DAC Posted January 22, 2015 Share Posted January 22, 2015 Tikka CTR seems very appealing for an all around rifle ,my worries come from the short barrel 51 cm , i'm limited to factory ammo , with a 61 cm barrel i have no problem to get supersonic at 1000m (i have a problem just to hit the target ) but from my calculus 308 with a 51 cm get transonic at maximum 800-900 m . Anyone have a short barrel Tikka , how about the velocity lost compared with a longer barrel or with the factory data of amunition? I expect to loose around 30 m/s - 35 m/s from a 61 cm barrel to a 51 cm barrel ..but can't be sure. Thank you P.S. This is the only factory ammo i found ,who gets to 1100 m supersonic from short barrels : http://www.hornady.com/store/308-Win-17 ... nce-Match/" target="_blank" target="_blank BC=0.53 Velocity=846 m/s Velocity reported from 20" barrel=823 m/s Velocity i expect in the worst scenario =810 m/s ========Google Translate============ Tikka CTR virker veldig attraktivt for en rundt rifle, mine bekymringer kommer fra den korte fat 51 cm, jeg er begrenset til fabrikk ammo, med en 61 cm fat jeg har ikke noe problem å få supersonisk på 1000m (jeg har et problem bare for å treffer målet: oops:), men fra min kalkulus 308 med en 51 cm få tran ved maksimal 800-900 m. Alle som har et kort fat Tikka, hvor om hastigheten tapt sammenlignet med en lengre fat eller med fabrikkdata for amunition? Jeg forventer å tape rundt 30 m / s - 35 m / s fra et 61 cm fat til en 51 cm fat ..men kan ikke være sikker. takk P.S. Dette er den eneste fabrikken ammo jeg fant, hvem som får 1100 m supersonisk fra korte fat: http://www.hornady.com/store/308-Win-17 ... nce-Match / "target =" _ blank BC = 0,53 Velocity = 846 m / s Velocity rapportert fra 20 "fat = 823 m / s Velocity jeg forventer i det verste scenariet = 810 m / s Quote Link to comment Share on other sites More sharing options...
M67 Posted January 22, 2015 Share Posted January 22, 2015 I had a 50/60cm barrel (it was 60, and was cut to 50, but i do not remember exactly when) for a Sauer200STR some years ago. I shot it with factory Lapua 167 and 155gr, and reloaded with 155gr to factory velocity. I do not remember velocities, nor did i care about supersonic - i am purely a civilian shooter, and i feel the "fear of becoming subsonic", while it is a factor in some cases, is mostly a military matter, or even a myth to some extent. In my experience, people with military shooting background (if not very extensive) will very often disbelieve reports of accurate shooting beyond supersonic range. In my experience, we se accurate shooting at all velocities, possibly somewhat degraded by super-sub transition in some cases or conditions, but generally unproblematic. If this was such a problem, how could we shoot pistols or 22LR? While 1000m is on the long side for a 308, it works quite well, depending on the target and the wind. I have shot that 50cm barrel out to 1350m with relatively good results, it is quite hard to predict where the bullet will land on your first shot (with some "dope"you will get the elevation right) sideways, but generally good ammo will group well in calm winds. Velocity variation will kill good groups, simply because of the very long flight time. Here are a few pictures from a frozen lake shoot we did a few years back. 800m 1090m, (60cm black bull) This is not "best of", we shot two groups each. The sighter group at 1090 At the 1090m range, a fellow shot his 30-06 with 168gr SMKs, and they invariably arrived sideways. The Scenars, even if they were slower, gave at least fair accuracy. Bear in mind it was -15°C or so and accurate shooting suffer when you are cold and fingers get numb etc. This summer i have shot 175gr Scenar-Ls quite a lot (>1000rds, during summer) and out to about 1250m - (and shot sub half-meter groups at 1250), but with the bulk beiing between 400 and 800 (at 800m surprising accuracy can be had, palm size groups). I only shot a hundred rds or so at 1km. This is with a 70cm barrel mostly. Anyway, the problem, in most respects lies behind the rifle, in the failure to appreciate even the subtlest wind changes, that will move these slow and low BC bullets to the side of the target. Second challenge is in velocity variation, which will give elevation distribution. I have been launching the 175s at about 860m/s, and frankly i have not calculated the velocity at 800, 1000, and certainly not at 1250m, and i care very little about it. Accuracy on the target is what counts. K Quote Link to comment Share on other sites More sharing options...
VeT|Us Posted January 22, 2015 Share Posted January 22, 2015 Siste setningen er ren poesi. Quote Link to comment Share on other sites More sharing options...
M67 Posted January 22, 2015 Share Posted January 22, 2015 175 Scenar-Ls at 800m this summer. K Quote Link to comment Share on other sites More sharing options...
DAC Posted January 23, 2015 Author Share Posted January 23, 2015 Thank you M67 . I will order the rifle , i prefer stainless but is not available yet . Maybe i read to much and i shoot to less From what i shoot with 180 gr (this ammo Sellier Belot PTS http://www.sellier-bellot.cz/rifle-ammu ... roduct=272" target="_blank" target="_blank) i got no problem to get over 800m , only problem remains the wind , if at my position i get closer to the reality in estimating wind (cross checked with anemometer) , to decide the wind along the line of sight is still a huge challenge for me , need more and continuous practice i guess. From what i read (internet forums) seems like heavy bullets 175 gr and over are more stable on their trajectory when the speed gets under speed of sound , and 150-168 gr seems to get tumbling at low velocities , but no personal experience in comparing this weights . As a personal experience i noticed i'm better at estimating wind (but a beginner ) in higher winds then in slow breeze and i try to shoot in the highest value of wind , maybe the surroundings give me better visual indicators on high value...i don't know if is good or not is just like worked best for me until now. For me the most consistent bullet was the one from RWS , RWS Target Ellite 12.3 grams http://rws-munition.de/en/sports/produc ... l#!0/1/283" target="_blank" target="_blank (they are using Sierra Match King 190 grains https://www.sierrabullets.com/store/pro ... -MatchKing" target="_blank" target="_blank) , very forgiving on wind with my poor experience in reading wind and violent on target , a hit is a loud sound of steel , but don't use this under 500 even 550 m on steel , have the habbit to make nice holes in steel Quote Link to comment Share on other sites More sharing options...
M67 Posted January 23, 2015 Share Posted January 23, 2015 Maybe i read to much and i shoot to less Dont we all ? to decide the wind along the line of sight is still a huge challenge for me , need more and continuous practice i guess Again, for everyone. One can read ones eyes out, of course reading do no harm, and reading and listening to tips from those tha really know will help to an extent. It is much better than making up ones own theories usually, but one need to read those knowledgeable... Anyway, to put it into practice one must practice. Is there a method? Probably, and some approaches are more effective than others. But in the end it comes down to practice. Repetition is the mother of skill... accuracy is the mother of wind reading. One of the most underestimated skills in wind reading is in my opinion basic shooting skill. Only when you completely trust your own shooting, you will know what the wind did, and did not, and what you did, and did not, and you will learn more about the wind the better your basic shooting skills are. Learning, both are slow processes, and is learned at the range only. Basic shooting practice is however much more available for most people. I practice about once a week on an indoor range, shoot possibly 30 or so matches per year in total, and there are two things that clearly show, very, very clearly: - consistently high scores correlate almost perfectly to the amount of practice, - theoretical knowledge correlate very poorly to shooting skill, or if you want, points on the scoreboard. Get the basic shooting - position, breathing, aiming, trigger pulling - out of your head and into your spine, then use your head for wind calling. A researcher that had gone through the practice regimes of top athletes in several sports, including skill/coordination types, concluded that to reach world class level in almost any sport took about 10 000 hours of practice... heavy bullets 175 gr and over are more stable on their trajectory when the speed gets under speed of sound , and 150-168 gr seems to get tumbling at low velocitie Dynamic instability is caused by form, not mass. Many bullets will develop precession motion due to dynamic instability over long ranges, only a few (most notably the 168gr SMK) will tumble because of it. The SMK will "disappear" even while (predicted) supersonic as per my limited observations, as will some 6.5mm bullets. Many will loose velocity faster than predicted, and some will be less accurate. Sg (static stability) decrease sharply at the speed of sound, as the center of drag moves forward below sonic velocity. But as velocity decays much faster than spin, static stability increases with range. It drops at the transition to subsonic velocity, but not so much as to cause instability. This is my understanding of the matter, and please do not regard it as fact, I will stand to be corrected quite happily. It is formed by studying books on ballistics though, not internet forums As a personal experience i noticed i'm better at estimating wind (but a beginner ) in higher winds then in slow breeze and i try to shoot in the highest value of wind This is common i think. It is much easier to overlook small clues than large ones. Often shifts in direction can have a large effect, more than shifts in velocity, and maybe strong winds do no not change direction as often, or as unnoticed? Sometimes groups are strangely large in light wind, and smaller in strong wind. However, (at least when i shoot) misses in strong winds are most often much bigger misses than in a light wind. under 500 even 550 m on steel , have the habbit to make nice holes in steel What steel quality are you using? We use SSAB Hardox 450 almost exclusively, and 10mm plate are not damaged by even 300Win Mag at 300m K Quote Link to comment Share on other sites More sharing options...
DAC Posted January 28, 2015 Author Share Posted January 28, 2015 I don't know what steel it is , something regular , nothing special . I got news , if i order now the rifle (CTR) i will get it in September ....long wait . Quote Link to comment Share on other sites More sharing options...
M67 Posted January 28, 2015 Share Posted January 28, 2015 A Sauer 200STR (if in Norway) you will have next friday - at worst. K Quote Link to comment Share on other sites More sharing options...
DAC Posted January 28, 2015 Author Share Posted January 28, 2015 Well Romania is not Norway , in many aspects we have a better living here when we compare with western/northern Europe but when it comes to guns and gun ownership is a crappy country if you are curious about how crapy can be about guns take 2 min and read here some facts (post no 4) http://www.kammeret.no/forum/viewtopic.php?f=13&t=71972 . Tikka Varmint and Super Varmint i can get in the same day i get the permit from the police (i need to apply for each gun i want to buy and can take up to 45 days to get the permit , was in same until a mad man shoot his wife and another few persons present there in a public place , was no precedent like this , shocking and ..this is it, new law ... ..so we have instead of few hours of wait , maximum 1 day, now 45 days of possible wait) . Sauer STR is not a bad suggestion i want to change the stock and the trigger anyway (X-ray chassis and Bix and Andy trigger) so the final price will be close to an STR for less quality... . Quote Link to comment Share on other sites More sharing options...
M67 Posted January 28, 2015 Share Posted January 28, 2015 A Sauer 200STR (if in Norway) you will have next friday - at worst. If you have the licence. What i mean is the gun is in stock at all times more or less. Time from application to permit approved may well take more than 45 days here too, and 90 is not surprising anyone these days. K Quote Link to comment Share on other sites More sharing options...
DAC Posted February 16, 2015 Author Share Posted February 16, 2015 @M67 You have any idea about velocity loss with a 6.5x55 in 50 cm barrel ? As a rule of thumb , how many m/s i can loose per length unit? Seems like a stupid thing to do (velocity loss=lower BC , unburn powder e.t.c. ) but i'm sure someone already did this test . Quote Link to comment Share on other sites More sharing options...
M67 Posted February 16, 2015 Share Posted February 16, 2015 Of course Both 6.5x55 and 308Win. http://www.kammeret.no/forum/viewtopic.php?f=17&t=89782&p=943302#p943302 The velocity loss seems quite similar for both the 6.5x55 and the 308Win at about 4m/s cm, going from 70 to 40cm. This is in keeping with findings from other sources, citing 4-5m/s cm for the 6.5x55. This may provoke some in the "308 is best for short barrels"-crowd, so i might as well stir them thorougly... Actually, a 40cm barreled 308Win, loaded to max or slightly beyond, is in any way as fierce as a 6.5x55 regarding unburnt powder and muzzle blast. The amount of powder is very similar. Anyway, one do not shoot to preserve powder, so that unburnt 1% do not keep me awake... Keep in mind that i only fire a few shots per length, and the difference between each shot is large. But still, somewhere along those lines. K Quote Link to comment Share on other sites More sharing options...
DAC Posted February 17, 2015 Author Share Posted February 17, 2015 Thank you ! Valuable information , i wish i meet you earlier in my shooting path Quote Link to comment Share on other sites More sharing options...
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