Having read about this phenomena in another thread, where a bullet pushed at a high velocity can break up after a few hundred meters of flight, I have a few questions...
What are the maximum velocities being achieved by civilian shooters? - and at what point do the laws of physics prevent more, and for what reasons? (not encouraging 'pushing the limits'...just curious)
What are the actual reasons for a bullet to break up, and is it mainly lighter bullets...or can this happen with 140-200 gn bullets?
disintegrating bullets
Moderator: dromia
Forum rules
All handloading data posted on Full-Bore UK from 23/2/2021 must reference the published pressure tested data it was sourced from, posts without such verification will be removed.
Any existing data without such a reference should be treated as suspect and not used.
Use reloading information posted here at your own risk. This forum (http://www.full-bore.co.uk) is not responsible for any property damage or personal injury as a consequence of using reloading data posted here, the information is individual members findings and observations only. Always verify the load data and be absolutely sure your firearm can handle the load, especially older ones. If in doubt start low and work your way up.
All handloading data posted on Full-Bore UK from 23/2/2021 must reference the published pressure tested data it was sourced from, posts without such verification will be removed.
Any existing data without such a reference should be treated as suspect and not used.
Use reloading information posted here at your own risk. This forum (http://www.full-bore.co.uk) is not responsible for any property damage or personal injury as a consequence of using reloading data posted here, the information is individual members findings and observations only. Always verify the load data and be absolutely sure your firearm can handle the load, especially older ones. If in doubt start low and work your way up.
-
kennyc
- Posts: 2340
- Joined: Wed Jul 20, 2011 11:21 pm
- Home club or Range: hunters NRPC
- Location: Reading West Berks
- Contact:
Re: disintegrating bullets
as far as I am aware, the bullets disintegrate when the rotational forces exceed their ability to stay together, that would probably be more a problem with very light for calibre bullets being used in very tight twist barrels, isn't this one of the limiting factors in maximum useful muzzle velocity's?
-
Dougan
Re: disintegrating bullets
So like centrifugal force!? - so how fast do bullets rotate? (typical weights and twists)
I know I could research this online...but if anyone knows the numbers (revs per second?) of hand...?
I know I could research this online...but if anyone knows the numbers (revs per second?) of hand...?
Re: disintegrating bullets
Bullet RPM = MV X 720/Twist Rate (in inches) so:
3300x720/8 = 297,000 RPM or quite a lot. Consider as an alternative a .308 with a 1:12 barrel at 2800fps is 168,00RPM
3300x720/8 = 297,000 RPM or quite a lot. Consider as an alternative a .308 with a 1:12 barrel at 2800fps is 168,00RPM
-
Dougan
Re: disintegrating bullets
Ok, I'm trying to get my head around that - I can see how fast that is (!), and the difference lighter bullets make...
...excuse me being thick, but where does the '720' come from in the equation?
...excuse me being thick, but where does the '720' come from in the equation?
Re: disintegrating bullets
MV x (12/twist rate in inches) x 60 = Bullet RPM
-
Dougan
Re: disintegrating bullets
Ok that I get - so does a lower twist rate increase the RPM?...I would have thought the opposite! (my head is starting to hurt :lol: )ovenpaa wrote:MV x (12/twist rate in inches) x 60 = Bullet RPM
Re: disintegrating bullets
a lower number twist rate such as 1:8 will give a higher RPM than a higher number such as 1:12 for the same MV
-
Dougan
Re: disintegrating bullets
Ok, now I am really being thick ( 
) - though I think the penny has finally dropped....1:8 is 1 turn in 8" (yes?) and therefore a tighter/quicker twist than 1:12...which is 1 turn in 12" (yes?)...
...for some reason (i think from TR rifles) I've got the impression that the bigger the first number is, the tighter the twist is ( i.e a 14:1 is tighter than 10:1) - this is because I know that 14:1 is better for shorter range (TR 155/.308), and 10:1 is better for long range...but I've had it the wrong way round (shouldn't be admitting to this online :roll: ), as I've assumed that tighter twists stabilise a bullet sooner...so better for short range...?
I think I need to read up on this stuff...anyone recommend a good book?...preferably in 'layman's terms'.....
) - though I think the penny has finally dropped....1:8 is 1 turn in 8" (yes?) and therefore a tighter/quicker twist than 1:12...which is 1 turn in 12" (yes?)......for some reason (i think from TR rifles) I've got the impression that the bigger the first number is, the tighter the twist is ( i.e a 14:1 is tighter than 10:1) - this is because I know that 14:1 is better for shorter range (TR 155/.308), and 10:1 is better for long range...but I've had it the wrong way round (shouldn't be admitting to this online :roll: ), as I've assumed that tighter twists stabilise a bullet sooner...so better for short range...?
I think I need to read up on this stuff...anyone recommend a good book?...preferably in 'layman's terms'.....
Re: disintegrating bullets
Bryan Litz - Applied Ballistics For Long Range Shooting would be a good one to start with. Look for a used copy of the first edition as opposed to a new copy of the latest edition and you should save yourself about GBP35
Who is online
Users browsing this forum: No registered users and 8 guests