#11
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One can use the JBM twist rate stability calculator to determine the twists suitability to a particular bullet.
https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi |
#12
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My Cooper 21 VE with 10 twist will not shoot the 25gr. Hornady V-Max. You get improved cylinder patterns if you do. I have not tried any other 25 gr. projectiles in it.
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Danny ************************************************** The 11th Commandment: Thou shallt not fold thy Pizza. Products that I am looking for but can't seem to find no matter how hard I look: Leopold Scopes, Forester reloading equipment and Victorianox knives. I video recorded all of my Highpower Rifle matches. Pretty soon I am going to watch them all in reverse order so that I can watch those F Class guys GO HOME and leave us alone so that we can shoot Highpower Rifle. |
#13
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Do yourself a favor and enjoy your 17 caliber, but go with at least a 1/9 twist barrel and you will never be sorry. Bill K
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#14
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well by now I think we figured out a 1-10 twist is out for the 25 gr vmax, my 10 twist shoots the 20 gr vmax, 25 gr hornady hp , 25 and 30 gr berger as well as the various 20's.
if you are building a rifle go with a 1-9, if buying you are stuck with what's on it unless you re-barrel. I shoot the 25 vmax in my 17 v-raptor aka 17x28 and it does very well even at the 3200 fps vel and it is a 1-9 twist.
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I post here because it keeps the riffraff away. 'Life's Journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting, Holy sh!t... What a Ride! |
#15
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Bill K, I meant exactly what BCB said, but he phrased it better than I did.
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#16
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A 1:10 works fine on the 25 Vmax, even in the FB. The bullet is doing nearly 3870 with Benchmark out of a 26" barrel in 17 FB, it has lots of spin to stabilize. If I was building I would do 1:9 but really, if 1:10 is what I had I would shoot them and just get them running as close to max as I could. My CZ 17 HH has a 1:9 twist and only moves the 25 Vmax 3300 fps, and it stabilizes fine. The extra 600 FPS will offset the slower twist in almost all rifles. I shoot 40 grain Vmax out of 22 Hornet with a 1:16 twist at 3100 FPS and they are very accurate out well past 400 yards.
30 grain Berger at 3650 FPS out of a 26" VS SF Reminton Last edited by Dean2; 09-02-2019 at 05:43 PM. |
#17
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Back when the 25 V-Max had just recently come out I was spending a lotta time with one a those inaccurate CZ's , it had a 1 in 10 cause my primary objective was .20 grain V-Max's. I was saddened to hear that the 1 in 10 wouldn't stabilize the 25 V-Max, had to be true cause it was so stated by one a those know absolutely everything guys .
I've come to believe since then that there are dang few absolutes. I also learned a well worked CZ is more accurate than 95% a the people can shoot even though some a the "never seen an accurate one" folks will swear they don't. I came to believe too that altitude does matter to this topic. This group is not in any way an anomaly with this .17 Ackley Hornet. About 5200 Ft of elevation above sea level. That aside almost every .17 I've had put together since has a 1 in 9, for insurance as was stated above I think. Keep us posted as to your experiences .
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"Shoot safe!!" montdoug |
#18
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Great shooting Doug!
I would have never thunk it,after all I've read about the 25 V-Max I am pleasantly surprised.I do believe our altitude has a bunch to do with this as well as cartridge size aka velocity.I may just try my 17Ackley and the big V-Max
On a side note my 17PPC 10 twist works well with the 30 grain Kindler Gold out to 1000 yards.The point is you never know till you try. Matt
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NRA Benefactor Member VHA Life Member IBS Member |
#19
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They may group well for some with 10tw barrels, especially those at higher elevations, but you won't be getting the full BC of the bullet.
Elevation benefits bullet BC, from a slower twist barrel, much more than does velocity. |
#20
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I purchased my first 17 rem in the mid 80's. Remington recalled it late 80's with barrel hardness issues, it shot very well but powder fouled badly(17-20 rounds). The new barrel would go 40-50 shots before groups started to open. The factory replacement barrel was a 10 twist, wouldn't shoot the Berger 30's at all. Assembled a Shilen 1/10 AR upper in early 2000's shot all the 20-25's very well, except the 25 vmax. The 5 shot groups would all have 1-2 that showed some instability. I'm at about 950' elevation, I have thought about taking 100 vmax loads to Montana pd shoots(3200'), I think I could add 50 yards of consistent hits on pd, over a standard 25 gr hp.
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