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Any one have any experience with this bullet? I may spec out a 22-243 reamer and am interested in the correct freebore for this bullet. I know Hornady recommends a 1 in 8 twist barrel. Anyone have any different views on twist rate and stability? Other comments welcome.
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Campfire Oracle
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Lotsa guyz here shoot that bullet, and like it. I'm guessing the 1 in 8 is right...I tried them in a 1 in 9 .223AI and I might as well have put them in a sling shot....
Last edited by ingwe; 07/12/11.
"...the left considers you vermin, and they'll kill you given the chance..." Bristoe
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Campfire Ranger
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My 22-204 reamer has .060" freebore, about perfect for the 75's. I've run 'em in my 22-250 Ackley at 3500, but not impressed with them on coyotes. Switched to the Berger 75 VLD's, but no kills to compare......yet.....come on snow......
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My 22-204 reamer has .060" freebore, about perfect for the 75's. I've run 'em in my 22-250 Ackley at 3500, but not impressed with them on coyotes. Switched to the Berger 75 VLD's, but no kills to compare......yet.....come on snow...... I'm interested in why you didn't like them for coyotes. I don't shoot the 55 gr. V-Maxes for coyotes, but my hunting partner uses them and I've never seen anything but hammered coyotes with them. The 40's and 50's not so much. After the original post I used an ogive comparitor to check the bearing surface lengths of several bullets. The looooong 75 A-Max's bearing surface is actually .080 SHORTER than a 55 gr. V-Max. It's also only .030 longer than the 52 gr. 7 ogive bullets I make on my own bullet dies. I don't know what the ogive on the 75 is but it must be near 15. Any other comments welcome.
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A 1:8 twist is recommended at .223 velocities to stabilize the 75gr Amax. I have shot them successfully in a 1:9 in several rifles. If you re shooting them out of a 22-243 then you don't need nearly as tight a twist barrel to stabilize them. One way to calculate bullet RPM is with he following. RPM = MV(fps)*(12/twist)*60 Bullets will stabilize between 200,000 and 250,000rpm and should be dept under 300,000 or you will see failures. A standard 223 in a 1:8 twist 2700*(12/8)*60 = 243,000RPM with my 223AI it looks something like this RPM = 3050*(12/9)*60 = 244,000RPM With your 22-243 I would guess your velocity would be in the 3400-3500fps range(maybe more but looking at a worst case) with a 12 twist you would be marginal at best 3400*(12/12)*60 = 204,000RPM With a 9 twist you would be golden 3400*(12/9)*60 = 272,000RPM Take it for what it's worth and consult a competent gunsmith but I would think a 1:9 would be where you want to be. I can't help you on the freebore question. Here is a clip from an article comparing the 223 and 220 swift Bullet stabilization in a sporting rifle generally occurs between 200,000 RPM and 250,000 RPM. Allowances for over rotation of light bullets for a given caliber as a compromise to fixed twist rates raise the ceiling to approximately 300,000 RPM. Three mainstream bullet manufacturers suggested that, while the actual number is influenced by jacket thickness and core type, bullet rotation should generally be kept below 300,000 RPM to avoid bullet failure. The .223 Remington with an 8" twist could basically cover all bullet lengths consistent with bullet weights from 52 grains to 75 grains. With an 8" twist, the .220 Swift would marginally manage the 75 grain bullet and be way over maximum rotation with a 52 grain bullet which would probably result in bullet failure. With a 14" twist rate the Swift can stabilize the 52 grain bullet, but not spin the 75 grain bullet fast enough to provide stability. My conclusion was that factory 14" twists are suitable to most .220 Swift applications and running a tighter twist could in a rare case result in bullet failure, however, it would seem a 10" twist would be a better compromise, but I am sure there is more to the issue. Please see distracted student, poor academic references in the first paragraph.
Last edited by ACLakey; 07/12/11.
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I'm interested in why you didn't like them for coyotes. Quartering at attitude, about 210 yards or so...... ![[Linked Image]](http://img848.imageshack.us/img848/8129/003tu.jpg) Bastard still ran better than a 100 yards and, while not going anywhere any more, was still trying to suck wind 20 minutes later. Bullet never made it inside.......
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Campfire Ranger
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My 22-204 reamer has .060" freebore, about perfect for the 75's. I've run 'em in my 22-250 Ackley at 3500, but not impressed with them on coyotes. Switched to the Berger 75 VLD's, but no kills to compare......yet.....come on snow...... I'm interested in why you didn't like them for coyotes. I don't shoot the 55 gr. V-Maxes for coyotes, but my hunting partner uses them and I've never seen anything but hammered coyotes with them. The 40's and 50's not so much. After the original post I used an ogive comparitor to check the bearing surface lengths of several bullets. The looooong 75 A-Max's bearing surface is actually .080 SHORTER than a 55 gr. V-Max. It's also only .030 longer than the 52 gr. 7 ogive bullets I make on my own bullet dies. I don't know what the ogive on the 75 is but it must be near 15. Any other comments welcome. I too wonder what you didn't like about their performance on coyotes. I shoot them out of a 1 in 8 22-250AI and I have nothing to complain about performancewise.
MAGA
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Just saw you posted while I was typing. FWIW I haven't had one explode like that yet, from 100-400+. Heck, even the one I put into an antelope behaved well enough I may use it if I draw a tag this year.
MAGA
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While it may fall in the fluke department, it doesn't instill a whole lotta confidence......
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I'm interested in why you didn't like them for coyotes. Quartering at attitude, about 210 yards or so...... Bastard still ran better than a 100 yards and, while not going anywhere any more, was still trying to suck wind 20 minutes later. Bullet never made it inside....... You should be more careful with your bullet placement and things like that wouldn't happen.  I would be surprised if that wasn't the exception rather than the norm.
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Campfire Ranger
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If I'd had one do that I'd probably be leery of them too. Guess if I shoot enough of them it'll probably happen eventually. 
MAGA
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All my money's in the VLD basket for the start of this year.
Time'll tell.......
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Campfire Ranger
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I'm down to the bottom of my box of amax's and was fixing to order some in the next week. I'll probably get some of the new tipped 62 grain x bullets to try, and if they shoot I'll probably poke a deer with one. It'd be interesting to see a side by side comparison between the amax and a vld to see how they stacked up.
MAGA
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I'm wanting to try the 75 Scirocco also.....
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Campfire Ranger
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I tried them and was sorely disappointed, the only bullet I've tried out of my rifle that wouldn't shoot worth a darn. I had high hopes for an amax/scirocco combination. Buuuut, with a 250 yard zero with the amax, I'm only a click to the right and dead nuts for elevation @ 200 with the 53 tsx.
MAGA
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I built a 22-250 to shoot that one specific bullet. The 75 grain A-Max. I wanted a Krieger barrel. I called Krieger and asked them what they recommended for a twist rate. Krieger said the 1in8 is perfect for that bullet. I can not answer about the chambering, my gunsmith did that to what he thought was right. Tom.
West By God Virginia
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I built a 22-250 to shoot that one specific bullet. The 75 grain A-Max. I wanted a Krieger barrel. I called Krieger and asked them what they recommended for a twist rate. Krieger said the 1in8 is perfect for that bullet. I can not answer about the chambering, my gunsmith did that to what he thought was right. Tom.
Does it shoot to your satisfaction? Any accuracy numbers at the longer distances?
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I've had them drive tacks in 222 Mag and 220 Roy and the bullet wasn't too "soft" for close range crows.
A friend had his 220 Rocket throated for such; I'd have to mike it to get the throating. .080 sound right?
Last edited by HawkI; 07/12/11.
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,080 sounds a little on the long side. As I said above, the bearing surface is actually shorter than the 55 VMax and only .030 (I think it was) longer than my 52 gr. hollow points.
Last edited by BangPop; 07/13/11.
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I built a 22-250 AI around the 75 gr Amax. I went with a 9 twist and settled on a load using H414 at 3400. I don't remember the exact freebore and I borrowed the reamer. My load data says I kiss the lands at 2.610" OAL. My kids absolutely love shooting that rifle at long range (500-900). So much so I just finished an 8 twist 223 so I could get "my" gun back.
"If it wasn't for the pu**y and the prestige.....nobody would want to be a gunsmith."
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