what powder should I try next

[taka]

Hi everyone,
I am new to F class, and am developing loads for the 75grn Amax, the rifle is a tikka T3 varmint with 24" barrel & 1:8 twist.
I have been using ar2208 so far, and have found an accuracy sweet spot from 24.6 to 24.8 grn ar2208 getting around 2800 fps muzzle velocity. Here is the interesting thing, I am not gaining velocity as I increase powder load?

From about 24.4grn upwards I am gaining little velocity, from 2804 up to 2815 at 25grn. Not keen to push it any further, I haven't had any pressure signs yet, but I don't want to flog the cases, so that only get 4-5 reloads.

Should I try a faster powder like ar2206H or ar2206??

I have been lurking in the ackground for a while, and found much good advice and info being given by experienced hands.

If I find I like the F-class shooting and comps, I probably will get a rifle made or the job, but at the moment the tikka is it and I know I won't be competitive with this but until I learn to shoot straight it wouldn't matter what I used


Oops forgot to mention it is a 223 cal.

cheers
Steve

[Malcolm Hill]

Hi Steve
The velocity you are getting in the 24 inch barrel is probably somewhere near the mark. You would probably be better off with 2206h in that short barrel. Also the 75 gn Amax is not legal for "F" class std, you would need to use the 80gn Amax to shoot in that class and 2206h would still more than likely give the best results in that short tube.
Regards Malcolm.

[taka]

Thanks Malcolm, I will give ar2206h a try.

Would I be correct in assuming the short barrel accounts for the lack of velocity increase as powder load increased past a certain point?

regards

steve

[Malcolm Hill]

Hi Steve
You are pretty much correct with what you have found with 2208 in the 24 inch barrel. The longer barrels suit the slower burning 2208 better and you may find that 2206H could have an advantage in your 24 inch tube. The loading data doesn't show much between the two powders in a 24 inch barrel but I would certainly give 2206H a try and see what happens. Keep us posted on the results as many would never have worked up loads for the heavier (75 and 80gn) bullets in a short barrel as most use 28-30 inch barrels.
Regards Malcolm.

[taka]

Thanks again Malcolm.

I will post results of what I find with 2206h, and then maybe 2206 depending on results. I am trying to generate around 2900 to 3000 fps with the 75grn amax, to counter the loss in bc from 80grn amax.

cheers

Steve

[mike H]

Thanks again Malcolm.

I will post results of what I find with 2206h, and then maybe 2206 depending on results. I am trying to generate around 2900 to 3000 fps with the 75grn amax, to counter the loss in bc from 80grn amax.

cheers

Steve

Hello Taka,
You will probably think this is a barbarian speaking here, but there is no easy way to get the velocities you are seeking in a 24" barrel. As Malcom mentioned, 80 grain projectiles, Sierra, Hornady or Nosler, are the only ones legal for F/standard, plus the 69 grain Sierra. If you are shooting F/open the 75 grains are fine.
The other thing to consider is the ranges you will be shooting, most of us try and get high velocity, in an attemp to do well at long range, completely forgetting that only a small number of ranges are the long ones.
As for thinking 75 grains may be better than 80 grains for the task you have in mind, forget paper figures, and try the heavier ones, sometimes no one told them , that they were no good.

Velocity and pressure in .223`s seems to have a broad range, throat length which affects case capacity, has a marked effect, as I see it.

As far as powders go, try them all, including Benchmark 2, going for accuracy first, personally I doubt there will be much gain in velocity, if any.
Good luck with your quest, I hope you will find F/class to your liking.
Mike

[taka]

The ranges I would be shooting go out a max of 700yds I think at my local range. There is a big comp there this weekend, and I am hoping to get down there and see what goes on. I am trying the 75grn amax as I think I would have dificulty getting enough powder in the cartridge with the length of the 80grn amax. at bout 30thou of the lands, the 75grn pills boattail sits just forward of the shoulder of the cartridge. Anyway I will get some 80grn and try them. Never know unless have a go!!!

Thanks for feedback mike, barbarians accepted

cheers
Steve

[taka]

Well it has been a while between drinks, but I have managed to test out some ar2206h with my rig.

The velocity is averaging at 2950fps with 24.2 grns ar2206h, with rem 71/2 primers and 75grn amax projectiles. I haven't managed to get any 80grn amax yet, but that is next cab of the rank for testing.

The groups are 1/2" to 3/4" (sub moa is goal) with this load (at 100yds), I have found this to be most accurate load with lowest sdev, I am sure the groups would be smaller if I could shoot straight, but I am getting better with practise.....

I am hoping to try @700yds this weekend, so will see how I go. My ballistics program gives me 16.5 moa elevation at 700yds, so I am looking forward to actual results to see the theory working!!

cheers

Steve

[taka]

Best laid plans.... I didn't get to try @700 last weekend. I hope to this Saturday. Practice but not sure what distance yet.. Anyway will post with reults of testing.

cheers

Steve

[bruce talty]

Best laid plans.... I didn't get to try @700 last weekend. I hope to this Saturday. Practice but not sure what distance yet.. Anyway will post with reults of testing.

cheers

Steve

G'Day taka,
They are shooting fixtures at 1000yds on Saturday at Belmont you will get a shoot on the open target or standard target i am going to Toowoomba on Saturday so i wont be there i shoot on the open target with my .308 it's is shooting very well with the new Dyers, i am shooting at Toowoomba prise meet on Sunday.Bruce