Home Forums Hunting & Shooting Custom Rifles & Wildcats 280 Rem to 280 AI

Looking at a used Remington mtn rifle in 280 that a buddy has. Was wondering if anyone on here does custom work and would be willing to spin the barrel back 3-4 thousands(so I’ve read) and cut the chamber for a 280Ai if some one on here does work or you know of anyone please pm me.
Thanks.

It shouldn’t be hard to get that job done. FYI those rifles are notorious for not grouping all that well. They will put two in the same hole then put the third high and right about an inch and a half. And, they seem to be awful hard to cure. I’d shoot it first to see how well it groups before I got too invested into it.

Spin a barrel back 3-4 thousands? I don't understand that. A gunsmith will have to set it back more than that to properly rechamber for the 280AI.
Don't know of anybody that I would want you to use. I only do my own work.

Think he may have confused three or four threads with thousandths.

dakotakidd, One of my favorite rifles started out life as a R700 Mountain Rifle in a 30.06. It would not shoot well (2+inch 3 shot groups) with the best loads and that was after much tinkering. I put a .280AI SS Krieger 24" number 2 on it and wow does it ever shoot well now. So, My advice is the same as brinky72's. Shoot it first.

dakotakidd,

I would think twice about rechambering. In factory ammo, the .280 Ackley factory round gets quite a bit more velocity than the standard .280 partly because it's loaded to higher pressure, 65,000 PSI versus 60,000 the plain .280--and handloading data also reflects that difference.

When both rounds are handloaded to equal pressure, there's really not much difference between them, because blowing the shoulder out on the AI doesn't gains relatively little powder room. Have played with more than one rifle in both the improved and standard chamberings, and the difference in velocity has been MAYBE 50-75 fps, which of course shrinks to much less at 300+ yards.

Should probably also mention that perhaps the easiest (and least expensive) way to get more zip from a standard .280 is to buy a pound of Reloder 26.

That’s a fact! Mine runs the 140 Tipped TBBC at 3145 and the accuracy is very good. Kinda took the fire out of me for wanting to Ackley it.

Care to share load data for .280 and RL 26? Haven't tried that combo yet. Looking for a good load for 150 gr. ELD-X .284 bullets.

I used QL for mine and used Alliant 270 Win data as a yardstick for charges.

Here is what QL shows for the 150 ELD X

Cartridge : .280 Rem.
Bullet : .284, 150, Hornady ELD-X 2826
Useable Case Capaci: 59.029 grain H2O = 3.833 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Alliant Reloder-26

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.006% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-10.1 95 55.76 2693 2416 41935 12573 97.6 1.281
-09.1 96 56.39 2729 2480 43559 12704 98.0 1.257
-08.0 97 57.01 2764 2545 45255 12826 98.4 1.235
-07.0 99 57.63 2800 2611 47027 12939 98.8 1.212
-06.0 100 58.26 2835 2678 48880 13042 99.1 1.191
-05.0 101 58.88 2871 2745 50818 13136 99.4 1.169
-04.0 102 59.50 2906 2813 52847 13219 99.6 1.148
-03.0 103 60.13 2941 2882 54969 13292 99.8 1.127
-02.0 104 60.75 2977 2951 57195 13355 99.9 1.107 ! Near Maximum !
-01.0 105 61.38 3012 3021 59526 13407 100.0 1.087 ! Near Maximum !
+00.0 106 62.00 3047 3092 61971 13447 100.0 1.067 ! Near Maximum !
+01.0 107 62.62 3082 3163 64535 13481 100.0 1.048 !DANGEROUS LOAD-DO NOT USE!
+02.0 108 63.25 3116 3235 67228 13512 100.0 1.029 !DANGEROUS LOAD-DO NOT USE!
+03.0 109 63.87 3151 3307 70055 13543 100.0 1.010 !DANGEROUS LOAD-DO NOT USE!
+04.0 110 64.50 3185 3380 73033 13571 100.0 0.992 !DANGEROUS LOAD-DO NOT USE!
+05.0 111 65.12 3220 3453 76164 13598 100.0 0.974 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 106 62.00 3198 3407 79037 12795 100.0 0.972 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 106 62.00 2815 2640 48137 13547 95.8 1.192

I'd also look at it with a borescope, and make sure the barrel was worth the work. Some Rem Factory barrels are not so great.

I'm having a .280 AI built, but it's a rebarrel from 6mm Remington, in a Ruger #1. I'm also getting an 8" twist.

Thanks for the info!

didn't P.O. Ackley design 280 AI neck/shoulder junction to be .004" shorter than parent cartridge?
-.004 provided enough crush to hold the case when fire forming.
Id say that's why the OP introduced the .004" figure in his enquiry.

However, brass headspace can vary greater than .004" from one case source to another so one should be prepared
to make allowance for variance.

Even if one wants to cut a completely new clean chamber in a factory .280 rem barrel ( if one has concerns about
any potential concentricity or mixed taper issues),... would 3 or 4 threads of setback be needed ?

How much actual setback is required so that a SAAMI 280 AI reamer will cut all the way back to the web.?

https://faq.nosler.com/index.php?action=artikel&cat=32&id=39&artlang=en


"There have been many variations of “improved” cartridges over the years, and even several different flavors within the “Ackley” cartridges.
The 280 is certainly no exception. When the 280 Ackley Improved was developed and standardized through the Sporting Arms and Ammunition
Manufacturers’ Institute (SAAMI) by Nosler®, the decision was made to honor Mr. Ackley’s original design intent by headspacing the cartridge
such that standard 280 Remington ammunition would chamber with slight (.003”/.004”) crush at the shoulder/neck intersection and fire form into
the Ackley chamber without the need to seat the bullet into the rifling. In fact, Mr. Ackley headspaced his “improved” cartridges by simply grinding
a standard “go” headspace gage for the parent cartridge back by 0.004” and using it to headspace the new version. This is also the way that
many large custom gun shops have chambered the 280 Ackley for almost 40 years. In order to achieve this, any standard 280 Remington firearm
being opened up to the Ackley must have the barrel set back one turn prior to reaming the chamber – simply improving the standard chamber without
doing so will yield excessive headspace, even though this was common practice for many gun makers over the years as well. Based on this design,
the 280 Ackley Improved was accepted by SAAMI in February of 2008 and has enjoyed tremendous success ever since.


Occasionally, a rifle that was “improved” by simply reaming the chamber without first setting the barrel back will turn up and result in questions about
its compatibility with factory ammunition. Unbeknownst to their owner, most of these guns have headspace dimensions of between 0.010” and 0.015”
greater than the SAAMI version of the 280 Ackley Improved. These rifles are perfectly functional so long as they are used with ammunition that has
been properly formed and sized to fit their chambers. If the customer wishes to use their rifle with modern SAAMI-compliant 280 Ackley ammunition,
it must be re-headspaced to properly chamber the ammunition."

This. Mine is a 280AI, but I'm getting great accuracy with the 150 ELDX at a chrono'd 3120 fps using RL26.

Bullets matter wayyyyyyyyyy more than headstamps.

Gun some 180 ELD's in your AO and see if your atmosphere is forgiving of same.

Hint....................

Or, just use good standard weight bullets if Napoleon complex isn't a factor

"Weight" is moot.

Hint.

Bless your heart.............

wow. I have a 280. I need some RL26!!

What platform?..................