Kirby Allen 224 AM progress?

[davewilson]

i can't imagine there's much difference at all in the amount of powder flying out the barrel no matter where you start ignition.this theory that the powder is burning in the case and the gases are about all that's going out the barrel seems very unlikely.peak pressure will occur getting the bullet fully engraved into the rifling,or very shortly after with these overbore cases and very slow burning powder.when at peak pressure,every grain of powder is burning that's gonna burn.as this powder burns it's gonna expand and travel down the barrel.i'm not sure there will be any less powder traveling down the barrel no matter where you start the ignition.

 

[sullijr]

A thought for you,,,will the hottest part of the powder burn if it is burning from front to back of the case occur in the case rather than in the throat of the chamber?The increase in barrel life will be worth the effort.

 

[Fiftydriver]

Cowboy,

Case life will generally be the same if you load to the same chamber pressures from what I am seeing. Only difference is that velocity potential will be higher with same chamber pressures so in theory you can load to lower pressures, get same velocity performance and dramatically increase case life if you want.

From my intitial testing it looks like the modification to the cases will add roughly 20 cents to the price of each case for the tubing and a little bench time. The tubes should also be able to be removed from old brass and fitted into new cases as well. More testing will be needed to prove this true but it should work if your careful with installing and removing the tubing.

With the added price is really only seems practical to use this system on the most severe of cases to promote throat life, such as all the Allen Magnums /ubbthreads/images/graemlins/grin.gif!!!

Kirby Allen(50)

 

[Fiftydriver]

BJ,

****, thats right, front ignition system testing has been terminated /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif!!!

Just kidding.

My barrels cost as much as my customers so it will limit the rebarrel jobs on my rifles as well!!

Kirby Allen(50)

 

[Fiftydriver]

ATH,

That is true and I will say you are probably far more educated on physics then I.

Perhaps what I should have said is that felt recoil is different. And it really is. Instead of the sharp slap of recoil that we are used to it is more of a slow rolling push. Probably the exact same amount of recoil energy but it feels different.

First few I shot I though I was having hangfires thats how strange it initially feels. Once you get to the higher pressure loadings, it begins to feel more conventional but still slightly different.

Personally I believe this is due to the fact there there is not that sharp spike in chamber pressure as there is with conventional ignition rounds. It is a much more gradual pressure curve as it is a more progressive and even powder burn.

Kirby Allen(50)

 

[Fiftydriver]

Dave,

With conventional ignition the powder is forced into the bore before it even ignites in these large capacity small bore cases. Peak pressure is not at the point of bullet engraving, it is generally when the bullet is at least a couple inches down the bore and in severe cases more then that.

With forward ignition, the powder is ignited at the front of the case. This area ignites and is converted to gas. THis is the "hot spot" if you will of the powder ignition. From there the powder burns from the front of the case to the rear instead of down the bore.

The powder ignition actually holds the unburnt powder IN the case until it is burnt.

This is not a new concept. Nearly all the military rounds over 50 BMG use front ignition for this reason and the results have been proven from their testing that this actually occurs.

The only problem is making it practical for conventional handloaders instead of 30 MM cannon fodder /ubbthreads/images/graemlins/grin.gif!!!

Kirby Allen(50)

 

[Fiftydriver]

Sullijr,

Thats the entire idea, keep the "burning" powder in the case as long as possible or totally if possible to protect the throat.

This is the main goal of these tests and we will see what happens. The system works, making it practical, accurate and consistant to use if the challange at hand!!

Kirby Allen(50)

 

[Guest]

Hi Kirby
Thanks for all the updates.
Very interesting on the front ignition.
Is the added bit purely a screw in tube with length set a bit short of the top of the powder column?
I would presume with this size case that would be sufficient without needing bleed holes in the sides of the ignition tube?
How is the accuracy looking at target velocities?
Keep on pushing the envelope!
APB

 

[Dan B]

Kirby...I just saw an ad last week for an in-line muzzleloader (can't remember the manufacturer) that is using a front ignition system. The removeable breech plug has a tube that extends forward and the powder is dumped into the barrel and surrounds the tube. Reminded me of what you are working on.

 

[Fiftydriver]

Same idea but without the case, alot easier to make cases for /ubbthreads/images/graemlins/grin.gif!!

Kirby Allen(50)

 

[Guest]

Hi Kirby
Any further progress to report?
APB

 

[Fiftydriver]

APB,

Well my friend, since I got back from the Wolf hunt in Canada, the calmest day we have had produced 25 mph winds!!! That has been nonstop going on three weeks now. Getting very old.

As such range testing has been on hold until the winds calm down some. Good news is I am getting work done on customers rifles since I can not test my own /ubbthreads/images/graemlins/grin.gif!!

Will post when I get some data soon.

Kirby Allen(50)

 

[Guest]

Kirby
thanks for the reply. Curious as to your progress obviously!
Shame about the weather over there.
I have been at the range a little myself this last week revisiting loads for my rabbit gun. Different batch of 205M would not shoot and also powder lot changed.
Went through the OCW again and am trying the russian made PMC primers which seem very good.
Wind not too bad here but mirage worst to deal with.
Look forward to your next report.
APB

 

[Fiftydriver]

Hoping to get some more bullets in the air with the 224 AM this weekend if things work out with the weather. As long as it will calm down to 20 mph winds or less I can at least do some chrono testing.

Tomorrow we have a high wind warning all day, 70 mph winds possible throughout the day. Good day to be in the shop working!!!

Kirby Allen(50)