Need advice on making AI brass

Why, isn't the pressure contained in the brass when firing? I'm not necessarily saying you're wrong, but it doesn't seem like there would be much pressure loss as the brass conforms to the (slightly) larger chamber
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Reloaders are not conditioned to think in the form of factors. I was accused of being involved in some risky stuff. I was forming cases with what most thought were over and above and way beyond what was necessary. Do not get me wrong I believe breakfast cereal is cute but I choose not to use it and when I eject the case the case is formed.

Just in case I should take my accusers seriously I called Hodgdon and gave them a rundown, they said I would be OK, as always there was the 'and then'.

Fire forming the cases: The cases shortened .045" from the end of the case mouth to the case head.

F. Guffey
 
pressure and volume are inversely proportional, 9% greater volume means 9% less pressure

If temperature if constant then where P = pressure and V = volume P1V1 = P2V2, as volume increases, the pressure of the gas decreases in proportion. Conversely as volume decreases, the pressure of the gas increases.
 
pressure and volume are inversely proportional, 9% greater volume means 9% less pressure

If temperature if constant then where P = pressure and V = volume P1V1 = P2V2, as volume increases, the pressure of the gas decreases in proportion. Conversely as volume decreases, the pressure of the gas increases.
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This is what i was saying.

Two ways to see what an AI 6mm remington does compared to a standard 6mm remington is to:
1) Take a standard chamber, and push a bullet until the bolt gets heavy, shooting it over the chroney and get an average velocity. Then, have that same chamber reamed for the AI, and load it until the bolt gets heavy, while trying to keep the brass and other components the same, except the added powder.
or
2) Take the average of several hundred or thousand data points from different ackley vs standard 6mm remington velocity measurements and approximate the gain.

option 1 will tell you how much you have Improved your rifle, option 2 tells you how much it improves the "average" 6mm rifle.
 
And I said I did not want anything between my case and chamber but air and then I said I did not want a lot of air.

F. Guffey
 
A 6mm AI supposedly had 9% more volume.
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Interesting. If you get a velocity increase of 9%, 100% of what your increased capacity is, then on a load achieving 3000 fps you should see a 270 fps gain. Half that would be 135 fps, one quarter (as one gun writer suggests) yields 67 fps.

If you google case capacities chart you should find a listing of most popular cartriges. There is also a calculator there that lets you plug in values to estimate velocity. You might enjoy looking there if you haven't already. That article also suggests you get a 4 to 1 relationship between capacity increase and velocity increase. So a 10% increase of volumn yields a 2-1/4% of velocity for example.

I look forward to hearing what your results are, please post as soon as you get your rig up and running.
 
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I would think you might be able to get case from the gunsmith since barrel was already chambered for the 6 RemAI. He should have some loading data and tell you how to form cases and he did shoot that barrel.

He may of shorten that barrel but your getting new chamber from his reamer.


I would think you want some of his data at least some of his start loads.
 
I would think you might be able to get case from the gunsmith
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There was a time I would ask the same question/make the same recommendation but I have all kinds of trouble finding a smith that can measure the length of the chamber from the shoulder to the bolt face and then there is the diameter of the chamber.

So the choir says fire a few cases and then mail the fired and formed cases to someone's favorite die maker and for $100.00s of dollars you can have a die made make you a set of dies; with no in-between choices. I am lucky, my dies and presses have threads.

F. Guffey
 
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Guffey, my post was for Mississippi. It's his barrel I'm posting about.
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That is something I intend to do.... talking with my Smith about it. He has stopped using 6mm AI's in favor of the Dasher for his own guns. So he is hooking me up with his dies. So he should have some insight... right now I'm planning to try the new 110 gr match kings .
 
Seems like when I rented a 30-06 AI reamer once,I was able to rent a headspace gage specifically made for the AI. You might check into that
 
Guffey, my post was for Mississippi. It's his barrel I'm posting about.
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Well forgive me; it is a good thing I am not sensitive. And then? There is that infatuated thing about head space gages. 'The head space gage'; one gage? I offered to modify a go-gage, I explained one gage was all the smith/reloader needed. And then there is the datum as in measured from, the measurement can be made from the shoulder or the datum, I like 'the datum' I can make gages with shoulders, I can measure the length of a gage with a shoulder with a datum type gage; again, I only require one gage, with one gage I can measure the length of 16 chamber in thousandths if the chamber has 'zero' clearance or '.016" clearance and everything in-between .000" and .016".

And then there is 'to infinity' I make infinity gages meaning there is no way the shoulder can be too far from the bolt face for me to measure.

F. Guffey
 
Having a couple of AI chambered barrels has fought me a few things. First you not getting anything for free with any of them. Granted some are better, a couple much better, but most are more for the appeal of something different.

For myself, I have a .223 and 30-30 both in 14" Contender barrels and then my custom built 25-06. They all shoot great but the best thing is the added barrel length of the 25. I had it built using a 28" 1-9 twist canted land Broughton barrel to take full advantage of the slower powders and heavier bullets. My standard hunting load uses the 120gr Nosler Solid Base at 3250fps. It has on quite a few occasions shot 1" groups at 300yds.

I started bout with a box of factory ammo in all of them. I shot a full box checking velocity as well as measuring case heads with a micrometer which hit down to .0001". This gave me a somewhat standard to work with.

Problem is differences in cases from one brand to the next or even from batch to batch using new unfired. I settled on using Remington and Lapua for the 25 as the readings I got with both using standard loads were the most consistent and almost equal. I do however admit I could get a bit more pressure from the Lapua than the Rem but at that point I had already backed off to the load I'm using.

So you have to have standards to work with. I never seated bullets into the lands I simply did a top end standard load quick work up using new brass that shoots really well for a fire form load using Core Lokts so I could at least shoot hogs with them while fire forming at the same time. Once they were formed I loaded them up to my Ackley loads and go from there. So far I have gotten almost a dozen loads out of most of my original 100 formed cases. My biggest issue is loosing them while hunting.
 
Having a couple of AI chambered barrels has fought me a few things.
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Me to: There is no advantage to having a 257 Weather Mag if the barrel is not 26 inches long or at least 2 inches longer than a 257 Roberts barrel. Same with a 7mm57 Ackley improved, I was going to build a 338/06 and then changed my mind, I build a 338/280 Remington with out the improved shoulder and the larger diameter chamber. Basically I increased the length of the chamber from the shoulder to the bolt face .051".

Hatcher increased the length of the chamber .070" +/- a few, in the old days I referred to it as the Wildcat Hatcher 30/06 +.70". In his version he did not experience case head separation and I have asked if someone handed him the wrong rifle.

F. Guffey
 
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