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Author Topic: 51 g bbt  (Read 102 times)

oneshot61

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51 g bbt
« on: August 17, 2017, 08:58:43 AM »
Hey Mr Bob. I shoot your 51g bbt design in my ace .25 with good success. I'm currently building a multi caliber capable gun and I'm wondering what the ideal twist rate is for that bullet at 1000-1050 fps??



rsterne

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Re: 51 g bbt
« Reply #1 on: August 17, 2017, 10:22:50 AM »
The bullet is designed for a 15.5 - 16" twist, and designed for the length to fit an MRod or Hatsan magazine.... but pushing it that close to Mach 1, I would suggest the 14" twist .25 ACP barrel from TJ's.... assuming your mould is the 0.250/0.252" version.... If your mould is the 0.253/0.255" version, you would have to size it down a long ways to fit that barrel, as it is 0.243" land and 0.250" groove.... What is the twist rate of your Ace barrel?....

Bob
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oneshot61

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Re: 51 g bbt
« Reply #2 on: August 17, 2017, 11:17:49 AM »
Thank you...1-18 twist on the ace. At 100 yards 950 fps I see the slightest hint of yaw. I'm having a hollow point made also that may affect the accuracy in a good way out of the ace. I really want to see how far I can accurately push the .25 bbt before I move on to .257.

rsterne

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Re: 51 g bbt
« Reply #3 on: August 17, 2017, 11:38:52 AM »
18" is definitely stretching it for the 51 gr. BBT.... Some guys are having success in the 17.7" LW, some not so much.... Glad it's working for you, but drive it faster it probably won't....

Bob
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