VTR .223 Too short for 75gr.?

ktm300

ktm300

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Help me out here guys.
My Rem VTR was shooting 55gr. sierra blitzking's sub-MOA all day yesterday, I switched to 75gr. V-max and now I can't get any sort of consistency. All over the paper from 80m. WTF!!

Is it the short VTR barrel? It's got a 1:9 twist, I thought that was good for the heavier bullets.
 
Hhmm, interesting. The only reason I wanted to try the 75gr. was because the Lyman manual said it works good with the 1:9 barrels! But from what I'm reading now, that doesn't seem to be the case.
 
Yeah, its not the length of your barrel, but the twist rate. You'd probably need to go 1 in 8 to shoot the 75 gr bullets. Your 1 in 9 typically starts to top out at around 70 gr, depending on bullet length of course.
 
69'ers are great but anything heavier in my XCR won't stabilize unless the bullet is slightly shorter for it's weight. Remember, it isn't the weight, it is the length of the bullet that needs stabilizing.
 
It's not the weight of the bullet but the length of the bullet's bearing surface. 75gr.-77gr. BTHP match bullets are commonly used with 1:9" barrels. However, in the A-Max's case, 1:9" may not be sufficient. FWIW, Hornady has even said as much.

What makes you believe that it's necessarily a stability issue? Are the bullets keyholing on target? Perhaps, it not stability related at all. It could be that your particular barrel, chamber, or load combination are not optimized. Is this your first time shooting the 75 gr. A-Max?

Too many variables here to be absolutely sure
 
Welcome to the world of "Specialty" bullets and bullet stabilization issues!

ktm300 said:
Help me out here guys.
My Rem VTR was shooting 55gr. sierra blitzking's sub-MOA all day yesterday, I switched to 75gr. V-max and now I can't get any sort of consistency. All over the paper from 80m. WTF!!

Is it the short VTR barrel? It's got a 1:9 twist, I thought that was good for the heavier bullets.
Click to expand...

The longest bullet that is garanteed to stabilize in 1:9" is 69gr SMK.
Anything more and you start getting issues (most of the time).

You need 1:8" for 75gr A-Max, it's printed on the box.
You need 1:7' for 77gr SMK and longer bullets.

Some lucky shooter which live at high altitude can shot 75gr Amax from true 1:9" when it's hot but BC is can be 20% lower than when the bullet is trully stable.

Welcome to the world of "Specialty" bullets and bullet stabilization issues!

Alex
 
+1 on trying hotter loads, if you are on the paper at 80m. An unstable bullet won't be able to hit the target (at all) at that distance. If you are able to keep all your bullets on the target even if the group is several inches in size, that means that you are so close to being stabilized that it only takes a little tiny bit more velocity to fix things.
 
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