Having just acquired a chronograph I’d like to know if a spread of 80.2 FPS is the norm for factory ammunition. The group was fairly acceptable, but I was surprised by the spread over 5 shots. Is it possible to get better consistency hand loading and if so what could the spread be reduced to. I accept there are probably other variables answering this question but if anyone could give a rough answer I’d be interested.
Hand loads v Factory
- Thread starter Herb64
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Stalker62
Well-Known Member
I recently did the NRA hand loading course.
Factory ammunition (GGG 155gr in .308) ES was @ 20fps.
One of the 'never hand loaded before' students managed an ES of 7.
If I can get an ES of under 10, I am high fiving myself...
Also consider the quality of your chronograph when relying on any readings.
Factory ammunition (GGG 155gr in .308) ES was @ 20fps.
One of the 'never hand loaded before' students managed an ES of 7.
If I can get an ES of under 10, I am high fiving myself...
Also consider the quality of your chronograph when relying on any readings.
That’s a course I’ve looked into and will as likely try and do at some point. I’m hoping the chronograph is accurate but intend running it against a friends at sometime in the near future. Thanks for your reply.
That’s one of the reasons I’m interested as want to stretch out against steel. The group is dead fox or deer all day long.Unless you want to shoot to a thousand yards don't worry about it.
That group is excellent. Put the crono away, it only puts doubt in your mind, same with a bore scope, like smelly dog said it really only matters when your really stretching the distances.
I was shooting next to my mate, on a steel target at 200 and 300 yards, I handload and he was picking a random cartridge from about 5 different manufacturers. He hit that target just as many times as I did. All would have resulted in a dead fox.
I was shooting next to my mate, on a steel target at 200 and 300 yards, I handload and he was picking a random cartridge from about 5 different manufacturers. He hit that target just as many times as I did. All would have resulted in a dead fox.
Got my 9.3 ES to 12. Lapua components
Len the dog
Well-Known Member
Is your friend’s chrono calibrated against a known standard?
Comparing one instrument against another is meaningless unless one of them is calibrated, even then there is an acceptable tolerance for that instrument and likewise for yours, readings between the two could be at opposite ends of their tolerance for one shot and then reversed for the next, rendering any comparison completely meaningless.
A chrono is useful for ballpark figures and for seeing how different charges behave as you work upwards, but the data is pretty irrelevant for most uses.
Great to hear from you Muir and I agree I should have gone 10 but a little ammo shortage kept it to 5.
One on top of two
Well-Known Member
Julian , you can easily check your chrono against your own ballistic data By Truing your drops at 2- 3 distances
For instance if your data is telling you your drop at 300m is an 4” drop And 400m is a 6” drop And 500m is a 10” drop
Test it . As long as your input data is 100% correct physics will take of the rest .
For instance if your data is telling you your drop at 300m is an 4” drop And 400m is a 6” drop And 500m is a 10” drop
Test it . As long as your input data is 100% correct physics will take of the rest .
Good idea Steve. That’s tomorrow sorted.
Your post suggests that the shot dispersion is a result of the Extreme Spread?? Not sure if thats what you were getting at? It's not going to have that scale of effect assuming the target was at a usual close zeroing range. Further out sure you will see increasing vertical dispersion. If thats 100 yards/m then I would be saying the vertical is breathing and/or rest, not ES.
IF the point was to tighten the group then I suspect you are barking up the wrong tree. Hard to say without some data. Calibre, weight, average muzzle velocity, standard deviation, range? The trouble with ES alone is that one crappy bullet can give you huge ES but the others can be pretty tight?? Hence the focus on standard deviation (or average error to us campaign for clear English wonks).
I am not really sure what you are trying to achieve? Small ES and SD are all well and good but very few of us are ever going to shoot stuff where it matters, certainly not stalking. It is a bit of an indicator of the quality of a reloading process (and equipment) so it is worth something perhaps. Just don't go down the rabbit hole of looking for low single digit SD's when the application does not warranty all that cost and effort.
An SD of 3 is not going to compensate for wobble off a set of sticks.
IF the point was to tighten the group then I suspect you are barking up the wrong tree. Hard to say without some data. Calibre, weight, average muzzle velocity, standard deviation, range? The trouble with ES alone is that one crappy bullet can give you huge ES but the others can be pretty tight?? Hence the focus on standard deviation (or average error to us campaign for clear English wonks).
I am not really sure what you are trying to achieve? Small ES and SD are all well and good but very few of us are ever going to shoot stuff where it matters, certainly not stalking. It is a bit of an indicator of the quality of a reloading process (and equipment) so it is worth something perhaps. Just don't go down the rabbit hole of looking for low single digit SD's when the application does not warranty all that cost and effort.
An SD of 3 is not going to compensate for wobble off a set of sticks.
Unless you're into long range target shooting, ES and SD are pretty irrelevant numbers
Any live target you might have shot at would be dead with any of those five shots
You've just bought a chrono and already you're worrying
FFS don't buy a borescope
Cheers
Bruce
ASl sniper.177
Well-Known Member
I think extreme spread for factory ammunition has improved in the last few years. When i first had factory ammunition put over a chrono,which were Winchester ballistic silvertips in 55 grain 243,they ranged from 3675 fps to 3825!
when I got into reloading I realised how bad those figures were! The best I've had when reloading was an ES of 2 over 10 shots for 48.5 grains of N165 under a 105 grain A-Max in243 Ackley. For me,if i can get .25 moa or less at 100 yards for the rifle and bullet combo,i have no excuse when i miss. Then it's just down to the nut behind the butt.
when I got into reloading I realised how bad those figures were! The best I've had when reloading was an ES of 2 over 10 shots for 48.5 grains of N165 under a 105 grain A-Max in243 Ackley. For me,if i can get .25 moa or less at 100 yards for the rifle and bullet combo,i have no excuse when i miss. Then it's just down to the nut behind the butt.
100% correct input? That’s an unrealistic expectation bearing in mind the uncertain degree of accuracy of any factory BC figures (never mind that BC varies with velocity).
In any event, the 80 fps ES isn’t so out of the ordinary to suggest there’s any fault with the chronograph anyway.
One thing I found interesting was the weight of the bare cases varies significantly.
As the external sizes shouldn’t vary it must be the internal dimensions.
Going up the weights means the free space inside the case reduces.
I know it affects the point of impact, it must therefore affect the velocity?
As the external sizes shouldn’t vary it must be the internal dimensions.
Going up the weights means the free space inside the case reduces.
I know it affects the point of impact, it must therefore affect the velocity?
Smellydog
Well-Known Member
Thats why I like compressed charges.
Short of plinking loads it seems dumb not filling a case completely.
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