6mm-250 Ack Imp Load Data?

V

varminter22

New member
Hello Gents!

After a lengthy absence from much rifle shooting, I'm hoping to get going again.

Some time ago, I had a Rem 700 (VSSF) rebarreled with a couple of Hart heavy barrels, one is .22BR and one is 6mm-250AckImp.

Will be using R-P brass and Fed primers in the 6mm-250AI.

Will be initially trying Berger 80 gr Varmint, Hornady 75 gr VMax, and Nosler 70 and 80 gr Ballistic Tip bullets.

Although I would not be adverse to buying a new powder, I have the following powders:

Varget

Benchmark

Vihta Vuori N133, N135, N140, N150, and N160.

Load Data for 70 to 80 grain bullets has not been easy to come by.

Might you have some data I can start with?

Your assistance appreciated!

P. S. The only load I've fired in it so far is a few 75 gr VMax over 37.5 gr of Varget.
 
OK, some comments.......

#1, this forum isn't known for posting loading data. Altho loads are casually mentioned the posting of "favorite" or "pet" loads is kinda' frowned upon.

#2, since the focus of this pertickler site is bench rest (both Bench Rest and benchrest ;) ) most of the guys here focus on very narrow parameters..... f'rinstance when I picture your type of cartridge only one class of bullet comes to mind... HEAVY. Like 105 and up. It is my opinion that this size of case is poorly suited to 70 and 80 grain bullets. It's OK, but seriously overbore. I also picture only one type of load.... HOT. This is because I'm fairly convinced that only by burning hot can one achieve the consistency of velocity desired by the target crowd. It is for this reason, possibly, that posting data is avoided. I load HOT but safe. IMO this requires scrupulous attention to detail and a deep understanding of "pressure signs" and what constitutes them. I feel strongly that when loading hot loads must be carefully weighed and attention paid to powder temperature among other things.

#3, I would think you could find tons of stuff over on 6MMBR.com. I popped over there for a moment and spotted quite a few posts about that size of cartridge.

#4, barrels and setups vary in their ability to handle loads..... a load that may be safe in one Rem700 setup may be over-pressure in another. I will say this, when you've worked up loads to the extent that they're loosening the primer pockets please back off a full grain if you're weighing each and every charge and back down at least TWO grains if you're throwing them from any sort of metering device. And I do mean ANY sort of metering device. It has been my experience that even the most expensive or "accurate" metering powder droppers will vary day to day. All metering devices are highly dependent on technique.

Sorry to be of little help but them's some of my thoughts....

al
 
One commonly thinks one can find virtually everything on the internet. But I've had little success in finding data for 6mm-250AI with 70 to 80 gr bullets.

The 6mmBR site speaks of the heavier bullets.

Hodgdon does provide some info.

I'll work from that - and extrapolate. I was just hoping someone might have some other starting data.
 
I shoot the 6/250AI, but it's obvious that we travel in different circles. I shoot 105 grain Amax and the bigger Sierras in a 1:8 twist barrel. My suggestion is for you to give Hornaday a phone call to see if they have a starting load. But you could also start out with the 6XC data and kinda work your way from there.
gary
 
4895 ought to work well in your 6-250 Imp with 70-80 grain bullets. I'd start with data for the plain old 6-250 which is more available. Also not too far off the 6XC but its hard to find data for lighter bullets in that case as well. It is possible to select a generally good powder starting from a full load in a .22-250 as a starting load for your 6mm. It'll be light but then work up to a full power load. You'll be getting around 3400-3500 with the bullets you mention. Other powders to look at are VV140, 4064, H322 and 748. 4350 might work well with the 80s. If Varget worked well with 75s it won't be far off with the 70 or 80. This is an easy cartridge to develop and many powders will work. All the mid size 6s are that way, IMO.
 
You might take a look at........................

Hodgdon's H-414, which is really close to Win. 760. I consider 748 a bit "quick" from your statements, but, give it a whirl, ya never know....

With the H-414, I'd start the 70 grainer with around 34-35 gr. and see how things go. It should prove to be an enjoyable groundhog getter.

Be careful, and have fun. :D
 
Thanks, guys!

I did call Sierra today and got some good ideas.

I think a call to Hornady is in order too.

Thanks again!
 
I shot a case packed full of Win 760 with a 70g bullet out of a 28" 12 twist barrel for a velocity of 3800 fps, tiny, tiny groups. I used a 10" drop tube to get all the powder in the case.

Work up to that load in your rifle, start off with a 4" drop tube.
 
Whatever keithcandler tells you about a 6/250 Imp. you can take to the bank. With 70 gr. bullets Varget & AA 2520 works well. IIRC my 6/250 Imp topped out at 41.0grs. of Varget & about the same for the AA 2520. Start lower & work up please.
 
Going from a 10" drop tube way down to 4"s is way more than the required 10% less for starting loads... :)
 
How about using the new Lapua .22-250 brass to form your cases instead of Remington brass ?
If that brass is compatible with your chamber.


Quickload will give you an idea where to start loading.


What twist do you have in those Hart barrels ?

What are you using for dies?


Glenn:D
 
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Will have to check on the exact twist rate (I can't recall right now!) - but the riflesmith indicated it is twisted for 70 to 80 gr bullets.

Reddings dies.

I do wish Lapua had make .22-250 brass when this rifle had a .22-250 barrel.

I may get some Lapua .22-250 brass to try, but this rifle was chambered around a big quantity of Rem brass (before Lapua announced .22-250 brass.)
 
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