3400 fps with 75A-Max in 22-250?? Is It Possible??

[HEAD0001]

I have shot my 22-250 at 300 yards to work up my load, and to zero my ground hog rifle. And here is what I came up with while shooting the 75 grain A-Max.

First I zeroed the rifle at 300 yards. and it is shooting some mighty good groups at that distance. And the rifle is zeroed very well.

Then I went to 400 yards after setting my Zeiss Conquest 6.5X20(adjustments 1/4 MOA per click) up 9 clicks from the 300 yard zero. Then I went to 500 yards and went up an additional 7 clicks to zero the rifle at 500 yards. I also shot to 600 yards, but not enough to give exact numbers.

So when I am zeroed at 300 yards I need to add 16 clicks to change that zero to 500 yards.

So I plugged these number in a ballistic calculator and figured backwards that in order to have a 9 click raise(2-1/4 MOA) at 400 and 16 clicks(4 MOA) at 500 yards. The velocity I come up with in the calculator is 3400 fps.

Now these are shot groups at these distances. These are several groups at each distance, with extreme care taken to double check my numbers.

Most guys say you can not get 3400 fps from a 22-250 with the 75 A-Max in a 22-250, but it sure looks like I am getting that??

Am I crazy??

Before you ask, my chrono is broken, or that would solve the problem pretty quick.

Also the barrel on my 22-250 is a 28" full bull Krieger. Tom.

 

[bozo699]

I have chronograph-ed 3540 out of my 22-250AI with 70 grain bullets, I was quite a bit over book to do it, I think it would be tough out of a standard 22-250?
Wayne

 

[alton9]

Head0001,
What twist are you using? I have a 9 twist at the smith's now; I am hoping to shoot the 75gr. A-Max too. Also, got any load data you would share?
Thanks

 

[m500]

The new Hornady manual lists the 75 a max up to 3300 at a length of only 2.490 from a 26 inch barrel. 3400 would seem within reach.

Also, were you shooting at altitude which would flatten your trajectury? Did you enter your actual barometeric pressure in the calculator?

 

[HEAD0001]

The twist on the Krieger is 1in8. And I am shooting in WV, so no high altitude shooting. I have heard in the past that people can achieve slightly higher velocities with a Krieger barrel.

My chrono is broken so I could not check the velocity.

And all I know is the actual trajectory of my bullet matches the trajectory on a ballistics table of a 75 grain A-Max at 3400 fps. Tom.

 

[MrMajestic]

I think the Grund Sows better beware. It does look more like AI velocities but stranger things have happened. Your calculations are sound and if the pressure signs are safe run with it.

 

[alf]

The 16 clicks for 500 jive with a velocity of 3400, but the 9 clicks for 400 doesn't, when I played with the calculator. You have to get down to the lower 3200's to get that to match.

Regardless, you're guessing til you actually chrono it.

 

[HEAD0001]

Thanks Alf. That is pretty close to what I came up with also. I also know the actual scope height can also change these numbers a bit. But it is pretty close. Tom.

 

[357Mag]

Head -

Howdy !

I myself am a bit skeptical, that 3,400 can be had from your rifle/cartridge combo. I'll tell you why I say that....

I shot a .224" cal wildcat, based on .35 Rem necked-down to .224" cal.
.22-35 had more case capacity than a stock .22-250; and less than .22-250AI.

From a 28" SS 1-8 5-groove Broughton .224" calibre barrel, .22-35 could put 3,500fps on a 75 "A"-Max w/ a combo of 40.5gr AA3100; and FED LR Magnum Match.

The accuracy load was the same powder/charge/bullet; and FED LR Match primer for 3,420 fps.

I used the longer barrel length to finesse' powder burn rates and subsequent powder charges. Good vel and superb accuracy were arrived @ via use of a comparatively SLOW powder, when others would have reached for a faster powder. Use of a faster powder would not of itself, necessarily delivery faster load velocities.

Given the use of AA3100 ( a sample selection ), I doubt the same charge of AA31000 could be/should be shot in a .22-250. And, were the .22-250's barrel length to be 26" ( for example ); I don't see how/why a .22-250 could come up w/ the vel you seek.

If you are shooting typically 500yds and under w/ your .22-250, might I
suggest you try some Sierra 65s SPBT's ? I think you'll be much less likely to " shoot through " a groundhog at all ranges vs a 75 "A"-MAx, and the 65's BT helps keep KE up for those longer 450+ shots.

Just my opinion(s).

Regards,
357Mag

 

[harry.hacking@kiewit.com]

Look at Hodgdon Superform Max Load standard 22-250 70gr, 3499 fps, 63,000 psi.

 

[NateG]

QuickLoad says a 75Amax loaded at 2.490 OAL, reaches max pressure with H4350 (slightly compressed) at 37.4 grains, and gets 3414 out of a 28" tube. So, yes, 3400 is probably reasonable. But there are a lot of potential errors that come from back-calculating speed or BC from drop on target. (Is the distance really correct? Is the scope/sight calibration accurate? Are you using true arcminutes or the approximation of 1" per 100 yards... etc.)

Note about QuickLoad, all the usual "work up to the load" disclaimers apply, plus, with QL, it's much better at comparing the performance of two things (what if I use a shorter/longer barrel or change powders) than predicting the actual performance (what speed will my rifle get out of this powder/bullet combination)