#1
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6mm twist rate ???
im looking to build a 6mm-223 aka 6x45
but kinda unsure on twist rate to use some say 1:12,1:14,1:10 or 1:8 so im abit arggh 🤯 im looking at Sierra 85gn flatbase softpoint varminter or Sierra 85gn HPBT gameking as they appear to good at 6x45 speeds on lightish game the barrel will be stainless,light/med varmint profile and 21inch finish length appears ill roughly get 2700-2800fps range depending on powder,projectile and twist combo of course
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Disabled Hunter Getting It Done |
#2
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I'd think you would want at least a 10tw on that. You aren't going to be launching bullets at warp speeds in something like that anyway so you could easily get away with a 8tw and not have to worry about tearing bullets up.
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#3
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A 1:9 twist will stabilize all the way to low 90gr bullets and meet your needs. A 1:8 twist is needed for 100-115gr bullets.
If you plan to run the lighter 60gr class of bullets favored by 6PPC then a slower twist rate might be better suited. |
#4
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Thanks for replies so far
i had planned on 70gn upwards however i feel 85 grainers ethier hp or sp better suited to my purposes ive had one guy here who has build a few 6x45s lately says 75gn hp seirra all the way but he has 1:14 twist and his reamer set fo 75gn hp he also said slower the twist lower presures bit more gained fps this my first wildcat so all abit new haha im on low income so when i spend big $$(very rarely) i wanna get it 100% first go Regards Muz
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Disabled Hunter Getting It Done |
#5
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1-9 or 1-10 either should. Work ok
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I post here because it keeps the riffraff away. 'Life's Journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting, Holy sh!t... What a Ride! |
#6
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It started out as a factory rifle with 1:9 twist, which shot well with almost everything. I was able to stabilize the SMK 95GR bullets. I overhauled the rifle and re-barreled with 1:8 twist to shoot 105gr and heavier bullets.
I recently built a 6x45AI that I designed to shoot mid-80gr bullets. I went with a 1:9 twist so that if I wanted to shoot lighter bullets (70gr's) then there wouldn't be any issues. I used same logic as my experience with 243 Win. The difference between 6x45 and 243 with same bullet is simply velocity of +300fps difference. If you choose a +80gr bullet that is a boat tail then the faster twist rate will help it stabilize. |
#7
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I went with 26”,1-8” on a 6TCU. I can always cut some off, hard to put it back on.
The 243/6mm bullets I have not had any issues with, as this have with some 22’s. I had used some of my liter bullets in 243 in years past with no problems. I went with the 8” twist with the thoughts of it helping with splat factor. I have run 55-85 grain bullets, with 70 grain showing some of the better results on paper and critters. This rig is fairly heavy as I wanted to be able to do my own spotting. I have some that are some what liter for carry purposes. |
#8
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I have a 6mm rifles with barrels from 14 twist to 7 twist and don't recall ever wishing I had a slower twist barrel on any of the rifles. The 90 gr. Nosler AB and the 95 gr. Nosler are excellent game bullets in that might do better with a 9 twist barrel. Those are my favorite hunting bullet choices in my 243 and 6mm Grendel. CFE223, Leverloution, and 2000MR powders give me the best velocity in my 6x45 and 6mm Grendel.
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#9
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Don't be afraid of an 8 twist and lighter bullets.
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#10
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If you chamber for a 105-108 you will be jumping a long way for the lighter varmint bullets. I am sure you thought of this already.
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