Elwood Posted January 6, 2014 Report Share Posted January 6, 2014 All content courtesy of Laurie Holland Enter a season of national GB F-Class Association rounds in the F/TR class and see if you can repeat the final assertion - with the 175gn SMK at any rate. The standard 155gn Scenar is still a competitive F/TR bullet at 1,000 if it shoots accurately enough and you can repeat the precision at 3,050 fps or so. The 175 is hopelessly ballistically uncompetitive at this distance, both in its dropping into transsonic flight and in the extra windage required. That's not a criticism of a fine bullet design, rather a comment on choosing horses for courses. Most people quote comparative wind drift values for the 'standard' 10 mph 90-deg crosswind and that exaggerates the real differences between match performance. I've applied ballistic programmes to the actual shot to shot MOA changes in my match wind plots many times to recalculate the actual wind change between shots, and it's smaller than most people imagine when formulated as a 90-deg wind change in mph. That's from matches over many distances at Bisley, Diggle, and Blair Atholl. Even so, the F-Class target with its 0.5-MOA rings is very small and we're assuming here that you have a perfect elevation zero and the rifle / ammo also holds perfect elevation as the half-MOA ring diameter only applies at the horizontal centreline - have a high shot that's a marginal Five at 6 or 12 o'clock and almost any windage error drops a point. So we're talking (generally) the equivalent of 1 to 3 mph 90-deg wind speed changes between shots. (The actual wind speed change may be larger on the range, but it's surprising how rarely we shoot in a true 90-deg angle wind, hardly ever at Diggle and Blair.) Bryan Litz classes an 'expert' LR match shooter as being capable of reading the effective wind changes to 1 mph, so we're talking plus or minus 1 mph wind effects on the bullet. (Actually, the really top guys and girls read wind changes to half-mph equivalents or less - that's why they're top in this game!) At 600 yards, a 155.5gn Berger LR BT at 3,050 fps moves 0.42-MOA in a misread 1 mph 90-deg change, so remains comfortably in the 5-ring but only if the rifle and ammo shoot world BR size groups (ie no group dispersion adding to or subtracting from the wind effect), and only if the rifle is perefectly zeroed and holds its elevation nearly perfectly. There is half-MOA from the exact target centre to the edge of the 5-ring on the 'waterline' and one gets a little more from a 0.30" dia. bullet in inward scoring if it just breaks the line. Note though that a mere tenth MOA lateral error in the shooter's aim, or just over a half-inch could put the bullet just outside the '5' if thnat error reinforces the wind effect, likewise a rifle + ammo shooting into 0.3-MOA groups at this distance would have the same effect if the shot were at the outside of the dispersion limits on the downwind side. (For anybody who thinks 0.3-MOA groups are easy-peasey at 600 yards, I'd refer them to Mole-e-30's posts of UKBRA 600 yard benchrest competition results, and remind them that these comps see 5-shots fired quickly to reduce wind effects.) Under the same conditions and provisos, the 175gn SMK at the equivalent MV of 2,875 fps MV moves 0.45-MOA, hardly worth bothering about. If the 175gn SMK load and rifle shoot into a 0.2-MOA group under benchrest conditions, and the 155.5gn load struggles to achieve 0.5-MOA, the less ballistically efficient 175 will trump the expensive Berger every time. So, the lesson for 'short-range' 308 shooting in prone, known distance TR type disciplines is .... go for precision before ballistics. Move back to 1,000 and what do we see? Under the same scenario - a wind change misread by a 1 mph 90-deg angle equivalent, the 155.5gn Berger / 3,050 fps now moves 0.85-MOA, a comfortable '4', but easily a '3' if the aiming precision, elevation and grouping issues apply. (The F-Class target is 1.0-MOA from the exact target centre to the outside of the 4-ring laterally.) The bullet is estimated to be travelling at 1,337 fps at the target, 1.19 MACH and therefore barely affected by transonic turblulence, if at all. (1.2 MACH is the guideline mark.) The 175gn SMK / 2,875 fps MV combo moves 0.9-MOA, still in the 4-ring if everything else is perfect, and you can say that what's 0.05-MOA compared to an extra £20 for a box of bullets? That extra half-inch movement may make the difference betweeen a saved or lost point at the margin, and GB FCA national rounds are often won or lost on single points after four or five matches in a weekend and 75 to 90 score shots. HOWEVER .... it's not just windage effects. While the 155.5 was still travelling at 1.19 MACH at 1K, the 175gn SMK at equivalent MV has dropped nearly 100 fps and is computed to be travelling at 1.1 MACH putting it into transonic speeds. Whether it'll really be doing that speed is questionable as even Bryan Litz's long-range G7s are averages based on less than 1,000 yard distances and some bullets may see funny transonic effects that increase air-drag as they drtop into the zone and hence lose speed faster than calculated over the last 100 yards in these competitions. What transonic effects do definitely do to the 175gn SMK (been there, got the teeshirt) is to (1) increase the group size relative to those attainable at shorter ranges and (2) increase the wind effect to something greater than the ballistic program predicts when you get very close to the speed of sound, and (3) often ruins elevation consistency. One lesson that anybody who regularly shoots .308 Win at on the small F-Class target centre is that the cartridge and modern bullets are well within their ballistic comfort zone at 800 yards, start to get iffy at 900, but this can be completely overcome by maximising MV and choosing the most ballistically efficicient bullets that still group exceptionally well, but that at 1,000 yards life is now VERY hard and you need every advantage you can dig out, no matter how small on paper. Laurie, on 01 Jan 2014 - 5:30 PM, said: At 1,000 your 155gn Scenar is estimated to be travelling at 1,266 fps and will move sideways 0.9-MOA (9.44 inches) if you misread the wind by 1 mph. Your 175gn SMK load at 2,650 drops to 1,115 fps (subsonic) and moves 1.04-MOA (10.86 inches). That 175gn SMK load is very close to the one I used with that bullet in my first ever national F/TR season and while it shot well up to 800 yards was terrible at 900 and 1,000. One undoubted problem is that at a computed 1,115 fps terminal velocity, just 11 fps below the speed of sound, with an MV spread of say 25 fps around the average MV, some shots just remain supersonic at the target, while some go through the sound barrier a handful of yards in front of the target. The effects on my grouping on the target were truly bl***y awful! After my first ever comp at Blair Atholl in a cold early spring weekend shooting into an angled headwind and with regular rain and wind squalls, common sense should have dictated that I should have changed my sport to golf or tiddlywinks! That same load, if it groups tightly (mine did into 0.1 inches for 5-shots at 100 during load development) will perform superbly at 200 to 600 yards leaving it down to the shooter doiung his or her stuff. Laurie, on 01 Jan 2014 - 5:55 PM, said: I should perhaps add at this point that external ballistics comparisons aside, there are two other reasons why nine out of ten top GB F/TR shooters use Berger bullets. 1.) They group VERY tight and it's not usually difficult to get down to the essential quarter to third - MOA group size at 100 yards. Moreover, for whatever reason, a tight-grouping short range load usually still performs well in this respect at long ranges. 2.) The 155.5gn BT Fullbore model holds its elevation superbly at long range and that really is key in this game. Remember what I said before - perfect elevation gives you half-MOA (a bit over 5-inches) sideways latitude at 1,000 yards while a 1-MOA spread vertically on the target will theoretically just put everything into the 5-ring, but the further a shot deviates from the lateral centreline (the 'waterline' it's often called by top wind coaches), the less latitude you have in your wind-reading accuracy. A shot that is just in the 'Five' at 6 or 12 o'clock drops a point if it moves half an inch sideways from the vertical target centre. In last November's European F-Class Championship meeting, the F/TR team captain asked all team members to submit their individual match target plots to him at the end of the first three days (one day team shooting practice and two days' worth or 6 actual matches of individual match shooting) and what he was looking for wasn't how well individuals read wind changes - in the final day's shooting in teams, the wind coaches read the wind, not the shooters - but how good people's elevations were. They were used to select which eight team memmbers would shoot on the Sunday. Russell Simmonds, the team captain and the wind coaches went through the plots and said afterwards that the judgement of Solomon was needed as all dozen or so possible 'trigger-pullers' had produced exceptionally tight 'elevations' over the three distances - 800, 900, 1,000. Of that dozen all bar a couple were shooting the 155.5gn Berger. That sums up why people will pay the extra £20 a 100. Why have a good rifle built, put a £1,000 scope on the top, travel 450 miles to / from Bisley in my case, and pay for four night's accommodation, then risk wasting that time and money by choosing a bullet I'm not convinced will perform at 1,000 yards? That's not to say it MUST be a Berger. One or two people at this level use the new Sierra 155gn Palma Match King (p/n 2156), one or two the new 155gn Lapua Scenar L, and one (Steve Thornton) gets great results from a Dolphin Gun Co. built piece with Brian Fox's £28/100 Australian made HBC bullets. I've used this model extensively too, and if your barrel likes it, is a very good choice indeed which can hold its own against any 155gn 308 on the market. Laurie, on 01 Jan 2014 - 10:21 PM, said: Ballistically it's up with the best - Bryan Litz's range testing gives it an average G7 BC of 0.236 compared to the 155.5gn Berger's 0.237, ie to all normal intents and purposes identical within his own stated testing accuracy parameters. It ticks all the right design boxes with a long pointy front end and a nice shallow (7.2-deg, absolutely ideal) boat-tail angle. The 155.5 is a VERY tolerant design up front though, and the HBC is quite an aggressive secant-nose VLD type with a sharp shank to ogive transition. That can mean problems in getting jumps sorted, and some people say they can't get them to shoot. However SOME people also say that no bullet costing £0.28 each CAN shoot well, and SOME people (no names, no pack drill) referred to Steve T and his 'Aussie Shrapnel' ammunition. When Steve is on form, which is usually, he can really make his HBC loads perform at any distance from 200 to 1,000 yards. He was after all 13th F/TR overall (out of around ~200 entries) in the F-Class World Championships at Raton in August with 436.23v (ex 475 possible) and was 3rd highest placed Brit behind Russell Simmonds and Paul Harkins beating the other 14 GB team members comfortably (in a lot of cases massively!). I don't shoot the bullet that much right now, but my first proper F/TR LR rifle, a Barnard P in an Eliseo tubegun stock shot them really well at modest MVs (just over 2,900 fps) over N150 and I just set them intially at 15 thou' jump and found that worked in the Broughton barrel the rifle then had on, so I never changed the setting. The problem with the Barnard / Eliseo set-up was weight - too much of it severely restricting scope and bi-pod options - so after I got a second F/TR rifle, I stuck a Nightforce 8-32 NF on it, added a front-rest riding plate and shot in Diggle F comps as an F/O entrant off a front-rest. Despite being 308 Win, I could usually keep up with the F/O rifle shooters to 800 yards with the HBC at 2,915 or so. I never shot it at 900 or 1,000 though - that's pushing your luck against a good 6.5-284 or straight 284. pcon, on 03 Jan 2014 - 02:26 AM, said: Hi Laurie, One that hasn't been spoken about is the Hornady 178 BTHP, I believe hornady have adjusted the shape of this bullet and it has similar BC's to the berger Juggernauts. Also much cheaper than the Bergers. Laurie, on 03 Jan 2014 - 11:36 AM, said: Maybe .... but can you get them? I've had very little luck getting examples of the new Hornady HPBT Match range, only the 225gn .308 seen to date. Looking at Hornady's revised 'emergency' production announcements of last year when the company said it would 'temporarily' stop making most of its products and concentrate on 'key' models to try to meet the vast US demand that had built up, the only BTHP Match that was included was .338-cal. My assumption is that this still applies as we start 2014. I'd wondered before about these bullets and tried to get some. they look good and if half of what Hornady says about concentricity, design + component + manufacturing standards is true, they should be outstanding performers. BUT .. after their launch, absolute silence. Internet forum trawls hardly produced a mention and then usually about US dealers who might have them in stock. SO .... either the punters don't recognise and buy a good thing when they see one, or they don't do what it says on the tin, or (what I think) Hornady introduced them just before US demand went haywire and the company couldn't make enough existing models to keep up with orders never mind use scarce production resources for new bullets whose sales hadn't taken off. This - and not just Hornady - begs the question about what is going to happen when (If?) the American shooting public regains enough sanity and confidence to stop panic buying. Will things go back 'to as before' and models like these and various Berger match bullets reappear? Or will the manufacturers quietly shelve many designs rather than go through the traumas of setting up production lines and relaunching them? Laurie, on 06 Jan 2014 - 2:39 PM, said: Bullet choice is partly about matching ballistics to match distances, partly about what works for you and your rifle. I used the 185gn Berger LRBT Juggernaut for a couple of seasons with very good results and still like this bullet. If you can get ~2,800 fps MV and small groups, it'll perform very well at 900 and 1,000 yards. I've tried 200-215gn models and had no luck with them and don't like the recoil. Returning to 155s, mainly, the 155.5gn Berger, I find the recoil significantly lower helping rifle handling, they group fantastically and LR elevations are good. No need to use high-energy powders to get enough MV for long ranges from a 30 or 323-inch barrel, so better barrel life too. It's very much what works for people. I've come to the conclusion that shooting should be like driving a car - the less you have to concentrate on the mechanical basics to the point where you do them withouit thinking about them the better. With a very heavy and stiff rear bag (Edgewood Mini Gator with grab handle filled with Chromite heavy sand), Dan Pahlobel's FLEX-Bipod and 155s, the rifle hardly changes position betwen shots so I'm reset quick and can give 100% of my time and attention to looking at the flags and/or other people's targets to see what the wind is doing. 2+20 shots is less tiring than using 'heavies' so you stay fresh to the end of a long match including club comps where there are often three shooters squadded to a target. Swarovski1, on 03 Jan 2014 - 1:51 PM, said: Hi laurie,we have spoken about the 30 cal bergers, what bullet make is dominating the 6.5 cal Laurie, on 06 Jan 2014 - 2:48 PM, said: Can't say - not enough experience with 6.5s and not many people use them in F-Class these days. I've had very good results with the 123gn Lapua Scenar up to 800 yards in .260 Rem and at 600 yards in my new 6.5X47 Lapua on its first outing on Saturday. Some people like 130gn VLDs in this class of cartridge and if they shoot well in your barrel are probably the optimal weight for 260 Rem, 6.5X47L, and 6.5mm Creedmoor. For 6.5X55mm, 6.5-284 and similar, there is an excellent choice of 139-142 grainers. I suspect most larger cartridge 6.5mm shooters here still use the 139gn Scenar. It's not as high BC as the Bergers, but is an excellent performer and many people have stuck with what they know. Across the Atlantic, the 142gn Sierra MK is regarded as THE bullet for LR in the large case 6.5s. Supposedly they're more consistently made now than they used to be, but a few years back their big downside was large variations in base to ogive measurements. So, if you try them I'd recommend measuring them and if ncessary batching them. oaken, on 02 Jan 2014 - 10:30 PM, said: I have long since sold my Ftr rifle and like Brillo would be well pleased to find a way to get my 26" Trg to shoot well at 1000yds.Is there a source of reliable info regarding various bullets ability to remain stable through the transonic? I'm particularly interested in the HBC.Is this something that the new Scenar L can do to some degree or is that just rumour? Laurie, on 06 Jan 2014 - 4:14 PM, said: No - there isn't any listing as to this factor, and standard BC + MV type results don't help no matter how good the data and the ballistics program. It's an experience issue, and often people won't share what works for them or doesn't. This might particularly apply to tactical rifles at very long range. After all if you've spent a lot of time, money and thought that sees you and your TRG or similar beat everybody else at long ranges, you'll probably be a bit wary of passing the 'tricks' on! The long and short of it is that a 28-inch or longer barrel is really needed for good performance from .308 Win at 900 and 1,000 yards (no pun intended). So we're looking at making the best of a not particularly great hand with a 26-inch barrel. 24-inches or less? Just don't go there! Despite what some people might say about 20-inch barrelled rifles achieving amazing feats at these distances allegedly in certain individuals' hands, I firmly believe that with two shooters of equal wind reading skill sharing a target, and using equally well specified and built rifles with similar round counts, if one has a 30-inch barrel and the other 26-inch the guy with the long barrel is going to whale the sh*t out of his partner if shooting F/TR on the little target. On the standard 2-MOA TR target, the scores might well end up the same, but a 10.5-inch dia. Five and 5.25-inch dia. V give no latitude to the 308 Win at 1K. F/O is different and a mild .284 Win or 6.5-284 Norma load might well embarass a hot 7mm WSM although over time, taking the rough with the smooth (etc, etc), the WSM will still come out on top by a modest margin. However, if you have a 26-incher, and you want to have a reasonable shoot at 900/1,000 a good choice of loads and bullets does help. When I first got interested in this, I wanted to shoot an SSR-15 with 26-inch barrel and the 80gn Sierra MK at (very) modest MVs. My research purely said some bullets work, some don't so I had to suck it and see. The 80gn 0.224 SMK worked OK at 1,000 even if I had to use ~80% more windage than the 6.5-284s with 139/140 at 3,000 fps that were then appearing - no F/TR at that time. This was also before the half-size targets were introduced (actually quarter-size if you work on the ring area available to you!) My bullets weren't just transonic - they were definitely subsonic at 1,000. (I had to keep requesting the target be pulled as the markers missed half the shots arriving for this reason.) This suggests one pointer that is backed up by other things I've since heard. A good 'old-fashioned' design with a tangent ogive nose may perform better in this situation than a more 'modern' very long pointy secant-nose VLD type. This was backed up by some research that John Carmichael (he of HPS-Target Rifle Ltd) did at Bisley maybe 20 years ago when 155s and even more so 155gn VLDs were pretty new in TR. He built and set up a good old-fashioned and large twin metallic coated screen chronograph in front of the target frame and shot various bullets at 800, 900, and 1,000 yards from a pretty standard spec TR rifle at the usual ~2,950 fps velocities. The Berger VLDs were going a lot faster at 800 than the 155gn SMK and Scenar. At 900, the VLDs had lot most of their edge. At 1,000, the VLDs struggled and tangent ogive bullets went faster and just stayed supersonic. So, the first rule appears to be to avoid VLD types - the 155gn Scenar may fall into this class, the 155gn HBC likewise. The second rule is to avoid anything with a sharp boat-tail angle, that is in double figures. The ideal BT angle is 7-8 degrees. That rules out the 168 and 180gn SMKs which most people know about, but also other 168s largely copying the Sierra from Speer, Nosler and Hornady. The Berger 168s are LR bullets and work fine. Another group to be avoided like the plague are Hornady A-Maxes with the sole and significant exception of the 208gn model, an excellent LR bullet. The 155 A-Max has a 13.5-deg angle, the 168gn 12.0-deg, and the 178gn model 12.6-degrees. All will likely generate extra turbulence at transonic speeds. The new HPBT Hornady match models are OK - the new 178gn is an ideal 7.7-degrees. A-Maxes are also secant ogive, albeit not as long radius as in Berger or JLK VLDs. The new HPBT models are dual ogive same as the Berger Hybrid which should be better thas secant at transonic speeds, but there's no real feedback around on this matter yet. Relatively blunt front-end models with very long BT sections seem to perform particularly well in transonic conditions. The improved match version of the Frankford Arsenal 173gn M1 .30-06 bullet was famous in US shooting circles for its 1,000 yard (and longer) stability a generation or two back. Not surprising as the US Army developed the cooking version shortly after WW1 through trial and error starting with the same weight Swiss 7.5X55mm bullet for LR (5,000 metres or so) in MG sustained fire. However, while it retained velocity and stability well, it was never a small grouping bullet in .30-06 and early versions of the 7.62/308 sniper and match cartridges. During the 1980s, the US Army commissioned Sierra to produce a model that provided the 168gn SMK's precision while performing at long ranges and that produced the 175gn SMK, although interestingly, Sierra went for a much shorter boat-tail section length than in either the M1 / Match or in its original LR 180gn MK version and surviving 190/200gn models. Which brings me onto the 190/200 SMKs that built up an excellent reputation amongst Match Rifle shooters (308 Win at 1,000 / 1,100, and 1,200 yard matches) as being outstandingly good transonic / subsonic performers until the modern 210gn models appeared. So ... try the 190gn SMK in as hot an N550 load as your rifle accepts and still groups well. Reasonably priced too! (But while a cheaper bullet, a 190 + high-energy powder at full pressures will reduce barrel life substantially, so it may well not be cheaper in the long-run compared to shooting a more expensive bullet over VarGet or N150!) Sierras and (maybe) the new 178gn Hornady aside, that leaves two options. Although the longstanding TR mantra says a good 150/155 with at least 2,950 fps MV, I reckon a lot of rifles in the discipline don't get that. Two pointers - (1) these guys and girls often don't rebarrell until they have 5,000 round plus down the tube and (2) the nominal MV that I've seen quoted for the current RWS is around 2,920 fps. (I'll see for myself soon as I have a 30-inch Paramount with slow twist 'tight' Krieger ex-TR rifle about to be used as an 'affordable' F/TR rifle and the RWS facftory ammo will provide the baseline performance figure.) The old Sierra 155 as still used in the RWS ammo needs a full 2,950 fps to guarantee every bullet being supersonic at 1,000 under 'standard conditions', and on a cold winter day (4-deg C / 40-deg F) a full 3,000 fps barely scrapes supersonic at 1K (1,129 fps estimated) so some bullets will likely drop through the sound barrier. Under standard conditions (29.92 inch Hg pressure / 59-deg F), this bullet at 2,950 fps moves into transonic flight at ~830 yards. So .... bullets that 'work' in TR should be the least bad in F/TR at reduced velocities. Finally, there is a crop of modern 308 bullets that meet our criteria - well designed, low BT angle values and tangent ogive with good-for-weight BCs. The bad news is that they're all made by Berger and hence not cheap! The ultimate bullet for your situation has been designed to remain 100% unaffected by trans and sub-sonic speeds when fired at 2,600-2,650 fps in 1-11.25 twist barrels as now used exclusively by the US military in their 'marksmen' and sniper rifles - the Berger 175gn Tactical OTM, an efficient design without the stability factor and with a G7 BC of 0.259 compared to the 175gn SMK's 0.243, only just behind the Berger 175gn LR BT's 0.264 (an excellent long-range bullet for 308 Win). I've loaded some for a 22-inch barrel Howa 1500 Varminter to see how it manages at 800, but not got around to trying it yet. In a slower twist barrel, you need higher MVs to get the same spin rate as 2,600 in a 1-11.25 - which is 166,400 rpm spin rate. 2,773 fps MV provides the same spin in a 1-12" twist barrel, so that's what I've loaded the bullet to (more or less) in the 1-12 twist Howa. If your TRG uses 1-12 you could do the same. If it's 1-10", forget it as the MV would be much slower than you'd want. This bullet at ~2,775 fps MV stays comfortably supersonic to 1,000 and is just above transonic speed at 900 under standard conditions. The bad news is of course it's an expensive Berger, and just as bad is usually unobtainable here and when I bought 200 they were more expensive than the 155.5gn BT Quote Link to comment Share on other sites More sharing options...
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