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twist rates ????


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Ok,same guns,same home loads. What effect would take place if you whent from 1/12 to 1/10. Just zeroed and shot the 308 24" 1/10 twist in whilst load developing ,worked loads up in 0.5 increments from 37g to 43.5g min to max with lapua case,ccibr primers,lapua scenar heads with n140 powder. According to my book and other info the 1/12 should get better moa with the higher weights of powder ie 43+g,but mine is a 1/10 and the moa is much better with 37-40g of powder range. Is it because the faster the twist the better the bullet stabilizes and less velocity is needed hence the better moa is lower down the scale. Im just thinking allowed.

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Anyone marry poppings,farther christmas or the easter bunny will do. I have had some more thoughts about why my groups opened up. The barrel was getting warmer,i did take the mod off and removed the bolt to aid cooling for around 10 min after every 3 shot group and or my barrel was getting dirty. Next load development day I will start with my max powder weights and work my way to the min to disprove or prove the hot or dirty barrel thoughts. Ps all loads shot fine with no stiff bolts or pressure sighns so safe to use.

Edited by Albert 888
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I thought (simplistically) twist was to do with bullet length and velocity ... longer (therefore heavier) needing tighter twist for optimum stabilisation at higher vel? Maybe the sweet spot for your combo is just where you found it .... less powder.

Have you tried a ladder test for OCW? At least it's a systematic approach and if nothing else shooting loads as a round robin will cure one of your variables ... There are other but this seems straight forward .. and like all systems the best is just round the corner ..

optimalchargeweight.embarqspace.com/ocw-instructions/4529817134

If you record the chrono data for all shots you should get a picture of the optimum velocity for your barrel/bullet/powder combo. Its frustrating but fun

Edited by seeker
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Twist....can be a can of worms!

I like as slow a twist as possible as in my experience faster than standard limits one to heavy and longer bullets.

That is due to me being a hunter over a target shooter.

I am in the camp that believes a bullet can yaw if spun to quick. Well actually I know it can as I have seen it.

This is why your data is limiting the velocity a little!

Maybe!

U.

Edited by Underdog
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Im not worried just setting things straight im my head. I am really greatfull for all the info I have picked up allong the way. Will stay with the 155 lapua secenars for now until I get a load im happy with. Then will try the 208 amax. Thanks agian. Will look on the net for ladder charts. ,im logging all data and groups at the mo.

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Thanks again fister I am jotting all your info down. Going to be doing 100m -300m mainly so best stick with the 155s. the amax thing and twist thing has come form me wanting to use the 75s in the 223 1/9 but it struggles with 69s.Want to find a good load for diggle,im currently drumming up the courage to go and also harass some others to join me.

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