7x64 vs 7x57 Ackley Improved

[angusb1]

I've never given much thought to the Ackley Improved chamberings but read the other day in another thread on here that the 7x57 is one of the most improved by the Ackley rechambering and that it gains another 100-150fps. As far as I can tell this would make it similar to the 7x64. On the down side, I realise it would only be possible to get factory ammo in the standard chambering which would be slower than the equivalent 7x64 factory ammo, but it seemed like a way to possibly get a little bit of extra range over the standard chambering when you were reloading.

Is it a difficult/expensive piece of work to do for a gunsmith to rechamber a 7x57 to AI? Any idea of roughly what it might cost? I guess you'd have to pay for the reamer plus labour?

It could possibly make some older rifles I've been looking at even more appealing, since I've been looking at 7x64s and there are very few about but there are lots of nice old 7x57s second hand.

 

[HandB]

Good question - from what I have heard, it is difficult to recut a used chamber as the heat from firing makes the steel problematic to cut cleanly. But I wouldn't even worry about squeezing more fps from a 7x57. With streamlined bullets it is already a highly capable cartridge at long range as the Boer marksmen showed. I shoot an elderly 7x57 BSA just inside an MOA at 600 yards without even getting up to book max powder charges.

 

[Heym SR20]

Why bother with the AI. The original high velocity loading of the 7x57 ran a 140gn at 2,800 fps. The 7x57 has more case capacity than 7mm-08 which also does 2800, so in a reasonably modern rifle not hard to get a longer streamlined bullet of 140 to 156 gn to shoot at good velocities especially with modern powders.

Or just go with 7x64 which gives another 150 + fps over the 7x57.

have a read of Modern Bullets Can Elevate The 7x57 Mauser's Performance

And

7x57

 

[enfieldspares]

Factory 7x57 is loaded to be safe in old single lug early Mauser rifles. In a modern rifle it will be fine. But FWIW is 2,800 really needed for most UK stalking? Even on the hill?

 

[Lateral]

I have a 7x57R, and 7x64.

The 7x57R is a tamer version than the straight 7x57, with a lower max pressure rating, but has dropped Muntjac to Fallow, without any dramas.

My 7x64, with 22" barrel, is just excellent. Norma Oryx 156gr, home loaded to 2925fps, & Norma Vulcan 170gr, 2916fps. It likes the heavier bullet.

If you want to use factory, forget the AI, or anything oddball. You can get factory Geco 7x64 170gr soft points for sensible money.

 

[Kalahari]

The GECO 7 x 64 stuff really works well in my 7 x 64.

David.

 

[angusb1]

Thanks gents. Sounds like the AI isn't worth the hassle and expense.

Why bother with the AI. The original high velocity loading of the 7x57 ran a 140gn at 2,800 fps. The 7x57 has more case capacity than 7mm-08 which also does 2800, so in a reasonably modern rifle not hard to get a longer streamlined bullet of 140 to 156 gn to shoot at good velocities especially with modern powders.

Or just go with 7x64 which gives another 150 + fps over the 7x57.

have a read of Modern Bullets Can Elevate The 7x57 Mauser's Performance

And

7x57

Cheers for this. I'll have a read.

 

[harrygrey382]

About 90% of the AI performance increase is due to the pressure increase - load the original up and the difference will become negligible. You’ll retain smoother feeding then as well as not having to worry about annealing due to shoulder changes and other AI issues. Of course the 7x64 will always have the edge given equal pressures, whether those extra FPS are worth it or needed is another matter.

With all this talk of running 7x57 at higher pressures I’m surprised a certain member hasn’t posted that we’re all inexperienced and need to learn about reloading fundamentals which we clearly know nothing about...

 

[NP435]

I get 2750 with H4831sc under a 140 Barnes TTSX now with a 22 inch barrel ,AI =why in my world. a 280AI might be interesting if I didn't have the 7x57. Was my son's rifle I hunt with it because hunting with him is impossible.

 

[levigsp]

The AI "thing" is either in you or not. If like me its in you you do it because you can, if not you stick to standards. i have a couple of AIs and Im going to build another[7x64] I already have the 308 ai and 375hh ai. , extremely long case life, a little more fps if needed dependent on original case. I love mine, but still use my 243 90% of the time.

 

[Lateral]

The AI "thing" is either in you or not. If like me its in you you do it because you can, if not you stick to standards. i have a couple of AIs and Im going to build another[7x64] I already have the 308 ai and 375hh ai. , extremely long case life, a little more fps if needed dependent on original case. I love mine, but still use my 243 90% of the time.

There's nothing wrong with wildcats, odd balls, but some, are a total PITA in the beginning.

Having had a 20ppc, a superb round, I'm not in a hurry to go too far from the "norm" these days.

As It is, I seem to favour the less popular chamberings in the UK, liking some of the more traditional European offerings. Factory ammunition is available for all, mostly, but it can be difficult to get.

So I understand the AI thing, it just doesn't appeal. I've had my fire-forming, neck turning experience

 

[Uncas]

I have a 7x57R, and 7x64.

The 7x57R is a tamer version than the straight 7x57, with a lower max pressure rating, but has dropped Muntjac to Fallow, without any dramas.

My 7x64, with 22" barrel, is just excellent. Norma Oryx 156gr, home loaded to 2925fps, & Norma Vulcan 170gr, 2916fps. It likes the heavier bullet.

If you want to use factory, forget the AI, or anything oddball. You can get factory Geco 7x64 170gr soft points for sensible money.

Norma vulkan 170 gr factory states 2'760 fps, how are you managing the extra 156 fps without excess pressure?

 

[scrumbag]

@Uncas, have a look at Reloder powders and RS70 particularly for faster shooting of heavier bullets.

I'd get a 7x64. Lapua Brass is out there if you want it. Geco Brass works well too for once fired factory.

Scrummy

 

[Lateral]

Norma vulkan 170 gr factory states 2'760 fps, how are you managing the extra 156 fps without excess pressure?

Ben,

Factory is always lower, because they have no control over the rifles that it will be put through.

I'm reloading for my own rifle, and can check for pressure signs, step, by step. I can't comment if the same load will be safe in another 7x64.

To be fair, 150fps, isn't a missive increase in % terms. Here are the results from three loads I tried. The first two loads were very accurate, but I ran out of light for the third, so I have just used it to get the velocity data.

Because I want to try it on driven boar, accuracy isn't the priority, but I'm pretty sure it will shoot sub 1". The first two loads were pretty much single holing.

On the last load, I shot at an old tree stump, and this is what I retrieved from behind it.

 

[Ratwhiskers]

l sometimes wonder how many folks actually bother to read the forward sections of either of Ackley's books, before that is, they skip right along to the nice pictures of all the modified cases and the velocities at the end of the loading charts.
Ackley himself wrote that many of his experiments were not intended to find the fastest velocities per cartridge, but to look at pressures and the reduction thereof while improving efficiency and maybe some velocity advantages over the parent case. He himself even accepted that many of his experiments lead him nowhere...
One thing he did notice was that case life in some of his offspring could be almost limitless, once the forming was complete and the round run at the original velocities, which very often were more than enough in the parent case it's self (as has been noted above in previous posts).

Now, l run a 7x57 Ackley, currently with just 140BT's at 2900ft/sec or thereabouts...... "Boring!!" l hear the cries..... Yup!! it is...!! and extremely accurate and running at low pressure too l might add. And while l'm at it, l can run just about any bullet length l care to experiment with in a Sako 75 lV action magazine without the OAL issues incurred by some longer cartridges in some magazine profiles.

 

[NP435]

l sometimes wonder how many folks actually bother to read the forward sections of either of Ackley's books, before that is, they skip right along to the nice pictures of all the modified cases and the velocities at the end of the loading charts.
Ackley himself wrote that many of his experiments were not intended to find the fastest velocities per cartridge, but to look at pressures and the reduction thereof while improving efficiency and maybe some velocity advantages over the parent case. He himself even accepted that many of his experiments lead him nowhere...
One thing he did notice was that case life in some of his offspring could be almost limitless, once the forming was complete and the round run at the original velocities, which very often were more than enough in the parent case it's self (as has been noted above in previous posts).

Now, l run a 7x57 Ackley, currently with just 140BT's at 2900ft/sec or thereabouts...... "Boring!!" l hear the cries..... Yup!! it is...!! and extremely accurate and running at low pressure too l might add. And while l'm at it, l can run just about any bullet length l care to experiment with in a Sako 75 lV action magazine without the OAL issues incurred by some longer cartridges in some magazine profiles.

Curious on the barrel length? Not bashing interested.

 

[Ratwhiskers]

25"s sir, for your interest.

l cut her long enough to give me movement further down the line should l find as had been my intention, to take her to Africa and run heavy for calibre bullets at decent velocity but again with the intended low pressure. Yes l could have just bought a 7mm rem mag, or a 7x64 both of which PMP produce and are easily obtainable should l be parted from my ammunition upon arrival, but so is the 7x57, so no real biggy there either, and l've witnessed it's performance first hand.

Velocity in some cases comes at a price, be it increased barrel wear due to the need for faster powders, or some that just burn increased volumes. Then there's the payback of recoil, coming again from velocity and increases in bullet weight and a whole pile of Newton's laws, equal and opposite's and all that great stuff.

l found a way to make the brass from .270win cases and achieve 5' of the 7% improvement without even having to fire form, and the accuracy is amazing. So no need to push the case walls back to 7x57 and the blow then out again, or buy expensive new 7x57 parent and do the same, l just pick up cheap donors and fettle on the loading bench and go right from there.

ln the fullness of time l intend to run several other possible bullets through her to see what performs to our liking and then it's be down to travel and funds available.....

 

[angusb1]

l sometimes wonder how many folks actually bother to read the forward sections of either of Ackley's books, before that is, they skip right along to the nice pictures of all the modified cases and the velocities at the end of the loading charts.
Ackley himself wrote that many of his experiments were not intended to find the fastest velocities per cartridge, but to look at pressures and the reduction thereof while improving efficiency and maybe some velocity advantages over the parent case. He himself even accepted that many of his experiments lead him nowhere...
One thing he did notice was that case life in some of his offspring could be almost limitless, once the forming was complete and the round run at the original velocities, which very often were more than enough in the parent case it's self (as has been noted above in previous posts).

Now, l run a 7x57 Ackley, currently with just 140BT's at 2900ft/sec or thereabouts...... "Boring!!" l hear the cries..... Yup!! it is...!! and extremely accurate and running at low pressure too l might add. And while l'm at it, l can run just about any bullet length l care to experiment with in a Sako 75 lV action magazine without the OAL issues incurred by some longer cartridges in some magazine profiles.

Thanks for posting this. I wasn't aware of the advantage of getting longer case life. It does make sense that there is no free lunch in terms of increased velocity coming at the expense of barrel life too, thanks.

 

[angusb1]

Ben,

Factory is always lower, because they have no control over the rifles that it will be put through.

I'm reloading for my own rifle, and can check for pressure signs, step, by step. I can't comment if the same load will be safe in another 7x64.

To be fair, 150fps, isn't a missive increase in % terms. Here are the results from three loads I tried. The first two loads were very accurate, but I ran out of light for the third, so I have just used it to get the velocity data.

Because I want to try it on driven boar, accuracy isn't the priority, but I'm pretty sure it will shoot sub 1". The first two loads were pretty much single holing.

On the last load, I shot at an old tree stump, and this is what I retrieved from behind it.

View attachment 191775View attachment 191776View attachment 191777

View attachment 191772

Thanks for posting this. Interesting to see the 7x64 can be loaded to give similar velocities with 170gn bullets as with factory 140gn in some rifles.

 

[levigsp]

So I think the 7x64 is under estimated and over looked because people dint understand it and don't load accordingly! Using 165gn+ bullets it will out perform any other similar case capacity cartridge, simply because of its design. I know one hundred percent that people will run programs and calculations etc saying that a certain weight of powder with this bullet or that is the max and in every case they are well below the max, both in pressure and speed of bullet.
quick load tells me that max for my favoured pig gun is ;Alliant Reloder-26 98 2631 3631 , its actually over 300fps faster and still bellow pressure. similar results with all load tables. i have 2 7x64s and i get same sort of results with both.