280AI with too much head space...options?

[25WSM]

It's an easy fix. Just have to set shoulder back the amount of the excess headspace and put it back on. Your writing on the barrel will rotate down a little bit but not a problem unless you want the writing right above the stock. Once the writing is under the stock put the correct designation on it.
Shep

 

[shortgrass]

Lots of confusion over the .280 Ackley (SAAMI/Nosler) and P.O. Ackleys' version. My personal .280 Ackley (SAAMI/Nosler) was cut with a Manson reamer and head spaced with Mansons' gauges. I can close the bolt on the GO with a piece of .002" steel shim stock stuck to the base of the gauge with slight resistance, but I get absolutely NO CRUSH on Win. head stamped .280 Rem brass OR Nosler .280 Rem brass. I always mark a .280 A.I. barrel either (Traditional) for P.O.s version, or (Nosler) for the current SAAMI version depending upon what my client wants. Redding makes 2 different sets of dies for the .280 A.I. and they have a short article/explanation under FAQS on their web site of 'why' and what to do about it. But, I do agree, your chamber is cut too deep. Getting it fixed properly should solve a lot of problems. I just don't know about a guy that will call himself a 'gunsmith' that rents chambering reamers. He must not plan on being in business long. Cut 3 chambers with a reamer that you bought and you will more than pay for the reamer and gauges and make profit, too. Treated properly, that same reamer will cut many, many many excellent chambers. I have rented reamers twice in the past 30 yrs and been disappointed both times! Renting reamers is for the hobby guys, not the serious. I own over 80 chambering reamers in the tool storage draws and have no regrets as I buy those that I feel I will have repeat calls for. Ya', its quite a chunk of change, but its just part of the cost of doing business.

 

[Coldfinger]

My 280 Rem, a Remington 700 Mountain rifle, shot just under an inch with my reloads. It was easy to get there, and I didn't think much of it.
A close friend shoots a 280 AI. I liked what his gun was producing, so, off the gun was sent to the same gunsmith that did his. The gun returns, and load development starts.... and I've struggled. Three different powders and a number of different weight bullets and manufacturers. Nothing better than 1 1/2", and not even consistent at that. Even tried factory Nosler Trophy ammo that friends gun runs to 3/4". Still an 1 1/2" in my gun.

Being a bit frustrated, had the gun looked at by another gunsmith. First thing he did was strip the bolt, and get out his go/no go gauges. First gauge was the go gauge and all good, as I expected. When the bolt closed on the no go, made me bit sick. With no resistance.

So. He's come up with options to bring it back into spec.
I'd like to have some input on what can or should be done to the rifle now.
And what conversation I should have with the gunsmith that did the original work.

thanks in advance. Doug

Try a field gauge I've got a couple Mauser 308's and Ruger 257 Roberts that close on no go gauges. They shoot fine tho. Check the bullet weight your running with twist rate.

 

[kfreeze]

My 280 Rem, a Remington 700 Mountain rifle, shot just under an inch with my reloads. It was easy to get there, and I didn't think much of it.
A close friend shoots a 280 AI. I liked what his gun was producing, so, off the gun was sent to the same gunsmith that did his. The gun returns, and load development starts.... and I've struggled. Three different powders and a number of different weight bullets and manufacturers. Nothing better than 1 1/2", and not even consistent at that. Even tried factory Nosler Trophy ammo that friends gun runs to 3/4". Still an 1 1/2" in my gun.

Being a bit frustrated, had the gun looked at by another gunsmith. First thing he did was strip the bolt, and get out his go/no go gauges. First gauge was the go gauge and all good, as I expected. When the bolt closed on the no go, made me bit sick. With no resistance.

So. He's come up with options to bring it back into spec.
I'd like to have some input on what can or should be done to the rifle now.
And what conversation I should have with the gunsmith that did the original work.

thanks in advance. Doug

The no go gauge is for custom chambers only, and is rarely used by the rifle builders I know. (They use a .002" shim on the go gauge). The correct gauge that he should have used to determine if you have excessive headspace is called a field gauge. That is the one that the bolt should never close on.

 

[25WSM]

I don't know why you would say that a no-go is only for custom Chambers. I don't know one smith that owns a field guage. I don't own a field guage. Any smith worth his salt can do a chamber and be within the go and no-go tollerence. If I can't hit that spec between 0 and . 003 then I really screwed up. Sammi should just burn that spec sheet for field guages it's just sloppy. The only purpose I see for them are old military rifles. I don't work on the old military rifles anymore. But every smith I know and myself feel that if your bolt closes on the no-go it's too deep. Doesn't matter if it's a basic 308 or a 6br or 280 or 280AI. Custom chamber has nothing to do with it. Custom barrel or rechambered factory barrel has nothing to do with it. You hit the spec or you don't.
Shep

 

[antelopedundee]

I'd just fire form cases by jamming a bullet in the lands assuming that they are like new. They will be a tad longer than normal, but no biggie. Just set your sizing die to partially resize them until they chamber.

 

[Hayudog]

I'd just fire form cases by jamming a bullet in the lands assuming that they are like new. They will be a tad longer than normal, but no biggie. Just set your sizing die to partially resize them until they chamber.

At this time, that's my plan. I'd had a marginal time finding a load Up to this point. If I can't make it run, I'll chalk it up to experience and start over with a better barrel. I'll get fresh new brass and basically fire form it. Hopefully I can find an accurate lower pressure load, hot loads always make me nervous. Considering, the brass I've shot already, shoulder moved .oo6, and then stabilized.

 

[Hayudog]

It's an easy fix. Just have to set shoulder back the amount of the excess headspace and put it back on. Your writing on the barrel will rotate down a little bit but not a problem unless you want the writing right above the stock. Once the writing is under the stock put the correct designation on it.
Shep

Agree. My local guy said exactly that. And I might do that. I have Peterson's brass arriving in a couple of days. It comes annealed I think. I may just fire form it, and use a Lee collet die and watch the shoulder to make sure it's stable. If after the second firing it's stable, I should be ok. Most of the stretch will be on the first firing. Since it's going to be a low volume hunting rifle, once I get a load that's consistent, it's just load and hunt. Checking zero will be the volume being shot through it..

Again, thanks all for the input. Everyone's comments and input has helped me at least formulate a plan.
Doug.

 

[kfreeze]

I don't know why you would say that a no-go is only for custom Chambers. I don't know one smith that owns a field guage. I don't own a field guage. Any smith worth his salt can do a chamber and be within the go and no-go tollerence. If I can't hit that spec between 0 and . 003 then I really screwed up. Sammi should just burn that spec sheet for field guages it's just sloppy. The only purpose I see for them are old military rifles. I don't work on the old military rifles anymore. But every smith I know and myself feel that if your bolt closes on the no-go it's too deep. Doesn't matter if it's a basic 308 or a 6br or 280 or 280AI. Custom chamber has nothing to do with it. Custom barrel or rechambered factory barrel has nothing to do with it. You hit the spec or you don't.
Shep

You are correct sir. I should have said custom cut chambers, meaning not factory mass produced by the cheapest guy they can get to run a cnc. That being said who knows if the guy was told not to set it back and just put the reamer in and clean up the chamber. I'm seriously questioning the person who did the works ability as well, but thats really the only way to tell if it's unreliable/ unsafe deep.

 

[antelopedundee]

Agree. My local guy said exactly that. And I might do that. I have Peterson's brass arriving in a couple of days. It comes annealed I think. I may just fire form it, and use a Lee collet die and watch the shoulder to make sure it's stable. If after the second firing it's stable, I should be ok. Most of the stretch will be on the first firing. Since it's going to be a low volume hunting rifle, once I get a load that's consistent, it's just load and hunt. Checking zero will be the volume being shot through it..

Again, thanks all for the input. Everyone's comments and input has helped me at least formulate a plan.
Doug.

If you intend to keep the rifle I wouldn't mess with setting the barrel back; just re-fire form and shoot the thing until it's shot out. Size and expand the case neck .001 under bullet diameter. With no primer seat a bullet long in the case. Chamber this dummy round in your rifle. It may take a small amount of effort, but it should go. Extract the round and you should now have a round that is seated to touch the rifling. Seat your bullets in your loaded rounds about .002 or so longer and maybe with a bit more neck tension. When you fire them you should have a case sized to the rifle's chamber. The idea behind seating to touch or lightly jam is to keep the case from moving when the firing pin hits te primer so that all of the pressure is directed forward.

 

[arch408]

First, why did you mess with a gun that shot 1/2 groups?!!!!!!!! Ackley designed his improved head spaces to be less than factory specs. I believe they were .0001 inch. So a factory barrel needs to be set back to accomplish that. That was make sure that factory brass would would have an interference fit so the brass could be fire formed. It sounds like the barrel was not set back or the reamer run in too far. Ackley used the go gauge as the no-go gauge to set the head space. lMO, you have three choices. One, have the barrel set back, or maybe surface grind the recoil lug to set the headspace if it's thick enough. I've done this. Two which is what I would do; rechamber to the .280 Gibbs which would increase the powder capacity which would give you a pretty good velocity increase. Three, neck out the cases to 30 caliber and than neck them back down to .284 adjusting your die until the cases would chamber with a slight bolt resistance (which is the way the original case should have been) and then fire form. On subsequent resizing, adjust the die so it barely allows the cases to chamber. (Shade tree mechanicing, but it might work.) Definately my last choice.
P.S. If you are going to trash the barrel, send it to me, I'll pay for shipping and I'll give it a good home. It's obviously a good barrel.

 

[CTK]

I went down this road 10 or so years ago. Get a new barrel and have a smith that is very familiar with the Sammi cartridge chamber and thread.

 

[Joefrazell]

Probably gunna have to turn the barrel and re chamber. I'd call the original gunsmith

 

[25WSM]

All the smith had to do is measure how much the reamer went in too far and cut that amount off the shoulder and end of barrel. The chamber does not need to have a reamer put back in it. It's a 30 min job at most and will work properly when done. If he takes a 280rem go guage and add shims to the the rear of it till the bolt won't close on it and measure the shim stack thickness that is how much needs to be cut from the shoulder and rear of barrel. Re-chamfer the corner of the chamber and screw the barrel back on. Very simple fix. If you lived here I would just fix it for you.
Shep