Question for Mr Timm

B

BEN243

New member
This question was asked over on "24HCF" ... I was just wondering what your feelings were on the subject since you built one.

Does Ackley Improving the .243 eliminate the problem with pressure spikes for 100 grain bullets (by changing shoulder angle) or isn't there enough data on the .243 AI to know
for sure ?

Ben
 

Hey Ben,

Ain't no cowboy named "mr. Timm" here. I'm Steve
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I haven't been over at 24HCF for several months, although I did made a single brief post there yesterday. Sometimes I lurk a bit, but there's too much hatred there for this Catholic boy who volunteers many hundreds of hours a year to helping folks.

To interesting stuff and nice things:

I've owned three .243 Winchester Ackley Improved rifles over the years and goodness knows how many regular .243 Winchesters.

To be totally honest with you, the .243 Winchester has always been a rather nice cartridge to work with and it's given me no grief. The load data seemed to progress in a fairly linear fashion and, like any other round, occasionally got squirley as maximum was reached. One observation I will make is that I always had trouble getting small velocity extreme spreads with the .243 Regular.

The .243 Ackley seems to me to be more of a really good thing. The load data develops nicely and the extreme spreads (and resulting SC) are MUCH smaller than the parent round.

The smaller ES/SD exhibited by the .243 Ackley would eliminate vertical grouping at longer ranges and make first-shot kills more certain.

Same comments, IN SPADES, when discussing the .223 Remington versus the .223 Ackley Improved.

There are some cartridges that exhibit this tightES/SD tendency and they aren't all Ackleys. For sinstance, I cannot tell you how many twenty-shot aggregates I've fired with the 210-grain Partition in the .338-06 and gotten an extremem spread of 10 or 12 fps. And once I shot ten rounds with the same load combination with an extreme spread of ZERO fps.

I've got a cowboy mind, but I've always thought of the low extreme spread phenomen as belonging to rounds or load combinations that are "better balanced" than most.

Anyway, in answer to your question, I've always found the .243 Ackely Improved to be a total sweetheart of a cartridge. I love it.

All the best,

Steve
 
Hey Steve. I talked to a gunsmith in Bend about setting back the barrel on my 243 and recutting with a shorter throat designed for 75gr bullet's. He told me it would be expensive as I would need to have a special reamer made with a short throat. So I've been thinking about the 243 ACK myself for a long time. Do you know if it has a shorter throat standard? Also I've heard dies are to hard to recut with new reamer's. You know anything about that? I was thinking if I did this, get the chamber and my die both cut with the same reamer.
 
What kind of dies are you going to re-cut? most loading dies are surface hardened for long life an will likely kill any reamer not made of carbide.
Ive made custom dies by using redding comp dies because the sleeve is made ov very soft steel. Using the same reamer to cut your chamber and redding comp dies IMHO will make a more accurate rifle.

Here's a set I built for a 204 apache (6.8spc necked down to 204 with the shoulders blown out to 30*).
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Runnout was increadibly small when doing it this way
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If you need a full length loading sizing die you could purchase a "die blank" and use a regular reamer on it.
112.jpg
 
I ordered the chamber reamer and re-size reamer from JGS. Photobucket gave me a heck of a virus last night so I aint going back there on this puter to dig out more photo's for you.
 


Originally Posted By: Don FischerHey Steve. I talked to a gunsmith in Bend about setting back the barrel on my 243 and recutting with a shorter throat designed for 75gr bullet's. He told me it would be expensive as I would need to have a special reamer made with a short throat. So I've been thinking about the 243 ACK myself for a long time. Do you know if it has a shorter throat standard? Also I've heard dies are to hard to recut with new reamer's. You know anything about that? I was thinking if I did this, get the chamber and my die both cut with the same reamer.

Friend Don,

I don't believe that there is any standard. The throating is probably pretty much what the gunsmith orders.

I've had two throatings in the .243 Ackley. My first barrel was a Schneider and I had it throated short, basically for a 70-grain Nosler Ballistic seated nicely in the neck. The barrel was a slow twist, 1-12", and I was not concerned with 100s, although it shot the 95 BT decently.

Later barrels were always chambered for the 95 Ballistic seated to the base of the neck. This makes the 70s and lighter bullets jump, but if the throat OD is tight the accuracy is normally quite good.

The problem is that in 6mm, the bullet lengths are so different that the ogives cannot be caught by a single throating. This leaves you with the choice of either throating for the light bullets (55-70) and deep-seating the 95-100s .... or .... throating properly for the 95-100 grain bullets and letting the lighter bullets jump to the throat.

If the rifle is to be a dedicated predator gun, the choice is simple, throat it short. My problem has always been that I am much more a big game hunter than anything, so I've found happiness in throating for the 95-grain Ballistic.

By the way, the 95-grain Ballistic was the brain-child of Gail Root, who was without a doubt one of the finest ballisticians who ever worked in the industry. Gail was a .243 Winchester nut (even on HUGE elk) and the 95-grainer was his baby for big game. Gail also designed the 70BT for varmints and predators. He loved that bullet, as well.

The 55 Ballistic was designed by Gail; he referred to it as a "ball with a point on it" and always wished he had about five more grains of weight to work with, so he could give it a longer bearing surface. In the end, though it gave him fits, he was delighted with how the 55 turned out.

Hope this helps,

Your friend Steve
 
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