VarmLR

On 5/12/2020 at 11:39 PM, Scotch_egg said:

I always liked the 155’s

 

Velocity over BC

BC  over velocity.  Tomatoes tomaytoes 😉

What happens through transonic  matters.  I've shot next to mates shooting 155's at 2900fps or close on and did as well if not better with 190s at 2550fps over 1000yds.

The ideal though is high BC for mass and high velocity so in .308 an SMK 155 Palma  driven at 3000fps tends to do pretty well!

23 hours ago, Andrew said:

I won't roll crimp but I am a huge proponent of using a Lee Factory Crimp Die. It doesn't require a cannelure. I crimp every round i load. If Lee doesn't make one for the cartridge I'm shooting , I have them make one custom. (A 9.3x57 was my most recent purchase) It will lower your ES and SD. From the 22 Hornet to my 300 Win Mag Long Range Target loads, my loads are not fully finished until they are crimped.~Andrew

 This ^^^^

On 5/13/2020 at 7:57 PM, borbal said:

.... or you can simply try it out at http://www.geoffrey-kolbe.com/trajectory.htm where range angle is a variable.....

That's a useful reference.  Isn't the thread though as much about trying to understand the principles involved and finding perhaps empirical answers to calculating it? Admittedly without something to help with the maths when in the field, if a battery device goes down it's handy just to have a little written table with a list of look up (or down) angles and corresponding horizontal correction for distance as an approximation to the factors involved.

That's a big improvement on previous models Andrew for sure.  I had to get mine fully DEVCON bedded with pillar bedding at the rear (as standard) and it was more consistent when done.

I gave up on the standard smk175's once I'd tried the TMK 175's.   High price but higher BC. I've also found the smk 190's to be excellent at range as it seems to remain stable past transonic.

Depends if you use holdover or dial.  I use an NSX with an NP1 ret for hunting and the lack of clutter in the ret and easy turret adjustment makes dialling a breeze.  For plinking I can see that maybe using a mil hash or moa hash ret allows easier corrections using the ret.

Buy used.  There was a really nice NSX in the private ads lately and used also buys you a decent DMR which are pretty bomb proof.

20 hours ago, Charlts said:

I like the GRS stocks, one of my Creedmoors is in a Hybrid stock which has done everything from stalking to banging steels exceptionally well. I’ll probably end up letting it go soon as it doesn’t fit with the direction my shooting is going in these days.

I have that stock for my .308 Tikka and it's one of the most comfortable shooting stocks I own.  I'd second that as a good recommendation.

Hard to argue against Tikka Andrew, in any calibre!  They're fab rifles.

4 hours ago, Dellboy said:

BBC and factual in the same sentance   now there is a leap of faith

🤣

They're about as impartial as Mr Creosote was to Lobster!  😂

For comparison in a 1/8 twist 24 inch barrel, same brass, same primers (KVB Magnum....just thicker cups), same bullet, RS62:

43.9grn RS62 = MV 2,700fps 139 Scenar

42.6grn RS62 = MV 2600fps 142 Hornady SST

Yes, RS 62 is single nitrocellulose base but coated with camphor to improve temperature stability.  It's energy (heat of explosion) is similar to H4350 which was the go-to powder for 6.5CM.  Kinder on barrels than RS60 and doesn't appear to pressure spike like some Vhit powders. (some have a tendency for most velocity gain at the top of their pressure curves and combine that with temperature sensitivity and pressure spikes can be quite spectacular!  I've experienced this with N140...don;t know if N160 is the same).  Note that RS62 has a higher energy than N160, and greater bulk density so you can get more into the case before compressed loads start.  I have mixed feelings about compressed loads.  On the one hand, you get uniformity with slight compression of load density and hence ignition and burn rate, on the other with just slightly more compressed loads you can crush the kernels and increase rate of burn slightly in doing so depending on the energy of the primer used.  Small primers seem more consistent with compressed loads in 6.5 I guess because they have lower ignition energy than large primers but that's not fact, just speculation based on results.

Magnus effect.....lets throw in "dynamic jump" too and how that's affected by global positioning just to muddy the waters a bit more 😂

I was once "beasted" on a shooting course for daring to suggest your point of aim should lower with a downhill or uphill shot.  I didn't know the maths then but had done enough shooting to realise it was a truth.  Trouble is neither did the Colour who thought I was being a smartarse so made an example of me!.....and looking back on it quite rightly as in battle conditions it was another complication a section didn't need.

Back to the present and if in doubt about my ballistics theory, Litz's Applied Ballistics for Long Range Shooting is on my shelf and comes out quite often.  For those who can patiently follow the maths (and there's a lot of it) it makes perfect sense. As BD has pointed out, you simply treat it as a vector and work out the effects of gravity and the effects of the other components such as drag, to come up with the answer.  In simple terms, because I'm a simple chap, the explanation is that once the line of sight to the target is anything other than horizontal,  gravity remains a constant (downwards part of the vector) and acts to pull the bullet away from the line of sight,  gravity both helps slow the bullet (acceleration acting against the bullet's horizontal  inertia) and since the horizontal vector is the horizontal to the target from the firing point, gravity acts over a shorter horizontal distance (ie the 9.81m/s acts vertically downwards, not at an angle perpendicular to the arc of flight when inclined or declined) hence the projectile doesn't fall as far under the line of sight as if the target was horizontal.  It took a while for me to get my head around that but Litz explains it well (see P47 of Applied Ballistics).

The "Shooters' Rule" is an approximation of the affets of up or downhill shooting and more advanced ballistics apps ask for this angle and do the simple calculation based on the "Shooters' Rule"

This rule is simply: Multiply range to target by the Cosine of the Look angle.  This gives you the approximate horizontal range to the target which you then use in your bullet drop calcs.  However, this approximation doesn't allow for the other constant that is NOT affected by incline, which is drag, so technically you should also apply apply the drag of the actual trajectory distance and the gravity part of the Cosine of the Look angle and this gives the more accurate drop.  You could go on refining it further but this is as far as most tend to go.   As long as you understand the principles and know how to use your app, or can approximate angles and use even a phone to work out the cosine you have a quick reference.  For hunting inside 400 yds I would suggest KISS principle applies!  Litz maintains that  the way to apply the drag coefficient (and this is genius) is simply to modify the G7 BC to be less than it actually is so that there is a proportionality between look angle and BC correction factor, and this is the modified factor used together with the horizontal distance which gives the best approximation of actual drop.

He proposes that a scale factor "f" is used to modify BC where:

f= 1+1.3 x 10 (to the -5) x h

where "h" is the difference in altitude between the shooter and the target.

Fore clarity, I'll use his worked example below for a 155gr .308 bullet with an MV of 3000fps and a G7 of 0.233:

Look angle is for this example 45 degrees and target is at 1000 yards at a 45 degree look up angle.  Drop below target without correction is calculated as -219.3".

From the Cosine rule h = 2000x Sin(45) = 1414ft  (note Brian has made an error in the book and used the MV instead of the distance!) so the target is 1414ft above the shooter;

If the shot were downhill the target would be at -1414 ft;

Using the correction factor equation, we have:

f= 1 + 1.3 (10 to the -5) x 1414 = 1.018

So for this shot, you would correct the BC by 1.018 so BC (corrected) would become 0.223 x 1.018 = 0.227 and that is what you would use in your calculator for 1000 yds.

Best really to read his fairly short chapter on this if still confused!

One thing we seem to have used a lot at home which we never had before because we take too much for granted, is a UVC cabinet into which post, the odd bit of shopping and anything else we may need to sterilise from time to time goes in.  It's used most days presently.

We also keep more hand cream around as with more washing of hands it's essential to keep skin moisturised.  I was the typical macho type to begin with until my own hands started cracking and bleeding, now I realise I was just being an idiot.

The really disappointing thing is when this all kicked off, people around here (can't speak for anywhere else) behaved like selfish animals, hoarding so much that they would normally never have bothered with that shelves were stripped of essentials within a few days of the pandemic being announced here, and during lockdown, things got worse.  We saw families going in together pushing a cart each and filling each one up with the same things depriving those in need of essentials.  The greed and selfishness disappoints more than the government's lack of initial decision making nor anything else happening since.  It's not the government who should be ashamed, it's the general public.

Meantime we haven't been able to buy flour, yeast, some pastas, rice or similar here even up until yesterday as the same arseh@les are not doubt still at it.  Our local appliances outlet nearby sold out of freezers within the first week.  They're now shut anyway.  

Outcome:  The British (probably here I can generalise a bit!) have been their own worst enemies and far from being the caring, responsible society sometimes portrayed, have largely shown themselves to be utterly selfish, greedy, uncaring "I'm all right Jack" types and sod anyone else.  I have to admit as much as I am now tempted to behave the same way, my dignity won't allow it.  Just because some people are like that doesn't mean I have to be unless my family is really put at risk, but this isn't the Third World, and there are towns in Russia where queuing for food and empty shelves is a daily reality even in 2020 out of the pandemic.  The most important lesson that we should take from this as a nation is to re-educate the nation that there's enough to go round of everything so it should become socially unacceptable, just as drink driving is, for people to hoard the way they have.  Most of that no doubt will be wasted when there's people starving and homeless.  People who hoard make me sick.

We have a lot to be grateful for and haven't really gone without much food wise.

One area notably badly prepared is our health system./  Those with pre-existing conditions, such as myself, found ourselves locked out of regular treatment for illnesses or serious chronic injuries for the duration and it's had a massive impact on my life in terms of pain and suffering.  I did eventually get seen after the doctors realised that without treatment I could end up paralysed but boy did it take some pushing on my part!

As far as the contagion goes, yes it's highly infectious beyond a doubt.  As the models V's reality, well recent studies in two American states show quite dramatically that far from being the 3 to 5% mortality predicted, those states from a very large proportion testing positive show a trend of between 0.045% and 0.15% (different states), which appears little different to their normal seasonal flu mortality rates.  I disbelieve most of what the media says on the subject and still don't believe we have anything like enough reliable data in the UK to suggest we're any different as for all we know, we've all had it or a majority have.  That's the good scenario I know, the bad may yet reveal itself in time.  You won't be able to plan for this much better than we have.  The timescale for action was out by a few weeks but would that make any difference to total deaths longer term? Probably not.  It just flattens peaks which helps our beleaguered health system cope better.  I do not trust some of the Globalist agendas at play in all of this nor the UN, nor the statistics portrayed on TV which are wholly unreliable for now.  

That's right. I was told that there are some already reserved, many going out to institutions world-wide and UK availability is very limited and shrinking daily.  As you say, expensive but one of those books that comes along every 25 years or so which, for the serious shooter and amateur military historian is a "must have".  I seem to have amassed a large collection, some my late Father's and it's really interesting to look at the different takes and information each provides.

The story of AI was quite amusing, for those who don't know...... Two blokes working from a garage tendered for an MOD contract as in "what have we got to lose?" and the end result was that their novel and unique (at the time) unit construction chassis system won out.  Allegedly when MOD procurement contacted them and said a few high ranking officers were coming to inspect their premises, they had kittens!  Within days they had procured a unit on a nearby industrial estate, moved their lathe and a few workbenches in there with some stores and barrels plus a few bits of rifles scattered about on benches.  They had no budget remaining for a fancy restaurant meal so hoped a pint and a sandwich would do!  As it turned out the officers were impressed less with what they saw and more that it wasn't just "two blokes working out of a shed" 🤣 and said as much, then settled for a pint and a sarny!  The rest as they say is history.

The truth did come out though after the contract was awarded and whilst AI produced the first 110 or so rifles of a 1200 unit order, another (non firearms) company was handed the rights to complete the rest under licence.  However, they looked at the specs and because the firing pin materials were so expensive (as an example of a cost cutting opportunity) they decided that another type of steel would be cheaper....and so-on.  The end result was that there were many accidental discharges as the pins snapped near the heads at the rear end, firing the pin forward into a chambered round, setting it off.  As a result of that, the contract was handed back to AI on the understanding they'd meet demand which to their credit, they did.

I love the fact that their history and success follows that of so many others working from garages and sheds (Trevor Bayliss anyone?) and that the UK still has loads of people like this all over the country.  

My business is no comparison at all but I've been working out of a garden workshop successfully for ten years now and I wouldn't want that to change!

I wouldn't wish to comment on someone else's private life decisions.  It's up to them although they're undoubtedly  in the public eye and should expect to both set an example as "role models" whatever that pertains to these days (and goodness knows most so called role models are anything but!) and expect some flack from time to time as the bad comes with the good.  One thing I respect Harry for was his service.  I may have lost a lot of respect for him since that time and do not care at all much for his Mrs, but that's as far as it goes.  If he wishes to get rid of his guns, that's his affair (and his loss),  Whether he did or didn't wish to tread that path is nothing to do with us but even if he really wished to keep them  I doubt that he got much of a chance to shoot anyway.  Let them be.  The gutter press hound them more than enough without idle gossip having a pop.  That, I would hope, is beneath us.

Great method.  A cross between a military range card and empirical surveying using a map....simple genius!  Thanks for sharing.

You have to be very consistent with 223 brass if you're aim is consistently precise grouping and low ES.  It's a small case and I check my new batches by volume from a random sample of 10 and take an average.  I then batch them, if needed, so the cases are all within 1gr H20, no more, no less.

Your load for the 60Vmax of well over 24gr is a very hot load indeed and may prematurely bow the case heads so worth checking for loose primers with each reload.  I was using 31.6gr N133 under a 60g V Max and only got 4 or 5 reloads from PPU before primers started dropping out.  With a 26inch barrel that translates to 3150 fps and is accurate.  I now use Norma brass which is more consistent and lasts longer.

Great author too 😉  He really knows his onions.    Shrivenham Small Arms Collection museum has bought some of the books and I wouldn't be surprised if many similar organisations world wide won't snap up a fair few copies.  Anyone interested in a copy will need to be quick as there are limited numbers available.

Received a message fro Steve Houghton to say that the collection will be sold by invite only,.   I think that they will be mainly to people that he already knows and may include a select few who have purchased the book.  I expect many if not most will have a fairly eye watering price tag!  They're a slice of working history and if i could afford one, I'd buy one of offered.  Vermin control of course!

Many of them are being sold off later in the year.  I've asked to be notified as there's one or two on that list I'd love to own!

Great stuff.  I have a few older publications from other authors on UK small arms history but this one has the advantage of being 20 years more up to date for starters!

Written by Steve Hougton.

Has anyone else been fortunate enough to get hold of a copy of the above?  I was thrilled that despite very limited numbers in the publishing run, I've somehow managed to snag a copy.   Very much looking forward to reading this one!

H4350 is, or was (when still available for import), one of the best suited powders for Creedmoor and usable for just about all the popular bullet weight ranges.  RS62 comes very close on heat of explosion (energy) and seems to be the most popular replacement for H4350 from what most people post and certainly from my own use with it.  Load quantities are remarkably similar to H4350 too where just as many people recognise in .308 that Vhit N140 or TR140 (RS50) that 43.5 to 44 grains under a 150gr bullet is a reliable go-to load for many, so in CM, using LRP brass 42 to 42.5gr H4350 or RS62 gives similar results under many 139/140gr bullets (around 2800fps/24" barrel).  This might also imply that burn rates as well as HOE are very similar between the two.  I'd continue with your 4350 and when done use RS62 with the caveat that some modification of load would be needed to optimise results and to keep safe.  N160 has lower bulk density so you can't get as much in the case (920g V's 960g for RS62) and is a lower energy powder better suited to taller powder columns or longer barrels shooting heavies.   RL19 has been used but from what I've read so far (I haven't tried this one) results seem to be a little erratic and it seems to do better with hotter loads.   Personally of all the current crop of powders I'd be sticking with RS62.  

On 4/18/2020 at 7:08 PM, Montey said:

I was advised to contact Kent police by a friend who is a serving officer who I shoot with I think it was good advice as it seems every county has its own policy ( we see this a lot don't we ) 

kent were really helpful and used the fraze common sense a lot I'm very impressed with the answers I got from both the main office and my local enquiry officer. 

Common sense dictates I'm more at risk riding a horse or using a chain saw both of which I do a lot of as part of my work.

 

Yes, that about sums it up.  There isn't currently any globally agreed strategy by police service areas across the UK.  Each one seems to have a slightly different take.  I called and got an email (Glos) whose stance is different from neighbouring counties (for now).  In my case I was advised, paid or NOT, if the farmer relies on me (as he does as the chap is in his 70's) for vermin control then especially during lambing it becomes something of an animal welfare issue so they were happy for me to carry on and control vermin for that reason alone providing that social distancing was maintained and common sense maintained (that phrase again).   I am not getting into the crop protection side of things because that may be more difficult to defend politically although we can all see the obvious need...it's the farmer who decides if he can sustain any losses not random forum members or BASC officials.  Animal welfare is more of a politically acceptable one so is easier for some to justify I guess.

I've taken the step of keeping in regular contact with the farmer to ensure he lets me know when he needs me up based on any fox or corvid trouble.  If he doesn't, I don't go, if he does, I'll be there.  One thing I'm acutely aware of is during lockdown there are many more people out using POWs, straying off those paths and permissive paths so there is more likelihood of coming across members of the public off the beaten track where normally they wouldn't be. 

That and the chance that they may call the police of they hear shooting (as happens pretty regularly at a guess).  In these unusual times I have decided much against my normal judgement that I'd call in to raise an incident number based on my shooting land covered for those days I get called out.  That prevents unnecessary waste of policing resources in the event the public out for exercise hear shots or see someone with a rifle and report it in.  Normally I wouldn't as that's the thin end of an unwanted controlling wedge but we're not dealing with normal times.

I keep my kit lightweight....no bipod or LR rifle set-ups, but a sporting rifle and lightweight belt mounted telescoping vanguard tracking tripod weighing next to nowt.  I don't want to be seen with anything blacticool which gives the ignorant the wrong impression.  For cals, I just take one....223.

Lockdown has had odd effects on people, that's for sure.   We can all get a little frustrated and polarised but it's worth remembering that for the most part, UKV seems more like a family with shared interest and it's really not worth any of us falling out over such trivial matters when BD has it right here...two technical sides to the argument and the truth, as with so many things, may be part way between.  There's a lot of invaluable experience and knowledge on here folks and for the most part it's shared with generosity and real zest for the sport.

As for BD....ingesting Lexicons must surely mean his local supermarket has run out of bread again?