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New guy here putting together a bolt .223 build and im having a hard time deciding on 7 twist, 7.7 or 8...
Bartlein will be the barrel i will most likely use on the heavy varmint profile or M24.
Any and all input will be well taken.
Thanks
What bullet/bullets do you plan on using ? What's it being used for (target or hunting)? Get it twisted for the bullet/ bullets (weights) you plan on using and get it throated accordingly. .
9 twist will work with themTarget. No hunting whatsoever.
As i said, 600-800yds max with 69gr SMKs FGMM. And assorted 55gr when doing up close shooting.
9 twist will work with them
Is this something you're building or just buying ?
If it was me building this rifle for the same purpose I would plan on using 80 grain bullets for those distances and use a 7 twist to open up the option of trying some 90 grainers.
Before anyone gets excited about me recomending 90 grainers (and the freebore needed for them) in a rifle intended for 69gr smk's. it has been discussed here before(by people with experience) that a rifle throated for 90's works just as good as it ever could with the 69 - 80's. There are a few shooters here who do just that and even the light 55 grain bullets (long jump with the 55's). And I especially wouldn't hesitate on the long throat using ball ammo at 100-200 yards.
Don't forget there is a case capacity advantage with the longer throat over a shorter one(say .077 vs .169).
But if your heart is set on 69er's and less go with an 8 twist, 7 will be just fine too.
Ooooo you recommended 90 grainers!
IME 77gr will go 600+, but you'd be giving up a bunch to a good 80/(90shhhh) load.
Under 600, the 77/69 will do just fine, and the 55gr does fine from a 1:7
-Mac
Target. No hunting whatsoever.
As i said, 600-800yds max with 69gr SMKs FGMM. And assorted 55gr when doing up close shooting.
Before you decide, ask yourself how serious you are when it comes to hitting targets at 600 yards. My Howa-1500 "fun gun" with a 1:9 twist shoots SMK 69gr bullets great, always sub 1/2 MOA at 100 yards and frequently sub 1/4 MOA. It will also lob those 69gr bullets down range 600 yards for fun. You can ring a steel target much of the time, but not always if the wind is blowing. If that satisfies you, 1:8 will be fine.Target. No hunting whatsoever.
As i said, 600-800yds max with 69gr SMKs FGMM. And assorted 55gr when doing up close shooting.
Of course, a gun set up for 80gr VLDs will still shoot 55 grain bullets, but it won't be optimum.
Since the bullet diameter is fixed by the caliber of the gun, heavier bullets suitable for long range competition are longer than lighter bullets of similar shape. Therefore the chamber optimized for a cartridge loaded with a long bullet will likely have a throat which is longer than desired for shooting shorter (lighter) bullets. They'll shoot, but it might be impossible to achieve best accuracy (precision actually) with a cartridge shorter than optimum for a particular chamber.What exactly are you referring as not optimum? Can you elaborate please?
Good reply,Fingi - I shoot a .223 GAP bolt rifle in F-TR competitions at 300/600 yd. It has a 26" 7-twist barrel. I did not reload when I first received the rifle new, but fortunately it shoots FGMM 77s like a laser. Per your question, I shot plenty of commercial ammo from this rifle, including 40 gr Varmint loads and 55 gr ball and soft points. There has been absolutely no issues whatsoever getting good precision out of this rifle, even with the lighter bullets. A 7-twist will not "hurt" the precision of a rifle with lighter bullets, and can be used with any .223 bullet made, up to 90 gr. However, a 9-twist (or slower) may significantly limit the bullets you can effectively use. To me it's a no-brainer, get the 7-twist and you'll never be limited by bullet weight.