G'day all
I normally post in 1000yard BR because longer ranges are my interest, but I've got a question some of you may be able to answer.
I've acquired a cheap, new .224 calibre barrel. It's cheap because everyone in long range shooting wants a 1:8 twist, generally for 223s. This one is 1:10. My question is: will 75 grain A-MAXs be stable when shot through this barrel? Hornady states a minimum twist rate of 1:9 is required, but I've heard that the bullet is intended for 223 velocities. If I shoot it faster (22-250AI), it will spin faster. Will this stabilise the bullet?
I'll be using 69 grain MatchKings as well. Does anyone have any suggestions for other bullets? I'd like a high BC so I can shoot it at short ranges, like 500-600 yards. But I also like bullets that make cute, furry animals twitchy. There's plenty of them Down Under. I hope Sierra brings out the 69 grain BlitzKing. That won't make foxes twitchy, it'll make them bitsy!
Thanks fellas
Ben

I have seen NRA Highpower shooters using a 223 have no luck whatsoever with stabilizing the 75Amax in a 1:9, but it could happen. The Hornady 75bthp, being shorter, and even the 77gr SierraMK (designed for AR15 mag length loads), both are commonly used in a 1:9.
The extra speed of your 22-250AI could do the trick, but sounds iffy.
Check an earlier thread about high BC .224's; JLK is the manufacturer, and may have a good bullet for your application.
Good luck!

I am also using a 22/250 AI with a 1in 10 twist barrel, but on my experience and research believe that you have little chance of getting the 75 Amax to stabilise in your barrel.

My current shilen 1 in 10 twist barrel was originally chambered for the .224 Clark, and I chronographed the the 75 Amax at velocities up to 3,830 fps, but it always keyholed into the target, despite a rotational velocity of 275,670 revs per minute.

Research by a group of benchresters found that you needed 280,000 rpm to get the Amax to stablise, and best accuracy was between 290,000 and 320,000. Exceeding this often caused the bullet to come apart.

I have found that my 22/250 AI achieves 3,430 fps with the 69 grain Sierra HPBT and consistently produces sub 0.5 moa with this bullet. I tried the Berger 70 grain VLD which has a BC of about .400, but although it did not keyhole, accuracy at velocities up to 3,450 fps was a disappointing 1.5+ moa. I had the impression, the barrel was struggling to stabilise this bullet, which was understandable as Berger recommends a 1 in 9 twist for this bullet.

Nosler also make a 69 grain HPBT but I have not yet seen it in Australian gunshops. The JLK 65 grain VLD might be
an option if you want a high BC bullet, but you would have to go to the trouble of importing them. Good luck, Brian.

G'day Brian
Thanks for the advice. You only live about 5km from me. Where do you shoot? I'm usually found at Lower Light (SARA, not SSAA, although I am a member of both).

Importing is easy. Use Grafs http://www.grafs.com/index.cfm (cheap and helpful).
They ship with FedEx who have their own customs agents. You can then track the order on the Net.
If you get a B709A (import permit for everything to do with guns: scope rings, actions, bullets, just not "items of warfare". Oh well, can't have everything you want) from the Firearms Branch (SA Police) there is generally no problem. Speak to Jim Scott. If you have a shooter's license and a genuine reason, turnaround is about 24-48 hours for the permit. You can even get the permit after the bullets have arrived in country (usually Sydney)!

Order under US$120 (US$100 wholesale) and you won't need an export permit from the US State Dept. Order under AU$300 and you might even escape import duty and GST! But the Government doesn't like to give honest shooters a break, so duty (5%) and GST (10%) will likely be charged (even on freight). It will probably still be cheaper than any gunshop in our city, and you can get gear they just won't stock.

Thanks for the advice. I've posted in four places and the last two posts have been the only help I've had.
Good shooting, mate
Ben (Goodwood)

G'Day Ben,
Currently, I am not a member of any gun clubs, although I was a member of SSAA for several years back in the mid 1960's. Then the range was at McHargs Creek, and they were just talking about moving to the Para Range. Since then when not hunting, I have spent thousands of hours testing, developing, and chronographing various loads with the many wildcat or improved cases I have used.

I have contacted the Firearms section on a few occasions, and have imported using the 709A form, some 30 grain .172 calibre bullets on two occasions, and am about to try and get some more from Genco.

I visited Graf's website, and thank you for the advice on the importing procedures, and I was surprised at the variety of items that can be imported. I would like to contact you by email to fine tune the importing procedures, as I agree the local gunshops have a very limited stock of components and are very expensive. Fellow CrowEater, Brian.