280 to 280 AI

[crabo]

Can this be done with just a reamer, or does the barrel need to be set back to make it work? SS Remington 700

Who would be good to rent a reamer from?

Thanks

[swheeler]

To make it work like Ackley intended the barrel needs to be set back

[crabo]

That's what I wanted to know. What's the general consensus? Worth it?

[swheeler]

If I was to do another AI cartridge 280 would probably be the one, K Jarrett is rather fond of the round.

[B R Shooter]

To make it work like an Ackley, where the case must crush at the shoulder to fireform a factory loaded case, then setting it back is better. If you approach this as fireforming a wildcat cartridge, then you could run the reamer in to the shoulder, and fireform. No set back needed.

People get so worked up over this. Simply fireforming with a bullet seated long with a good case grip, and you have a formed case. That .004" longer case will never be an issue in the reloading dies.

The most common example of this nowadays is the Dasher case. We are talking a full .100" for shoulder move, not a mere .004".

[nanuk]

or start with a 7mm08 barrel to rechamber... no setback needed

[swheeler]

To make it work like an Ackley, where the case must crush at the shoulder to fireform a factory loaded case, then setting it back is better. If you approach this as fireforming a wildcat cartridge, then you could run the reamer in to the shoulder, and fireform. No set back needed.

People get so worked up over this. Simply fireforming with a bullet seated long with a good case grip, and you have a formed case. That .004" longer case will never be an issue in the reloading dies.

The most common example of this nowadays is the Dasher case. We are talking a full .100" for shoulder move, not a mere .004".

BRS:Only problem with that anolgy is that the head to shoulder gets .107"longer and the neck actually lengthens by .017"(using the now SAAMI spec Nosler submitted 280AI) so headspace datum line may only move difference between go and no go but to clean up the chamber the very least headspace will now become .017" but more likely .019-.020, very few factory rifles are set min hs. I would rather have one set up just like PO intended, but being a handloader I can make either chamber work, ones a wildcat and the other is an Ackley improved chamber. my .02

[B R Shooter]

I have done this same routine on 257AK cases and not had the excessive stretch you are referring to. But maybe the 280 is different. Dasher cases stay fairly close to length, but there are many different reamers for them out there, case length must work with the chamber.

[swheeler]

Since the new neck is longer but the cartridge/chamber length is the same, if you just ream to touch the .375" datum line(maintain existing headspace)then you have .017"(at the very least) at the base of the neck left the original 17*30' shoulder angle instead of the new desired 40*. To clean that up you have to ream to depth of original shoulder/neck junction position, which remember is .017 deeper than new shoulder/neck, you now created .017" headspace. The last I did was in fact 257Rob AI, great little cartridge, and so for the 7x57AI. I'm probably on the opposite side of the fence concerning what most say about the 06AI, I like it. The 450 Watts AI I couldn't tell you because I'm not up to finding out what it is capable of, 100 grs of powder and a 500 gr bullet appeared to be mild from reading brass/extraction signs, but I am sure it would kill a dear or elk just fine.

[Doc_Stihl]

I've read from several sources that the 280AI has just about the best performance increase over factory of any cartridge.

[swheeler]

OK Doc you're talking me into it, stop that now!:)

[dk17hmr]

Do it properly and set the barrel back....or better yet buy a new barrel blank. Hard telling where it might end up might as well make it work with ammo you can buy at the store.

280 AI is high on my list. I love my 280. When I do build a 280 AI I will probably set it up as a heavy long range rifle.

[izzyjoe]

I've been searching for a cheap 700, or 70 action to build a 280AI. I run across one few months back, but I'd already spent my funds on something else. I'm thinking about a 26" barrel with a 1-9 twist to stabilize the heavy's. One of these days!

[leftiye]

I picked up a Rem 700 7mm Rem. mag on Gunbroker for about 400. Gonna make a tight twist 264 mag out of it. Fills the same bill for me. I've got a 280, have liked them since I was in high school (early 60s). My first custom rifle was a 6mm AI which I designed the ctg myself, then found our that P.O. had already done. I've got nuthin' agin' wildcat or improved cartridges. But if you want a magnum, get one.

[B R Shooter]

Since the new neck is longer but the cartridge/chamber length is the same, if you just ream to touch the .375" datum line(maintain existing headspace)then you have .017"(at the very least) at the base of the neck left the original 17*30' shoulder angle instead of the new desired 40*. To clean that up you have to ream to depth of original shoulder/neck junction position, which remember is .017 deeper than new shoulder/neck, you now created .017" headspace. The last I did was in fact 257Rob AI, great little cartridge, and so for the 7x57AI. I'm probably on the opposite side of the fence concerning what most say about the 06AI, I like it. The 450 Watts AI I couldn't tell you because I'm not up to finding out what it is capable of, 100 grs of powder and a 500 gr bullet appeared to be mild from reading brass/extraction signs, but I am sure it would kill a dear or elk just fine.

Great numbers, but done right, you only have .004" difference to deal with. That is the difference between a parent case go gauge and an Ackley go gauge. And that .004" figure is as assumption of the brass thickness. I have easily felt the difference between pieces of brass when fireforming which is the brass thickness differences closing the bolt. Never had cases stretch out as you say. To each his own. There are many things to deal with when forming "true" wildcat cartridges. The Ackley is a point and click wildcat that is intended as a no-brainer.

[swheeler]

Uh huh;) cheeeeeeese

[leftiye]

Even taking wheeler's specs, the non- set- back chamber would be useable, and easily doable. A little taper in the chamber which you might or might not size down (or you could open the size die a bit) each firing woudn't seem to be much of a problem. Especially if you neck only sized.

[swheeler]

Even taking wheeler's specs, the non- set- back chamber would be useable, and easily doable. A little taper in the chamber which you might or might not size down (or you could open the size die a bit) each firing woudn't seem to be much of a problem. Especially if you neck only sized.

I guess anything is "doable" the point I was trying to get across was without reaming to past existing headspace datum line(shoulder as BRS calls it?) you have NOT cleaned up the old chamber, at the very base of the neck you still have the original shoulder angle, now it may be small distance but its still there. You have created a wilcat that has a chamber with 2 shoulder angles, 40* most of the ways and the last bit before the neck/shoulder junction is still the original angle of parent cartridge. Then he says I reamed it this way and don't get any of the excess stretching you're talking about DUH, you never finished reaming the Ackley improved chamber! Ever wonder why Ackley him self set back one thread to ream?? I'd draw a picture BUT I DON'T THINK IT WOULD HELP! Crabo you want one have it done right, you won't be sorry;)

[crabo]

i've always done things right when I do them. I have a SS 700 with a synthetic stock. I always hated the stock so I put a B&C Medalist on it. I have a 30+ year old Vari-X III on it and was thinking about a new scope and a rechamber.

I would always rather have a tricked out, great shooting gun, than 2 or 3 stock guns.

[swheeler]

i've always done things right when I do them. I have a SS 700 with a synthetic stock. I always hated the stock so I put a B&C Medalist on it. I have a 30+ year old Vari-X III on it and was thinking about a new scope and a rechamber.

I would always rather have a tricked out, great shooting gun, than 2 or 3 stock guns.

A man after my own heart, good for you!

[Newtire]

A man after my own heart, good for you!Hi, I had the thought of trying out the .280 Improved. My trouble is that I have a .280 Handi-Rifle with a nice 26" barrel. I see I can get a 7mm-08 barrel for this thing but then those are only 22" long. So, the gain I got from the "Ackley-ization" would just be lost by the shorter tube. I can't set this barrel back as it's a single shot.

I am kind of getting the idea that I might be able to ream out this existing chamber but then would have to fireform the .280 cases to stretch them out to fit the overly long chamber and then just neck size my brass so that I won't set the shoulder back again. Is this the case? I have already successfully made up a bunch of .280 cases by creating a false shoulder (neck sizing the .30-06 brass in a Standard .280 die just enough to allow the case to fit). I fired these using a "start load" with a J-word and they turned out great. I'm thinking that this might be possible to do but wouldn't want to push a good thing too far. If I only end up gaining a hundred FPS or so, I would rather just leave it a standard .280.

I was thinking of using some 280 Nosler AI cases maybe so as to still have a neck left when I was all done.

So, would this be kind of a "Stretch-.280 AI" in the end? I have a .30-30 AI and a .257 AI and they are both really great cartridges.

Sorry so long of a post but seems this alteration takes a little more explaining since I can't turn the barrel back. In the end, this might just be more of a PITA than it would be worth! Any thoughts?

[swheeler]

You can form cases by creating a false shoulder, that way you insure that the case is stretching in the right place, the shoulder/body and not back near the head. That is why I don't use the jamb the bullet into the lands method for something like this, primer expolosion can move the case forward by seating the bullet deeper, then all the stretching is rearward. You would have to take the nosler 280AI brass and neck it up to create a false shoulder, then fireform and neck size only for the 280AI grande wildcat you made. The problem with a chamber like this is down the road someone else may end up with the rifle, could turn out bad.

[Newtire]

You would have to take the nosler 280AI brass and neck it up to create a false shoulder, then fireform and neck size only for the 280AI grande wildcat you made. The problem with a chamber like this is down the road someone else may end up with the rifle, could turn out bad.I got thinking about the next person down the line getting ahold of this weird chambering like you said and decided that this would not be a good thing to do. Thanks for the great advice!

[leftiye]

I guess anything is "doable" the point I was trying to get across was without reaming to past existing headspace datum line(shoulder as BRS calls it?) you have NOT cleaned up the old chamber, at the very base of the neck you still have the original shoulder angle, now it may be small distance but its still there. You have created a wilcat that has a chamber with 2 shoulder angles, 40* most of the ways and the last bit before the neck/shoulder junction is still the original angle of parent cartridge. Then he says I reamed it this way and don't get any of the excess stretching you're talking about DUH, you never finished reaming the Ackley improved chamber! Ever wonder why Ackley him self set back one thread to ream?? I'd draw a picture BUT I DON'T THINK IT WOULD HELP! Crabo you want one have it done right, you won't be sorry;)

Nobody is arguing in favor of not setting back the shoulder. Do you have a need that people think like you do, or is it just that people should not disagree with you? By all means - "do it right" - unless as in the case of the break action, you can't. Then it will probly would function just as well (or better) with .017" of 30 degree neck left behind. You would think Ackley would have set the shoulder .017" further forward rather than setting barrels back.

[Newtire]

You would think Ackley would have set the shoulder .017" further forward rather than setting barrels back.Didn't he do that so that you could shoot a factory cartridge in it to turn it into his Ackley version?

[swheeler]

Didn't he do that so that you could shoot a factory cartridge in it to turn it into his Ackley version?


Voila! Forget your AI handloads at home when you're a 1000 miles away on a once in a lifetime elk hunt, get by with a box of factory ammo. With a correctly reamed chamber(just like the OP Crabo asked about;)) you can safely shoot those factory rounds without having a head seperation, putting an eye out or injuring your guide.:)

[leftiye]

Didn't he do that so that you could shoot a factory cartridge in it to turn it into his Ackley version?

Like you couldn't safely fireform the shoulder seventeen THOU further forward? If you couldn't then you would lose many of your cases as it is also.

[GabbyM]

I could of set back a couple rifle barrels in half the time some of you have spent here typing arguments on why we don't need to do all that work. While we're at it and setting head space anyway. We could square up the Remington receiver face.

[B R Shooter]

You folks with your .017" plus or minus, don't make a lick of sense. With the shoulder angle aside, there is only .004" difference in headspace between a standard parent case and an Ackley chamber, .004" SHORT!

An excerpt from Manson Reamers:

Because the cartridge must be held secu
rely during fireforming, the dimension
between the breech face and the neck/shoul
der junction becomes critical. P.O.
Ackley, who popularized improved calibers,
recommended that this dimension be
reduced
by .004”/.006” from the standard minimum for a particular caliber.


Reducing this dimension compensates for
cartridge tolerances and ensures that
fireforming can be done safely.

This shorter chamber provides a crush of the brass. Some brass is thicker than others, and there is actually a .004" to .006" variance for this. You can talk all you want about .017" of something, but the bottom line is there is .004" of difference.

I started this out by saying, if you chambered UP TO the neck/shoulder junction, NOT PAST IT NOT BEFORE IT, you could fireform brass safely by standard methods of fireforming wildcat cases. This ca be done by a hard bullet jamb, a false shoulder, etc, either method works as long as you have a tight brass fit in your chamber. You need this so the firing pin hit doesn't move the brass forward.

I will also say, that it is not completely uncommon to see a factory chamber with .004" clearance. You can also do this in resizing if things are a little out of spec, a die a little too deep, or a shell holder a little less than the .125" depth it should have. Add those together and you ca push brass back far enough to create the exact .004" plus chamber.

If you have a notion that you may sell a gun in the future, then set the barrel back. If you're going to shoot it until it's a smoothbore like I do, I don't worry about that.

95584

[swheeler]

I could of set back a couple rifle barrels in half the time some of you have spent here typing arguments on why we don't need to do all that work. While we're at it and setting head space anyway. We could square up the Remington receiver face.

Absolutely Gabby makes perfect sense;)

[leftiye]

Exactly - what BR shooter says. Boolit hard into rifling. light oil coating on case, mild load. It's over.

Actually, a standard case should headspace on the normal base of the shoulder/neck adequately to fireform. Regardless of how chamber is cut. Unless case has been sized, or sized too much.

[UBER7MM]

Crabo,

.
What's wrong with your 280?

[white eagle]

I picked up a Rem 700 7mm Rem. mag on Gunbroker for about 400. Gonna make a tight twist 264 mag out of it. Fills the same bill for me. I've got a 280, have liked them since I was in high school (early 60s). My first custom rifle was a 6mm AI which I designed the ctg myself, then found our that P.O. had already done. I've got nuthin' agin' wildcat or improved cartridges. But if you want a magnum, get one.

It aint about wanting a magnum its all about per for mance
if you end up stepping into magnum shoe's mo betta

[swheeler]

You folks with your .017" plus or minus, don't make a lick of sense. With the shoulder angle aside, there is only .004" difference in headspace between a standard parent case and an Ackley chamber, .004" SHORT!

An excerpt from Manson Reamers:

Because the cartridge must be held secu
rely during fireforming, the dimension
between the breech face and the neck/shoul
der junction becomes critical. P.O.
Ackley, who popularized improved calibers,
recommended that this dimension be
reduced
by .004”/.006” from the standard minimum for a particular caliber.


Reducing this dimension compensates for
cartridge tolerances and ensures that
fireforming can be done safely.

This shorter chamber provides a crush of the brass. Some brass is thicker than others, and there is actually a .004" to .006" variance for this. You can talk all you want about .017" of something, but the bottom line is there is .004" of difference.

I started this out by saying, if you chambered UP TO the neck/shoulder junction, NOT PAST IT NOT BEFORE IT, you could fireform brass safely by standard methods of fireforming wildcat cases. This ca be done by a hard bullet jamb, a false shoulder, etc, either method works as long as you have a tight brass fit in your chamber. You need this so the firing pin hit doesn't move the brass forward.

I will also say, that it is not completely uncommon to see a factory chamber with .004" clearance. You can also do this in resizing if things are a little out of spec, a die a little too deep, or a shell holder a little less than the .125" depth it should have. Add those together and you ca push brass back far enough to create the exact .004" plus chamber.

If you have a notion that you may sell a gun in the future, then set the barrel back. If you're going to shoot it until it's a smoothbore like I do, I don't worry about that.

95584

Glad you posted that! .017+.004=.021 or .017+.006=.023" sure helps confirm what I said;) I think if you stop and think about it you will see exactly why PO wanted set back before reaming to AI chamber, well maybe not;)

[B R Shooter]

Read my first line, the .017" don't make a lick of sense. I have no idea why you are hung up on something that is non-existant.

[swheeler]

I'll try one more time in a different form;

1 EXISTING 280 CHAMBER length from head to shoulder/neck junction 2.199
2- 280AI CHAMBER length from head to shoulder/neck junction 2.182
______
.017
3 You say ream to shoulder/neck junction with AI reamer, THE ORIGINAL CHAMBER IS ALREADY LONGER AT SHOULDER/NECK JUNCTION THAN THE ACKLEY CHAMBER BY .017". You know 2.199 minus2.182 = .017";)By reaming to this position you just ADDED .017" to existing headspace(which can be from 0-.005 and still be in spec)

You are misconstuing what is said above- they want a crush fit of .004-.006

in Ackleys own words- THE GO GAUGE NOW BECOMES THE NO-GO GAUGE


Say you are a right handed shooter and fire a round in a chamber done your way, have a case head seperation, hot powder gases carrying shards of gilding metal follow the firing pin back and escape around the shroud putting your right eye out, you have now beco
me lefteye

I do not know how I could explain it any clearer? I think 99.9% of the people here get it, some just like to argue;) I have done my best to keep you safe and it's up to you to learn now. For that reason I'm out of here.

[crabo]

Crabo,

.
What's wrong with your 280?

Nothin', but as we all know, what's that got to do with anything? Sometimes we just got to fix what ain't broke... Actually, I will probably leave it the way it is. I am enjoying the discussion.

[B R Shooter]

I will check my reamer drawings when I get home. I do know there are SEVERAL DIFFERENT 280AI prints and reamers being used, the original Ackley is different than the SAAMI. So first off you need to decide what you start with. I would expect, if you started with a SAAMI 280, and used a SAAMI 280AI, there would be the .004" shorter difference in the later, at the neck/shoulder. I have a full set of JGS prints at home, I'll check those.

Regardless, let's assume you have a rifle with a standard 280 chamber, you have fired brass in the gun without issue. Your brass is already a fit to that chamber. Unless you pushed the bajeebers back on the shoulder while resizing, the brass will be a decent fit. If you ran a AI reamer just to the N/S, no more, no less, there would be minimal issue if any when that brass is fired. You certainly wouldn't experience ahead separation.

This .017" is in the differences of reamers/chambers. Do a search, do some reading. There are indeed differences with this "improved" cartridge. I will bring my prints into work on Monday, scan them, and post them both for all to see.

[kywoodwrkr]

Friendly Google:
http://gunsmithtalk.wordpress.com/2012/07/17/280-ackley-improved-emperical-headspace-test/

[B R Shooter]

Yes, I saw that same website.

So I checked my JGS prints. The standard 280 Rem print, #3118, shows a dimension to the N/S as 2.1924". The 280 AI print, #3056, shows a dimension as 2.1884". Exactly .004" short! Imagine that!

Look, this whole discussion was about fire forming. There are so many variables/tolerances to deal with, some common sense has to prevail. Even setting back a barrel takes special care. The short AI go gauge has the parent case shoulder angle, and it takes a close feel, because you will be using that same sharp angle that is shown in the sketch of the chambers I posted above, not a full contact shoulder fit. Don't be surprised if you feel some brass closing fine, some loose, and some very tight while fire forming. Brass thickness varies, and that crush ASSUMES .004" is the thickness.

[UBER7MM]

Nothin', but as we all know, what's that got to do with anything? Sometimes we just got to fix what ain't broke... Actually, I will probably leave it the way it is. I am enjoying the discussion.

I hear ya'. I think the 280 Remington, as is perfectly fine on its own. And I'm learning about the AI as well. Down side is higher pressure. Setting back the barrel would be a show stopper for me. If it were just a bit of play with the finish reamer then it might be a consideration. Lot of folks like 'em. Lots of comparison with the 7mm Rem Mag.

Enjoy,

[Newtire]

I could of set back a couple rifle barrels in half the time some of you have spent here typing arguments on why we don't need to do all that work. While we're at it and setting head space anyway. We could square up the Remington receiver face.My question was about how to do this to a single-shot H & R but not too practical setting that one back. I kind of get the idea that I could just do the same thing I did to make the .280 cases out of those .30-06 cases but the wildcat I would create would be a little longer than the normal 280 AI. Since it's not too bad a rifle as it is, think I'll just leave it alone.

[swheeler]

Friendly Google:
http://gunsmithtalk.wordpress.com/2012/07/17/280-ackley-improved-emperical-headspace-test/

Interesting yes, but has absolutely NOTHING to do with the discussion at hand. This internet expert is comparing TRADITIONAL 280AI to SAAMI 280AI, nothing at all about reaming an existing 280REM chamber to AI configuration, be it the traditional or the saami spec. If you take him at his word/pictures(I think I'll believe SAAMI and the reamer manufactures over him;)) then BOTH AI configurations will have to have barrel set back to remove the .017" too deep on original 280 chamber. Since it is now a legitimate/standardized cartridge I see no reason to pick the traditional reamer out of the line up, use the SAAMI reamer and gages, set back a thread and have fun:)

[B R Shooter]

You are one hard headed person, and I mean HARD!

[swheeler]

Not hard headed, just trying to disspell internet myths and wives tales;)

[B R Shooter]

The only myth and incorrect information being given here is your .017" that is floating around in your head.

[nanuk]

Hi, I had the thought of trying out the .280 Improved. My trouble is that I have a .280 Handi-Rifle with a nice 26" barrel. I see I can get a 7mm-08 barrel for this thing but then those are only 22" long. So, the gain I got from the "Ackley-ization" would just be lost by the shorter tube. I can't set this barrel back as it's a single shot.
Any thoughts?


Tim, on the GBO site did his by going to the shoulder/neck junction as per BR Shooter, and stamped it 280AckImpImp

as to the discussion/argument going on here:

When I did my research on the AI line, I got ahold of the Ackley books and read on why he did as he did

my understanding is that the Ackley shoulder actually rotates around the "Datum Line", and has nothing to do with the neck/shoulder juction. That is WHY there is a "CRUSH" and not just a good fit. with minimum spec ammo, in a chamber reamed as per BRShooter's suggestion, you could have a Headspace issue

so, SWheeler is discussing the Ackley theory, and BRShooter is discussing using an Ackley reamer to make a Wildcat, that one "Could" fire factory rounds in.... IF reamed correctly.

this is MY understanding.. .YMMV

[Newtire]

Sorry, but you lost me a couple of datum lines and shoulder angle differences back!

[swheeler]

I downloaded the SAAMI drawings to post here, max cartridge-min chamber, think you can click on the link and open, hope you can anyway:)97109 97111

[swheeler]

Left click on the print and it will enlarge to read.

breechface to shoulder/neck junction 280 rem-2.1924 remember this chamber is already there -existing
breechface to shoulder/neck junction 280 Ack- 2.1742
--------
.0182"


If you started with a min spec 280 rem chamber(which you aren't going to find in a production rifle;0)and reamed to max spec 280AI you still are going to be over by some margin. Best do it right from the start and keep all your fingers and both eyes, then we won't have to use handles like righteye and lefteye;)

If anyone has Nosler #6 reloading manual it has both Sammi max cartridge drawings for 280 and 280AI, they show 280 rem is .017" longer to neck/shoulder junction

4d reamers drawings shows 280 rem neck/shoulder .024" longer than TRADITIONAL 280AI reamer

[B R Shooter]

Wheel ol' boy.....you are back-assward. Look at your OWN drawings again. A standard 280 is 2.1924", the AI is 2.1742". If you set a barrel back and reamed to this dimension, the chamber would be SHORT by .018", and I doubt you would ever close a bolt on the brass this way. Maybe you would, but one thing is for sure, you surely wouldn't have a danger of case head separation, everything would be extremely tight.

Here are the chamber prints from JGS:
97165
97166

JGS shows a .004" short dimension to the N/S line, which is standard with any of the reamer makers. Call ANY reamer maker, and ask them what the AI GO gauge is, and you will be told, it is a .004" short gauge that has the same shoulder angle as the parent cartridge. This .004" is for the brass crush when closing on a standard piece of brass. Ask them about the .018" shorter dimension.

When I started this "discussion", I commented about reaming to the EXISTING N/S and no more. The only thing this would do is give at most, .004" excess headspace. And this could easily be handled by long seating a bullet.

This .017", that has now morphed into .018", was taken out of context, was touted as a LONGER chamber, which it isn't. In effect, you could not ream an existing chamber and use a ACK GO gauge, because it would not have the N/S to gauge to. If you set the barrel back, then you could ream to the shorter gauge.

I have no idea why there are so many variable dimensions around on this cartridge, to me, people could create a bad situation if they aren't thinking things through.

One more thing, a factory chamber is BIG, I don't think you would be able to buy a reamer as big as that, most reamer makers grind to a minimum SAAMI. Trying to ream a factory chamber and think your reamer will match the factory chamber won't happen.

I'm finished with this discussion. There is a saying that is "you can't argue with a liberal". It's true. I have no idea of your political orientation, but you are so fixed on wrong information, nothing gets through.

[swheeler]

You HAVE to set back to ream the Ackley chamber so the headspace will not be excessive-period. The go-gage of the parent cartridge becomes the no-go gage, A CORRECT 280AI CHAMBER WILL NOT CLOSE ON A 280REMINGTON GO GAGE-PERIOD. With the way you describe in your own words- ream just to the neck shoulder junction- you are never going to get a slight crush fit.


Liberal? Your the one with Liberal headspace!;)

[felix]

Ackley's chamber design rule has always been a crush fit on a new SAAMI sized case during bolt closure. That was his chamber rule which makes his case slopes secondary in design. My dad was present when PO and Roy Weatherby were discussing chambers at one time. ... felix

[B R Shooter]

You HAVE to set back to ream the Ackley chamber so the headspace will not be excessive-period. The go-gage of the parent cartridge becomes the no-go gage, A CORRECT 280AI CHAMBER WILL NOT CLOSE ON A 280REMINGTON GO GAGE-PERIOD. With the way you describe in your own words- ream just to the neck shoulder junction- you are never going to get a slight crush fit.


Liberal? Your the one with Liberal headspace!;)

That's what I said! An Ackley go gauge is .004", READ FOUR THOUSANDS, shorter than the parent go-gauge. Where is your coveted .017", or .018" in all this?

I said it is possible to ream to the existing N/S and fireform. It is only .004" long. Where is your plus .017"?

[swheeler]

Ackley's chamber design rule has always been a crush fit on a new SAAMI sized case during bolt closure. That was his chamber rule which makes his case slopes secondary in design. My dad was present when PO and Roy Weatherby were discussing chambers at one time. ... felix

Thank you Felix!:) Now I just have walk away this is becoming a waste of time, think I go ream an Ackley chamber correctly:)

[leftiye]

No ship! Frum the git go.

[swheeler]

To make it work like Ackley intended the barrel needs to be set back

Do tit this way Crabo and you'll be fine;)

[Changeling]

You will never be sorry if you do, just make sure you have a top notch gunsmith do the work. I have one set up on a custom 1909 Mauser action with a HART Magnum barrel that is absolutely the finest shooting rifle I have ever shot! The speed and accuracy is amazing.
Good luck with your project. Forget about a 7 mm Mag. the barrel will loose 2 to 300 fps after 1000 to 1500 rounds. The 280 AI will be going strong and kick the Mag any day of the week.


Do it properly and set the barrel back....or better yet buy a new barrel blank. Hard telling where it might end up might as well make it work with ammo you can buy at the store.

280 AI is high on my list. I love my 280. When I do build a 280 AI I will probably set it up as a heavy long range rifle.

[nanuk]

My question was about how to do this to a single-shot H & R ...


Newtire... start with a 7mm08 and ream away!