7mm-08 AI

WARDY1

Well-Known Member
Looks like i'm having my sako rebarreled as above just a few questions.

For those that have this calibre;

What weight Bullet do you use and what velocity do you get from what length barrel?

I am looking to use 120 to 140's some sort of bonded bullet.

Am i right in thinking its a 1:9.5 twist?

Cheers

Steve
 
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For goodness sake don't use the term 'heads' on here you will get your head shot off!
Matt
 
:lol: My ............... my that's a rather large calibre to get a head up the spout :eek:.

Now then :-

Am i right in thinking its a 1:9.5 twist?

I believe my 7x57 has a 1 in 9" twist and shoots the 139's well.

I am looking to use 120 to 140's some sort of bonded bullet.

Hmmmm why the need for bonded bullets? However if you want to use them go ahead ;) it's your money. I use 139 grain Hornady Spire points and this one was recovered after pentrating over 3 feet of Whitetail Buck:-

41059835.jpg

Hornady 139 Grn BTSP :D launched at 2850fps from a 22" barrel.

For those that have this calibre
Well I have a 7mm calibre just not one chambered for the 7-08 of any type
 
I'm on my second 7mm-08, a Blaser with a 22.5" barrel and use 120 Gr B/Tips although I have also used both Sierra and Hornady in the same bullet weight. Both VARGET and RL 15 produce excellent accuracy and I load them at an average of 3,000 fps. The Nosler B/Tips are regarded as a bit fragile by some but I find them absolutely fine on Roe and Muntjac. I have also used them on occasional Sika with good results. If I was mainly shooting the larger species I would use the heavier 139/140 Gr offerings - Hornady 139 BT are very good. Out of interest why the AI chambering?

Regards,

KRS
 
KRS

Thanks For the information.

AI Because its available and a little more speed especially if using the 140's.

Steve
 
I doubt if you'll get much more speed from the AI. More speed is generally minimal unless you are strapped to slow powders and/or increase the barrel length. I've owned AI calibers from 220AI Swift to 30-06AI and got nothing in return for the efforts. Handloader (US) magazine did an article about increasing case capacity and it was found that velocity increased or decreased, percentage-wise, at 1/4 the increase in powder capacity. According to their findings, if you managed to squeeze in, say, 12% more powder you'd perhaps net 3% increase in velocity if all other things remained equal.

As I have a Pressure Trace unit for measuring chamber pressures and pressure curves while the bullet travels the bore, I tend to think of things in relation to pressure, not velocity. In a given bore, pushing a given weight of projectile, it takes "X" amount of pressure to reach a given velocity. Plain physics. Now, if the pressure were reduced by increasing the volume of the case, the resulting velocity will drop in proportion to the increase of case capacity. So. We add powder to reach the previous pressure and attain the previous desired velocity. Ok. We just added powder to gain back what we lost which is Ok, I guess. But what if the cartridge was already loaded to maximum allowable pressures?? Can we add powder? Nope. Not safely. We need to change powders if we want more speed, or we need to follow Weatherby's play book and either free-bore the chamber (throat) and/or increase barrel length to add speed while keeping pressures at an allowable level.

This all sucks to hear but it's the truth. My 30-06AI got no increase in velocity at all. Ackley once wrote that cartridges that are already operating at maximum efficiency, and pressures for the weapons they are chambered in, are poor candidates for Improving as little is gained. I tend to agree but that's JMHO. ~Muir
 
I've owned AI calibers from 220AI Swift to 30-06AI and got nothing in return for the efforts. ~Muir
I am thinking of getting a 220AI Swift. Mainly because it is a little different and it is not a 22/250AI;) in your experience is this worthwhile or a waste of time? The gunsmith is trying to persuade me to go 22/250AI or maybe even 22BR.
 
Looks like i'm having my sako rebarreled as above just a few questions.

For those that have this calibre;

What weight Bullet do you use and what velocity do you get from what length barrel?

I am looking to use 120 to 140's some sort of bonded bullet.

Am i right in thinking its a 1:9.5 twist?

Cheers

Steve

Hi Steve,

I have recently purchased 7mm-08 AI. Uses Sako 75 action. My barrel is 19" with 1-9 twist.

I have used it for target practice and took it out this weekend. I use Feds 140grn until I have enough to home load. So far of the two cull candidates spotted in my scopes cross hairs I have had two grand results. Fox @ 180yrds and my 1st melanistic fallow buck at 80yds. Both hit the deck and the meat damage is much less than a .243.

With Jetz Mod added the kick is way sub .243 and the sound is even less than a .243. Bit of a mule without mod, but with mod, I see the hit and the fall without lifting off the scope.

I have to say I am extremely happy with the rifle and the loads. Still have got to see what happens when I home load. But as a guide, sub inch @ 100. 1-2 Inch at 200, 4" groups at 300.

As muir said, will you see the benefit of the AI, probably not, but as a calibre, I'll never change.

Love it , Mega confidence.

Regards
ArthursC
 
I am thinking of getting a 220AI Swift. Mainly because it is a little different and it is not a 22/250AI;) in your experience is this worthwhile or a waste of time? The gunsmith is trying to persuade me to go 22/250AI or maybe even 22BR.

Nick how about a 5.6x57 if you want something a bit different,not that i've got one but am thinking about it.
Neil
 
Ok i've took the plunge now but with a standard 7mm-08, i may have the barrel 24" to start though.

Thanks for the replies.

Steve
 
I am thinking of getting a 220AI Swift. Mainly because it is a little different and it is not a 22/250AI;) in your experience is this worthwhile or a waste of time? The gunsmith is trying to persuade me to go 22/250AI or maybe even 22BR.

Nick,
The 220AI got no faster BUT this was one of a few cases where sanely-loaded ammo showed extended case life. For that reason it was better than the standard Swift. Personally, I would go with a standard 22-250. Cheaper brass and dies, no resale problems. The 22-250 AI is another item to be passed on. Ask the gunsmith what pressures he generates? What barrel length???

Remember, Ackley had a full shop at his disposal. He had machinery for making reamers (I've run the same machinery he used) and he had access to a pressure gun. This makes last item makes all the difference in the experimentation he was doing. As he once told me, many things he did because he could, not because it was of any practical value. He wrote once -and this is always overlooked when talking about P.O.Ackley- that modern cartridges and especially those that are high pressure and "over bore" to begin with, shouldn't be "Improved" under most circumstances.~Muir
 
it seems that custom rifles have a poor resale so was thinking if i am getting one made it could be in something different. i have had a swift before which seemed to shoot pretty straight. did not reload so that wasn't a factor at the time. I guess from what you are saying that you wouldn't be recommending a 22-243AI then;)
 
Ok i've took the plunge now but with a standard 7mm-08, i may have the barrel 24" to start though.

Thanks for the replies.

Steve

Excellent choice, Wardy, the reloading kit will be easier to obtain in the standard chambering and loading data easier to reference and experiment with. It really is a nice calibre to load for.

Regards,

KRS
 
Look up "over bore" in a reloading lexicon! There is just so much powder you can "burn" in a .224" bore. There is so much more to ballistics than VELOCITY.~Muir
 
Look up "over bore" in a reloading lexicon! There is just so much powder you can "burn" in a .224" bore. There is so much more to ballistics than VELOCITY.~Muir

well why did you have a 220 swift AI then? surely this is "over bore";)
 
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