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ai308

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  1. ai308

    1st shot in a string velocity

    Yes, I had the same idea. ?
  2. ai308

    1st shot in a string velocity

    Unfortunately, the range was closed.
  3. ai308

    1st shot in a string velocity

    If it would happen only for the 1st shot, it would be an explanation. But it happens for the 1st shot of every 5 shot string.
  4. ai308

    1st shot in a string velocity

    I' will try single feed tomorrow.
  5. ai308

    1st shot in a string velocity

    I did 10 5 shot strings, all showing the same behavior.
  6. ai308

    1st shot in a string velocity

    Rifle. I did publish just one 5 shot string as an example. Have shot 10 of them in sum, each with 0.1gr increase of RS62.
  7. ai308

    What bullet for .260 for an AI

    Maybe ask Graeme from sportingservices about the barrel. Got mine also from him. Could choose between Lothar Walther and Sassen Engineering. Or find out the twist by yourself:
  8. Hi guys, I've an issue with the measured velocities I'm getting from my AX308 out of a 26" 1/8" .260rem barrel. I've done some load development and just recognized some weird behaviour when firing a string of 5 rounds out of the magazine: The 1st shot of each of the series had a higher velocity (about 20 - 30 fps) than the other 4. When I finished a 5 shot string, I reloaded the magazine with another 5 rounds, prepared the LabRadar and started the next series. The behaviour is repeatable. Here''s an example of one of the series : ( 43.1 gr RS62 behind a 139gr Lapua Scenar ) 1) 2876 2) 2833 3) 2834 4) 2845 5) 2858 My 1st thought was about the time the 1st round of the new series is located in the chamber. It could take longer time for me to acquire a comfortable shooting position again and during that time, the powder temp increases. But I've checked it: hurried up for the 1st round and slowed down for the 3rd. Same behaviour. Also paid attention to consistent pressure on the bipod. As said, I've loaded from the Magazine. Maybe I should try with the single shot adapter? I've no idea, what else could cause this. My .308win also behaves in a similar way: Whenever I pause shooting for some minutes, the next shot will be around 20-30fps faster. Does someone have an idea?
  9. ai308

    What bullet for .260 for an AI

    I'm running the 139gr Lapua Scenar out of a 26" 1/8" twist .260 Lothar Walther barrel in my AIAX308 . My buddy is using the same one with his AT, which got a custom .260 barrel from the US.
  10. Btw, what are the best SD values you were able to achieve with RS50, RS52 powders? fps or m/sec? I've just recognized, that my buddy measures in m/sec but I'm using fps. After having done some further load development, I was able to achieve an SD of 10-12 fps with 44.6gr RS52 behind a 168gr Hornady HPBT. But only 2/10gr (+ or -) away from that, the SD just doubles. Using RS50, the best result I could achieve with the 168gr Hornady HPBT has been a SD of 14 fps at 44.4gr. But the 2nd day I fired the rest of the rounds loaded with the same parameters, I've got values between 25 fps and 36fps SD.
  11. Did you also try the Hornady 178gr ELD-M?
  12. Hi Chanonry, thanks a lot for your feedback. I' was just impressed by the high advertised BC of those. But I also suspected, that the attainable velocities with the .308 cartridge would be pretty low. Basically, .308 will remain a .308 . I've just checked some ballistic tables with AB and compared them to the .260rem. Not that impressive. Maybe I should tell you some background information: I got a 2013 AX308 some years ago. It has a 20" 1/12" barrel. Means, I'm a bit limited with my bullet choices. I've been running 175grSMK out of it, which were fine up to 800m (was limited by the range available) . Also tried the 175TMK. Groups were fine at 100m, but had no chronograph at this time. Then I recognized, that Sierra recommends at least a 1/10" twist for the 175gr TMK. I've verified it with Berger twist rate calculator , which confirmed that. Finally, I created a list containing bullets from Lapua, Hornady, Nosler and Sierra between 155gr and 185gr which are regularly available at my location. I sorted them under the criteria: BC / stability, availability, price. When it was about the BC, the 175SMK was still the best choice, at least according the twist rate calculator. Interestingly, the 175 gr ScenarL was a bit worse and the 155gr Scenar was in the range of "marginal stability". Besides the 175gr SMK were just 2 168gr bullets left: the Nosler CC and the Hornady HPBT match, which I'm running today. I know, there are better choices than the 168gr for ranges over 800m. But unfortunately, I don't have enough range available near my place to verify those at distance. That's why I try to find a bullet which at least got the performance 'on paper' and do some load development and velocity testing for the competition. I would continue to run the 175gr. SMK, but they're a bit pricey. I don't know, how the 155 Scenar and 175 Scenar L would perform with 1/12" barrel in real life. Just the twist calculator kept my away from them. Maybe you got some experience? Now about the heavy bullets. Last year, I extended my collection and got another AX308, model 2014 and a custom .260rem, 26", 1/8" barrel, which shoots great. But I'd like to have some improvement on the 2013 AX as well and the 1/12" twist 20" barrel is a limiting factor. That's why I had the idea to replace it by a longer 1/10" barrel. But as everything in life, it's just a compromise.
  13. Hi, does anyone have experience with heavy .30 cal bullets (like 208gr Hornady ELD-M) and a 10" twist 26" .308 barrel? Would a short action system (AX308) be fine for those, or would I face issues when seating them to magazine length? (powder volume, mag length vs touching the lands) How do they perform compared to rounds in the 6.5 calibre? Thanks a lot!
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