7mm - 08 Ackley Improved information Blog!

[plumbs7]

Thanks Norm and David for the input, I would like to keep this going and may change the title as a blog for this little ripper.its a very efficient round , as the 180's are nearly as big as the case ! I think 30" barrel seems to be about right . And the Bart seems a cracker too!
I first saw Steve ( footsore) shoot this at Crowsnest and had an instant podium finish in very tricky conditions . I'm not a top f open shot , but I feel that it's a cartridge that one could shoot from 300 yds to 1000yds competativly . After Christmas I'll go back to standard. I'm shooting in Goondawindi opm ( just the Saturday) on the 5 th of Sept.I think. Aginast all of the usual suspects in qld f open , most likely!

So If anyone has anyone has anything to share on the 7-08ai, it would be interesting.
Regards Graham Sells.

[Steve N]

I have a 31.5 inch straight cylinder 1.25" Lilja barrel that has not shot well at all with AR2209 but is accurate with a compressed load of AR 2213sc pushing 180 vlds. Nodes with 2209 are very pronounced but never really tighten up to less than around 3/4 moa at best. Willadas comments about spluttering last breaths are interesting. 2209 is definitely the adi powder of choice but does not seem to like my barrel.
Steve.

[Quick]

Gents,

Im using palma brass with CCI450. I do believe the place to aim for with this cartridge is around the 2750-2780fps mark. Much more and its likely pushing to much pressure to be consistantly accurate.

Im using Berger 180gr VLD and they just work. Very easy to tune and find a load with them. If your having issues with hybrids, I'd try the VLD. Given what MV some people run the 284 at, the 7mm08AI gives up nothing to them.

I have currently approx 1300rds on my barrel. Currently on 2nd chamber with about 300 - 400rds on current chamber. But only cut 1inch off so barrel is 29". I'll rechamber again at 2000rds if it looks good. Im using a Benchmark 1-9T Max HV. The 9T has the bullet at 1.5 SG and i think thats perfect.

This rifle has 1x equal first, 1x 2nd by 1X and 4th In OPM competition with current barrel. I havent got to do as much competition as i would like but its up there for sure.

My load looks like this:

180gr VLD 10 thou jam
47.3 AR2209 (2yr old batch)
Lapua 308 Palma brass w/ 310nk loaded round
CCI450 Primer
2765fps with single digit ES and SD IIRC.

I dont worry to much about MV, I let the target tell me what works. I chrony after to see what its doing and to help get drop for ranges I havent shot with it.

Any other info just ask.

[williada]

Great info Shaun. The powder column just might be more efficient at those velocity nodes with your gear than the .284. Does it pressure the cases? How does it run in colder conditions? In Gippsland Victoria, we can shoot in 8-9 degrees at times and sometimes at home you are cracking the ice off the puddles. Like right now, its raining its guts out. David.

[plumbs7]

Sorry Shaun to jump ahead . But David yes at 46.7 2209 large rifle lap cases are showing signs of pressure slightly with primer pockets , but nothing alarming! I have tuned this in the winter so will have to back off .2 gr maybe in the summer . But I'm amazed at the velocity I'm getting as the barrel runs in. Have about 150 rounds on the board now .
Regards Graham.
Ps I'm using 180 hybreds !

[Quick]

David,

Cooler temps its fine. I shot it down to around 15 deg with no issues and up to mid 30s with no issues. Theres pressure at times with a click at the top of the bolt lift but not all the time. Primer pockets still very tight. I have 48 cases with over 15 firings and no issues.

[williada]

Thanks Shaun,

Its good to know. That long case life is just so important. It means you are not chasing a tune either, which is so important for consistency.

What you guys are telling us, will hopefully build an Australia wide knowledge of range conditions for the major events, and the most suitable calibres for the local conditions and the nodes that are generally acceptable. This will make the competitions more exciting if they are close, it will see if you have got what it takes to succeed under the pressure of tight competition and save people a lot of time and effort going to events just to be flogged.

I hope you guys learnt from Brisbane and will continue these dialogs after each major event. There are a lot of positive spinoffs. David.

[Quick]

Ive been to belmont twice now. Hope to go every year for either QRA Queens or Nationals. I think I'm gonna keep the 7mm08AI for a while as it just seems to tick all the boxes for me right now.

I cant take all the credit though, alot goes to our Coach Brett. Hes a mountain of knowlegde and advice for younger guys like myself.

[Steve N]

Shaun I shot with Brett at Belmont a couple of months ago and have been talking to one of your mates Marlon over here at the Gemfields shoot last week. Both have said that your rifle goes very well. I am using the same palma brass, primer and projectiles as you but just cannot get 2209 to work anywhere near as good as 2213. Marlon is a fan of barrel tuners and has me thinking maybe that is the worth a try. The problem with 2213 is that I am using 50gr to get an accurate 2750fps with a 10 thou jump but because it is compressed it is a lot of fiddling to get seating depths the same. Loads of 2209 from 46 to 48gr make bullet seating easy and give very good velocity from 2750 up to 2880 with the heavier charges but accuracy is erratic.
I have a new reamer and new 30" barrel so will see how the next one goes. Perhaps my current barrel will work better with 2209 shortened and rechambered..
Steve

[Quick]

Steve,

Feel free to send your barrel to my smith and try my reamer. Whats your new specs?

[Steve N]

Shaun the neck is .312" but not sure of exact freebore. Is long and throated for 180's seated to neck shoulder junction. Thanks very much for the offer but will see how this one goes with a set back and recrown. The barrel is up to about 1300 rounds now so is probably due for a touch up.
Steve

[Quick]

No problems mate. Yeah keep an eye on throat due to the 09 and 13SC. It has a habit of hurting them a bit.

[KHGS]

No problems mate. Yeah keep an eye on throat due to the 09 and 13SC. It has a habit of hurting them a bit.

Throats & primer pockets (not to mention barrel life) will & do always suffer when chamber pressures are run to the upper level seeking the highest possible MV. Smaller cases can offend more in these areas than larger cases run at 3/4 throttle which is where the widest tune band almost always is. 2209 & 2213 are not measurably harder on throats than any other ADI powder when chamber pressures are in the correct range.
Keith H.

[plumbs7]

Hi all , today I prepped 3 off 7-08 case to fireform and to foul the barrel for Gundy Opm on Saturday. I don't want to waste good 168's and 180's to just throw money done the drain . So I stopped into my local gun shop and picked up a box of 7 mm 100 gr varminters for $48.00.
Got home and checked that they would still be near the lands when seated , all good ! I thought since I was just fouling the barrel I would chuck in 30 gr of 2209. Went out and fired them and then looked down the barrel and there was a lot of unburnt powder left in the barrel! Not good !
Does anyone have quick load and do us a huge favour and run a load I have in mind. I have heaps of 2207 ! Would about 30 gr with a 100 gr pill work just as a pre match fouler / fireforming load ?

Kind regards Graham Sells.

[KHGS]

Hi all , today I prepped 3 off 7-08 case to fireform and to foul the barrel for Gundy Opm on Saturday. I don't want to waste good 168's and 180's to just throw money done the drain . So I stopped into my local gun shop and picked up a box of 7 mm 100 gr varminters for $48.00.
Got home and checked that they would still be near the lands when seated , all good ! I thought since I was just fouling the barrel I would chuck in 30 gr of 2209. Went out and fired them and then looked down the barrel and there was a lot of unburnt powder left in the barrel! Not good !
Does anyone have quick load and do us a huge favour and run a load I have in mind. I have heaps of 2207 ! Would about 30 gr with a 100 gr pill work just as a pre match fouler / fireforming load ?

Kind regards Graham Sells.

You could try 41 grains of 2206H or 42 grains of 2208. It is a really bad idea to use very light loads of slow burning powders such a 2209 for any purpose. This is a very risky practice, rifles have been blown up doing this!! these blow ups while rare are vey catastrophic & are caused by detonation.
Keith H.