280 AI loading question

S

Savagehawg

New member
I just purchased a 280 AI with a 26" Barrel and a 1:8 twist, i have never loaded for this caliber before, i can not find any factory ammo for break in, Only bullets i have at the moment is 150 grn partitions, i have some 162 grn ELDX en route, 7mm bullets are hard to find at the moment.

Looking for any suggestion on powder, i have RL-19 and have access to RL-22 which by load data seems to get higher velocities, just curious what some of you are using.

Thanks
 
The beauty of Ackley Improved cartridges, is you can load & fire standard (aka parent) rounds in them.
Hence if you see any regular 280 Rem ammo, you can shoot it and comes out the improved case.

Both your RL19 & RL22 are suitable powders for the 280AI. And both will work for the 150gr & 162gr.

I haven't tried the Staball6.5 yet. I've heard it is doing well in cartridges in the 308 volume cartridges. (42-48gr)
But your AI is getting closer to 7mm Rem Mag volumes. So while i'm sure it will work, it may not be ideal.
 
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Savagehawg,

I'm not clear from your post if you meant that you can't find factory 280 AI or that you can't find factory 280 Rem. As the others said, you just fire the latter in the 280 AI chamber to blow the shoulder out to get your AI brass. If, however, you have 280 Rem fired brass and want a load for blowing out the case, any starting load in any manual will do the job of forming the brass in the AI chamber. If you are saying that you have neither, you can take 270 Winchester cases and expand them to 7 mm with a 284 Lyman M Die (something helpful to own anyway to use instead of the expander ball on your sizing die's decapper stem, as it doesn't tend to tilt case necks and helps you seat bullets straight and concentric and the same die will work for 284 Rem or AI). You would then use a 284 Rem starting load for the shoulder blow-out.
 
I have new 280 AI Brass, sorry what I meant to say is not having any luck finding 280 or 280AI factory ammo for break in, i prefer to put about 20 factory rounds down a new barrel before i start load development, just going to load up some 150grn midrange loads for break in since i have those on hand because thats what i load in my 7mm-08, but my 280 AI im going with a heavier higher BC bullets
 
If you haven't used the brass before, go for a starting load (bottom of the table). This is always recommended practice, as a couple of times I've run into starting loads that were already maximum loads in the gun I had with the components I had. This will still burnish the bore but won't cut into your case life much.

I usually shoot ten or twenty rounds and clean after each shot. This removes copper that has grabbed at rough spots and is protecting them from being burnished by the next bullet. Usually, by 10 rounds, I can tell the copper fouling has diminished. Occasionally it takes 20. If that doesn't help, I look at firelapping.
 
I do a modified form on Unclenick's method.

As he mentioned, every gun is different and you should start at the lower loads listed in a trusted manual.

I however leave the copper in my barrel.

1 & clean with mixture of Hoppes #9 and Kroil for first 3 rounds.
Then 3 & clean 4 times.
Then one last 5 & clean.
 
if you have a quality barrel, break in is a waste of time and money. If you are shooting benchrest, you would know what to do there.

Quality barrels take 40 to 100 rounds to settle. During that time, you will also gain about 50 to 90 fps of velocity. Cleaning all the time just pushes that window out and adds to the frustration for no reason at all except to buy a new barrel sooner and keep the proponents of old wives tales happy.
 
I would agree that a hand-lapped barrel is already broken in except for toolmarks in the throat. For many commercial barrels though, sharp toolmark edges seem to benefit from burnishing, especially for the first 7 to 10 rounds. Folks have advocated the process of gradually increasing rounds between cleanings for as long as I can recall, but I've never seen an explanation given for the advantage of doing this over firing fewer total shots with the same total number of cleanings. Indeed, with only one exception, I've not seen more than ten rounds help anything much, fouling-wise. There is also an opinion that failing to let the bore cool well between it's first shots can contribute to heat walking down the road, and cleaning certainly allows time for cooling.

The problem with break-in theories is proving them. You have each barrel just once, making it impossible to do more than one break-in procedure with it in new condition, thus to compare the results. The only definitive proof of which way (or no way) is best would require the opportunity to compare several statistically significant size samples of the same kind of barrel from the same maker, using an objective measure of the effect. Alas, unless the military decides to do it, I doubt it's going to happen.
 
Savagehawg said:
I just purchased a 280 AI with a 26" Barrel and a 1:8 twist
Click to expand...

What gun is that? My gut feeling is R17, H4831sc, H4350, N165, IMR 7828SSC are the ballpark.

Have you considered the 150CX? Maybe with H4831SC….could be a nice hunting/accuracy combo.
 
Unclenick said:
The problem with break-in theories is proving them. You have each barrel just once, making it impossible to do more than one break-in procedure with it in new condition, thus to compare the results. The only definitive proof of which way (or no way) is best would require the opportunity to compare several statistically significant size samples of the same kind of barrel from the same maker, using an objective measure of the effect. Alas, unless the military decides to do it, I doubt it's going to happen.
Click to expand...

Actually, I have done it, both for other barrel manufacturers, and for my own company. In one case, I was given a 55 gallon barrel of 5.56NATO to complete the test. Another gave me 20K of .308 match ammo. But with the cost of ammo these days, doubt I ever get to do what I did again. Reports, data, statistical analysis, the whole shebang. The very detailed data went to change some manufacturing process details and was under a paid contract with an NDA.

But I had 30+ sets of twin .223 Wylde Barrels and 10 sets of twin .308 barrels. The "broken-in barrels" had shorter life, took longer to settle and produced the same group sizes as the "no break. Also where is became obvious to me that Varget is not a good powder for barrel life in Gas Guns.
 
Nathan said:
Have you considered the 150CX? Maybe with H4831SC….could be a nice hunting/accuracy combo.
Click to expand...

Are you guessing, or have you tried that? It is an amazing combination (impact velocity needs to be over 2000 fps). H4831SC is my powder of choice for the 7mm bore and perfect for the .280AI.
 
Savagehawg said:
I have new 280 AI Brass, sorry what I meant to say is not having any luck finding 280 or 280AI factory ammo for break in, i prefer to put about 20 factory rounds down a new barrel before i start load development, just going to load up some 150grn midrange loads for break in since i have those on hand because thats what i load in my 7mm-08, but my 280 AI im going with a heavier higher BC bullets
Click to expand...
Why not load develop and "break in" at the same time?
As a side note, if a barrel needs "break in" it's a pretty crappy barrel.
 
MarkCO,

Interesting result. The main benefit I see to the 10-shot break-in is just slower copper accumulation. I had one really vexing Garand barrel (original military one) that shot great right up to about shot number 40, after which its groups fattened significantly due to copper accumulation that took a lot of Sweets 7.62 (this was long before the Bore Tech and other chelating cleaners were available) and several hours to patch and soak and repeat to get clean. That one got firelapped (which I look at as a kind of extreme break-in method), and it ceased opening groups before the end of a match, and cleaning became a breeze. The pre-40-shot groups were no better. Just the post-40-shot groups.
 
I've had best results with RL19 and IMR4831 in my standard 280 with 139 Interbonds. Data indicates using slower powders with 150 and heavier bullets.
 
Unclenick, I agree some poor quaility barrels of today and some "production" barrels from the past would benefit from a limited break-in. Tubbs system and fire-lapping have helped some of those quicker. Too much heat, of course, is always a problem. But a nicely coppered bore will survive that abuse better than a pristinely clean bore. Hundreds of hours in the metallurgy lab, including SEM on barrels definitely gave me some new information and understanding.
 
MarkCO, Got question, what barrel are you using on your 280AI. Could you also name barrels in your comment, "I agree some poor quaility barrels of today".
 
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