Ackley question

Gibbs or another, lesser known, inventor. Take it to a 'smith, have the chamber cast or try to get a measurement from a fired case.
.Just noticed you're in Denver; take it to the gunsmithing school (forget the name at the moment) let a student get the practice and practical experience.
 
Milehighshooter said:
That is what I am thinking. Factory ammo closes like, well, factory ammo, no resistance at all. My fire forming loads DID close hard, and seemed to have formed properly. The stuff I did myself was WW +P brass and seems to have worked as intended. I'll have to see what they do with the Lee AI dies. Might end up having to just hand load for forming, possibly send off a fired case to get dies made.
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Milehighshooter
I think you just hit the nail on the head my friend. It does seem a headspacing issue but by handloading and having the projectile into the lands you avoid the case moving forward on firing. You can still use your dies just adjust differently until you get your new one. Lee do brilliant custom dies thats who did mine.
Cheers mate
Bob
 
Spooksar said:
It may be a Gibb chamber. Gibbs pushed the shoulder forward a bit
Click to expand...
Spooksar
So did Newton.
My 25 wildcat pushes the shoulder forward to shorten the neck from .311 to .257. Blew fhe case out almost straight and a 35 degree shoulder angle.
Fortunately i didn't have to worry about datum lines or seating bullets into the lands. I used the rimmed 303 british as my base case so no issues.
20200314_103228.jpg

My 25 wildcat
Cheers mate Bob
 
Wow! Thread from the dead haha!

Bob what I finally ended up doing was using 7x57 brass so when I necked down it left a donut in the neck. I adjusted the die to neck down just until I could force the bolt closed to hold everything in nm place. Made 30 or cases that way, and it worked great. Its my dad's rifle, and he used it last year for his final hunt ever (he's still alive but "retired" on a very limited buck tag, and scored a 175" mule deer).
 
Milehighshooter said:
Wow! Thread from the dead haha!

Bob what I finally ended up doing was using 7x57 brass so when I necked down it left a donut in the neck. I adjusted the die to neck down just until I could force the bolt closed to hold everything in nm place. Made 30 or cases that way, and it worked great. Its my dad's rifle, and he used it last year for his final hunt ever (he's still alive but "retired" on a very limited buck tag, and scored a 175" mule deer).
Click to expand...
Milehighshooter
Sorry to hear your dad had to retire from hunting but sounds like he got a good buck to go out on.
Sound like you ended up doing what I do, partially size the neck and form.
Do you still use the rifle and what loads do you use.
PM me with your loads if you prefer.
Cheers mate Bob
 
Photo of said Dad, deer, rifle.

This was just in November. Not sure I'll use the gun again, I may, seeing as this was a giant pain in my rear getting loaded.

I'll try and find the load, not sure the charge at the moment but I know it was 4831sc and Barnes 100gr ttsx
 
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I'll try and locate the charge, but at the moment im a few homebrew lagers into it! Im pretty sure it was in the upper 40's.
 
Milehighshooter said:
Photo of said Dad, deer, rifle.

This was just in November. Not sure I'll use the gun again, I may, seeing as this was a giant pain in my rear getting loaded.

I'll try and find the load, not sure the charge at the moment but I know it was 4831sc and Barnes 100gr ttsx
Click to expand...
Milehighshooter
If'n it was 4831sc pm me if you still use the rifle and I'll give you a load I use in mine and my son's that will amaze you with velocity.
Bob
 
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I think your getting ahead of yourself, when fireforming a basic case to a Ackley you always deal with the created headspace, the idea of fireforming is to address that headspace by fireforming the case to fit the chamber...Your center case did not fully fireform, once you get a proper fireform you no longer have headspace, setting the barrel back is old stuff in some cases depending on caliber in question...reload that center case with 8 to 10 grs. of Unique, a piece of Kleenex, some cornmeal and a wax topping, point the rifle up and shoot it, you should get a fully formed case this time, all your doing is changing the shoulder..

Fireing a std 257 Roberts in your chamber could indicate the std 257 had headspace however, and that would in fact require a rechamber turn back in some cases but if you can get the gun to fireform cases it won't be needed, may require custom dies or recut dies..
I see you have some fireformed cases, so obviously you did something right on them??
If you intend to use bullets then use a warm load, you need to blow the case back and the shoulder forward..I use warm handloads, that I hunt with in my 8mm/06 Ackley and fireform when I hunt, sometimes rockchucks or jack rabbits and I shoot 100 rounds or more in a day..I reload those cases for elk and deer..

You might try pointing the gun up to get a full shoulder blow out..
 
Here is what is going on.
Originally, the rifle started in 257 Roberts, correct?
That original 257 chamber was made to a set of Sammie gauges go no go.

Commercial ammunition makers must produce ammunition that is right at go gauge or slightly less than go gauge for chambering reliability as we all like it when we can close the bolt on a commercially produced "factory" virgin never fired round.

So let's just say for arguments sake that your headspace dimension over sammi 257 Roberts go gage is .120 and the headspace dimension over your commercial 257 Roberts ammo is .115 to .117, .003 to .005 thousanths under the go of .120 is pretty typical.

Ok so the commercially loaded round runs .003 to .005 under.
Then along comes a guy who wants the improved chamber.
The chamber gets reamed so the new chamber shoulders clean up the old, at this point the original .120 headspace dimension probably looks more like .105/.110 so .015 .010 under go gauge.
Ok, so you chamber the commercially loaded round that's already .005 under, combine that with a chamber depth that's .010 to .015 on the deep side and you get a headspace dimension over that round that measures .100 a full .020 under the gauge. And so you fire that round, The firing pin drives the entire cartridge to the front of the chamber where ignition occurs, the case forms adhering to the chamber walls, the remaining pressure backs the primer out of its pocket until that movement rearward is stopped by the bolt face. The amount of primer sticking out of the center case in your photo line up reveals the exact dimension that cartridge is under size vs chamber depth.
This is why when you went to 7x57 brass with ghost shoulders to hold headspace while firing it worked fine, but in theory you're no longer dealing with an Ackley chamber but more of a Gibbs approach to an improved chamber.
One other thing, it's easy to see in your photos the brass shows where the old chamber leaves and the new chamber and shoulder pick up, see the signature in the brass. Also the shoulder length dimension on a 257 Roberts and a 257 Roberts Ackley improved are the same. For the Ackley the shoulder angle, shoulder diameter, and overall taper is what is changed for the Ackley, NOT the dimension from head to shoulder, clearly from your photos it is easy to see the head to shoulder dimension is longer, how much longer is the question, well that amount is expressed once again by the amount of primer you have protruding from the one case. Obviously you've found a fix by ghosting shoulders on 7x57 brass. The right fix is set the barrel back to go gage then .005 tighter than go so essentially your go gauge becomes a no go by .005 then you can improve commercially loaded ammo to the improved version...., no friggin around,....just done...boom...reload it. Life goes on...no drama.
 
Stuart Satterlee said:
Here is what is going on.
Originally, the rifle started in 257 Roberts, correct?
That original 257 chamber was made to a set of Sammie gauges go no go.

Commercial ammunition makers must produce ammunition that is right at go gauge or slightly less than go gauge for chambering reliability as we all like it when we can close the bolt on a commercially produced "factory" virgin never fired round.

So let's just say for arguments sake that your headspace dimension over sammi 257 Roberts go gage is .120 and the headspace dimension over your commercial 257 Roberts ammo is .115 to .117, .003 to .005 thousanths under the go of .120 is pretty typical.

Ok so the commercially loaded round runs .003 to .005 under.
Then along comes a guy who wants the improved chamber.
The chamber gets reamed so the new chamber shoulders clean up the old, at this point the original .120 headspace dimension probably looks more like .105/.110 so .015 .010 under go gauge.
Ok, so you chamber the commercially loaded round that's already .005 under, combine that with a chamber depth that's .010 to .015 on the deep side and you get a headspace dimension over that round that measures .100 a full .020 under the gauge. And so you fire that round, The firing pin drives the entire cartridge to the front of the chamber where ignition occurs, the case forms adhering to the chamber walls, the remaining pressure backs the primer out of its pocket until that movement rearward is stopped by the bolt face. The amount of primer sticking out of the center case in your photo line up reveals the exact dimension that cartridge is under size vs chamber depth.
This is why when you went to 7x57 brass with ghost shoulders to hold headspace while firing it worked fine, but in theory you're no longer dealing with an Ackley chamber but more of a Gibbs approach to an improved chamber.
One other thing, it's easy to see in your photos the brass shows where the old chamber leaves and the new chamber and shoulder pick up, see the signature in the brass. Also the shoulder length dimension on a 257 Roberts and a 257 Roberts Ackley improved are the same. For the Ackley the shoulder angle, shoulder diameter, and overall taper is what is changed for the Ackley, NOT the dimension from head to shoulder, clearly from your photos it is easy to see the head to shoulder dimension is longer, how much longer is the question, well that amount is expressed once again by the amount of primer you have protruding from the one case. Obviously you've found a fix by ghosting shoulders on 7x57 brass. The right fix is set the barrel back to go gage then .005 tighter than go so essentially your go gauge becomes a no go by .005 then you can improve commercially loaded ammo to the improved version...., no friggin around,....just done...boom...reload it. Life goes on...no drama.
Click to expand...

Very true a good gunsmith will always turn the barrel back one full turn and rechamber, I’ve had a few Ackely improved cartridges done and my gunsmith always turns the barrel one turn then rechambers, I’ve never had a problem with any of my improved cartridges.
 
Milehighshooter said:
Last year when I fired this gun for the first time, I got mostly good results. But I also had 3 cases totally rupture just above the head.

Today I went to the range, with some factory ammo, as well as hand loads (both in standard configuration) but with the bullets seated VERY long and into the lands, or close to it.

My question, is my suspicion correct that some garage hack smith just ran an Ackley reamer into the chamber, without setting the barrel back?

View attachment 240602 View attachment 240603 View attachment 240604
Click to expand...
@Milehighshooter
Definitely looks like it. Once your sales are formed correctly just neck size and avoid bumping the shoulder back until they become hard to chamber.
Bob
 
Milehighshooter said:
Pictures go:
Factory 257R
Factory 257R fired in my gun
Handloaded 257R with bullets jammed into the lands.

The longer base to shoulder, as well as the primer not being blown out, are my areas of concern
Click to expand...
@Milehighshooter
The longer base to shoulder just means a different fire forming process as you have discovered.
If the loaded round is with the bullet jammed into the land you may want to look at getting the rifle long throated if the magazine length allows. This would allow you to use the case to the full potential.
20200314_103228.jpg

As you can see by the canulre on the 25 cal 117 grain SST it is seated well out and is still about 40 thou off the lands. This allows the full use of the case. Could be well worth thinking about.
Bob
 
450 Dakota said:
It might be a little on the loose side but the real question is how does it do once cases are fire formed. If your splitting cases after a couple of firings then it definately has too much headspace. Looking at the pictures the factory firing doesn't appear to have a crisp shoulder so the case moved some and that is why the primer is extended. The case you seated long has a crisper shoulder. That's why you seat bullets long to fireform on rimless case. If it was a belted case not as critical because the belt doesn't allow much movement. Nosler manual says to seat bullets long and use a light to medium charge of a faster powder. The shoulder is going to move or grow on an ackley improvement as that is how you increase the shoulder angle and capacity as the neck shoulder line can't move. I would load some to just get the bullet to the rifling if it will reach. You should be able to pull the bullets out some on the factory shells if you have the equipment. You can decrease the charge a couple grains if you want. I shoot a 257 Roberts, 35 Whelen and 375 H&H all Ackley Improved. Hope this helps some.
Click to expand...
@450 Dakota
The placement of the belt on some magnum cases can vary by 10 thou or more and it is advisable that you reload them as if they were a standard rimless case and size ed according to the datum line.
Weatherby cases are the exception as they are only made by Norma as a rule.
Bob
 
I have chambered several Ackley rifles. I chamber so the bolt is very snug on the factory unfired cases. Never had a problem.

Now various cases are various lengths among manufacturers and lot numbers. I always started with 100 new cases of the same manufacturer and lot number. And I sorted by length using a gauge I make using the finishing reamer. Chamber so the bolt is snug on the shortest case.

Very important with belted cases, I have seen belt thickness from 0.211 inch all the way up to 0.218 inch. Chamber using a go gauge and you are already in trouble.

375 H&H below prior to fire forming in a 375 Ackley chamber. Note the belt thickness, 0.218"

This is W-W brass. Nice belt thickness. A good number of the Weatherby cases I have checked run about 0.212". Guess what happens when you chamber using the standard 0.220" go gauge.

However, to continue the discussion, back when I was building the heavies on belted brass I chambered somewhat loose. You want all manufacturers cartridges to fit that chamber, especially when your run out of R-P cartridges and your PH has some old unknow cartridges under the seat of the land Rover. Bench rest and accuracy rifles, different story.

Jd8Eton.jpg
 
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Read Ackley's books. He recommended chambering at least 0.004" short. But with some cases this is not enough. This is why I selected new brass and chambered for a snug bolt closure.

Belted cases, yep to the above about chambering to the shoulder. Guess why a lot of fired belted cases have the bulge just above the belt?? A combination of a too large chamber and too much headspace on the belt, resulting from chambering with the go gauge.

Around 120 reamers and chamber tooling in the big Kennedy Chest. One day I will have to count and make a list. Pilot bushings in the top tray, in sets of 0.0002" increments for the bore sizes. About 20 Ackleys. So I have chambered a few barrels over the years!.

rMRKlC6.jpg
 
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