Ideal twist rate for cast. 223 ?

[Wolfdog91]

So built my first AR upper from scratch and I'm beyond happy with it and wanna do some more. Would like to do a upper specifically for cast .223. I've had had decent enough luck with .55gr lee boolits out of my 1/7 twist 5.56 16" ( decent plinking accuracy and function of the weapon ) but would like to build some that more optimized for this need. I remember there being talk of optimum barrel length and twist compared to what I was using but can't seem to locate it. So if those folks wouldn't mind repeating [emoji28] what would be a good place to start when it comes to barrel selection for a cast specific AR. 55gr - 75 gr cast PC GC pills will be the main thing.
Thank [emoji846]
O and my new "poverty Precision" built that I must say I'm very proud of [emoji41]
https://uploads.tapatalk-cdn.com/20230517/bfb21f701daefb7b3af1dddff28bec9f.jpghttps://uploads.tapatalk-cdn.com/20230517/d81ee39ec74df9b1433570309d34a9b6.jpg

Sent from my motorola edge 5G UW (2021) using Tapatalk

[Winger Ed.]

I'd go with a 1/10 or 1/12.
I'd also check into casting with Zinc to be able to get the speeds and pressure on up close to jacketed levels
so it could reliably cycle an AR.

[Rapier]

For cast a 10 twist and 16" with carbine gas tube would be fine. All you need is about 2,200 fps or so. With PC a 16-2O Bh will do well should not be any leading if the bullets are hard enough.

[Texas by God]

One in ten twist is good for cast in the 6.8 SPC and the 7.62x39 as well…..
To consider for future builds!
I only have one factory built upper. It’s more fun and custom fit to do it yourself.


Sent from my iPhone using Tapatalk

[Larry Gibson]

A 14" twist is optimum for that cast bullet and many other cast bullets. The 14" twist was standard for the 22 cal CF's for the 222 Rem up through the 220 swift shooting 55 gr bullets many moons ago. It was only with the advent of shooting in sub freezing weather that the 5.56 M16 was changed from a 14" twist to a 12" twist and then to a faster twist for even heavier bullets. If you want to shoot those 55 gr cast bullets at HV with very good accuracy then go with the 14" twist.

A 20" minimal length is what i recommend but a 24 - 26" barrel length would be best.

[TD1886]

A 14" twist is optimum for that cast bullet and many other cast bullets. The 14" twist was standard for the 22 cal CF's for the 222 Rem up through the 220 swift shooting 55 gr bullets many moons ago. It was only with the advent of shooting in sub freezing weather that the 5.56 M16 was changed from a 14" twist to a 12" twist and then to a faster twist for even heavier bullets. If you want to shoot those 55 gr cast bullets at HV with very good accuracy then go with the 14" twist.

A 20" minimal length is what i recommend but a 24 - 26" barrel length would be best.

If you're talking barrel length on an AR15 24 and 26 inch barrels are too hard on the barrel nut threaded tenon. That's a lot of leverage on that tenon with those two barrel lengths and if you must have you bipod on the barrel to help support it and that negates having a free float tube.

[WinchesterM1]

i just built an ultra light weight Ar with a Brownells Retro 20" barrel 1/12 twist. with a leupold 1-4x it shoots right around 1.5 at 100 with the NOE 62 rn