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1/32 twist

PostPosted: Sun Feb 12, 2017 9:54 am
by floydp
hello to all looking for a starting load for 450 bm in 1/32 twist 18in barrel thanks for info

Re: 1/32 twist

PostPosted: Sun Feb 12, 2017 12:13 pm
by Hoot
floydp wrote:hello to all looking for a starting load for 450 bm in 1/32 twist 18in barrel thanks for info


Floyd, do you have a bullet in mind? I would suspect that you would want 250gr max, given the slower twist. Might be a good match for the 225gr FTX and they're less expensive than the 250s. This is all speculative since I've never used a barrel with that twist rate and barrel twist is not a parameter you can adjust in QuickLoad.

Hoot

Re: 1/32 twist

PostPosted: Sun Feb 12, 2017 2:21 pm
by floydp
HOOT I was looking at two hornady #45177/451771 fmj-rn and #451871/45187b fmj-fp TONY M SAYS THAT THE 225FTX DOS NOT DO WELL WHIT THE 1/32 TWIST ?

Re: 1/32 twist

PostPosted: Sun Feb 12, 2017 9:29 pm
by Hoot
floydp wrote:...snip...TONY M SAYS THAT THE 225FTX DOS NOT DO WELL WHIT THE 1/32 TWIST ?


I would not have guessed that Floyd, but again I stress that I have no experience with that barrel twist rate. Still has me scratching my head though...

Lets see if any other member bought one of them and will step in.

Hoot

Re: 1/32 twist

PostPosted: Sat Feb 25, 2017 2:28 pm
by Bmt85
I was playing with a twist rate calculator and it's saying the 225 ftx should stabilize just fine. I'd say give em a try. As long as they stabilize, they should give you better accuracy then 230gr RN.

Re: 1/32 twist

PostPosted: Sun Feb 26, 2017 8:47 pm
by pitted bore
Bmt85 wrote:I was playing with a twist rate calculator and it's saying the 225 ftx should stabilize just fine. I'd say give me a try. As long as they stabilize, they should give you better accuracy then 230gr RN.

Bmt85-
What muzzle velocity were you using in your calculations with the 225-grain FTX bullet?
Thanks.
--Bob

Re: 1/32 twist

PostPosted: Mon Feb 27, 2017 4:43 pm
by Bmt85
2000 fps, 30 degrees Fahrenheit, 0 ft Elevation gave a stability factor of 1.68

2300 fps, 60 degrees Fahrenheit, 1000 ft Elevation gives a stability factor of 1.93

Minimum stability factor of 1.5 is recommended, marginal stability is around 1.0-1.4 . I have seen some instances where a cartridge had a factor of 1.2 and was still accurate out to 300yds. So try it and find out