7mm Allen Mag test rifle finished.....

[ricka0]

[ QUOTE ]
<font color="purple"> Ok If anyone can shoot a hole through this theory, I welcome that shot.
This is more or less an [sic] emperical process based on accurate barrel
life in several calibers as reported to me by lots of folks plus a
couple dozen barrels I've worn out. All I did was study the data and
determine what math would give a best-fit formula. And if someone has
a better method, I'd like to know what it is.
</font>

[/ QUOTE ]


I have a MS in Applied math. Here is my review:

In scientific parlance, you don't have a theory - perhaps a conjecture. In colloquial terms, you can use theory.

&gt;&gt;All I did was study the data and determine what math would give a best-fit formula.

How did you measure best fit? I can easily get an exact fit to your data using splines or high order polynomials. Would a high order poly be a better predictor?; no - they oscillate wildly to fit thru each data point. How about a spline? Nope, splines can't be used to extrapolate data.

You have answered the problem yourself.

[ QUOTE ]
<font color="purple">
But this empirical formula has limits. The old .22 rimfire long rifle
burning 1 grain of powder in a bore whose capacity is 24 grains would
calculate to give a barrel life of some 1,728,000 rounds.
</font>

[/ QUOTE ]

IE, you can't extrapolate.

 

[Fiftydriver]

Alremkin,

No solid details yet on the 338 Allen Mag. I will tell you the reamer is ordered and finalized. Also, the test receiver is ordered as well as stock and barrel. The test rifle will be a 55 to 60 lb heavy rifle designed specifically for extreme range shooting.

That said, I have reseached the possibilities of a light rifle in the 338 Allen Mag and will tell you that there is a receiver that will work with this round that weighs in at only 48 oz. Now this is not an ultralight receiver but for the power level of this wildcat, this is a pretty slim receiver.

I suspect that it would be very possible to build a 12 to 14 lb rifle in the 338 Allen Mag with a 30" #7, heavy fluted barrel using this receiver and a McMillan stock.

Whatever design the 338 Allen Mag is, I will say I am trying to get Richard Graves to get tooled up for a 400-425 gr .375" bullet to use on the same case configuration.

What would you think about a 375 Allen Mag?? /ubbthreads/images/graemlins/grin.gif

Sorry I am not being very kind. Details will be coming by the end of the summer. In fact bullets will be in the air by around October so you should get the entire scoop before then I promise you.

Good Shooting!!

Kirby Allen(50)

 

[Buffalobob]

Big Bore

I wrote up a long post agreeing with you but then I remembered Kirby has asked for "peace". So I have erased it.

 

[Fiftydriver]

Buffalobob,

Thanks for your restraint. If anyone has anything to bring up for or against the Allen Mags I will freely discuss their opinions, my reasonings and design features and we can all keep our blood pressure where it needs to be.

Hell, their just rifle rounds.

I do need to make a correction to the componants list for the 7mm Allen Mag test rifle. I am using a Shilen 27" Match stailness barrel, not a Lilja.

I apologize for this. I use so many Liljas its hard to type anything else /ubbthreads/images/graemlins/grin.gif!! Anyway, the 30", 1-7 liljas are coming but I wanted to throw some bullets now so I ordered in a Shilen 1-9 from MidwayUSA. Just wanted to clear that up.

This barrel is polishing up well except for the bottom land at the muzzle, still fouling pretty heavily, every other part of the bore is great but this one land still fouls for about an inch into the bore.

Anway, I had to range test some rifles so I could ship them and decided to drop three through the 7mm Allen Mag on paper and see what this light contoured barrel would do with virgin fireforming loads.

The first two shot cut each other in half and the third landed slightly higher for a total group ctc measurement of 0.626". Nothing spectacular but still, 0.626" ctc for three shots with virgin brass that undergoes a major transformation upon fireforming I feel this is very good. Bullet run outs were also in the .0004 to 0.006 range for these three rounds so that is pretty good considering that. I suspect with straight formed brass, this round will average well under my 1/2moa requirement.

It seems that this round is following suit with the shoulder crush fit theory and resulting in very accurate fireforming performance, totally usible for field use.

Just correcting my mistake mainly!!

Hope to get some serious load data developed by the end of this weekend.

Kirby Allen(50)

 

[Mysticplayer]

Kirby, congrats on a growing number of performance wildcat cartridges. Ah horsepower...

Great to hear that Richard is also coming up with cutting edge bullets. That will drive development of LR shooting to a new level.

Question for you on the WCC872. Where to do you buy it from and are there more then one lot? I am aware that this is surplus pulldown from military cannon fodder. Well priced but always concerned that some could be good and another batch - garbage.

As to barrel life, sort of like asking about gas mileage before stomping on a big block drag racer. Performance costs money. How many barrels do you want to buy?

Loving it...

Jerry

 

[Fiftydriver]

Jerry,

I get my WC872 from Jeff Bartlett at www.gibrass.com.

I do not know if there are different lots of powder, I am sure there is but I have only gotten one from Jeff.

I will say I have been burned in the past with poor quality surplus powder and since have not even bothered with the stuff. A fellow poster e-mailed me when I was loading for the 257 Allen Mag and told me about Jeff so I e-mailed him and he said his powder was fresh and clean and would perform extremely well in all my Allen Mags to date.

I ordered in 32 lbs and Jeff was true to his word. Great powder and came to $188 including Haz frieght and normal shipping costs, at $5.80 a lbs I can certainly not find any fault with this powder.

Good SHooting!!

Kirby Allen(50)

 

[7Rumloader]

Jerry the WC872 powder is listed as new powder and the WC760 is pulldown.
I am working with the WC872 in my 7RUM and have been satisfied so far.
jwp475 is also working with it in the 300RUM with good results.
Jeff at gibrass has good customer service and fast shipping. My powder was here in 3 days.

 

[Derek M.]

Hey Kirby, I was asking about magazine capacity, not case capacity. You and I had already talked about case capacity.

I was curious about how many rounds the rifle will hold. /ubbthreads/images/graemlins/smirk.gif

 

[reed mosser]

i have pretty much the same thing with a 30-338 laupa mag with a 35 degree shouder. In my 30 inch tube I shoot 98 to 100 grains of IMR 7828 to shoot the 150 hornadys at between 3700 and 3800 FPS. I don't know what grain bullets you are going to shoot but it should be similar to the 30. With 120 GR bullets the 9 twist I bet it will shoot at around 4000 FPS, good under 700 yard hog load. Good luck , its good to see someone pushing ballistics to the maxium. Reed

 

[Fiftydriver]

Derek,

Depends on if its a single shot or not /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif!!!

The H-S Precision DM system has a 3 round capacity.

Kirby Allen(50)

 

[Fiftydriver]

Reed Mosser,

Yes I believe they will be similiar in performance. We are looking to get 3900 fps with the 140 gr class bullets on the light end and 3200 fps with the 200 gr ULD RBBT on the top end. Lands right around your numbers.

Thanks for the kind words.

Kirby Allen(50)

 

[davewilson]

let's see, .2842 with a + or -.0000. i understand the dimension, i just never had the kahoonas to give that kind of tolerance to a machinist and expect him to buy me a beer after the softball game!

 

[daveosok]

I sure wouldnt buy you a beer with that tolerence. +/-.0000 expect 500 an hour to meet these standards lol.

 

[davewilson]

hey, that's not my tolerance,that's what kirby said, a few posts back, that he wants on his throat dimension! how bout one of those billy beers,would ya buy me one of those?