.20 cal BC's

[gbal]

Finman,even a 7x57 can miss!

 

But it is seldom the ballistic program in error-as I,and I think Laurie, mention-the input data is seldom spot on....unless you believe the laws of physics change shot to shot.

Actually an inch either way is pretty good. Of course one reflects on a miss-one likely culprit is data entry inappropriate/mismatch with program parameters.

One reason for researching ballistics is to be better able to note a 'miss' since you know what to expect-multiple practice will do this too,but then you start from a much weaker knowledge base.As I said,explicitly,different mind sets-one is an informed mind,the other is more tabla rasa. Reality is as ever holes on paper etc-real shooting performance.The issue was to preselect the likeliest tool for the job,then check it out;rather than jump in with less information and risk a poorer outcome,from a non optimum choice. Ignorance seldom remains bliss for long,in this game.

(How can you recommend 6BR without the research,by the way? Of course someone else has done it for you-and you access it...keyboard is convenient for that.)

I don't think there need be disagreement-each to his/her own preferences. If others are happy to risk a pork chop in a poke (( :-) )),that is their prerogative.Good luck.Others prefer to look before they leap.Humour us.It's a cognitive style thing,Mars and Venus without the genders,vive la difference.

 

gbal

[Finman]

My friend, I missed a 120kg warthog at 40yds with a 7x57, from a sitting supported position, you need not remind me . Information gained by other's experience is just a guide and not a definitive tool which will also prove its utility in our hands. Indeed, all of us sought information on the behaviour and ballistic efficiency of a cartridge/bullet before we took the plunge. And, in each case I'm sure, we found that information helpful, whether our experience eventually verified it or not.

 

I find it, however, hard to reconcile with the relentless pursuit of each and every detail of a ballistic issue on a theoretical basis without its real-life validation, as is the case here. I find it even harder to reconcile with sarcasm towards those who offer an experienced opinion...And, as we both agreed, the only true evaluation of ballistic evaluation happens on the range, not through the keyboard...

 

best wishes

 

Finman

[gbal]

My friend, I missed a 120kg warthog at 40yds with a 7x57, from a sitting supported position, you need not remind me . Information gained by other's experience is just a guide and not a definitive tool which will also prove its utility in our hands. Indeed, all of us sought information on the behaviour and ballistic efficiency of a cartridge/bullet before we took the plunge. And, in each case I'm sure, we found that information helpful, whether our experience eventually verified it or not.

 

I find it, however, hard to reconcile with the relentless pursuit of each and every detail of a ballistic issue on a theoretical basis without its real-life validation, as is the case here. I find it even harder to reconcile with sarcasm towards those who offer an experienced opinion...And, as we both agreed, the only true evaluation of ballistic evaluation happens on the range, not through the keyboard...

 

best wishes

 

Finman

 

I am pretty sure the whole end game was,and remains,real field shooting....so the assumption 'without real life validation' is ...errr,premature,and wrong. When that misguided assumption is removed,there seems no disagreement.

No one is advocating that if we get the right ballistics,we don't need to shoot at all,rather such ballistics would be a good start for live shooting.

 

atb

g

[.300wm]

Would someone kindly explain the correct procedure for finding BC using a chrono at differing distances?

I am assuming it goes something like this.

 

- measure MV

-place chrono at varying distances

-shoot over chrono at new distances, record velocity

-adjust BC in computer program until it correctly matches velocity at the further ranges?

 

Cheers

[Laurie]

Despite being entirely a paper-puncher (where a good understanding of and attention to external ballistics often pays off especially in the long-range game), I have a lot of sympathy for Finman's viewpoint. The problem is that ballistics are now 'too easy' so to speak. Get a reasonably reliable BC, know the MV or have a good estimate of a ballpark figure, and hey presto you can bore people to death lauding some theoretical choice of bullet and cartridge, needing only a PC (if in the IT stone-age like me) or a clever app on some fancy pocket size device or other to prove it.

 

How often do you hear people say that they're having a custom rifle built and it'll have this barrel, that twist rate, the other chamber throat freebore and the so & so cartridge all because the 'app' says that the HornaBerger 99.5n sooper-dooper combo VLD-Hybrid-Ultra Max has a BC that's 0.001 higher than the next best model on the market? Fair enough, as one says, BUT .......!! BUT, what if the 95.5 doesn't group to save its own life in that barrel? ..........OR, if to get it to group like anything half decent, loads and pressures have to be kept right down and you lose 100 or 150 fps over what the cartridge should do (ie what the aspirant shootist thinks it should do)? ............OR, if it most unreasonably and inconveniently blows primers before achieving those MVs? OR ... (worst of all in the target shooter's world), some ar**h**e can shoot better than you, and read the wind that bit better than you and he / she quite (in fact totally) unreasonably gets higher scores with an 'inferior' bullet over a load that sees cases last more than a couple or three firings?

 

Been there, got all these teeshirts at one time or other. There's a lot to be said for seeing what other people have already proven to work and starting there. Being a trailblazer is an exciting concept and I wouldn't ever discourage people from trying something different - I just warn them that BCs and ballistics programs only tell you so much, and sometimes real life turns out very different with outcomes that can be both disappointing and very expensive.

 

There is one area that is totally lacking in external ballistics software and bullet evaluation that can affect the L-R competitor positively or negatively. Some bullets seem to hold elevations at a given velocity in a given rate of twist barrel better than others even though the program + BC says there's little or nothing between them in terms of wind drift and retained velocities. I think Finman is saying that in shorter distance field shooting, experience shows the same sort of thing happens, although we're taking a different set of performance indicators into account.

[Sherlock]

I spent a lot of time validating the true BC's of the bullets I use... test testing them over and over.

My procedure is using 2 identical chronographs - one 10 ft front of the muzzle - the other placed 200 and then

300 yrds away. Now this might not be the most scientific way - and I am sure that someone will mention the

atmospheric conditions or the coriolis effect on bullets - But it works. Mmy first time hit rate is much higher using this technique , rather than totally rely on using publisied BC figures which are undoubtedly used as a marketing tool.

 

Its a simple matter of working out the velocity drop at various distances and fitting it to a more realistic bullet BC. I did extensive testing on several different bullets with the two 204 R I have owned.

 

All of my testing show that the 40 Vmax and 39 grn SBK have a BC of between 0.240 and 0.250.

If you look at Nosler - they state a much more realistic 0.239 for the same weight and virtually the same design of bullets.

 

 

Ranges below 300 yrds the 204's initial high velocity compensates for ( shall we say , their Inflated publicised BC) . After 450 yrds - the bullets BC really starts to show - This is where you need to get your figures correct,, or any errors are magnified.

 

My experience using a BC of 0.275 for the 40 grn Vmax - are at 500 yrds - the bullets would always strike well low. Sure as night follows day.

 

The same bullet with a BC of 0.240 would hit centre mass - the difference in terms of using the validated BC instead of the publicised BC, , is about 3.5 inches - and that's enough to miss a rabbit - or worse injure it.

 

 

 

 

Kindest regards

S

[Laurie]

Would someone kindly explain the correct procedure for finding BC using a chrono at differing distances?

I am assuming it goes something like this.

 

- measure MV

-place chrono at varying distances

-shoot over chrono at new distances, record velocity

-adjust BC in computer program until it correctly matches velocity at the further ranges?

 

Cheers

 

 

Yes, that's the theory. But (I keep using this BUT word today!) there are problems / issues. Like (1) it's damn hard to get a conventional chronograph lined up 500 yards away so that the bullet passes through its skyscreens in that fairly small window; (2) the two chronographs have to be calibrated against each other - spoils the object of the exercise if chrono #1 reads 3% fast and chrono #2 that amount low; (3) even if (1) and (2) work out, the bullet's calculated average BC only applies to that distance at that MV.

 

There's a guy in the US called Derrick Martin who built some of the best competition ARs in the American NRA High-Power Service Rifle game some years back and was a top national competitor. He shot for the US National Guard team and built a lot of military team rifles. The downside was that as a reservist, he found himself called up for Gulf War 2 and had to shut up shop. While serving, he suffered various injuries and ended up on the sick for a fair time, but I'm pleased to see he's back in business.

 

http://www.accuracyspeaks.com/

 

The reason I mention him is that he got very interested in whether the then newfangled 0.224" 80gn VLDs used in the 223 Rem gave any real as opposed to theoretical advantage over the the then nearly ubiquitous 80gn Sierra MK. In this pre-Litz world, long before military establishments like the US Army Aberdeen Proving Ground would let civilians fire bullets over their incredibly expensive Doppler radar gear, we had G1 BCs with all their faults, and often quoted too on the basis of a single and improbably high speed. Derrick plus A.N. Other whose name I now forget was one of the first to actually test bullets at a reasonable distance. Ideally, it would have been 600 yards in this instance as that's the range that US Service Rifle shooters fire the final National Match stage over, prone and slowfire with targets marked for each shot and where the BC/MV combination is most important. Despite using a custom built bolt-action rifle with a 20-inch match AR barrel screwed on, it was found that 500 yards was the furthest distance where they could get at least a few readings at the target end of the range. (The results showed that the 80 SMK did better than it should and that contemporary same weight VLDs did worse and the resulting real difference was small.)

 

What Bryan Litz uses is a private range facility with a chronograph at the muzzle plus microphones situated along the range at very carefully measured and equal distances and all connected to a bit of IT with some custom software he devised. He fires a number of shots downrange and the mikes pick up the sonic crack as the bullet passes over, advises the laptop/tablet or whatever he uses and it calculates the time between mikes down to a small number of miliseconds, and from there the average bullet speed between each set of points. A program then runs an iterative ballistic calculator multiple times until an average BC value is provided that matches the MV + time / speed intervals downrange.

 

As a starting point, atmospheric pressure, temperature etc are recorded and the results are subsequently adjusted to what would have applied if 'standard ballistic conditions' had ocurred during the tests.

 

All of this would be very interesting, but basically useless if the G1 BC norm were applied as the effective BC varies so much according to bullet speed. As a former USAF rocket scientist and professional consulting ballistician, Litz looked hard at all the Gx 'reference projectiles' and discovered that the US Army G7 model (actually for a medium calibre artillery shell) was very close to the shape of a modern streamlined boat-tail bullet and through on the range experiments proved to his own satisfaction that real results from experimentally derived G7 BCs were acceptably close to predictions if this reference-norm was used. Therefore he can quote a single average G7 BC value confident that it would only vary by around a top figure of 4% over a 1,000 yard flight from a reasonably large range of MVs. In the case of G1 results where the BC value might be 15 or more % higher at a 3,000 fps MV than it is at say 1,200 fps 800 yards downrange, the methodology would only give a set of sectional BCs, so that speed-stepped values as supplied by Sierra woulkd have to be used. (Bryan has also compared the overall accuracy of the single average G7 value against the Sierra method of multiple BC value steps and found that a single average G7 normally gives more realistic results than the stepped method.)

[gbal]

Is that agreement I see on the horizon?

"We all seek information to make informed choices'-I think has to reduce the 'keyboard jockey ' jibes,to a personal choice about how much info one wishes.

 

I've already pointed out that the intention is field shooting- the issue is what's the best tools,which are then field tested-I see no rebuttal of this principle.

 

On a new build,some specifications have to be relatively hard wired-chamber etc-essentially a cartridge decision,hence 'what is the best,or better yet,what are the front runners,and can they be separated for the proposed use,and one chosen?'

On your points Laurie,of course there are some risks-but whatever is chosen the risks remain,and a decision has to be made-you cannot tell what accuracy eg will be until that rifle is chambered and that bullet fired (though there might be some data on 'risk' components-eg,and very simply-seating depth sensitive bullets versus tolerant ones).The point has to be though,some of these have to be decided ,so that the rifle can be built. One point in detailed research would be to see if there are any useful options that allow plan B (another bullet) if the master design fails.

I have repeatedly argued against the hunt for the false "holy grail of 50 more fps or small decimal BCimprovement" -even if real/accurate-in at least varmint rifles out to 300y-the likely candidates are all so close,pragmatically the differences are academic/negligible.

You must of course know what pertains in your rifle from live firing at various ranges.

Beyond,and as range increases,the previously small differences accumulate-there may be others as yet poorly understood,as you note Laurie-we can only do our best as of now.

There is no rational case to choose third best ballistically,unless cost etc thave to come into play,perhaps.

I've pointed out some of the issues with "BC's" and Laurie has added to that.There are more.Some comments seem to confuse 'some published BCs are not very accurate' as negating the question "Given that inaccuracy,how do we make best informed choices with more accurate BC?",a very different question-hence the 'how should BC be measured,and reported' posts to get 'more accurate' BCs-and examples of how the current published ones are misleading-the problem,not the solution.

The question has been and remains,how do we make the best decisions with current information,knowing some parameters (BC noteably) are deficient.We have to commit to some chambering,and accept that more detailed specification (none were asked about in the OP application though LR targeteers seem to do this-choose bullet,chamber to suite) might carry some risks if they don't work out.(new barrel/chamber next season probably needed anyhow!)

 

I did ,on this point,say that I would not chose small BC or fps advantages over accuracy,so the point has been made....the snag is accuracy can only be known after chambers etc are completed and the rifle fired...I'm afraid hindsight isn't much of a design guide!

For those who seem to have missed it,one of the drivers is that when detailed examination of the ballistic data is done,compromises start to appear that a simple bullet weight/calibre/bc criterion alone miss-there are "interactions" which always complicate even confound easy solutions(bullet weight/BC/velocity?twist is especially complex and compromise rich)-bearing in mind that for every complex problem there are several simple solutions,all of which are wrong ! :-)

 

Some will quite understandably make choices at a pace that others might not...I am reluctant to make analogies with something less tangible or even central to this forum,but "marry in haste,repent at leisure" comes to mind,though it is occasionally observed in the breach,so I hope it lightens the discussion.

I'm off to play with my old Remington....rifle or typewriter-I keep options open!

 

I take it as axiomatic ,for what it's worth,that:

 

"The best is temporary".

 

good,or better,shooting to all

 

gbal

[gunner]

Well, I can't add much to the topic of the accuracy of claimed bc's, but I can recommend the Nosler 40gn BT! I'm surprised more 20 cal' shooters don't use them. I know there are cheaper alternatives but IMO they are better made than the likes of Hornady. Definitely worth a try it you do go for a .20!

After reading this im going to try em ! Iv been using 39 S-Bk exclusively which are a great bullet ( Sunday @170 2x magpie then 341yard carrion ) Re the bc on the sierra they have shown to me to be about 250 to match the real field drop data out to 500 . The finish on the nosler iv got look better quality because on many of the sierra theres little dimples in the jackets showing mainly on the concentricity gauge as the dial ball rides over them ! Cheers

[gbal]

After reading this im going to try em ! Iv been using 39 S-Bk exclusively which are a great bullet ( Sunday @170 2x magpie then 341yard carrion ) Re the bc on the sierra they have shown to me to be about 250 to match the real field drop data out to 500 . The finish on the nosler iv got look better quality because on many of the sierra theres little dimples in the jackets showing mainly on the concentricity gauge as the dial ball rides over them ! Cheers

 

Good luck Gunner-can you rport back-the Sierras seem to shoot crows ok,but thee might be (small) accuracy gains for your rifle with Nosler-accuracy just has to be 'try and see'.I don't have any data at all on 39 Nosler-or any others- for 20 cal,as only 204 ruger is commercially available:

 

Fed 40 SierraBK BC .287 @3750 4.7/7.8

Horn Vmax 40 BC .275 @ 3900 4.3/7.8

Rem 40 Accutip BC.257 @ 3900 4.3/8.6

Nosler 40g BT BC .239 @ 3625 5/10.2

 

Broadly consistent- BC and velocity can help a little-using the makers figures of course-but go for accuracy!

 

 

 

 

 

There are three commercial loadings using the Nosler 40 g Ballistic Tip in 223,one in 222rem mag,with published data as follows:

 

Fed @ 3700 BC .221 300 drop/drift 8.0/10.8

Black Hills @3600 BC .200 6.3/12.7

Ultramax @3200 BC.221 7.8/13.2

 

Nosler 222Rem Mag @3650 BC.221 5.7/11.0

 

Hmmm ....... always liked the 222rem mag!

 

It's clear there is broad ball park agreement,rather than exact uniformity-I'd go for accuracy,as always (and Bergers for uniformity).

 

gbal

[Finman]

I spent a lot of time validating the true BC's of the bullets I use... test testing them over and over.

My procedure is using 2 identical chronographs - one 10 ft front of the muzzle - the other placed 200 and then

300 yrds away. Now this might not be the most scientific way - and I am sure that someone will mention the

atmospheric conditions or the coriolis effect on bullets - But it works. Mmy first time hit rate is much higher using this technique , rather than totally rely on using publisied BC figures which are undoubtedly used as a marketing tool.

 

Its a simple matter of working out the velocity drop at various distances and fitting it to a more realistic bullet BC. I did extensive testing on several different bullets with the two 204 R I have owned.

 

All of my testing show that the 40 Vmax and 39 grn SBK have a BC of between 0.240 and 0.250.

If you look at Nosler - they state a much more realistic 0.239 for the same weight and virtually the same design of bullets.

 

 

Ranges below 300 yrds the 204's initial high velocity compensates for ( shall we say , their Inflated publicised BC) . After 450 yrds - the bullets BC really starts to show - This is where you need to get your figures correct,, or any errors are magnified.

 

My experience using a BC of 0.275 for the 40 grn Vmax - are at 500 yrds - the bullets would always strike well low. Sure as night follows day.

 

The same bullet with a BC of 0.240 would hit centre mass - the difference in terms of using the validated BC instead of the publicised BC, , is about 3.5 inches - and that's enough to miss a rabbit - or worse injure it.

 

 

 

 

Kindest regards

S

 

Τhat is exactly my point: the .204 is not a target round and is not a 500yd rifle. With that in mind it is, IMHO, imperative that the velocity characteristics of the rifle are exploited and, once a bullet which gives good accuracy in one's rifle is found, practice allows development of the relevant skill necessary to engage a vermin sized target out to 300yds. Any shot above that distance is marginal and, it could be argued, unethical on a live target.

Hence, the OP question was answered by the second message.

 

the rest is interesting and informative discussion on the subject of BC....

 

Best wishes

 

Finman

[gbal]

Panos,I'm old school enough to think,initially,that any shot at small vermin beyond 300y,especially with a sub 6mm,and in wind,is indeed challenging....but grant also that gear has improved-especially bullets,and BC is a guide to that,and there are several more or less equivalent choices out to about 300y-where velocity and small BC differences lead to field equivalence-though it remains essential to know your rifle/bullets actual performance.Any BC,including the accurate value,is only a (good) guide.Beyond 300...?

I read Sherlock's excellent post to be underlining the errors that published BCs lead one into-beyond 350y,because those BCs are almost always optimistic at such distances,as indeed Sierra's published data for reducing velocity show clearly.

 

What follows from this generally agreed fact,is not that we should dismiss all figures,but that we should use accurate figures .Alas,we don't have the BC version of the chronoscope-but we do have much more accurate BCs from actual testing -as Sherlock et al,or Bryan Litz' s careful 'lab' work.

Then a longer shot that would have been at best a miss,would ballistically become 'a centre mass hit'.

The best strategy to me remains : choose the best BC bullet for your cartridge, using real BCs,then field check it's performance.Then develop shooting skill and judgement when not to fire.

 

All the other genuine issues are just as valid for lesser BC bullets,so start with the best. You cannot determine accuracy in advance-it is possible that whatever bullet you try may be lacking in accuracy -this has no known correlation with BC at all-indeed it is really unique to that rifle. So simply must be field tested,rifle by rifle,along with drop/drift.

There is no a priori reason NOT to start with the best BC bullet (assuming it fits your useage-terminal effectiveness will be important for varmints-though completely irrelevant for targets.)

 

I have 'conceded' that others of a different disposition/personality type-to be PC - might throw out the baby with the bathwater,dismissing all numbers (BC included) on the grounds of some (correctable) inaccuracies. Accurate BCs (and velocities etc) are obtainable,and many will see merit in using them.

And still realise that human error in wind reading,especially,is way more important than a couple of decimal points.Field testing on inanimate targets should make that clear,and impose ballistic and ethical limits on the ranges shot at vermin (I have often enough suggested at least an 80% hit rate allows a discussion).

( I don't think one 7x57 miss condemns that fine old cartridge,either !)

 

Lest we go on much more,could someone give a coherent argument as to why one would not begin with the best BC bullet,and only go for a lesser one when that first choice was found field deficient for varminting in some other a priori unpredictable way? ( cost and the like,excepted).

 

I absolutely agree the discussion on BC has covered new ground,all of it consistent with being aware that BC is not the be all and end all.And especially, the need for accurate relevant figures ((otherwise it's Neanderthal in,Neanderthal out. :-) and it probably worked OK for clubs! ))

The ultimate defence of empirical science is that it is better to know than not to know.

But practicing science is not for all; the benefits ,however,remain a universal choice,take or leave.

 

gbal

[Andrew]

Panos,I'm old school enough to think,initially,that any shot at small vermin beyond 300y,especially with a sub 6mm,and in wind,is indeed challenging....but grant also that gear has improved-especially bullets,and BC is a guide to that,and there are several more or less equivalent choices out to about 300y-where velocity and small BC differences lead to field equivalence-though it remains essential to know your rifle/bullets actual performance..

 

gbal

Well said. BC's are a good guide when making choices for bullets. Plugging said numbers into a proigram to check relative preformance can be entertaining; it's how I came to shoot 40 grain VM when my mates are doting on the faster 32 grain.

But in th eend, you can't learn to shoot small bores from a balllistic's program. You need to burn some powder in the field, in the weather, where BC's become somewhat irrevelant compared to heat, cold, mirage and wind. We shoot very small vermin -prairiedogs- and all the doping and drop charts in the world might get you on target at 400 yards but not as effectively as experience.~Andrew

[gbal]

Well said. BC's are a good guide when making choices for bullets. Plugging said numbers into a proigram to check relative preformance can be entertaining; it's how I came to shoot 40 grain VM when my mates are doting on the faster 32 grain.

But in th eend, you can't learn to shoot small bores from a balllistic's program. You need to burn some powder in the field, in the weather, where BC's become somewhat irrevelant compared to heat, cold, mirage and wind. We shoot very small vermin -prairiedogs- and all the doping and drop charts in the world might get you on target at 400 yards but not as effectively as experience.~Andrew

Andrew,thank you for confirmation of the key isssues,from experience of more varmints in an afternoon than most over here might encounter in a season!

The best BC,accurate rifle performance,and even accurate ballistics programmmed to your field data is a very good start-it will put you and your bullet in the ball park,eliminating most of the wilder errors,missed shots you never even see splash for,and enable you to BEGIN TO LEARN from diverse field experience-most especially the vagaries of wind,which just cannot be programmed in any detail(all you get,per shot,is one fixed mph!) yet is the essence of effective small varmint shooting.

All the research,keyboard shooting -call it what you will-when done thoroughly PREPARES you to learn most efficiently about shooting effectively in the field.,with that equipment and ballistics. It remains for me far and away the best approach,but it is in itself no more than the end of the beginning (though a much better beginning than anything else).

 

What is the point of reinventing the crooked wheel?

Do we need to experience first hand all the snakes to appreciate the ladders?

Is not our unique human progress built on accumulated knowledge?

 

This soap box rests it's case.

 

gbal

[Big Al]

Τhat is exactly my point: the .204 is not a target round and is not a 500yd rifle.

 

 

BCs are highly variable and indeed not that great in the smaller calibres. Using a 50-55gn bullet in a .204, as far as I'm concerned defeats the purpose.

 

Bottom line: want to hit stuff at 400yds? get a 6mmBR and up.

 

Have you considered the performance of a 20BR running 55gr Bergers at 3600 before you made these bold statements?

 

I would expect not.

 

Here is a comparison on the drop/drifts in a 10mph wind between a 6BR running 105 Amax @ 2850 and a 20BR running 55gr Bergers @ 3600 in a 10mph full value wind. Both can be done quite comfortably by all accounts based on published load data and neither is 'hot' with around 30grains of similar powder.

 

 

400yds - drop/drift

20BR - 15.5 & 10.2 - recoil = 2.91

6BR - 27.2 & 11.2 - recoil = 5.04

 

500yds - drop/drift

20BR - 30.1 & 16.8

6BR - 50.1 & 18.2

 

If you really wanted to push it out for fun then here's a long range one

 

1000yds - drop/drift

20BR - 225.6 & 87.2

6BR - 331.8 & 89.6

 

I feel that right from the start you have looked at this thread through blinkers and thinking of the .204 Ruger or its closer siblings Tac/Prac. Of course these are just statistics and to some people they are rubbish, they seem to think its much better off getting out and lash a load of lead down the field with the wrong rifle.

 

Of course you can continue to bitch about me being a keyboard shooter which of course is nothing but speculation and a means of distracting from the facts. Or you could consider me someone who is doing his homework before spending a lot of cash on a rifle he alone might want and then and only then the time in the field working through the real world drops/drifts.

[Big Al]

Well said. BC's are a good guide when making choices for bullets. Plugging said numbers into a proigram to check relative preformance can be entertaining; it's how I came to shoot 40 grain VM when my mates are doting on the faster 32 grain.

But in th eend, you can't learn to shoot small bores from a balllistic's program. You need to burn some powder in the field, in the weather, where BC's become somewhat irrevelant compared to heat, cold, mirage and wind. We shoot very small vermin -prairiedogs- and all the doping and drop charts in the world might get you on target at 400 yards but not as effectively as experience.~Andrew

 

I agree but the statistics can certainly help you to choose the right rifle to go and do it with.

[Andrew]

 

I agree but the statistics can certainly help you to choose the right rifle to go and do it with.

Sometimes! I bought my 204 CZ Varmint because the shop it was in had it priced at $475, NIB, and tossed in a set of rings to go with! For that money I could be talked into another 20 cal... ~Andrew

[Finman]

Have you considered the performance of a 20BR running 55gr Bergers at 3600 before you made these bold statements?

 

I would expect not.

 

Here is a comparison on the drop/drifts in a 10mph wind between a 6BR running 105 Amax @ 2850 and a 20BR running 55gr Bergers @ 3600 in a 10mph full value wind. Both can be done quite comfortably by all accounts based on published load data and neither is 'hot' with around 30grains of similar powder.

 

 

400yds - drop/drift

20BR - 15.5 & 10.2 - recoil = 2.91

6BR - 27.2 & 11.2 - recoil = 5.04

 

500yds - drop/drift

20BR - 30.1 & 16.8

6BR - 50.1 & 18.2

 

If you really wanted to push it out for fun then here's a long range one

 

1000yds - drop/drift

20BR - 225.6 & 87.2

6BR - 331.8 & 89.6

 

I feel that right from the start you have looked at this thread through blinkers and thinking of the .204 Ruger or its closer siblings Tac/Prac. Of course these are just statistics and to some people they are rubbish, they seem to think its much better off getting out and lash a load of lead down the field with the wrong rifle.

 

Of course you can continue to bitch about me being a keyboard shooter which of course is nothing but speculation and a means of distracting from the facts. Or you could consider me someone who is doing his homework before spending a lot of cash on a rifle he alone might want and then and only then the time in the field working through the real world drops/drifts.

 

 

We've a saying where I come from: where you are I've been and where I am you'll come...we will talk then...

 

How's the 17Rem by the way?.??

 

Finman

[6.5Grendel]

I have been following this thread from the sidelines with interest .

My 2p

I can see both sides of this thread and i enjoy the 'theoretical' aspect of shooting as well as 'time in the field' (which i don't get enough of) but bottom line is what works in your rifle. You can try and narrow that down with research but at the end of the day if your barrel doesn't like a particular bullet then its back to the drawing board . The only way to find out is to try various load combinations ie trigger time.

You may very well be lucky and have your research pan out with a calibre / bullet combination thats works out of the box and if so then happy days but from personal experience that is rarely the case . Does this mean i need more research or more trigger time? Personally , I'd rather be out shooting .

Andy

[Big Al]

We've a saying where I come from: where you are I've been and where I am you'll come...we will talk then...

 

How's the 17Rem by the way?.??

 

Finman

 

More distraction and subject avoidance, are you by any chance a politician?

[Finman]

More distraction and subject avoidance, are you by any chance a politician?

 

The numbers, sir, mean little when you see what's happening in the real world: name the 1000yds record held by the 20BR...or the number of shooters that prefer it for 200-300-600yds competitions...one, usually, builds a rifle round a cartridge not a bullet and experience then decides the right combination for each discipline. The subject of 'this BC is better than that BC' was analysed very substantially and eloquently by Laurie a couple of messages back...

 

With that in mind, all my rifles are "the right" ones, for the disciplines I use them for, the 'wrong' rifle is usually at the "wrong" hands....

 

See what you'll decide and let us know how you're getting on with it...

 

Best wishes

 

Finman

 

PS: no news on the .17Rem then?

[Big Al]

The 1000yd stat was just to reinforce the 400 & 500yd comparisons, of course there are better options to be competitive at 1000yds but it doesn't change the fact that as a 400-500 yard varmint rifle the 20 cal can be a serious contender if chambered right. Just because they are not used by you or the masses in such a configuration doesn't mean they are wrong or can't do the job well.

 

The simple fact is you still haven't qualified these crazy statements you made about .20 not being a 400-500yd round or that 55gr was defeating the point, both of which of course are not so accurate in light of the figures I gave you.

 

As for the .17 Rem, Im still looking, might you know of a nice one somewhere as Im keen to buy one if its right?

 

Im not sure there is much more we can debate, only by looking at figures will I be able to make a final decision, thats what I feel I have to do as Im not the kind of guy to just randomly take a punt.

[Laurie]

Big Al,

 

what length barrel do you need to get to 3,600 fps?

[Big Al]

Ive been told 26" will do it Laurie but I would be happy with less speed from a shorter tube.

 

I would be keen to find out an QL data on this.

[Finman]

The 1000yd stat was just to reinforce the 400 & 500yd comparisons, of course there are better options to be competitive at 1000yds but it doesn't change the fact that as a 400-500 yard varmint rifle the 20 cal can be a serious contender if chambered right. Just because they are not used by you or the masses in such a configuration doesn't mean they are wrong or can't do the job well.

 

The simple fact is you still haven't qualified these crazy statements you made about .20 not being a 400-500yd round or that 55gr was defeating the point, both of which of course are not so accurate in light of the figures I gave you.

 

As for the .17 Rem, Im still looking, might you know of a nice one somewhere as Im keen to buy one if its right?

 

Im not sure there is much more we can debate, only by looking at figures will I be able to make a final decision, thats what I feel I have to do as Im not the kind of guy to just randomly take a punt.

 

With the same rationale a 22.250AI could do what you wish, with less hassle...and so would a .243... But then of course there's the issue of 'recoil' (jungle re has an interesting quote from edi as his signature, worth checking out...)

In any case, you wish to convince yourself that you found the wheel first, be my guest...as for the 17Rem, didn't it shoot sooty cases??

 

All the best of luck in your quest...!

 

Finman