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The only difference physically is the twist rate; if I remember correctly Terra stated that the contours, interior chrome, chamber specs, etc would be identical to the 1:9's.

The 1:7 will allow you to stabilize heavy bullets (75gr+) better than the 1:9. Typically I find that the 1:9 tends to shoot slightly better with bullets I have used below 69gr.
 

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Before you rush out to grab a 1/7 be sure you're willing to commit to 60gr+ ammo -- I just noticed the following on Speer's site:

Q. I'm shooting 50 grain soft points in a 223 semi-auto and the bullets are coming apart in flight. What's wrong with these bullets?

A. Nothing. Most likely, your rifle has a twist rate of 1-7 inches, intended for 62 grain military ammo. Several bullet makers compared notes and all had the same observation: muzzle velocities over 2800 ft/sec in a 7" twist will tear apart conventional 22 caliber bullets. Try our 62 grain FMJ or 70 grain semi-spitzer to keep bullets together.
 

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It depends on the bullet too. Thin skinned varmint or "match" bullets will blow apart easily for sure. We've run M193 out of our 1/7's without much troubles for years. If you bench them you'll see a little difference in accuracy of course but for punching holes, no worries.
 

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Before you rush out to grab a 1/7 be sure you're willing to commit to 60gr+ ammo -- I just noticed the following on Speer's site:

Q. I'm shooting 50 grain soft points in a 223 semi-auto and the bullets are coming apart in flight. What's wrong with these bullets?

A. Nothing. Most likely, your rifle has a twist rate of 1-7 inches, intended for 62 grain military ammo. Several bullet makers compared notes and all had the same observation: muzzle velocities over 2800 ft/sec in a 7" twist will tear apart conventional 22 caliber bullets. Try our 62 grain FMJ or 70 grain semi-spitzer to keep bullets together.
all my 1/7" Ar15s stabilize 55 grain ammo just fine, out of 5 rifles 1 doesn't like 45 grain ammo...
 

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Hot rounds may wear a 1:7 faster but really it's about being able to stailize long bullets properly for decent accuracy.
 

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Any news on the 1:7" barrels?

To those saying 1:7 won't work for less than 60gr, there's >2500 Monarch 55gr steel cases in the recycling plant that would disagree. All from a 16" 1:7" Colt barrel, with no accuracy issues (considering iron sights, short barrel, and cheap ammunition - I see no keyholing and consistantly shoot 2-3" at 100m which is a limitation of my shooting ability with irons). That said, I do see increased accuracy (from a bench rest) when swapping to heavier loads; I like having that *option* available. :)

David
 

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any updates on these?
 

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the first set have been run for minis and micros. They haven't told me when they will be available in 12"-16".
Like the cat that got its tail caught in the sliding door.







it won't be long now.
 
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