FT/LBS data for shortened rifles required please

[8x57]

yes quite a surprise but i nearly always use the 308 for deer! the 223 is purely a foxing gun and until i get the chrono and check the data so is the 243! maybe i shouldn't have listened to the wife when she said size doesn't matter!

i wonder what load was developed for the rpa woodland stalker with the 16inch barrel in 243 to achieve the legal dose??

Perhaps it doesn't achieve the legal dose. I know a friend of mine was quite surprised when he put his .243 loads over the chronagraph and found that they were barely achieving 1700 ft/lb and that was with a 22" barrel. There will probably be a lot more shooters who are totally unaware that their .243 only just scrapes through, or perhaps doesn't.
I like to play on the safe side also and stick to something like a .308 normally, though I do like the idea of a .222/.223 for smaller deer.

 

[Sharpie]

i wonder what load was developed for the rpa woodland stalker with the 16inch barrel in 243 to achieve the legal dose??

It never was possible. As for using factory ammo ...

Maybe another of the reasons why they went bust.

With the .308 it was possible in the 16.5 inch barrel, but don't ever shoot one without a moderator unless you are already deaf. Was unfortunate to shoot next to one fitted with an RPA muzzle brake. That was torture.

Good luck with the .243, TBH I think you will struggle to get a deer legal load in any bullet weight, nevermind 100 grains for Scotland.

Fact is not many .243s used in Scotland on large deer are legal. If using factory ammo, thats probably none. Even with standard barrels. Why is this not better known ?

 

[8x57]

"Fact is not many .243s used in Scotland on large deer are legal. If using factory ammo, thats probably none. Even with standard barrels. Why is this not better known ?"

I wouldn't go quite so af as to say that Sharpie, but it's got to be a close run thing with a lot of factory ammo.

Just to stir things up a bit I would say that we seem to have a habit of trying to use cartridges that are at their design limits in this country. For example the .243win was originally intended as a long range varmint round with coyotes in mind, and the .17HMR was intended for praire dogs. I'm not saying that what many people are using them for is unsuitable (deer and fox in the case of .17 HMR), just that we should remember what they were originally intended for.

 

[deeangeo]

http://www.ebay.co.uk/itm/Competiti...782?pt=LH_DefaultDomain_0&hash=item564b7b4716

Might be an interesting way to go..??

Incidentally, my Lyman book shows the formula for calculating ME is:
Bullet Weight x Velocity x Velocity divided by 450400 = ME
Cheers, ATB

 

[Sharpie]

my Lyman book shows the formula for calculating ME is:
Bullet Weight x Velocity x Velocity divided by 450400 = ME

The exact divisor depends on the assumption made for acceleration due to gravity at the earth's surface.

See Muzzle energy - Wikipedia, the free encyclopedia

The modern figure generally used gives a divisor of 450435. (i.e. 32.1738 x 7000 x 2)

But for historical reasons a slightly lower figure was chosen. If Wikipedia is correct, the precise divisor ought to be 450282. So for the sake of consistency, the lower figure is generally used.

But such tiny differences only make a difference of e.g. 0.6 fpe in 1700. And measuring muzzle velocity to that precision will not happen.

 

[Sharpie]

I wouldn't go quite so af as to say that Sharpie, but it's got to be a close run thing with a lot of factory ammo.

I was being intentionally controversial

Pete Moore is usually open about this when he tests rifles.

E.g. in the current issue of Shooting Sports he tested a Howa .243 with 20" barrel, and found:

Winchester Ballistic Silver Tip 95 grains 2910 fps 1790 fpe

PPU soft point 100 grains 2627 fps 1540 fpe

Norma V-Max 75 grains 2976 fps 1475 fpe

I daresay there is a factory round that would be legal in Scotland in that rifle, perhaps the PPU load was unrepresentative of what better 100 grain loads could achieve. But I still think many Scottish stalkers using factory ammo might get an unpleasant surprise if they chronoed their rifles.

And only one load out of three was legal for England/Wales either, which is not encouraging.

 

[8x57]

Yes I realised what you said was a bit tongue in cheek and possibly just waiting for a bite from the .243 lobby.
I also agree that if folk were to actually test their loads over a chronagraph and work out their actual not theoretical muzzle energies there would be a few surprises. While I have a fondness for shorter barrels myself I tend to stick to at least 20" and in calibres were muzzle energies tend to be higher just to be on the safe side.

 

[jcampbellsmith]

The exact divisor depends on the assumption made for acceleration due to gravity at the earth's surface.

See Muzzle energy - Wikipedia, the free encyclopedia...

Surely the answer then, is to use a gravity meter and park it alongside the chronograph, then you will be able to use the actual g appropriate to your locality rather than rely on a nominal figure for g?

Regards JCS

 

[Sharpie]

Surely the answer then, is to use a gravity meter and park it alongside the chronograph, then you will be able to use the actual g appropriate to your locality rather than rely on a nominal figure for g?

Nope, the answer is to use a properly defined unit of energy e.g. Joules.

Some of the problem cancels out if you weigh the bullet using balance beam scales, then local g doesn't change the reading i.e. you get a reading of mass, not weight. Beam scales will give the same reading in any gravity field.

But use digital (strain sensor) or spring scales. Then the weight you measure depends on the local value of g. So you truly measure weight, not mass.

Taken to extremes, shoot any bullet in a zero g environment and it will have exactly zero fpe muzzle energy, as measured in that gravity field.

fpe is an archaic measure that is only meaningful if everyone agrees to use an arbitrary figure for g. Its not a proper measure of anything, but its all that we have (until we adopt e.g. Joules).

That would be fine, but it seems few agree on the value, so we have 450200, 450240, 450230, 450400, 450430, etc. etc. all used.

However in small arms ballistics the old imperial measurements are very well suited to the practical problems. Measurements in grains, 'thou, feet, inches at 100 yards, MOA, fps etc. just work nicely. I'd hate to have to convert to grams, millimetres, metres/sec etc, the units are just wrong .

 

[Dalua]

Surely the answer then, is to use a gravity meter and park it alongside the chronograph, then you will be able to use the actual g appropriate to your locality rather than rely on a nominal figure for g?

Regards JCS

This is doubtless what the forensic ballisticians do when stalkers with short barrels are arrested on suspicion of failing to meet minimum ME rrequirements.

 

[Sharpie]

This is doubtless what the forensic ballisticians do when stalkers with short barrels are arrested on suspicion of failing to meet minimum ME rrequirements.

Indeed so, that explains why the courts are blocked with so many pending cases, and why we hear of so many convictions . Seizure of rifles and ammo on suspicion of such offences is so commonplace that it would probably be best to hand them over for destruction rather than risk being caught out. Perhaps its time for an amnesty...

 

[splash]

Will recheck tomorrow as Quickload is on another laptop than the one i'm on today.
Atb
Coldweld

 

[Tackleberry270]

A chrono will be a far more useful tool than QuickLoad.
Just to put into context if one does not know how to calculate muzzle energy what use will QuickLoad be if basics are not understood?
This is not meant as a slight, just pointing out that £150 could be better spent elsewhere.

+1

Every rifle is different and for a number of reasons your guesses could still be 100s of fps out. I know this because when I bought a Chrony none of the loads in 3 different calibres matched up with the load data.

 

[deeangeo]

This is doubtless what the forensic ballisticians do when stalkers with short barrels are arrested on suspicion of failing to meet minimum ME rrequirements.

Hell - who told them? was it the deer?

 

[reelme]

Hello all again, well i got hold of a chrono and here's the results for the 243 some shockers here! the ft/lbs data came from strelok the chrony is a gamma master chrony which was set up approx 16 feet away from the muzzle-
65 gr vmax with 40gr varget 3037fps - 1332ft/lbs
90 gr speer sp 34gr rel15 2657fps - 1411ft/lbs
85 gr sierra bthp 35.3gr varget 2723fps - 1399ft/lbs
85 gr sierra bthp 34.7gr H4895 2855fps - 1541ft/lbs
58gr hornady v-max moly coated 3380fps - 1473ft/lbs
95gr winchester ballistic silvertip 2851fps - 1714ft/lbs
100gr prvi sp 2707fps - 1630ft/lbs
80gr remington sp 2868fps - 1463ft/lbs
100gr federal powershock sp 2602fps - 1506ft/lbs
85gr federal bthp vital shok 3047fps - 1752ft/lbs

these are the results i got today with the 243 17 1/2" barrel

 

[howa243]

Thank you for posting your results. I may have a re-think about what I was about to do.

 

[Sharpie]

Hello all again, well i got hold of a chrono and here's the results for the 243 some shockers here! the ft/lbs data came from strelok the chrony is a gamma master chrony which was set up approx 16 feet away from the muzzle-
65 gr vmax with 40gr varget 3037fps - 1332ft/lbs
90 gr speer sp 34gr rel15 2657fps - 1411ft/lbs
85 gr sierra bthp 35.3gr varget 2723fps - 1399ft/lbs
85 gr sierra bthp 34.7gr H4895 2855fps - 1541ft/lbs
58gr hornady v-max moly coated 3380fps - 1473ft/lbs
95gr winchester ballistic silvertip 2851fps - 1714ft/lbs
100gr prvi sp 2707fps - 1630ft/lbs
80gr remington sp 2868fps - 1463ft/lbs
100gr federal powershock sp 2602fps - 1506ft/lbs
85gr federal bthp vital shok 3047fps - 1752ft/lbs

these are the results i got today with the 243 17 1/2" barrel

Thank you for posting these results. You have done a good service for others who may not understand quite how marginal a shorter barreled .243 can be.

Its usually an eye-opener when you first use a chrono.

You have access to a great variety of ammo, excellent data.

Check them again when your pro chrono arrives, but I think the pattern is clear.

I've checked the two marginally legal England/Wales loads, and Strelok is spot-on with ME.

Easy enough to calculate yourself, muzzle velocity x muzzle velocity x bullet weight, then divide by 450430.

Good luck.

 

[j0e_bl0ggs]

I believe the relevant data was in my original question but was asking if anyone could advise for example if they had similar guns and loads!! so I' m sorry if my question and request for advice seems substandard for yourself but the world would be a very sad place if we were all budding Einstein's like yourself! so let's get back on topic now and the next time I'm struggling with quantum physics and the theory of relativity I know who to ask

I would say that quantum physics and relativity are a way too complicated subject for you so after you finish insulting me here have a think about what little you actually know!

Shame we cannot all be knowitallkeyboard warriors.

Oh welcome to my ignore list!

 

[reelme]

I would say that quantum physics and relativity are a way too complicated subject for you so after you finish insulting me here have a think about what little you actually know!

Shame we cannot all be knowitallkeyboard warriors.

Oh welcome to my ignore list!

firstly joe if i have offended i apologize!
i obviously mistook your initial slight as coming from a 'knowitallkeyboard warrior' which obviously your not ! so lets not fall out when we don't even know each other and keep the sport that we love united without in-house bickering.
all the best to you
reelme

sharpie yes some real eye openers there, i had a few other loads to try out but didn't have enough daylight!
will keep you posted when my crimbo chrony arrives,
all the best
reelme