes. Anything heavier is 1 1/2 - 3 inches at 100yds.
I'm lucky that my 1:12 VSS 223 will shoot 69gr BTHP into bugholes. Anything heavier is 1 1/2 - 3 inches at 100yds.
Re: Will rounds tumble at 100 yards?
Personally, I'd pull the trigger at 25 yards first. If the holes in the paper are anything but perfect circles, no point going further.
Personally, I'd pull the trigger at 25 yards first. If the holes in the paper are anything but perfect circles, no point going further.
Re: Will rounds tumble at 100 yards?
well, its the height of ninjaness for yer ar to throw spinning bullets like little ninji stars...
sareeossly tho, for a 1 in 9 go 69 grainers as the ceiling and theyll stay stable to around 6-700 yards. ive played with this a bit.
well, its the height of ninjaness for yer ar to throw spinning bullets like little ninji stars...
sareeossly tho, for a 1 in 9 go 69 grainers as the ceiling and theyll stay stable to around 6-700 yards. ive played with this a bit.
