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

[Hayudog]

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

 

[JMW67]

was it a rebarrel or just a rechamber just curious the barrel can be set back a thread or two and rechambered

 

[cohunt]

will it close on a field gauge? technically its still within specs unless it will close on a field gauge

the barrel can most likely be set back a turn though --but then again, wouldn't the new smith that you took it to know that? If he doesnt, then I would find a new smith.

How are you sizing your brass? what dies are you using? saami/nosler or other dies? how much are you bumping the shoulder?

too much/too little headspace wont necessarily make an gun "inaccurate"

which chamber was it machined to? the nosler 280 ai saami or another? did you ask, or spec out a specific chamber?--might read this article

Nosler FAQ - The 280 Ackley Improved – which version do I have, and is it ok to shoot with factory ammo?

There have been many variations of “improved” cartridges over the years, and even ...

faq.nosler.com

 

[26Reload]

If I can see a picture of that that rifle....might make a suggestion...
Idaho is big state...what part....
If it's the older version noodle barrel...mine being rechambered definitely likes lighter weight bullets....although i got 168 to shoot decent..getting that heavy bullet out of the barrel was leading to a lot of hat brims being chewed up.....that was 2630fps...
Going lighter yeilds a faster bullet and much less recoil....and no shortage of good bullets....

 

[quigley257]

You need to know which reamer version of 280 AI was used to do the conversion(there are a couple versions out there), then use the matching HS gauges. Another easy check is to see if the crown was damaged at all during the process.

 

[Bob Wright]

Measuring fired brass to unfired brass using a headspace guage is a first step. It will give you an answer. It may be +.004, .005 or way more.
If its .004 for example it may be OK to reload to those numbers moving forward. If its going even longer you may start having problems with factory ammo "nailing primers", headspace separations (ugly and dangerous).
So, if you don't reload, your gunsmith probably can measure your brass, fired and unfired and give you a verdict, especially if you use factory ammo. Normally once fired still can grow a few thou.
Factory ammo has headspace already and if your chamber headspace is out of spec being too long, its adding additional space leading to problems that cannot be fixed if nothing is done.

 

[Hayudog]

will it close on a field gauge? technically its still within specs unless it will close on a field gauge

the barrel can most likely be set back a turn though --but then again, wouldn't the new smith that you took it to know that? If he doesnt, then I would find a new smith.

How are you sizing your brass? what dies are you using? saami/nosler or other dies? how much are you bumping the shoulder?

too much/too little headspace wont necessarily make an gun "inaccurate"

which chamber was it machined to? the nosler 280 ai saami or another? did you ask, or spec out a specific chamber?--might read this article

Nosler FAQ - The 280 Ackley Improved – which version do I have, and is it ok to shoot with factory ammo?

There have been many variations of “improved” cartridges over the years, and even ...

faq.nosler.com

It closed on the no go gauge. Said out loud the name of his gauges, and said they weren't cheap. He name dropped, but it didn't register with me. I wouldn't know good/expensive to poor/cheap. Made a video to send to the other gunsmith, demonstrating his tools and technique. New gunsmith has said exactly that. Remove and turn down the current barrel. He also said there could be other tasks that could be needed, but we'd know more when he had looked into it further. Was just asking openly to get a variety in responses. And I had hoped that the headspace issue would have a degree of accuracy related Issues that would be cleaned up. Time will tell.

I had issues with new 280 Rem brass being loaded for fire forming, 4 of the first 30 did not fire. I do not have any resistance closing on factory 280 Rem ammunition.

As far as dies, started after fire forming with RCBS . The ones marked FL 280 Ackley Improved. Part number 17001. I had set them up to only size the neck. Brass after fire forming closed easily, and wasn't convinced that the shoulder needed to be pushed back if it wasn't fully forward.
Ive had positive results with Lee collet dies. I've picked up a neck sizing die for .280.
As far as the requested chamber to be reamed for, unless specified , I would think it would be the 280 AI saami. It's stamped on the side of the barrel now. 280 Ackley Imp.

 

[Hayudog]

If I can see a picture of that that rifle....might make a suggestion...
Idaho is big state...what part....
If it's the older version noodle barrel...mine being rechambered definitely likes lighter weight bullets....although i got 168 to shoot decent..getting that heavy bullet out of the barrel was leading to a lot of hat brims being chewed up.....that was 2630fps...
Going lighter yeilds a faster bullet and much less recoil....and no shortage of good bullets....

Western part. Guns at the shop now. It's a year And a half old, stainless light barrel.

 

[Hayudog]

You need to know which reamer version of 280 AI was used to do the conversion(there are a couple versions out there), then use the matching HS gauges. Another easy check is to see if the crown was damaged at all during the process.

I'll find out which reamer was used for sure. I'm asking the gun store shop owner to reconnect with the original gunsmith, I didn't make the original contact. And I will ask about the crown. Thanks.

 

[cohunt]

as I said, just because it closes on a "no-go" gauge does not mean its technically out of spec---not necessarily good, but also not out of spec

if it wont close on a go gauge its out of spec--too short
If it closes on a no-go gauge then its time to check with a "field gauge"
If it closes on a field gauge then its out of spec --too long and possibly unsafe

Head Space Gauges Explained - EABCO

Explains the difference between GO, NO-GO, and FIELD headspace gauges for custom and SAAMI head space.

www.eabco.com

sounds to me like your "old" smith used a 280 Improved reamer to ream the chamber but did not set the barrel back by a turn
did you check out the link I posted? it will help you learn about the different reamers made for the 280 Improved over the years and how the chambers are cut

.the rcbs dies you are using are for the saami chamber so if he didnt set back the chamber after he cut it then your dies will size the brass too small --sounds like you either need to have the barrel set back, or buy a set of the "old" 280 Improved dies to work with your chamber --or you could try the redding .014" shorter shell holder(11649 -- "#1 + .014") and see if it fixes your problem : https://www.midsouthshooterssupply.com/item/0007611649/-number-1-plus-14-shellholder

here is another link to read from redding : https://www.redding-reloading.com/tech-line-a-tips-faqs/133-280-changes

 

[crystalgayleguy]

I have a model 70 feather weight classic in 280 rem I tried several different powder and had imr 4831 shoot ok but to me it should have shot better so I tried the one powder I didn't try was h1000 140 gr bullet starting load 4 rds 58 grs 4 at 60 grs four at 62 grs the 58 gr loads shot a one hole it was 0ne gr under starting load

 

[lancetkenyon]

Like others have stated, the original Ackley version of the .280AI (.280 AI 40* or .280 Rem Improved 40*) is different than the SAAMI Nosler version of the .280AI.

Headspace in the SAAMI .280AI (by Nosler) is shorter than the original .280 AI 40* by PO Ackley.

If the gunsmith has an older .280AI reamer (to PO Ackley spec), the headspace guage of the new SAAMI .280AI will not work correctly.

If you have a way to measure your actual fired case from base to shoulder datum with a .420" comparator, or know someone who can, post that measurement. I would not be surprised if you have the original wildcat PO Ackley chamber rather than the SAAMI version reamer. That would clear the gunsmith from any wrong chambering job. You would just have to order the correct dies (and g0/no go gauges).

You could jam the bullets into the lands for your fire forming loads to keep the case head tight against the bolt face to eliminate failure to fire issues. Just make sure you don't have a max load.

 

[Hayudog]

Measuring fired brass to unfired brass using a headspace guage is a first step. It will give you an answer. It may be +.004, .005 or way more.
If its .004 for example it may be OK to reload to those numbers moving forward. If its going even longer you may start having problems with factory ammo "nailing primers", headspace separations (ugly and dangerous).
So, if you don't reload, your gunsmith probably can measure your brass, fired and unfired and give you a verdict, especially if you use factory ammo. Normally once fired still can grow a few thou.
Factory ammo has headspace already and if your chamber headspace is out of spec being too long, its adding additional space leading to problems that cannot be fixed if nothing is done.

I've pretty much abandoned my 280 Rem brass that I had fire formed. Picked up locally Nosler 280 AI brass. So, I've only gotten through about 20 pieces of it.
Checked what I've gone through. Overall length has not changed. Fired 2x. Shoulder has moved about .oo6 . Measured with a Hornady headspace gauge.
Doug

 

[cohunt]

I've pretty much abandoned my 280 Rem brass that I had fire formed. Picked up locally Nosler 280 AI brass. So, I've only gotten through about 20 pieces of it.
Checked what I've gone through. Overall length has not changed. Fired 2x. Shoulder has moved about .oo6 . Measured with a Hornady headspace gauge.
Doug

then you should be within saami specs, as the allowable variance is .010" and new brass will be to minimum (or less) than sammi specs so it fits in any chamber

what brand gauges did your new smith use? forster uses a .004" clearance for their "no-go", yet manson uses .006" clearance -- the field gauge should always be .010" as the saami spec for the 280AI (saami) is 2.140-2.150" to datum line


if you had the old chamber then your brass would have moved at least .014"