IF, the recutting from 280 Rem to AI goes badly (nothing is going to blow up (anyone who knows about false shoulder fireforming already know that) I do own a bbl. vise and wrench to pull the bbl, cut it off enough to start clean and cut a new chamber.
So you own the tools to pull the barrel and chamber it correctly? Are you chsmbering this yourself?
Maybe my ignorance is showing but is an AI conversion really worth it? As I asked earlier, what's lacking in the 280 Remington? And if lacking, then maybe it's time to move on to another "off the shelf cartridge.
"Worth it" is a judgement call for the rifle's owner to make.
I don't know how much case capacity would be gained by rechambering from 280 to 280AI, but probably not enough to make a noticeable different in trajectory. The 280 has approximately 67 grains of total case capacity and doesn't have a particularly tapered case, so the increase in case capacity is likely to less than 10%, resulting in a potential increase in velocity of less than 3%.
PROS: Increased case capacity equals increase velocity potential and less case stretching.
CONS: Additional cost of dies, the gunsmithing work to do the rechamber job, and (usually) less resale value because, usually, there is less consumer demand for rifles chambered for wildcat cartridges that, in most cases, need to be handloaded.
EDIT: I went through a wildcat phase and still have some of them, but have decided that, for me, the CONS tend to overshadow the PROS most of the time.
Last edited by 260Remguy; 09/01/17. Reason: Added what I'd forgotten to post originally
I checked my reamer 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" shorter.
The short AI go gauge has the parent case shoulder angle, and it takes a close feel, because you're using that same sharp angle that is shown in the sketch of the chambers, not a full contact shoulder fit.
If you have a "factory" 280 AI, don't be surprised if you feel some 280 brass closing fine, some loose, and some very tight while fire forming. Brass thickness varies, and that crush ASSUMES .004" is the thickness.
So if the 280 Rem chamber is redone to 280 AI, stopping at the neck shoulder meeting point, the headspace will be 4 thou over the AI minimum chamber. 100s of thousands of 30-06 round have been fired through the trusty M-1 with 7-9 thou "slop" w/o blowing up. The "at most" 4 thou "slop" (thinest brass there is) a'int gonna take apart any modern bolt gun.
While you may not get P.O.'s crush fit with loaded Nosler 280 AI, you might with thick 280 ammo like remington or reformed military 06'.
I don't recall P.O. mentioning the false shoulder method which is by far the best way to fit any belted or bottlenecked brass to a particular chamber. Superior to depending on a crush fit since brass varies so much.
The job will be finished over the weekend and I'll post some pics of the bolt position with a 280 AI no go gauge, a 280 AI go gauge, a loaded 280 round and a loaded 280 AI round. Each will just be closed to the start of resistance with extractor and ejector removed.
I checked my reamer 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" shorter.
The short AI go gauge has the parent case shoulder angle, and it takes a close feel, because you're using that same sharp angle that is shown in the sketch of the chambers, not a full contact shoulder fit.
If you have a "factory" 280 AI, don't be surprised if you feel some 280 brass closing fine, some loose, and some very tight while fire forming. Brass thickness varies, and that crush ASSUMES .004" is the thickness.
So if the 280 Rem chamber is redone to 280 AI, stopping at the neck shoulder meeting point, the headspace will be 4 thou over the AI minimum chamber. 100s of thousands of 30-06 round have been fired through the trusty M-1 with 7-9 thou "slop" w/o blowing up. The "at most" 4 thou "slop" (thinest brass there is) a'int gonna take apart any modern bolt gun.
While you may not get P.O.'s crush fit with loaded Nosler 280 AI, you might with thick 280 ammo like remington or reformed military 06'.
I don't recall P.O. mentioning the false shoulder method which is by far the best way to fit any belted or bottlenecked brass to a particular chamber. Superior to depending on a crush fit since brass varies so much.
The job will be finished over the weekend and I'll post some pics of the bolt position with a 280 AI no go gauge, a 280 AI go gauge, a loaded 280 round and a loaded 280 AI round. Each will just be closed to the start of resistance with extractor and ejector removed.
But how can that be? Here you said:
Originally Posted by Woolrich
Okay, I'll try and show a real gunsmith doing a real test revealed.
Bottom line: there is NO difference in headspace between a 280 Rem, 280 Ackley and 280 AI SAMMI.
Again, best of luck. This really is just a simple procedure that you have somehow gone and complicated far beyond what needs to be.
If you think .004" is a lot, you really need to catch up on both chamber and cartridges variances.
In the real world there is no practical difference.
If you can show me where P.O. ever heard of false shoulder fireforming, I'd appreciate it.
As for "over complication" you are correct. Pulling a barrel and setting it back when there is no need is silly but does line the pocket of "gunsmiths".
No "luck" involved. Just a simple case of doing the research, having the right tools/gauges and not just parroting back what is the conventional wisdom.
Curious: How many K Hornets, Gibbs chambered rifles, 400 Brown Whelens, 30-30 AI, 257 AI, 303 Epps do you own ? Built em' all, Got em' all, none have blown up.
The title of the thread is rechamber question, it seems like you weren't here to ask anything, but to show us that we don't have a clue.
Never said that. As you pointed out, the 280 AI does have "slightly shorter" headspace than a 280 Rem.
That difference is .004 which is insignificant given the variances in factory chambers and cartridges.
As I pointed out, many military rifle were set up with what you might call excess headspace to ensure function. All factory belted cartridges are undersized for the same reason. My M-1s and K98s have yet to explode.
Attributing "evil" motives to a simple question is really reaching.
The photos I post after the holiday will tell the story.
I agree with montanabadger, and not to put to fine a point on it, will add that you come across as a real azzwhole, Buster.
GTC
Member, Clan of the Border Rats -- “Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it.”- Mark Twain
I must work with this guy. Azzhat will come ask for help with his machine. Then argue with every bit of advise you give. Very frustrating.
Hate the idea of you having to associate with Larry Root on a daily basis,.........that IS who this clown is, in his latest sock puppet incarnation, ya' know.
GTC
Member, Clan of the Border Rats -- “Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it.”- Mark Twain
To be called a nasty name by a guy who apparently doesn't know there are no Grizzly bears in McCain country is a compliment.
I did not ask for "help". I asked for advice (not advise). What I received was name calling, recycled opinion, nothing picked from P.O.s written word, no acceptance that .004 means nothing and more insults.
Dillon, I agree it's frustrating that facts are non-existant but hot air enough to fill the Hindenburg. (yes I know it did not use hot air)
Then how did you know???? You broke and you just proved it, Jakoff. (much more appropriate, since you know and call Bricktop if you need help). You know it, I know it, we know it. Drip, drip, drip, drip....
Find your own pet Monkey yet? The Monkey be the doer I'm sure.You be the doee.
The title of the thread is rechamber question, it seems like you weren't here to ask anything, but to show us that we don't have a clue.
Never said that. As you pointed out, the 280 AI does have "slightly shorter" headspace than a 280 Rem.
That difference is .004 which is insignificant given the variances in factory chambers and cartridges.
As I pointed out, many military rifle were set up with what you might call excess headspace to ensure function. All factory belted cartridges are undersized for the same reason. My M-1s and K98s have yet to explode.
Attributing "evil" motives to a simple question is really reaching.
The photos I post after the holiday will tell the story.
Belted cartridges headspace on the belt not the shoulder, so they don't apply to this thread.
"Before you criticize someone, walk a mile in their shoes. That way, you'll be a mile from them, and you'll have their shoes."